KR101983368B1 - Organic Light Emitting Display Device and Driving Method thereof - Google Patents

Abstract

The present invention relates to a peak luminance controller for controlling a maximum luminance per frame; A programmable gamma unit for outputting a gamma voltage corresponding to a first luminance control signal supplied from a peak luminance control unit; A data driver for converting the RGBW data signal based on the gamma voltage supplied from the programmable gamma unit and supplying the RGBW data signal to the display panel; A line current calculation unit for calculating a current value expected to be consumed for each data line when the RGBW data signal is displayed on the display panel; A maximum current line selection unit for extracting a data line through which a maximum current flows based on the current value supplied from the line current calculation unit; And an excess current limiter which receives information on a data line through which a maximum current flows from the maximum current line selector and changes a first luminance control signal so that a limit current is set on a data line through which a maximum current flows, A light emitting display device is provided.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an organic light emitting display,

An embodiment of the present invention relates to an organic light emitting display and a driving method thereof.

An organic electroluminescent device used in an organic electroluminescent display device is a self-luminous device in which a light emitting layer is formed between two electrodes. The organic electroluminescent device injects electrons and holes from the electron injecting electrode and the hole injecting electrode into the light emitting layer, and excites the excited electrons and holes, And emits light when it is dropped to the ground state.

In the organic light emitting display, when a scan signal, a data signal, a power supply, and the like are supplied to the subpixels arranged in a matrix form, the selected subpixel emits light, thereby displaying an image.

Some organic electroluminescent display devices have a subpixel structure (hereinafter abbreviated as RGBW OLED) that includes red, green, blue, and white. The RGBW OLED drives the selected subpixel of the RGB subpixels to emit more light on the display panel for white color coordinate correction.

RGBW OLED lowers the brightness through Peak Luminance Control (PLC) method if it is expected that high power consumption video will be displayed on the display panel to keep the power consumption below target. The peak luminance control method varies the gamma voltage according to the average picture level (APL) calculated for the maximum component of the RGB data signal, so that the consumed current can be lowered to the limit current or less.

The conventional method calculates the total current for the moving picture displayed on the display panel and adjusts the gamma voltage when the calculated total current is equal to or greater than the limiting current. Since the conventional method uses only the entire current, when a still image or a pattern is displayed on a part of the display panel, the current consumed by the display can not be lowered below the limiting current.

The present invention for solving the above-mentioned problems of the background art prevents a phenomenon in which an excessive current flows, and besides, a consumption current is limited to a specific current or less to prevent damage to the display panel Thereby preventing the device from being damaged due to the problem of sagging) and improving the lifetime of the device.

According to an aspect of the present invention, there is provided a display apparatus including a peak luminance controller for controlling a maximum luminance per frame; A programmable gamma unit for outputting a gamma voltage corresponding to a first luminance control signal supplied from a peak luminance control unit; A data driver for converting the RGBW data signal based on the gamma voltage supplied from the programmable gamma unit and supplying the RGBW data signal to the display panel; A line current calculation unit for calculating a current value expected to be consumed for each data line when the RGBW data signal is displayed on the display panel; A maximum current line selection unit for extracting a data line through which a maximum current flows based on the current value supplied from the line current calculation unit; And an excess current limiter which receives information on a data line through which a maximum current flows from the maximum current line selector and changes a first luminance control signal so that a limit current is set on a data line through which a maximum current flows, A light emitting display device is provided.

The line current calculation unit may calculate the total current value flowing in the entire data line for each frame based on the measurement data stored in the current table and the line current value flowing in each data line.

The line current calculating unit may set the data lines supplied with the same image or pattern as a block and calculate the block current value flowing in the block of each data line based on the measurement data.

The maximum current line selection unit compares the line current values flowing through the respective data lines to extract information on the data line through which the maximum current flows, compares the block current values flowing in the blocks of the respective data lines, The information of the block can be extracted.

The maximum current line selection unit may calculate information on the data line through which the maximum current flows and information on the line current difference between the data lines and calculate information on the block information of the data lines through which the maximum current flows and the value of the block current difference therebetween have.

The overcurrent limiting unit may include a first luminance control unit and a second luminance control unit so that a limit current is set in a block of a data line in which a maximum current flows or a data line in which a maximum current flows based on information of a data line through which a maximum current flows, Signal to the second luminance control signal.

The overcurrent limiting unit may use the information on the line current difference value or the block current difference value to determine whether the current or the remaining data line of the remaining data line or the remaining data line block by the current reduction ratio of the block of the data line in which the maximum current flows or the data line in which the maximum current flows The first luminance control signal may be changed to the second luminance control signal so that the limiting current is set.

When the first luminance control signal is supplied, the programmable gamma unit changes the gamma voltage so that the limit current of all the data lines is set. When the second luminance control signal is supplied, the limit current of the data line or the limit current of the block of the data lines is set The gamma voltage can be changed.

According to another aspect of the present invention, there is provided a method of generating a current table, comprising: Calculating a current value flowing through each data line based on the measurement data stored in the current table; Comparing each data line to extract a data line through which a maximum current flows; Setting a current of a data line through which a maximum current flows to a limit current of the data line if the data line through which the maximum current flows is equal to or greater than the limit current of the data line; And setting a limit current in the same ratio for the remaining data lines corresponding to the current ratio required when the current of the data line through which the maximum current flows is lowered to the limit current range of the data line. ≪ / RTI >

The step of setting the limiting current includes the steps of setting a limit current to a data line on which a maximum current flows or a block of data lines on which a maximum current flows based on information of a data line through which a maximum current flows or block information of data lines through which a maximum current flows, The control signal can be changed.

The present invention can reduce the current for each data line even for a special pattern that partially emits light, thereby preventing an overcurrent from flowing and reducing current consumption. In addition, the present invention limits the consumption current to a specific current or less for each data line to prevent damages of the display panel (more specifically, damage of the device due to the problem that the excessive current continuously flows to a specific region) There is an effect that life can be improved.

1 is a schematic view of an organic light emitting display device according to an embodiment of the present invention;
Fig. 2 is an exemplary circuit configuration of a subpixel. Fig.
Figure 3 is a schematic cross-sectional hierarchical view of a subpixel.
4 is a diagram for explaining the concept of compensation light emission of a subpixel.
5 is a block diagram schematically illustrating an image processing unit according to an embodiment of the present invention.
6 is a detailed block diagram of an image processing unit according to an embodiment of the present invention;
FIGS. 7 and 8 are diagrams for explaining an example of setting a limit current in a block of data lines; FIG.
FIGS. 9 and 10 are diagrams for explaining an example of setting a limit current in a block of remaining data lines corresponding to a block of data lines. FIG.
11 is a flowchart illustrating a method of driving an organic light emitting display according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of an organic light emitting display according to an embodiment of the present invention, FIG. Fig. 8 is a view for explaining the compensation light emission concept of a subpixel. Fig.

1, the organic light emitting display includes an image processor 100, a timing controller 120, a data driver 130, a gate driver 140, and a display panel 150. Referring to FIG.

The image processing unit 100 converts the RGB data signals RGB into RGBW data signals RGBW. The image processing unit 100 performs various image processing such as setting a gamma voltage to realize the maximum luminance according to the average image level using the RGB data signal RGB, and then outputs the RGBW data signal RGBW. The image processing unit 100 outputs the data enable signal DE together with the RGBW data signal RGBW. The image processing unit 100 may output at least one of the vertical synchronization signal Vsync, the horizontal synchronization signal Hsync and the clock signal CLK in addition to the data enable signal DE, .

The timing controller 120 receives a drive signal including a data enable signal DE or a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync and a clock signal CLK from the image processing unit 100. The timing controller 120 includes a gate timing control signal GDC for controlling the operation timing of the gate driver 140 and a data timing control signal DDC for controlling the operation timing of the data driver 130, . The timing controller 120 outputs the RGBW data signal RGBW in response to the gate timing control signal GDC and the data timing control signal DDC.

The data driver 130 samples and latches the RGBW data signal RGBW supplied from the timing controller 120 in response to the data timing control signal DDC supplied from the timing controller 120, do. The data driver 130 outputs the RGBW data signal RGBW through the data lines DL1 to DLn. The data driver 130 is formed in the form of an IC (Integrated Circuit).

The gate driver 140 outputs the gate signal while shifting the level of the gate voltage in response to the gate timing control signal GDC supplied from the timing controller 120. The gate driver 140 outputs a gate signal through the gate lines GL1 to GLm. The gate driver 140 may be formed in the form of an IC (Integrated Circuit) or a gate in panel structure in the display panel 150.

The display panel 150 includes a white subpixel SPw, a red subpixel SPr, a green subpixel SPg and a blue subpixel SPb (hereinafter referred to as " RGBW subpixel). ≪ / RTI > That is, one pixel consists of RGBW subpixels (SPw, SPr, SPg, SPb).

As shown in FIG. 2, one sub-pixel includes a switching transistor SW, a driving transistor DR, a capacitor Cst, a compensation circuit CC, and an organic light emitting diode OLED. The organic light emitting diode OLED operates to emit light in accordance with the driving current generated by the driving transistor DR.

The switching transistor SW operates in response to a gate signal supplied through the first gate line GL1 so that a data signal supplied through the first data line DL1 is stored as a data voltage in the capacitor Cst. The driving transistor DR operates so that a driving current flows between the first power supply line VDD and the second power supply line GND in accordance with the data voltage stored in the capacitor Cst.

The compensation circuit CC compensates the threshold voltage of the driving transistor DR and the like. The compensation circuit CC consists of one or more transistors and a capacitor. The configuration of the compensation circuit (CC) is very various, and a detailed illustration and description thereof are omitted.

One subpixel is composed of a 2T (Transistor) 1C (Capacitor) structure including a switching transistor SW, a driving transistor DR, a capacitor Cst, and an organic light emitting diode (OLED). However, when the compensation circuit (CC) is added, it is composed of 3T1C, 4T2C, 5T2C, and the like. The subpixels having the above-described structure may be formed by a top emission method, a bottom emission method, or a dual emission method according to the structure.

The RGBW subpixels SPr, SPg, SPb and SPw may be realized by using a white organic light emitting diode WOLED and RGB color filters CFr, CFg and CFb or by using a light emitting material included in the organic light emitting diode OLED RGBW color, and so on. The method of using the white organic light emitting diode (WOLED) and the RGB color filters (CFr, CFg, CFb) is as follows.

3, the RGB sub-pixels SPr, SPg, and SPb include a transistor TFT, RGB color filters CFr, CFg, and CFb, and a white organic light emitting diode WOLED. On the other hand, the W subpixel SPw includes a transistor portion TFT and a white organic light emitting diode WOLED.

The RGB subpixels SPr, SPg and SPb convert the white light emitted from the white organic light emitting diode WOLED to red, green and blue, and therefore include the RGB color filters CFr, CFg and CFb. On the other hand, the W subpixel SPw emits the white light emitted from the white organic light emitting diode WOLED as it is, so that the color filter is not included.

The method using RGBW subpixels SPr, SPg, SPb, and SPw deposits a white light emitting material on all subpixels unlike the method in which red, green, and blue light emitting materials are independently deposited on each subpixel. For this reason, this method can increase the size even when a fine metal mask is not used, and it is possible to extend the life and reduce power consumption.

The display panel 150 arranges subpixels in various ways to improve the color purity and the expression power as well as the target color coordinates. For example, the display panel 150 may have a structure in which RGBW subpixels (SPr, SPg, SPb, SPw) are arranged in this order. In addition, the display panel 150 may have a structure in which WRGB subpixels (SPw, SPr, SPg, SPb) are arranged in this order. In addition, the display panel 150 may have a structure in which WGBR subpixels (SPw, SPg, SPb, SPr) are arranged in this order. In addition, the display panel 150 may have a structure in which the RWGB sub-pixels SPr, SPw, SPg, and SPb are arranged in this order. Further, the display panel 150 may have a structure in which BGWR subpixels (SPb, SPg, SPw, SPr) are arranged in this order. The display panel 150 may have a sub-pixel structure arranged in various orders besides the examples shown and described above.

The organic light emitting display device described above uses RGB sub-pixels SPr, SPg, SPb, and SPw so that a desired color coordinate is displayed on the display panel 150. In addition to the W sub-pixels SPw, , SPb) to compensate for light emission.

For example, the W sub-pixel SPw and the GB sub-pixels SPg and SPb are compensated to emit light so that a desired white color coordinate (White) is displayed on the display panel 150 as shown in FIG. As another example, the W sub-pixel SPw and the BR sub-pixels SPb and SPr are compensated to emit light as shown in FIG. 4B such that the desired white color coordinate (White) is displayed on the display panel 150.

On the other hand, when the RGBW data signals RGBW are displayed on the display panel 150, the image processing unit 100 limits the currents flowing through the entire data lines, Can be set. In addition, the image processing unit 100 may set the same static image or data lines that display the same pattern as blocks, and set a limiting current for limiting the current consumed by the same.

In this way, the image processing unit 100 applies the limiting current according to the characteristic of the image or pattern, and applies the restricting current to the remaining data lines (or other data lines) corresponding to the blocks of the data lines or data lines to which the limiting current is applied, (Or a block of other data lines), which will be discussed below.

FIG. 5 is a block diagram schematically illustrating an image processing unit according to an embodiment of the present invention, and FIG. 6 is a detailed block diagram illustrating an image processing unit according to an embodiment of the present invention.

5, the image processing unit 100 includes a first data conversion unit 112, RGB to RGBW, a line current calculation unit 125, a maximum current line selection unit 126, A current limiting unit 127, a second data conversion unit 116, an RGB to YCbCr, an average image level calculation unit 117, a peak luminance control unit 121, a PLC, and a frame memory unit 128 , Frame Memory). The apparatus for interlocking with the image processing unit 100 includes a timing controller 120, a programmable gamma unit 135 and a data driver 130 (SD-IC).

The second data converter 116 converts the RGB data signals RGB to YCbCr data signals. The second data converter 116 may convert the RGB data signal RGB into a YCbCr data signal using a conversion formula as shown in Equation 1 below.

( Equation  One)

As described above, when the RGB data signal (RGB) is converted into the YCbCr data signal, the average image level calculating unit 117 can calculate the average image level based on this.

The average image level calculating unit 117 calculates an average representative value through the YCbCr data signal supplied from the second data converting unit 116 and calculates an average image level APL. In the case of the average image level calculating section 117, the average image level can be calculated using a data signal other than the YCbCr data signal. In this case, the second data converter 116 may perform another method, for example, a method of extracting only the maximum value of the RGB data signal without converting the RGB data signal RGB into the YCbCr data signal.

The average image level calculating unit 117 calculates an average representative value again in an Nth frame unit (e.g., 5 frames or 30 frames) so as to apply the same average picture level to a plurality of frames (a constant amount of frames) It can also be re-computed as a process. This is to prevent the flicker and the like from being accompanied by the calculation by expressing every frame. The average image level calculating unit 117 may calculate an average image level based on the movement of the image, or may calculate an average image level based on the change detection of the image or the like.

The peak luminance controller 121 controls the maximum luminance for at least one frame. The peak luminance controller 121 determines the maximum peak luminance according to the average picture level and outputs a first luminance control signal Plcc so as to attenuate the peak luminance so as to prevent deterioration of the device when the still picture shows high peak luminance Output.

The first data converter 112 converts RGB data signals RGB into RGBW data signals RGBW. The reason for converting the RGB data signal (RGB) to the RGBW data signal (RGBW) is to drive the display panel including the RGBW subpixel.

The frame memory unit 128 temporarily stores the RGBW data signal RGBW converted by the first data conversion unit 112. The RGBW data signal RGBW stored in the frame memory unit 128 is then supplied to the timing control unit 120 together with a driving signal and the like. The frame memory unit 128 is formed in a form embedded in the image processing unit 100 or separately formed from the outside.

The line current calculation unit 125 calculates a current value expected to be consumed for each data line when the RGBW data signal RGBW supplied from the first data conversion unit 112 is displayed on the display panel 150. [ The line current calculation unit 125 calculates the line currents flowing through the individual data lines along with the total current values flowing through the entire data lines on a frame-by-frame basis, based on the measurement data (measurement values of the RGBW data signal or the image for each RGBW data signal) The current value is calculated. Also, the line current calculator 125 sets the data lines supplied with the same image or pattern as a block, and calculates the block current value flowing in the block of each data line based on the measurement data.

The maximum current line selection unit 126 extracts and selects which data line the maximum current flows based on the line current value supplied from the line current calculation unit 125. [ The maximum current line selection unit 126 extracts and selects the data line through which the maximum current flows by comparing the line current values flowing through the respective data lines, and extracts and selects information about the line current difference value therebetween .

The maximum current line selection unit 126 extracts and selects blocks of the data lines through which the maximum current flows among the data lines set in the block, and extracts and selects information about the block current difference values therebetween. For example, the maximum current line selection unit 126 selects the first current line from the first block including the first data line to the i-th (i is an integer equal to or greater than 2) The block currents flowing through the second block including the first current block may be extracted and selected. However, the present invention is not limited thereto.

The maximum current line selection unit 126 extracts and selects information about a current difference value between the data line and the data line, as well as information about a maximum current flowing in the block of data lines.

The overcurrent limiting unit 127 receives information on a data line or a block of data lines through which a maximum current flows from the maximum current line selection unit 126, and limits the data line or the data line The first luminance control signal Plcc is changed to the second luminance control signal LPlcc so that the current is set. Changing the first luminance control signal Plcc to the second luminance control signal LPlcc means that the reference for setting the limiting current for each data line is changed instead of the entire data line.

The overcurrent limiting unit 127 limits the amount of the first luminance control signal Plcc so that a restricting current is also set in a block of the remaining data lines or the remaining data lines by a ratio required for decreasing the current of the data line or the block of the data lines, To the second luminance control signal (Lolcc).

The overcurrent limiting unit 127 outputs the first luminance control signal Plcc supplied from the peak luminance control unit 121 as it is or the second luminance control signal LPlcc in accordance with the above method. The overcurrent limiting unit 127 may set the restricting current to the remaining data lines or the blocks of the remaining data lines by the current reduction ratio of the block of the data line or the data line through which the maximum current flows, It is not limited.

The programmable gamma unit 135 receives the first luminance control signal Plcc or the second luminance control signal LPlcc from the overcurrent limiting unit 127 and outputs a gamma voltage corresponding thereto. When the first luminance control signal Plcc is supplied, the programmable gamma unit 135 outputs a gamma voltage that is changed so that a limiting current is set to all the data lines. Alternatively, when the second luminance control signal LPlcc is supplied, the programmable gamma unit 135 outputs a gamma voltage that is changed so as to set a limit current to a specific data line or a block of specific data lines. For example, the programmable gamma unit 135 may shift the gamma band from 1.2 gamma to 3.0 gamma according to the first brightness control signal Plcc or the second brightness control signal LPlcc, but is not limited thereto.

On the other hand, since the data driver 130 converts the data signal based on the gamma voltage supplied from the programmable gamma unit 135, the amount of current consumed by the variable luminance and the changed amount is different.

6, the image processing unit 100 includes a first gamma correction unit 111, a white color tracking unit 113, a uniformity compensation unit 114, a second gamma correction unit 115, Inverse Gamma Correction). In the case of the peak luminance controller 121, a pre-peak generator 118, a temporal peak controller 119, and a luminance controller 120 are classified into a pre-peak generator 118 and a luminance controller 120.

The first gamma correction unit 111 performs a de-gamma processing on the RGB data signals RGB included in one frame. More specifically, the first gamma correction unit 111 receives the inverse gamma (Inverse gamma) to prevent a bit overflow occurring during an operation of converting the RGB data signal RGB to the RGBW data signal RGBW, Gamma) is subjected to a de-gamma processing and converted into a linear shape, and bit stretching is performed. Here, the RGB data signal RGB may be changed from 10 bits to 12 bits by bit stretching by the first gamma correction unit 111 and output. At this time, the first gamma correction unit 111 may perform bit stretching using a lookup table, but is not limited thereto.

The chromaticity coordinate correcting unit 113 compensates the chromaticity coordinate deviation so that the white color coordinates of the RGBW data signal RGBW supplied from the first data converting unit 112 coincide with the target chromaticity coordinates. The color coordinate corrector 113 compensates the RGBW data signal RGBW so that some or all of the RGB subpixels, together with the W subpixels, are caused to emit compensation light so that a desired target color coordinate is displayed on the display panel. For an example of this, refer to the description of FIG.

The uniformity compensating unit 114 compensates the white color coordinates of the RGBW data signal RGBW supplied from the color coordinate correcting unit 113 so that the white color coordinates uniformly coincide with the target color coordinates. The uniformity compensator 114 may be integrated with the color coordinate corrector 113 into one block. The RGBW data signal RGBW compensated by the uniformity compensation unit 114 is supplied to the line current calculation unit 125. [

The second gamma correction unit 115 performs inverse gamma processing on the RGBW data signal RGBW supplied from the uniformity compensation unit 114 again. The RGBW data signal RGBW is stored in the frame memory unit 128 after the second gamma correction unit 115 performs inverse gamma processing.

The free peak generating section 118 serves to determine the maximum peak luminance according to the average picture level. The temporal peak control unit 119 smoothly attenuates the peak luminance in order to prevent deterioration of the device when the still image shows a high peak luminance. The luminance controller 120 generates and outputs the first luminance control signal Plcc based on the data obtained by the pre-peak generator 118 and the temporal peak controller 119.

According to the function of the blocks constituting the ideal image processing unit 100, the present invention can be applied to the rest of the data lines or the rest of the data lines corresponding to the blocks of the data lines or the data lines to which the limiting current is applied, A limiting current is also set for the block of the data lines.

Hereinafter, an example of setting a limiting current in a block of data lines and an example of setting a limiting current in a block of the remaining data lines corresponding to a block of data lines will be described in order to facilitate understanding of the present invention.

7 and 8 are diagrams for explaining an example of setting a limiting current in a block of data lines.

As shown in FIG. 7, a color corresponding to magenta is displayed in block form in a horizontal region corresponding to 1/10 of the display panel 150.

When the total limit current of the display panel is set to " PL " as shown in Fig. 8A, the color corresponding to magenta is emitted with a peak luminance. However, according to the present invention, the limit current of the block of the data lines of the display panel is set to " LL " lower than the total limit current " PL " Therefore, the color corresponding to magenta is adjusted to a luminance lower than the peak luminance and emitted.

As described above, according to the present invention, when a specific color is partially displayed (or emitted) on a display panel in part, the luminance does not vary corresponding to the total limit current PL of the display panel, The luminance is varied correspondingly. Therefore, in the case where a specific color is partially displayed on the display panel, the luminance can be varied corresponding to the limit current (LL) of the block of the data lines lower than the total limit current (PL), so that the consumption current can be lowered .

FIGS. 9 and 10 are diagrams for explaining an example of setting a limit current in a block of the remaining data lines corresponding to a block of data lines.

As shown in FIG. 9, the first monochromatic pattern C1 to the fourth monochromatic pattern C4 are displayed in a block form for each of the horizontal regions corresponding to 1/4 of the display panel 150.

10A, when the total limiting current of the display panel is set to " PL ", the first monochromatic pattern C1 emits light at a peak luminance and the second through fourth monochromatic patterns C2 to C4 are almost So that the light is emitted corresponding to the peak luminance. However, according to the present invention, as shown in FIG. 10B, the first monochromatic pattern C1 is adjusted to correspond to the limit current LL of the block of the data lines of the display panel and emits light. And the remaining second to fourth monochromatic patterns C2 to C4 are adjusted at the same rate as the current reduction ratio of the first monochromatic pattern C1 to emit light.

As described above, in the present invention, when a specific color is partially displayed (or emitted) on a display panel, the luminance of the block of data lines consuming the maximum current varies corresponding to the limit current (LL) of the block of the data lines. And the blocks of the remaining data lines are varied in luminance by the current reduction ratio of the block of the data lines consuming the maximum current.

Therefore, in the present invention, when the specific colors are partially displayed on the display panel, the luminance of the blocks of the data lines consuming the maximum current and the blocks of the remaining data lines is limited to the limit current LL of the blocks of the data lines of the display panel. So that the consumption current can be further reduced.

The following Table 1 shows the results of simulation obtained by displaying monochromatic patterns on the organic light emitting display device implemented in the comparative example and the embodiment of the present invention.

[Table 1]

Hereinafter, a driving method of an organic light emitting display according to an embodiment of the present invention will be described, and a method of limiting an excessive current supply will be described.

11 is a flowchart illustrating a method of driving an organic light emitting display according to an exemplary embodiment of the present invention.

First, a current table of the display panel for each pattern (RGB or RGBW) data signal (0 to 255) is generated (S110). The current table is obtained by displaying a monochrome image or pattern on the display panel, But it is not limited to this.

Next, a current value is calculated for each data line of the inputted frame based on the measurement data stored in the current table. (S120) A method of calculating the current value for the data lines is a method of calculating It can be calculated by reading the measurement data corresponding to the monochromatic pattern, but is not limited thereto.

Next, the respective data lines are compared to extract the data line in which the maximum current flows among the respective data lines (S130). The extraction method for the data line in which the maximum current flows is to compare the currents flowing in the respective data lines, But is not limited to.

Next, when the data line through which the maximum current flows is equal to or larger than the limit current of the data line, the current of the data line through which the maximum current flows is set to the limit current of the data line. (S140) The lowering method can be used to substitute the current of the data line through which the maximum current flows so as to correspond to the limiting current of the data line, but is not limited thereto.

Next, the limiting current is set to the same ratio for the remaining data lines corresponding to the current ratio required for lowering the current of the data line through which the maximum current flows to the limited current of the data line (S150). The method of setting the limit current may be, but not limited to, calculating the ratio of the amount of the reduced current when the current of the data line on which the maximum current flows corresponds to the limited current of the data line and applying it to the entire data line .

As described above, the present invention can reduce the current for each data line even for a special pattern that partially emits light, thereby preventing an overcurrent from flowing and reducing current consumption. In addition, the present invention limits the consumption current to a specific current or less for each data line to prevent damages of the display panel (more specifically, damage of the device due to the problem that the excessive current continuously flows to a specific area) There is an effect that life can be improved.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood that the invention may be practiced. It is therefore to be understood that the embodiments described above are to be considered in all respects only as illustrative and not restrictive. In addition, the scope of the present invention is indicated by the following claims rather than the detailed description. Also, all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

100: image processor 120: timing controller
130: Data driver 140: Gate driver
150: display panel 112: first data conversion section
125: Line current calculation unit 126: Maximum current line selection unit
127: excess current limiting unit 116: second data conversion unit
117: Average image level calculating unit 121: Peak brightness control unit
135: Programmable Gamma Division

Claims (10)

A peak luminance controller for controlling the maximum luminance for each at least one frame;
A programmable gamma unit that outputs a gamma voltage corresponding to a first luminance control signal supplied from the peak luminance control unit;
A data driver for converting an RGBW data signal based on the gamma voltage supplied from the programmable gamma unit and supplying the RGBW data signal to a display panel;
A line current calculation unit for calculating a current value expected to be consumed for each data line when the RGBW data signal is displayed on the display panel;
A maximum current line selection unit for extracting a data line through which a maximum current flows based on the current value supplied from the line current calculation unit; And
And an excess current limiter for receiving information on a data line through which the maximum current flows from the maximum current line selector and changing the first brightness control signal so that a limit current is set on the data line on which the maximum current flows, Organic electroluminescence display device. The method according to claim 1,
The line current calculation unit
And calculates the total current value flowing through the entire data line for each frame based on the measurement data stored in the current table and the line current value flowing through each data line. 3. The method of claim 2,
The line current calculation unit
Wherein the data line is supplied with the same image or pattern as a block, and a block current value flowing in a block of each data line is calculated based on the measurement data. The method of claim 3,
The maximum current line selection unit
Extracting information on a data line through which the maximum current flows, comparing the line current values flowing through the data lines,
And extracts information of a block of data lines through which a maximum current flows by comparing the block current values flowing in the blocks of the respective data lines. 5. The method of claim 4,
The maximum current line selection unit
Calculating information on a line current difference value between the data line through which the maximum current flows and the data line through which the maximum current does not flow,
Wherein information on a block current difference value between a block of the data lines through which the maximum current flows and a block of data lines through which the maximum current does not flow is calculated. 6. The method of claim 5,
The excess current limiter
Wherein the limit current is set to a block of the data line through which the maximum current flows or the block of the data line through which the maximum current flows based on the information of the data line through which the maximum current flows or the block information of the data lines through which the maximum current flows. And changes the luminance control signal to the second luminance control signal. The method according to claim 6,
The excess current limiter
The data line for which the maximum current flows or the block for the remaining data lines by the current reduction ratio of the block of the data lines for which the maximum current flows, using the information of the line current difference value or the block current difference value And changes the first luminance control signal to the second luminance control signal so that the limiting current is set. 8. The method of claim 7,
The programmable gamma portion
When the first luminance control signal is supplied, the gamma voltage is changed so that a limiting current of all the data lines is set,
Wherein when the second luminance control signal is supplied, the gamma voltage is changed so that the limiting current of the data line or the limiting current of the block of the data lines is set. Generating a current table for each image or for each pattern;
Calculating a current value flowing through each data line based on measurement data stored in the current table;
Comparing the data lines with each other to extract a data line through which a maximum current flows;
Setting a current of the data line through which the maximum current flows to a limit current of the data line when the data line through which the maximum current flows is equal to or greater than the limit current of the data line; And
And setting the limit current at the same ratio for the remaining data lines corresponding to a current ratio required when the current of the data line through which the maximum current flows is lowered to the limit current range of the data line. . 10. The method of claim 9,
The step of setting the limiting current
The limit current is set to a block of the data line through which the maximum current flows or the block of the data line through which the maximum current flows based on the information of the data line through which the maximum current flows or the block information of the data lines through which the maximum current flows, Wherein the organic electroluminescent display device comprises a plurality of organic electroluminescent devices.

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