KR20130079094A - Device and method for displaying images, device and method for processing images - Google Patents

Abstract

PURPOSE: An image displaying apparatus, an image displaying method, an image processing apparatus and an image processing method are provided to improve image quality by partially controlling the brightness of a sticking occurring area. CONSTITUTION: An image processor (100) receives an image frame, converts a gradation value of each pixel composing the image frame and generates a sub image frame. A controller (110) drives a display panel in order to sequentially display the image frame and the sub image frame. A frame storing unit stores the image frame. [Reference numerals] (AA) Image frame; (BB) Image frame/Sub-image frame/Control signal

Description

Image display device and image display method, image processing device and image processing method {Device and Method for Displaying Images, Device and Method for Processing Images}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display apparatus, an image display method, an image processing apparatus, and an image processing method, and more particularly, to an image display apparatus such as an organic light emitting display (OLED). Image display to improve image sticking and low gradation reproducibility using data, and to improve image quality by minimizing luminance deterioration in the whole area of the screen by partially controlling luminance only in areas where sticking occurs An apparatus, an image display method, an image processing apparatus, and an image processing method.

In recent years, organic electroluminescence display (OLED), plasma display panel (PDP) and liquid crystal display (LCD) have a smaller weight and volume than the cathode ray tube of the past. Research on flat panel display devices is being actively conducted.

The plasma display device displays an image using plasma generated by gas discharge, and the liquid crystal display device controls liquid crystal strength by controlling the intensity of an electric field applied to a liquid crystal layer having dielectric anisotropy formed between two substrates. An apparatus for displaying an image by adjusting the transmittance of light passing through a layer, and an organic electroluminescent display is an apparatus for displaying an image by using electroluminescence of specific organic materials or polymers, that is, emitting light when electricity is applied. to be.

Among them, an organic light emitting display device is a self-luminous device that does not require a separate backlight for providing light from the back of the liquid crystal panel like a liquid crystal display device, and the thickness of the device becomes thinner as the backlight is not used. Has an advantage. Although the organic light emitting display device is not shown in a separate drawing, OLEDs of R, G, and B are typically disposed between a single power supply voltage VDD provided from a power supply terminal and a ground voltage VSS of a power supply ground terminal. Arrangements are used to connect switching elements such as field effect transistors (FETs) between each OLED and the power supply voltage.

The driving method of the conventional organic light emitting display device is classified into a reset, a scan, and an emission time, respectively.

At the start of a unit frame for a specific image in the organic light emitting display, after the voltage is applied to compensate for the reset of the capacitor and the threshold voltage variation of the driving transistor at the reset time, the display scans the data as much as the display vertical resolution at the scan time. In the light emitting time, the actual OLED emits light.

However, in driving such OLEDs, when high gradation data flowing over current is maintained at the same position of the panel for a predetermined time or more, so-called image sticks in which a certain luminance portion of the high gradation data remains at the same position even after the high gradation is converted. Image sticking will occur. This shortens the life of the panel.

On the other hand, in the conventional organic light emitting display device, in order to express high gradation of 10 bits or more, the number of bits of the digital-to-analog converter (DAC) circuit in the source IC must be increased, thereby causing a cost increase and limited driving. The low level display is also limited because more voltage steps must be made within the voltage range.

Also, conventionally, when driving high-gradation data in which overcurrent flows at the same position of the panel for a predetermined time or more during the driving of the OLED, so-called image sticks in which a certain luminance component of the high-gradation data remains at the same position even after the conversion of the high-gradation gray scale is performed. Image sticking will occur. This shortens the life of the panel.

An embodiment of the present invention is to provide an image display apparatus and an image display method capable of improving an image sticking problem, which is one of problems of image quality deterioration, and at the same time expressing gray scales of 10 bits or more.

In addition, an embodiment of the present invention, an image display apparatus and method, an image processing apparatus, and a method for improving a picture quality problem due to sticking by dividing a spatial region in a screen into a plurality of blocks to control maximum gray scale data for each block, and the like. There is another purpose in providing this.

According to an embodiment of the present invention, an image display apparatus includes: an image processor configured to receive an image frame and convert a gray value of each pixel constituting the image frame to generate a sub image frame; And a controller driving the display panel to sequentially display the image frame and the sub image frame.

The image processor may determine a gray value of each pixel of the image frame by using a relation Vsub = Vmax-Vmain (where Vsub is a gray value of a pixel of the sub image frame, Vmax is a maximum gray value, and Vmain is a pixel of the pixel of the image frame). The sub image frame may be generated by converting according to the gray scale value.

The controller may drive the display panel to display the sub image frame for a display time smaller than the display time of the image frame.

The image processor generates the sub image frame by converting the gray level value of each pixel of the image frame by reflecting the luminance difference between the target luminance value and the actual luminance value corresponding to the gray value of each pixel of the image frame. It is characterized by.

The image processor may adjust a gamma value to adjust the maximum luminance and the minimum luminance of the sub image frame.

The controller determines a display time of the sub image frame by reflecting a luminance difference between a target luminance value and an actual luminance value corresponding to the gray value of the image frame, and displays the sub image frame during the determined display time. The display panel is driven.

The controller adjusts the display time such that the maximum luminance difference value among the luminance differences becomes the maximum luminance of the sub image frame, and adjusts the display time such that the minimum luminance difference value among the luminance differences becomes the minimum luminance of the sub image frame. It is characterized by adjusting.

The display time of the sub image frame is variable.

Also, an image display apparatus according to an embodiment of the present invention includes an image processor that compares image frames and performs conversion of gray value values in units of blocks if there are continuous image frames including blocks having gray values within a preset range; And a display panel configured to display the image frame having the gray scale value converted by the image processor.

The image display device further includes a frame storage unit for storing the image frame, and the image processor includes a continuous image frame including a block having a gray value within the preset range by comparing the image frame stored in the frame storage unit. And the gray value conversion is performed on the block in at least one image frame among the consecutive image frames.

The image processor may perform the gray value conversion on a block having a gray value within the range in subsequent image frames of the continuous image frames.

The image display device may include a controller configured to determine a driving time corresponding to a gray value in units of blocks; And a light emission controller configured to emit light of the display panel in units of blocks according to the determined driving time.

The image processor provides a frame accumulation result of the high gray scale values accumulated for each block unit to the controller, and the controller controls the light emission controller to adjust the driving time for each block unit of the image frame based on the accumulation result. Characterized in that.

The image processor may include: a divider dividing the image frame in units of blocks; A determination unit that determines whether the comparison result is equal to or less than a reference value by comparing pixel differences between previous frame data and current frame data for each block unit; A storage unit for accumulating and storing pixels having a reference value or less as a result of the determination; A characteristic analyzer for analyzing characteristics of accumulated pixels stored in the storage unit; And a pixel value changer for changing and outputting high grayscale values for each block based on the analysis result of the characteristic analyzer.

The characteristic analyzer may include a weighting unit that weights a time function to the frequencies of the pixels accumulated for each block, and the pixel value changing unit uses the weighting result of the weighting unit as the analysis result.

The characteristic analyzer may include a brightness calculator that calculates an average brightness of the pixels accumulated for each block, and the pixel value changer uses the brightness result of the brightness calculator as the analysis result.

The image processor may adjust a change range of the high gray scale values according to the difference value between the consecutive image frames and the degree of temporal maintenance of the difference value.

The image processor may increase the range of change of the high gray scale values when the temporal retention is large.

The image processor may set a short driving time of the color light emitting device in the display panel when the temporal retention is large.

An image processing apparatus according to an embodiment of the present invention includes a divider for dividing image data of an input unit frame in units of blocks; A determination unit that determines whether a comparison result is equal to or less than a reference value by comparing pixel differences between previous frame data and current frame data for each block unit; A storage unit for accumulating and storing pixels having a reference value or less as a result of the determination; A characteristic analyzer for analyzing characteristics of accumulated pixels stored in the storage unit; And a pixel value changer for changing and outputting high grayscale values for each block based on the analysis result of the characteristic analyzer.

The characteristic analyzer may include a weighting unit that weights a time function to the frequencies of the pixels accumulated for each block, and the pixel value changing unit uses the weighting result of the weighting unit as the analysis result.

The weighting unit may be configured to assign a higher weight as the frequency increases.

The characteristic analyzer may include a brightness calculator that calculates an average brightness of the pixels accumulated for each block, and the pixel value changer uses the brightness result of the brightness calculator as the analysis result.

The pixel value changing unit may adjust a change range of the high gray level values according to the difference between successive frame data and the degree of temporal maintenance of the difference.

The pixel value changing unit may increase the change range of the high gray level values when the temporal holding degree is large.

An image display method according to an embodiment of the present invention comprises the steps of: generating a sub image frame by receiving an image frame and converting a gray value of each pixel constituting the image frame; And driving the display panel to sequentially display the image frame and the sub image frame.

The generating of the sub image frame may include generating a gray level value of each pixel of the image frame using a relation Vsub = Vmax-Vmain (where Vsub is a gray value of a pixel of the sub image frame, Vmax is a maximum gray value, and Vmain is the And converting according to the grayscale value of the pixel of the image frame to generate the sub-image frame.

The driving of the display panel may include driving the display panel to display the sub image frame for a display time smaller than the display time of the image frame.

The generating of the sub image frame may include converting the gray level value of each pixel of the image frame by reflecting a luminance difference between a target luminance value corresponding to the gray level value of each pixel of the image frame and an actual luminance value, And generating an image frame.

The generating of the sub image frame may include adjusting a gamma value to adjust the maximum luminance and the minimum luminance of the sub image frame.

The driving of the display panel may include determining a display time of the sub image frame by reflecting a luminance difference between a target luminance value corresponding to the gray level value of the image frame and an actual luminance value, and during the determined display time. The display panel is driven to display a frame.

The driving of the display panel may include adjusting the display time such that the maximum luminance difference value among the luminance differences becomes the maximum luminance of the sub image frame, and the minimum luminance difference value among the luminance differences is the minimum luminance of the sub image frame. It characterized in that to adjust the display time to be.

The display time of the sub image frame is variable.

In addition, the image display method according to an embodiment of the present invention includes comparing the image frame, if there is a continuous image frame including a block having a gray value within a predetermined range, performing a gray value conversion in units of blocks; And displaying the image frame having the converted gray scale value.

The image display method may further include storing the image frame, and the converting the gray value value in units of blocks may include a block having the gray value within the preset range by comparing the stored image frames. The method may determine whether continuous video frames exist and perform the gray value conversion on the block in at least one video frame of the continuous video frames.

In the performing of the gray value conversion in units of blocks, the gray value conversion is performed on a block having a gray value within the range in subsequent image frames of the continuous image frames.

The image display method may further include determining a driving time corresponding to a gray value in units of blocks; And performing the process of the display in units of blocks according to the determined driving time.

The step of converting the gray scale value in the block unit may provide a frame accumulation result of the high gray scale values accumulated for each block unit to the controller, and the controller drives the image frame for each block unit based on the accumulated result. It is characterized by adjusting the time.

The step of converting grayscale values in block units may include: dividing the image frame in block units; Comparing the difference between pixel values of previous frame data and current frame data for each block unit to determine whether the comparison result is equal to or less than a reference value; Accumulating and storing pixels having a reference value or less as a result of the determination; Analyzing the accumulated characteristics of the pixels; And changing and outputting high grayscale values for each block based on the analysis result.

The analyzing may include weighting a time function to the frequency of the pixels accumulated for each block, and outputting the high grayscale values by using the weighting result as the analysis result. It features.

The analyzing may include calculating an average brightness of the pixels accumulated for each block, and outputting the high grayscale values by using the brightness result as the analysis result.

The step of converting the grayscale value in units of blocks may include adjusting a change range of the high grayscale values according to the difference between successive frame data and the degree of temporal maintenance of the difference.

The step of converting the grayscale value in the block unit may increase the range of change of the high grayscale values when the temporal retention degree is large.

In the step of performing gray value conversion in units of blocks, when the degree of temporal retention is large, the driving time of the block on which the gray value conversion is performed is set to be short.

The image processing method according to the embodiment of the present invention comprises the steps of: dividing the image data of the input unit frame in block units; Comparing the difference between pixel values of previous frame data and current frame data for each block unit to determine whether a comparison result is equal to or less than a reference value; Accumulating and storing pixels having a reference value or less as a result of the determination; Analyzing characteristics of the accumulated accumulated pixels; And changing and outputting high grayscale values for each block based on the analysis result.

The analyzing may include weighting a time function to the frequency of the pixels accumulated for each block unit, and outputting by changing the high grayscale values as a result of the analysis. It is characterized by using.

In the weighting step, the weight is increased as the frequency increases.

The analyzing may include calculating an average brightness of the pixels accumulated for each block, and outputting the high gray values by using the brightness result as the analysis result. do.

The changing and outputting the high grayscale values may include adjusting a change range of the high grayscale values according to the difference between successive frame data and the degree of temporal maintenance of the difference values.

The changing and outputting the high grayscale values may increase the range of change of the high grayscale values when the temporal holding degree is large.

1 is a block diagram showing the structure of an image display device according to a first embodiment of the present invention;
2 is a block diagram showing a structure of an image display apparatus according to another example of the first embodiment of the present invention;
3 is a diagram illustrating driving timing of an image display device of FIG. 2;
4 is an exemplary diagram illustrating a detailed structure of a pixel unit of FIG. 2;
5 is a graph showing a correlation between a driving voltage and a current flowing in a light emitting device;
6 is a graph of luminance error between 8-bit gamma and 10-bit gamma,
7 is a diagram illustrating luminance characteristics of a main frame and a subframe;
8 is a flowchart illustrating an image display method according to a first embodiment of the present invention;
9 is a schematic diagram of an image display method according to another example of a first embodiment of the present invention;
10 is a flowchart showing an image display method according to another example of a first embodiment of the present invention;
11 is a block diagram showing the structure of an image display device according to a second embodiment of the present invention;
12 is a block diagram showing a structure of an image display apparatus according to another example of a second embodiment of the present invention;
FIG. 13 is a diagram illustrating a driving timing of the image display device of FIG. 12;
14 is a diagram illustrating a detailed structure of an image processor of FIG. 12;
15 is a graph showing weighting characteristics by a time function;
16 is an exemplary diagram illustrating a detailed structure of a pixel unit of FIG. 12;
17 is a flowchart illustrating an image display method according to a second embodiment of the present invention;
18 is a schematic diagram of an image display method according to a second embodiment of the present invention;
19 is a flowchart illustrating an image display method according to a second embodiment of the present invention;
20 is a flowchart illustrating an image conversion method according to a second embodiment of the present invention.

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

1 is a block diagram showing the structure of an image display device according to a first embodiment of the present invention.

As shown in FIG. 1, the image display apparatus according to the first embodiment of the present invention includes a part or all of the image processor 100 and the controller 110.

The image processor 100 converts the pixel data values of the input image frame, that is, the pixel values, to generate a sub image frame. To this end, the image processor 100 may generate a sub image frame for an input image frame of 8 bits or more without a separate bit conversion, but the image frame after converting the image frame of 10 bits or more to 8 bits is used as the main frame. Subframes having the same content with respect to the main frame and having different gradation representations may be generated and output.

The generation of such a sub image frame may be performed in two ways, for example. One is to determine the pixel data value of the sub image frame by subtracting the input data value from the maximum gray scale value that can be represented by the data of the input image frame. For example, if the maximum possible gray level of 8-bit data is 256 (which includes "0"), and the gray level of the input data is 240, the pixel data value of the sub-image frame is a value corresponding to 15 minus 240 and 240. . In the embodiment of the present invention, this is expressed as being in a maintenance relationship. Another method is to determine the pixel data value of the sub-image frame so as to reflect as much as the error luminance value between the ideal luminance (or target luminance) of the input pixel data and the luminance (or actual luminance) displayed through the display panel. . Accordingly, for example, the input data 14 determines the pixel data corresponding to the adjacent 11 as the pixel data value of the sub image frame.

Furthermore, the image processor 100 needs to determine the display time of the input image frame and the sub image frame, that is, the emission time at which the image is implemented on the screen. In the first method, the sub image frame is larger than the display time of the image frame. It should be small but preferably determined below a certain multiple, such as 1/16. In addition, in the case of the second method, it may be possible to adjust the gamma value in addition to the display time. Therefore, embodiments of the present invention will not be particularly limited to how such display time is determined. Other details will be discussed later.

The controller 110 may generate and output an image frame, a sub image frame, and even a control signal provided by the image processor 100, wherein the control signal is an image frame and a sub image frame in which an image is implemented in a display panel. As the display time, for example, the control signal may be generated and output according to the information provided from the image processor 100.

So far, the main technical contents of the image display apparatus according to the exemplary embodiment of the present invention have been described. More specific details will be dealt with through other embodiments of the present invention described later.

2 is a block diagram illustrating a structure of an image display apparatus according to another example of the first exemplary embodiment of the present invention, FIG. 3 is a diagram illustrating driving timing of the image display apparatus of FIG. 2, and FIG. 4 is a pixel portion of FIG. 2. It is an exemplary figure which shows a detailed structure.

As shown in FIG. 2, the image display device according to an exemplary embodiment of the present invention includes an interface unit 200, a controller 210, an image processor 220, a scan driver 230_1, a data driver 230_2, and a display panel. 240, a part or all of the power supply voltage generator 250 and the voltage supply unit 260.

The interface unit 200 is an image board such as a graphic card, and converts the image data input from the outside to be suitable for the resolution of the image display device. In this case, the image data may be composed of, for example, 8 or more bits of R, G, and B video data, and the interface unit 200 may include a clock signal DCLK and vertical / horizontal synchronization signals Vsync and Hsync suitable for the resolution of the image display device. To generate control signals. Thereafter, the interface unit 200 provides the vertical / horizontal synchronization signal and the image data to the controller 210.

The controller 210 outputs a sub frame (or sub image frame) for the unit frame image of the inputted R, G, and B data. To this end, for example, when the controller 210 generates the image data according to the bit conversion as the main frame, the generated main frame is provided to the image processor 220 to receive and output a subframe generated based on the main frame. . In this case, the controller 210 inserts the sub frame data by dividing the time for displaying the image data of the unit frame, for example, 16.7 ms as shown in FIG. 3, and adjusts the light emission time of the inserted sub frame at the same time. In this case, the inserted subframe data may be included in the same image as the main frame, and only a gray scale may be expressed differently. Such sub-frame data is generated by changing the input R, G, B image data according to a design rule of the system so as to be image sticking compensation data and low gray level compensation data as R, G, and B image data. At this time, the image sticking compensation data outputs a low gray level which is a complementary relationship when the input gray level is high gray level, and the low gray level compensation data has an ideal luminance, that is, an error between an error-free luminance and a display luminance indicates that the display luminance of the subframe is increased. After adjusting the light emission time of the sub-frame, and further gamma, the data closest to the error is output and compensated.

For example, the controller 210 rearranges R, G, and B data from the interface unit 200 from, for example, 10 bits to 8 bits, and supplies the data driver 230_2 as data for the main frame first, and then the 8 bits The sub frame data compensated for the luminance error may be generated based on the data, and the sub frame data may be supplied to the data driver 230_2 again. In this case, data generation of the subframe is performed in cooperation with the image processor 220. For example, in the case of generating a subframe to improve low gray scale reproducibility using a subframe, the system designer may determine an ideal luminance and empirical principle, that is, measurement based on the gamma 2.2 luminance characteristic having a maximum luminance of 200 cd / m 2. The error luminance may be measured from the luminance generated. The grayscale data reflecting the calculated error luminance is stored in the image processor 220, and when the mainframe data of a specific grayscale is provided, the grayscale data matching the grayscale data is provided as a subframe. In this case, the luminance information may also be provided to adjust the emission time of the subframe. This will be discussed later.

In addition, when the controller 210 generates a main frame according to bit conversion with respect to the input unit frames of R, G, and B, the scan driver 230_1 displays the main frame and subframe data on the display panel 240. And a control signal for controlling the data driver 230_2. To this end, the controller 210 receives a vertical / horizontal synchronization signal from the interface unit 200 and controls a timing control signal for scanning the input R, G, and B data in the main frame scanning section and the emission time of the main frame. A signal for generating the same signal is generated, and a timing signal for scanning the calculated subframe data in the subframe scanning section and a signal for controlling light emission of the subframe are generated and output. This is illustrated in FIG. 3. The signal for controlling the emission time may be understood as a data signal for outputting main frame data and subframe data from the data driver 230_2 to the display panel 240.

The R, G, and B data of the main frame and the subframe converted by the controller 210 may express gray level information of the R, G, and B data by the logic voltage Vlog provided from the power supply voltage generator 250. There will be. The controller 210 may also include a gate shift clock (GSC), a gate output enable (GOE), and a gate start pulse (GSP) as a gate control signal for controlling the scan driver 230_1. Pulse) and the like, where GSC is a signal for determining the time when the gate of the TFT connected to the light emitting devices such as R, G, and B OLEDs is turned on / off, and GOE is a scan driver 230_1. ) Is a signal to control the output, and GSP is a signal indicating the first driving line of the screen of one vertical synchronization signal. Further, the controller 210 may generate a source sampling clock (SSC), a source output enable (SOE), a source start pulse (SSP), and the like as a data control signal. Here, the SSC is used as a sampling clock for latching data in the data driver 230_2 and determines a driving frequency of the data drive IC. The SOE transfers the data latched by the SSC to the display panel 240. The SSP is a signal for notifying the start of data latching or sampling during one horizontal synchronization period.

In order to perform the above function, the controller 210 according to the embodiment of the present invention may include a control signal generator (not shown) and a data reordering unit (not shown). Here, the control signal generator generates a gate control signal and a data control signal for displaying the main frame and the subframe on the display panel 240 within one unit frame time and provide them to the scan driver 230_1 and the data driver 230_2, respectively. It is desirable to. As will be described later, for example, when it is assumed that the time for displaying the unit frame image on the display panel 240 is 16.7 ms, the main frame and the sub frame for the unit frame image must be continuously displayed within the corresponding time. will be. In addition, assuming that the controller 210 processes data for a subframe in cooperation with the image processor 220, the data reordering unit may form and process only data of the main frame.

The image processor 220 is interlocked with the controller 210 and, for example, when the controller 210 rearranges the inputted R, G, and B data to form main frame data, the main frame under control of the controller 210. Subframe data for may be generated and provided. In this case, the image processor 220 may provide information for controlling the emission time of the subframe. To this end, the image processor 220 may store subframe data matching the input main frame data in a memory unit in the form of a lookup table (LUT) according to a design rule. In this regard, the image processor 220 according to an embodiment of the present invention may generate subframe data using two rules. In other words, the first method is to generate data in a complementary relationship with main frame data as subframe data. For example, if the data 240 is provided, the 8-bit data can be represented in 256 gray levels, so that data for 15 minus 240 minus 255 is generated as subframe data. In the second method, since the system designer already knows the luminance error from the ideal luminance and the substantially displayed luminance for the specific grayscale data, the subframe data for the mainframe data is stored after reflecting the luminance error. To output the subframe data. In this case, the light emission time for the subframe, and further, the gamma value adjustment may be determined by the system designer or may be determined by analyzing the data of the subframe.

Of course, the image processor 220 sequentially stores the main frame data and the sub frame data for the unit frame image in the memory unit under the control of the controller 210, and then, when requested by the controller 210, the main frame data and the sub frame data. Will output sequentially. Accordingly, the controller 210 provides the main frame data and the sub frame data to the data driver 230_2 within the set time so that the unit frame image can be displayed on the display panel 240.

The scan driver 230_1 receives the gate on / off voltage Vgh / Vgl provided from the power supply voltage generator 250 and applies the corresponding voltage to the display panel 240 under the control of the controller 210. The gate-on voltage Vgh is sequentially provided from the gate line 1 GL1 to the gate line N GLn in order to implement the unit frame image on the display panel 240. At this time, of course, the scan driver 230_1 operates in response to the gate signal for the main frame and the gate signal for the subframe generated by the controller 210 according to the exemplary embodiment of the present invention. This is illustrated in FIG. 3.

The data driver 230_2 converts R, G, and B video data provided in serial from the controller 210 into parallel, converts digital data into analog voltages, and corresponds to one horizontal line. The video data is provided to the display panel 240 simultaneously and sequentially for each horizontal line. For example, the video data provided from the controller 210 may be provided to a D / A converter in the data driver 230_2. The digital information of the video data provided to the D / A converter may be an analog voltage capable of expressing the gradation of color. It is converted and provided to the display panel 240. In this case, the data driver 230_2 may also output main frame data and subframe data in synchronization with gate signals for the main frame and the subframe provided to the scan driver 230_1.

The display panel 240 crosses each other to form a plurality of gate lines GL1 to GLn and data lines DL1 to DLn for defining pixel regions, and the pixel regions that cross each other are R, G, and B like OLEDs. The light emitting element of is formed. A switching element, or TFT, is formed in one region, more precisely, at the corner of the pixel region. In the turn-on operation of the TFT, a gray scale voltage is provided from the data driver 230_2 to the light emitting elements of the respective R, G, and B. At this time, the light emitting devices of R, G, and B provide light in accordance with the amount of current provided according to the change in the gray voltage. That is, the light emitting devices of R, G, and B can provide as much light as much current is provided. As shown in FIG. 4, the pixel elements of R, G, and B have a switching element M ₁ responsive to a gate signal S1, that is, a gate-on voltage Vgh provided from the controller 210, and a switching element M ₁ . When turned on, the switching elements M ₂ may output current corresponding to the R, G, and B pixel values of the main frame and the sub frame provided to the data lines DL1 to DLn.

The power supply voltage generator 250 receives a commercial power supply from the outside, that is, an AC voltage of 110V or 220V, generates and outputs DC voltages of various levels. For example, the controller 210 may generate and provide a DC 12V voltage to represent gray levels, and the scan driver 230_1 may generate and provide a DC 15V voltage as a gate-on voltage Vgh. The voltage supply unit 260 may generate and provide voltages of various sizes, such as to generate and provide a voltage of DC 24V.

The voltage supply unit 260 may receive a voltage provided from the power supply voltage generator 250 to generate and provide a power supply voltage VDD for the display panel 240 or provide a ground voltage VSS. Further, the voltage supply unit 260 receives a voltage of 24 V DC from the power supply voltage generator 250 to generate a plurality of power supply voltages VDD, and according to the control of the controller 210, a specific power supply voltage VDD. ) May be selected and provided to the display panel 240. To this end, the voltage supply unit 260 may further include switching elements that provide a specific voltage selected by the control of the controller 210.

In the image display apparatus according to the exemplary embodiment of the present invention, the scan driver 230_1 or the data driver 230_2 may be mounted on the display panel 240, and the voltage supply unit 260 may be a power source. The controller 210 may be configured to be integrated with the voltage generator 250, and the controller 210 may simultaneously perform the role of the image processor 220 when data is rearranged. Therefore, embodiments of the present invention will not be particularly limited to the coupling and separation of such components.

According to an embodiment of the present invention, by removing the image sticking problem as a result of the above configuration and at the same time improving the low gradation expression power, it is possible to improve the image quality of the image display device using OLED, for example, and to extend the life of the panel. .

5 is a graph showing a correlation between a driving voltage and a current flowing through a light emitting device.

An image display apparatus according to an exemplary embodiment of the present invention uses a method of calculating image sticking compensation data to remove image sticking using a subframe.

In FIG. 5, I ₂₅₅ is a current flowing when the input data is 255, which is the maximum value based on 8 bits, and I ₀ is a current flowing through a light emitting device such as an OLED when the input data is 0, which is the minimum value based on 8 bits. . As in FIG. 5, the current is linearly proportional to the voltage, and the voltage is directly proportional to the input data. That is, it can be seen that the overcurrent flows to the light emitting device as the input data is high gradation data.

For example, if the input grayscale is a Vmain voltage belonging to a high grayscale group, that is, the data 240, the low current flows, that is, the data 15, such as the voltage Vsub = Vmax-Vmain according to the data inserted into the subframe, that is, the data 15. Current reverse compensation is made. In addition, in the embodiment of the present invention to control the light emission time of the sub-frame to be less than a predetermined multiple of the light emission time of the main frame in order to minimize the effect on the gray scale display of the input image by the luminance of the compensation data as shown in FIG. It would be desirable.

FIG. 6 is a graph of luminance error between 8-bit gamma and 10-bit gamma, and FIG. 7 illustrates luminance characteristics of the main frame and the sub-frame.

The image display device according to an exemplary embodiment of the present invention may use a method of calculating low gray level compensation data to improve low gray level reproducibility using a subframe.

FIG. 6 shows a graph having a low gradation region of real data having a luminance characteristic with a maximum luminance of 200 cd / m 2 and a gamma of 2.2, and an ideal luminance with a luminance characteristic of gamma 2.2. Although 0.0158 cd / m 2, the displayed luminance is 0.0112 cd / m 2, indicating that an error of luminance 0.0045 cd / m 2 occurs. Although the error that occurs may be small, considering the viewing environment such as human visual characteristics and dark lighting sensitive to the change in luminance in the low gradation region, this error is perceived largely in human vision.

Accordingly, in the exemplary embodiment of the present invention, data corresponding to the luminance error between the ideal luminance desired by the designer and the luminance substantially displayed on the image display device is inserted and compensated in the subframe. 7, when the maximum luminance of the main frame is 200 cd / m 2, the maximum error and the minimum error with the ideal luminance are 1.28 cd / m 2 and 0.00022 cd / m 2, respectively.

In the embodiment of the present invention, the light emission time is adjusted so that the maximum luminance of the subframe is equal to 1.28 cd / m2, which is the maximum luminance error of the main frame, and the minimum luminance of the subframe is the minimum luminance error of the main frame. The gamma value of the subframe is readjusted to 1.8 to approach 0.00022 cd / m 2. For example, when the main frame data is 14, since the luminance error is 0.0045 cd / m 2d, the subframe data 11 closest thereto is calculated as compensation data to eliminate the luminance error. As described above, in the low gradation compensation method according to the exemplary embodiment of the present invention, it may be preferable to change the emission time and the gamma value of the subframe according to the emission time of the main frame, that is, the maximum luminance.

8 is a flowchart illustrating an image display method according to a first embodiment of the present invention.

For convenience of description, referring to FIG. 8 together with FIG. 1, the image display apparatus according to the first embodiment of the present invention generates a sub image frame by converting pixel data values of the received image frames, that is, pixel values (S801). . Here, the sub image frame is preferably an image frame having the same content and different gradation representation as the input image frame. Since the contents related to the sub image frame have been sufficiently described above, further description thereof will be omitted.

In addition, after the sub image frame is generated, the image display apparatus sequentially displays the image frame and the sub image frame on the display panel (S803). For example, assuming that the display panel takes 16.7 ms to display the unit frame, in the exemplary embodiment of the present invention, the image frame and the sub image frame are displayed within 16.7 ms. In this case, the sub image frame has a display time smaller than that of the image frame. For example, the sub image frame is preferably displayed below a predetermined multiple, such as 1/16. In this regard, since it has been described above sufficiently, further description thereof will be omitted.

9 is a schematic diagram illustrating an image display method according to another embodiment of the present invention, and FIG. 10 is a flowchart illustrating an image display method according to another embodiment of the present invention.

For convenience of description, referring to FIGS. 9 and 10 together with FIG. 2, in the image display method according to an exemplary embodiment of the present invention, subframe data is inserted by dividing a time for displaying image data of a unit frame and simultaneously inserted subframes. It is characterized by adjusting the light emission time of the frame.

In more detail, the image display apparatus changes input unit frame data capable of realizing a high gray level image, for example, as 10-bit R, G, and B data into mainframe data that can be expressed with a predetermined reference gray level (S1001). For example, the controller 110 of FIG. 1 may receive main 10-bit R, G, and B image data and generate mainframe image data which is bit-converted into 8-bit R, G, and B image data. However, in the embodiment of the present invention, since the input data may be used as mainframe image data, the present invention will not be particularly limited to such bit conversion.

In addition, the image display apparatus generates subframe data matching the input mainframe (S1003). To this end, it may differ slightly depending on whether the system designer aims to eliminate sticking or improve low gray scale reproducibility, but for the former purpose, the subframe data is the data that is complementary to the main frame data. Will be inserted. In other words, on the basis of 256 bits of 8 bits, data 15 having a complementary relationship is inserted into data 240. If the latter purpose is to insert into the sub-frame data that can compensate for the luminance error between the ideal luminance and the displayed luminance. In this case, the light emission time for the subframe can be adjusted together with the data insertion or the data insertion due to the luminance error compensation, and the gamma value can be adjusted together with the luminance error compensation. In this regard, since it has been described above sufficiently, further description thereof will be omitted.

Subsequently, the image display apparatus emits light by the light emitting device based on the main frame image data and the subframe image data (S1005). In other words, the color light emitting devices of R, G, and B formed on the display panel 240 of FIG. 2 receive mainframe data for 16.7 ms unit frame period, and emit light first to implement an image. After the reset, the subframe receives data and successively emits light to implement an image.

According to an embodiment of the present invention, as a result of the above method, it is possible to eliminate an image sticking problem and to improve low gray scale reproducibility, thereby improving the image quality of an image display device such as an OLED and extending the life of the panel. You can do it.

Although the image display method according to the exemplary embodiment of the present invention has been described above, the image display apparatus having the configuration of FIG. 2 may be implemented. However, the image display method having the other configurations may be implemented. Therefore, the image display method according to the embodiment of the present invention is implemented only in the image display apparatus and will not be particularly limited.

11 is a block diagram showing the structure of an image display device according to a second embodiment of the present invention.

As illustrated in FIG. 11, the image display apparatus according to the second exemplary embodiment of the present invention includes the image processor 1100 and the display panel 1110 in part or in whole.

Here, the image processor 1100 compares an input image frame, for example, a previous image frame with a current image frame, and determines whether there are continuous image frames including blocks having grayscale values within a preset range. If the determination result exists, the grayscale value may be converted and output in block units. For example, the image processor 1100 compares pixel data values of a previous frame and a current frame in units of blocks, and stores pixels that are equal to or less than a reference value or a predetermined value as a result of the comparison. The gray scale value within the preset range, that is, the high gray scale value, may be converted and output. Furthermore, the image processor 1100 may also output information such as coordinate values for the block to adjust the display time of the block including the converted high gray values.

In addition, the display panel 1110 displays an image frame including the gray scale value converted under the control of a controller (not shown) on the screen. In other words, the display panel 1110 may operate differently for each block with respect to the image frame. In this case, the gray scale value converted in the specific block, that is, the gray scale voltage corresponding to the gray scale value of which the high gray scale value is reduced is provided to the display panel 1110, but the display panel 1110 is configured to emit light by the reduced gray scale value, that is, the image frame. By adjusting the displayed time, the reduction can be compensated for.

So far, the brief description of the main technical content of an embodiment of the present invention. Other details will be described in detail through other embodiments of the present invention described below.

12 is a block diagram illustrating a structure of an image display apparatus according to another example embodiment of the present invention. FIG. 13 is a diagram illustrating a driving timing of the image display apparatus of FIG. 12, and FIG. 14 is an image processor of FIG. 12. It is a figure which shows the detailed structure of. 15 is a graph showing weighting characteristics by a time function, and FIG. 16 is an exemplary diagram showing a detailed structure of the pixel portion of FIG. 2.

As shown in FIG. 12, the image display device according to the embodiment of the present invention includes an interface unit 1200, a controller 1210, an image processor 1220, a scan driver 1230_1, a data driver 1230_2, and a light emission controller. 1230_3, the display panel 1240, a power supply voltage generator 1250, a voltage supplyer 1260, and a part or all of a frame storage unit (not shown).

Here, the controller 1210 receives a vertical / horizontal synchronization signal from the interface unit 1200 and generates a gate control signal for controlling the scan driver 1230_1 and a data control signal for controlling the data driver 1230_2. Furthermore, the R, G, and B data from the interface unit 1200 may be rearranged from, for example, 10 bits to 8 bits and supplied to the data driver 1230_2. Accordingly, the controller 1210 may include a control signal generator for generating a control signal and a data reordering unit for reordering data. The R, G, and B data rearranged by the controller 1210 may be set to correspond to the gray level information of the R, G, and B data by the logic voltage Vlog provided from the power supply voltage generator 1250.

In addition, the controller 1210 interworks with the image processor 1220 and the light emission controller 1230_3. For example, the controller 1210 may provide pixel grayscale values generated by data rearrangement of R, G, and B to the image processor 1220 to calculate the degree of image sticking for each region, and display panel 1240 according to the calculated degree. The light emission control unit 1230_3 may be controlled to control the light emission time in the specific region of FIG. In the image processor 1220, for example, the controller 1210 provides coordinate values of the corresponding block to the controller 1210, and the controller 1210 adjusts the duty ratio of the control signal output from the light emission controller 1230_3 based on the coordinate values. As described above, the light emission time (or display time) of the display panel 1240 may be adjusted. In other words, the controller 1210 can compensate for luminance by lengthening the emission time by decreasing the high gray level of a specific pixel for each block. In this case, the emission time may be adjusted based on the cumulative physical quantity of the pixels with respect to the temporal change amount of each block, and the cumulative physical quantity and the emission time may have an inverse correlation. In other words, the larger the cumulative physical quantity, the shorter the emission time can be formed.

The image processor 1220 divides the image data of the unit frame provided by the controller 1210 into a plurality of blocks, compares the difference between the data of each block in the previous frame and the current frame, and compares the accumulated pixels by the comparison result. The degree of sticking is calculated based on the characteristic, and the maximum gray scale data available for each block is controlled according to the calculated amount of sticking, and at the same time, the display panel 1240 of the display panel 1240 is controlled based on the frame accumulation value of the amount of sticking calculated for each block. Adjust the light emitting time. In this case, to calculate the degree of sticking, the image processor 1220 may calculate the degree of sticking of the image for each block for a predetermined time or the degree of sticking by analyzing the average brightness.

For example, the image processor 1220 receives image data of a unit frame from the controller 1210, divides the data into a plurality of blocks, and accumulates pixels whose difference between previous frame data and current frame data is less than or equal to a threshold (or reference value) for each block. In addition, the weighting result is calculated by weighting the time function to the accumulated frequency for each block, and the average brightness of the accumulated pixels is calculated, and the peak gradation value for each block is changed according to the calculated result, and the information on the emission time is provided. In addition, the controller 1210 may be provided. In this case, the image processor 1220 may use the difference between the pixel gray value of the previous frame data and the current frame data. For example, the threshold value is set to 5, the pixel gray value of the previous frame data is 240, and the pixel gray level of the current frame data. If the value is 239, the difference value is smaller than the threshold value 5, and thus the corresponding pixel may be subject to the pixel value change according to the temporal change amount, that is, the frame accumulation value.

Here, the temporal change amount is a temporal change amount of the image data in each divided region, and may be calculated based on the difference between successive frame data and the degree of temporal maintenance of the difference value. When the calculated temporal rate of change is small, the image data in each divided region may be adjusted so that the maximum data value of the image data is equal to or less than a predetermined value. Can be adjusted as possible. In other words, the greater the degree of temporal change rate, the larger the amount of change in the maximum data value of the image data.

In order to perform the above function, as illustrated in FIG. 14, the image processor 1220 compares a splitter 1400 that divides input image data into a plurality of blocks, and compares consecutive frames, that is, previous and current image data. Determination unit 1410 for determining whether the data difference per block is less than or equal to a threshold, a storage unit 1420 for storing pixels for each block when the determination result is less than or equal to a threshold, and a weighting unit for weighting a time function to a frequency accumulated for each block ( 1430_1), a brightness calculator 1430_2 that calculates and outputs brightness of pixels accumulated for each block, and a pixel value changer 1440 that changes and outputs a peak gray value according to the weighting result. Could be. In this case, the weighting unit 1430_1 and the brightness calculator 1430_2 may be referred to as the characteristic analyzer 1430 since the weighting unit 1430_1 and the brightness calculator 1430_2 analyze arbitrary characteristics such as temporal variation and brightness using the accumulated pixels.

Here, as shown in FIG. 15, the weighting unit 1430_1 reduces the sticking strength calculated when there is no difference in the frame data for less than a predetermined time, and increases the sticking strength as the sticking strength becomes longer than the predetermined time. It will be possible to improve the accuracy of the calculation. According to the sticking intensity calculated for each block by the weighting unit 1430_1, the pixel value changing unit 1440 changes the contrast curve corresponding to each block. In other words, in the region where sticking occurs, the high gradation on the contrast curve is lowered to reduce the amount of current flowing through the color light emitting device, and in the region where no sticking does not occur, the high gradation on the contrast curve is not adjusted. Will not. However, since the adjustment range may be limited when adjusting the high gradation for each block, it is possible to limit the amount of current in units of frames by adjusting the emission time for the shortage. Here, the limited range of control may mean that the high gradation is over-adjusted, for example, to cause a problem such as luminance unbalance. Therefore, the emission time may be adjusted according to the information provided by the brightness calculator 1430_2.

The scan driver 1230_1 receives the gate on / off voltage Vgh / Vgl provided from the power supply voltage generator 1250 to apply the corresponding voltage to the display panel 1240 under the control of the controller 1210. The gate on voltage Vgh is sequentially provided to the display panel 1240 from the gate line 1 GL1 to the gate line N GLn in order to implement a unit frame image.

The data driver 1230_2 converts R, G, and B video data provided in serial from the controller 1210 into parallel, converts digital data into analog voltages, and corresponds to one horizontal line. The video data is provided to the display panel 1240 simultaneously and sequentially for each horizontal line. For example, the video data provided from the controller 1210 may be provided to a D / A converter in the data driver 1230_2. The digital information of the video data provided to the D / A converter may be an analog voltage capable of expressing the gradation of color. It is converted and provided to the display panel 1240.

The light emission controller 1230_3 generates a control signal having a different duty ratio under the control of the controller 1210 and provides the same to the display panel 1240. The control signal is to set the duty ratio differently for each region of the display panel 1240 or to set the duty ratio differently only for a specific color light emitting device in a specific region. For example, the light emission controller 1230_3 may include a PWM signal generator. The PWM signal generator may generate a control signal having a different duty ratio for each block or specific light emitting device according to the control of the controller 1210. There will be. In this case, the light emission controller 1230_3 may further include switching elements. The switching element may be operated under the control of the controller 1210 to control an output time point of the PWM signal applied to the display panel 1240. There will be. For example, although the light emission control unit 1230_3 adjusts the light emission time of the block including the changed high gradation values, it is preferable to control the light emission time to be shorter as the amount of time change is larger.

Looking at the pixel portion of R, G, and B with reference to FIG. 15, the display panel 1240 includes switching elements M ₁ and data lines DL1 to DLn operated by the scan signal S1, that is, the gate-on voltage Vgh. ) of the modified and pixels values the switching element for outputting a current on the basis of M _2, and the switching element M ₂ according to a control signal supplied from the emission control section (1230_3) R, G, B containing the tone value provided by The amount of current provided to the light emitting device, more precisely, may include switching elements M ₃ for adjusting the light emission time. The R, G, and B light emitting devices of the display panel 1240 may be provided with control signals having different duty ratios for each region or for individual light emitting devices through one line in the light emission controller 1230_3. It is desirable to be designed to receive each control signal for each region via a line. However, the embodiment of the present invention will not be particularly limited in terms of how to form such a line as long as it can adjust the light emission time of a light emitting device displaying a high gray value or a light emitting device in a region including the light emitting device.

Except for the above, the interface unit 1200, the controller 1210, the display panel 1240, the power supply voltage generator 1250, and the voltage supply unit of the image display device according to another exemplary embodiment of the present disclosure will be described with reference to FIG. 12. 1260 is an interface unit 200, a controller 210, a display panel 240, a power supply voltage generator 250, and a voltage supply unit 260 of the image display device according to the exemplary embodiment described with reference to FIG. 2. It is not different from the description of) and I want to replace it with them.

As a result of the above configuration, the embodiment of the present invention can control the partial luminance of the area where the sticking occurs, thereby preventing the sticking problem in advance, and as a result, it is possible to extend the panel life compared with the conventional one.

17 is a flowchart illustrating an image display method according to a second embodiment of the present invention.

For convenience of description, referring to FIG. 17 together with FIG. 11, the image display apparatus according to the second exemplary embodiment of the present invention compares the input image frame and has continuous image frames including blocks having grayscale values within a preset range. In operation S1701, the gray scale value is converted in units of blocks. For example, the image display apparatus compares pixel values of a previous frame and a current frame in units of blocks, accumulates and stores pixels whose comparison result is equal to or less than a reference value, analyzes the characteristics of the stored pixels, and analyzes the high The grayscale values can be converted and output. In this case, the degree of conversion may vary depending on the degree of sticking. Other details have been described above sufficiently, so further description will be omitted.

In addition, the image display apparatus displays an image frame having the converted gray scale value on the screen (S1703). For example, if it is determined that sticking occurs in the lower portion of the screen, the image frame in which the gradation value of the corresponding region is converted is displayed on the screen. However, in the exemplary embodiment of the present invention, it is preferable to drive the light emission time of the lower portion, that is, the display time, from the peripheral area by the reduced gray scale value. In this regard, the above descriptions are also sufficiently described above, so further description thereof will be omitted.

18 is a diagram schematically illustrating an image display method according to a second embodiment of the present invention, and FIG. 19 is a flowchart illustrating an image display method according to a second embodiment of the present invention.

For convenience of description, referring to FIGS. 18 and 19 together with FIG. 12, the image display apparatus according to an exemplary embodiment of the present invention controls the peak gray level data for each block and simultaneously controls the emission time of the display panel 1240. That is, as shown in FIG. 18, when the sticking probability for each block increases, for example, when only the bottom portion of the input image data occurs, the peak gray level for each block is limited, and the light emission time control is minimized. It is possible to maintain the luminance of the region where no sticking occurs.

As shown in FIG. 19, the image display apparatus according to an exemplary embodiment of the present invention changes and outputs a high gray value according to a data comparison result of blocks of consecutive unit frames, that is, previous frame and current frame data (S1901). In other words, the image display apparatus divides the input unit frame into a plurality of blocks, compares the image data of the previous frame and the current frame for each divided block unit, and changes and outputs the high gray level values of the specific block according to the comparison result. do. Here, for comparison, pixel values may be compared. At this time, if the difference between the pixel values and the reference value is less than the reference value, the corresponding pixels are accumulated and stored, and the high gray value is changed based on the characteristics of the accumulated pixels, for example, the amount of temporal change. To print. In this process, the brightness of the accumulated pixels may be calculated to provide adjustment of the emission time, and may be utilized when changing the pixel value. In this regard, since the image processor 1220 of FIG. 12 has been sufficiently described, further description thereof will be omitted.

Subsequently, the image display apparatus drives the area of the color light emitting device that receives the changed high gray value differently from the surrounding area (S1903). In this case, in other words, it is determined that the original gradation value can cause sticking based on the amount of time variation, so that the gradation value is changed. The phenomenon can be improved. Therefore, the driving time of the color light emitting device to which the high gray value is applied is different from the peripheral area.

In addition, the image display device generates and outputs a control signal for controlling the driving time of the color light emitting element differently based on the changed high gradation value or the brightness information (S1905). In other words, it can be seen that the high gradation value in a specific block is changed according to the comparison result of the data. For example, a PWM signal for adjusting the emission time of the block can be generated by receiving the coordinate value of the block. . For this, for example, when using a triangular wave generator, a PWM signal whose duty ratio is adjusted according to the level of rising and falling of the DC voltage can be generated.

Thereafter, the image display apparatus outputs a high gray level value for each block to the display panel 1240, and controls to adjust the duty ratio of the control signal based on the high gray value (S1907). In other words, the generated PWM signal is applied to the corresponding block to control the emission time of the color light emitting device.

According to the above method, the embodiment of the present invention can control the partial luminance of the area where the sticking occurs, thereby preventing the sticking problem in advance, and as a result, the panel life can be extended as compared with the conventional method.

20 is a view showing an image conversion method according to a second embodiment of the present invention.

For convenience of description, referring to FIG. 20 together with FIG. 14, the image processor 1220 of the image display apparatus receives image data of an input unit frame and divides the data into blocks (S2001). It can be divided into various sizes such as 8 × 8, 4 × 4, 16 × 8, and 8 × 4.

The image processor 1220 compares the difference between the pixel values of the previous frame data and the current frame data on a block-by-block basis and determines whether the comparison result is less than or equal to the reference value (S2003). As described above, if there is not much difference by comparing the difference between pixel values, it is possible to first estimate that the corresponding pixel can be sustained for a predetermined time with high gradation.

Subsequently, the pixels less than or equal to the reference value are accumulated and stored (S2005).

In addition, the image processor 1220 analyzes the characteristic by using the stored pixels (S2007). Here, the characteristic using the pixels is to apply a time function to add weight as the time lasts for a long time and to calculate brightness through analysis of the pixels.

The high gray value is changed and output for each block unit according to the characteristic analysis result (S2009). In this case, the image processor 1220 may output the corresponding brightness information. The brightness information may be used to adjust the emission time of the light emitting devices to which the high gray value is applied since the change of the high gray value may be limited. Could be.

Although the image display method according to the exemplary embodiment of the present invention has been described above, the image display apparatus having the configuration of FIG. 12 has been described, but the image display apparatus having the other configuration may be implemented. Therefore, the image display method according to the embodiment of the present invention is implemented only in the image display apparatus and will not be particularly limited.

While the invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention.

100, 220, 1100, 1220: image processor 110, 210, 1210: controller
200, 1200: interface unit 230_1, 1230_1: scan driver
230_2, 1230_2: data drivers 240, 1110, 1240; Display panel
250 and 1250: power supply voltage generation unit 260 and 1260: voltage supply unit
1230_3: light emission control unit 1400: division
1410: determination unit 1420: storage unit
1430: characterization unit 1430_1: weighting unit
1430_2: brightness calculator 1440: pixel value changing unit

Claims (44)

An image processor receiving an image frame and converting a gray level value of each pixel constituting the image frame to generate a sub image frame; And
A controller for driving the display panel to sequentially display the image frame and the sub image frame;
And the video display device. The method of claim 1,
The image processor comprising:
The gray value of each pixel of the image frame is determined according to the relation Vsub = Vmax-Vmain (where Vsub is a gray value of a pixel of the sub image frame, Vmax is a maximum gray value, and Vmain is a gray value of a pixel of the image frame). And converting the sub image frame to generate the sub image frame. The method of claim 1,
The controller,
And drive the display panel to display the sub image frame for a display time less than the display time of the image frame. The method of claim 1,
The image processor comprising:
The sub image frame is generated by converting the gray level value of each pixel of the image frame by reflecting a luminance difference between a target luminance value corresponding to the gray level value of each pixel of the image frame and the actual luminance value. Display. 5. The method of claim 4,
And the image processor adjusts a gamma value to adjust maximum and minimum luminance of the sub image frame. The method of claim 1,
The controller,
The display time of the sub image frame is determined by reflecting the difference between the target luminance value corresponding to the gray level value of the image frame and the actual luminance value, and the display panel is driven to display the sub image frame during the determined display time. Image display device, characterized in that. The method according to claim 6,
The controller adjusts the display time such that the maximum luminance difference value among the luminance differences is the maximum luminance of the sub-image frame,
And the display time is adjusted such that the minimum luminance difference value among the luminance differences is the minimum luminance of the sub image frame. The method of claim 1,
And a display time of the sub image frame is variable. An image processor which compares image frames and performs gradation value conversion in units of blocks if there are continuous image frames including blocks having gradation values within a preset range; And
And a display panel configured to display the image frame having the gray scale value converted by the image processor. 10. The method of claim 9,
Further comprising a frame storage unit for storing the image frame,
The image processor comprising:
The image frames stored in the frame storage unit may be compared to determine whether there are continuous image frames including blocks having grayscale values within the preset range, and the image frames may be included in at least one of the continuous image frames. And converting the gray level value with respect to the image display apparatus. 10. The method of claim 9,
The image processor comprising:
And converting the gray level value to a block having a gray level value within the range in subsequent image frames of the consecutive image frames. 12. The method according to any one of claims 9 to 11,
A controller for determining a driving time corresponding to the gray scale value in units of blocks; And
A light emission controller which emits the display panel in blocks according to the determined driving time;
The video display device further comprises. 10. The method of claim 9,
The image processor provides a frame accumulation result of the high gray scale values accumulated for each block unit to the controller.
And the controller controls the light emission controller to adjust the driving time of each block unit of the image frame based on the cumulative result. 10. The method of claim 9,
And the image processor adjusts a change range of the high gray scale values according to the difference value between the continuous image frames and the degree of temporal maintenance of the difference value. 10. The method of claim 9,
And the image processor enlarges the range of change of the high gradation values when the temporal holding degree is large. 10. The method of claim 9,
And the image processor sets a short driving time of the color light emitting element in the display panel when the temporal holding degree is large. A divider dividing the image data of the input unit frame in units of blocks;
A determination unit that determines whether a comparison result is equal to or less than a reference value by comparing pixel differences between previous frame data and current frame data for each block unit;
A storage unit for accumulating and storing pixels having a reference value or less as a result of the determination;
A characteristic analyzer for analyzing characteristics of accumulated pixels stored in the storage unit; And
A pixel value changer for changing and outputting high grayscale values for each block based on an analysis result of the characteristic analyzer;
Image processing apparatus comprising a. 18. The method of claim 17,
The characteristic analyzer includes a weighting unit that weights a time function to the frequencies of the pixels accumulated for each block unit.
And the pixel value changing unit uses the weighting result of the weighting unit as the analysis result. 19. The method of claim 18,
And the weighting unit assigns a higher weight as the frequency increases. 18. The method of claim 17,
The characteristic analyzer may include a brightness calculator configured to calculate an average brightness of the pixels accumulated for each block unit.
And the pixel value changer uses the brightness result of the brightness calculator as the analysis result. 21. The method of claim 20,
And the pixel value changing unit adjusts a change range of the high gray level values according to a difference value between successive frame data and a degree of temporal maintenance of the difference value. The method of claim 21,
And the pixel value changing unit enlarges the change range of the high gray level values when the temporal holding degree is large. Generating a sub image frame by receiving an image frame and converting a gray level value of each pixel constituting the image frame; And
Driving the display panel to sequentially display the image frame and the sub image frame.
Image display method comprising the. 24. The method of claim 23,
Generating the sub image frame,
The gray value of each pixel of the image frame is determined according to the relation Vsub = Vmax-Vmain (where Vsub is a gray value of a pixel of the sub image frame, Vmax is a maximum gray value, and Vmain is a gray value of a pixel of the image frame). And converting the sub image frame to generate the sub image frame. 24. The method of claim 23,
The driving of the display panel may include:
And driving the display panel to display the sub image frame for a display time smaller than the display time of the image frame. 24. The method of claim 23,
Generating the sub image frame,
The sub image frame is generated by converting the gray level value of each pixel of the image frame by reflecting a luminance difference between a target luminance value corresponding to the gray level value of each pixel of the image frame and the actual luminance value. How to display. The method of claim 26,
Generating the sub image frame,
And a gamma value to adjust maximum and minimum luminance of the sub-image frame. 24. The method of claim 23,
The driving of the display panel may include:
The display time of the sub image frame is determined by reflecting the difference between the target luminance value corresponding to the gray level value of the image frame and the actual luminance value, and the display panel is driven to display the sub image frame during the determined display time. Image display method characterized in that. 29. The method of claim 28,
The driving of the display panel may include:
Adjust the display time such that the maximum luminance difference value among the luminance differences is the maximum luminance of the sub-image frame,
And adjusting the display time such that the minimum luminance difference value among the luminance differences becomes the minimum luminance of the sub image frame. 24. The method of claim 23,
And a display time of the sub image frame is variable. Comparing image frames and performing gray value conversion in units of blocks if there are continuous image frames including blocks having gray values within a preset range; And
Displaying the image frame having the converted gray value;
Image display method comprising the. 32. The method of claim 31,
Storing the image frame;
The step of performing gray value conversion in units of blocks,
By comparing the stored video frames, it is determined whether there are continuous video frames including blocks having grayscale values within the preset range, and the grayscales are applied to the blocks in at least one of the continuous video frames. An image display method comprising performing a value conversion. 32. The method of claim 31,
The step of performing gray value conversion in units of blocks,
And converting the gray level value with respect to a block having a gray level value within the range in subsequent image frames of the consecutive image frames. 34. The method according to any one of claims 31 to 33,
Determining a driving time corresponding to a gray value in units of blocks; And
Performing the process of the display in units of blocks according to the determined driving time
Image display method further comprises. 32. The method of claim 31,
The step of converting the grayscale value in the block unit may provide a controller with a frame accumulation result of the high grayscale values accumulated for each block unit.
And the controller adjusts a driving time for each block unit of the image frame based on the cumulative result. 32. The method of claim 31,
The step of converting the gray scale value in units of blocks may include adjusting a change range of the high gray scale values according to the difference between successive frame data and the degree of temporal maintenance of the difference. 37. The method of claim 36,
And performing the conversion of the gray scale values in the block unit, when the temporal retention degree is large, increasing the change range of the high gray scale values. 39. The method of claim 37,
The performing of the gray value conversion in units of blocks may include setting a short driving time of the block on which the gray value conversion is performed when the temporal retention degree is large. Dividing the image data of the input unit frame in units of blocks;
Comparing the difference between pixel values of previous frame data and current frame data for each block unit to determine whether a comparison result is equal to or less than a reference value;
Accumulating and storing pixels having a reference value or less as a result of the determination;
Analyzing characteristics of the accumulated accumulated pixels; And
Changing the high gradation values for each block based on the analysis result and outputting
Image processing method comprising the. 40. The method of claim 39,
Analyzing the characteristic includes weighting a time function to the frequency of the pixels accumulated for each block unit,
And outputting the high gray scale values by using the weighting result as the analysis result. 41. The method of claim 40,
In the weighting step, the weight is increased as the frequency increases. 40. The method of claim 39,
The analyzing of the characteristics may include calculating an average brightness of the pixels accumulated for each block unit.
And outputting the high gradation values by using the brightness result as the analysis result. 40. The method of claim 39,
The changing and outputting the high grayscale values may include adjusting a change range of the high grayscale values according to the difference between successive frame data and the degree of temporal maintenance of the difference values. 40. The method of claim 39,
And outputting the high gradation values by changing the high gradation values when the temporal holding degree is large.

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