KR20080098954A - Organic light emitting display device - Google Patents

Abstract

An organic electroluminescent display device reduces a manufacturing cost and matches the white balance. A pixel circuit(110) includes sub pixels of at least three colors among red, green, blue, and white sub pixels(120). A power supply unit(130) supplies the same power supply voltage to the sub pixel of two or more colors among the sub pixels. A driving unit(150) applies a scan signal, a data signal, and an erase signal to every one subfield of the sub pixel of the pixel circuit. The driving part applies the erase signal to the sub pixel in which the same power supply voltage is supplied among the sub pixels in the different point of time.

Description

Organic light emitting display device

1 is a diagram for describing an organic light emitting display device according to an exemplary embodiment of the present invention.

2 illustrates a subpixel circuit of an organic light emitting display device according to an exemplary embodiment of the present invention.

3 is a diagram for describing a method of implementing image grayscale of an organic light emitting display device according to an exemplary embodiment of the present invention.

4 is a diagram illustrating a configuration example of one frame of an image of an organic light emitting display device according to an exemplary embodiment of the present invention.

5 is a block diagram illustrating a driving circuit of an organic light emitting display device according to another exemplary embodiment of the present invention.

6 is a diagram illustrating a configuration example of one frame of an image of an organic light emitting display device according to another exemplary embodiment of the present invention.

(Explanation of symbols for the main parts of the drawing)

110: timing controller 120: driver

130: power supply unit 140: pixel circuit unit

150: subpixel

The present invention relates to an organic light emitting display device.

Among the flat panel display devices, the EL display device is a self-luminous display device, which does not require a backlight, which enables light weight and thinness, simplifies the process, enables low temperature production, and a response speed of 1 ms or less. As a result, it has a high response speed and exhibits characteristics such as low power consumption, wide viewing angle, and high contrast.

In particular, the organic light emitting display device includes a light emitting layer including an organic material between an anode and a cathode, and holes supplied from the anode and electrons received from the cathode combine in the organic light emitting layer to form an exciton, a hole-electron pair. The excitons emit light by the energy generated when they return to the ground state.

Such an organic light emitting display device includes a light emitting layer including an organic material. Since the light emitting characteristics of the red, green, and blue light emitting layers are different, a problem arises in that the cost increases because different power voltages are supplied.

Accordingly, an object of the present invention is to provide an organic light emitting display device capable of achieving white balance while reducing the number of power supply voltage sources.

Technical problems to be achieved by the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned above will be clearly understood by those skilled in the art from the following description. Could be.

In the organic electroluminescent display device according to an embodiment of the present invention for displaying an image by dividing one frame into a plurality of subfields to display an image, red, green, blue and white A pixel circuit unit including subpixels of at least three colors of subpixels, a power supply unit supplying the same power voltage to at least two subpixels of subpixels, a scan signal for each subfield to a subpixel of the pixel circuit unit, A driving unit may apply a data signal and an erasing signal, and the driving unit may apply the erasing signal to different sub-pixels to which the same power supply voltage is supplied.

An erase signal applied to the blue subpixel may be applied later than an erase signal applied to the red and green subpixels.

The erase signal applied to the red subpixel may be applied before the erase signal applied to the blue and green subpixels.

The pixel circuit unit may include a first transistor for transmitting the data signal in response to the scan signal, a capacitor for storing the data signal, a second transistor for generating a driving current corresponding to the data signal, and the data stored in the capacitor. And a light emitting diode that emits light corresponding to a driving current generated by the second transistor and a third transistor which transmits the erase signal.

The driving unit may apply the erase signal at different times for each of the red, green, and blue subpixels.

The organic electroluminescent display device according to an embodiment of the present invention for displaying the image by dividing one frame into a plurality of subfields to display an image, red, green, blue and A pixel circuit unit including subpixels of at least three colors of the white subpixels, and a gain adjuster for correcting gains of image signals of at least two colors of red, green, blue, and white differently for each color; And a power supply unit supplying a corresponding data signal to the pixel circuit unit, and a power supply unit supplying the same power voltage to subpixels of a color corresponding to gain-corrected image signals.

The gain of the red image signal may be smaller than the gain of the green and blue image signals.

The gain of the blue image signal may be greater than the gain of the red and green image signals.

The organic electroluminescent display includes a subfield mapping unit for mapping the data signals corresponding to the gain-corrected image signals for each subfield, and the driving unit by rearranging the data signals mapped by the subfield mapping unit on a frame basis. It may further include a data sorting unit for outputting.

The pixel circuit unit may include a first transistor for transmitting the data signal in response to a scan signal, a capacitor for storing the data signal, a second transistor for generating a driving current corresponding to the data signal, and the data signal stored in the capacitor. And a light emitting diode emitting light corresponding to a driving current generated by the second transistor.

The gain adjusting unit may correct the gain of the red, green, and blue image signals differently for each color.

Specific details of other embodiments are included in the detailed description and the drawings. Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. Like reference numerals refer to like elements throughout.

Hereinafter, a display filter, a manufacturing method thereof, a display device, and a manufacturing method thereof according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram for describing an organic light emitting display device according to an exemplary embodiment of the present invention.

Referring to FIG. 1, an organic light emitting display device 100 according to an exemplary embodiment includes a pixel circuit unit including at least three subpixels of a plurality of red, green, blue, and white subpixels 120. 110, a power supply unit 130, a timing controller 140, and a driver 150.

The pixel circuit unit 110 may include a plurality of red, green, and blue subpixels 120 positioned at regions intersected by the scan line and the data line to display an image image, and in some cases, the white subpixels. 120 may further include.

Hereinafter, for convenience of description, the pixel circuit unit 110 is illustrated and described as including the red, green, and blue subpixels 120.

The power supply unit 130 supplies the same power voltage V _DD to the red, green, and blue subpixels 120. Regardless of the light emission characteristics of the red, green, and blue light emitting layers (not shown) included in each of the red, green, and blue subpixels 120, the same power supply voltage V _DD is supplied to reduce the number of power supply voltage sources, thereby reducing costs. Can be saved.

Here, although the same power supply voltage V _DD is supplied to the red, green, and blue subpixels 120, the present invention is not limited thereto. That is, the same power supply voltage may be supplied to at least two colors of the subpixels, for example, the blue subpixel and the green subfill cell, and the same power supply voltage may be supplied to the blue subpixel and the red subpixel.

The timing controller 140 drives the control signal and the driver 150 to supply the power voltage V _DD of the power supply unit 130 based on the vertical sync signal Vsync and the horizontal sync signal Hsync supplied from the outside. A predetermined control signal for generating is generated.

The driver 150 sequentially supplies the scan signal Vs to the pixel circuit unit 110 in response to the control signal generated from the timing controller 140. In addition, the data signal Vdata and the erase signal V _E are supplied to the pixel circuit unit 110 in response to the control signal generated from the timing controller 140. Accordingly, the red, green, and blue subpixels 120 of the pixel circuit unit 110 emit light.

Here, the driving unit 150 of the organic light emitting display device 100 according to an exemplary embodiment may apply the erase signal V _E at different time points for each of the red, green, and blue subpixels 120.

That is, regardless of the light emission characteristics of the red, green, blue, and white light emitting layers (not shown), while supplying the same power supply voltage (V _DD ) to the subpixels of at least two colors of red, green, blue, and white, White balance can be achieved by applying the erase signal V _E to different sub-pixels 120 supplied with the same power supply voltage V _DD , which will be described later.

2 illustrates a subpixel circuit of an organic light emitting display device according to an exemplary embodiment of the present invention.

Referring to FIG. 2, the subpixel 120 of the organic light emitting display according to an exemplary embodiment of the present invention transfers a data signal Vdata from the scan line Sn by the scan signal Vs. T1, a capacitor Cst storing the data signal Vdata, and a second transistor generating a driving current corresponding to a difference between the data signal Vdata stored in the capacitor Cst and the power supply voltage V _DD . (T2), a third diode for erasing the data signal Vdata stored in the capacitor Cst according to the light emitting diode OLED emitting the light corresponding to the driving current and the erase signal V _E from the erase line En. It may include a transistor T3.

3 is a diagram for describing a method of implementing image gray scale of an organic light emitting display device according to an exemplary embodiment of the present invention.

Referring to FIG. 3, in the organic light emitting display according to an exemplary embodiment, a frame for implementing gray levels of an image is divided into several subfields having different emission times, and each subfield may emit light again. It is divided into an address section for selecting a subpixel, a light emitting section for implementing gradation according to light emission time, and an erasing section in which light emission is stopped.

For example, when displaying an image with 64 gray levels, a frame period (16.67 ms) corresponding to 1/60 second is divided into six subfields SF1 to SF6, and six subfields SF1 to SF6) are each divided into an address section, a light emitting section, and an erasing section.

That is, a scan signal Vs is applied to an address section in one subfield to select a subpixel to emit light, and a data signal Vdata is applied to the light emitting section to emit light, and the light emitting diode OLED starts to emit light. Emission signal V _E for erasing the data signal Vdata stored in the capacitor Cst is applied to the interval to stop light emission.

Since light emission is maintained for a time period from the time when the data signal Vdata is applied to the time when the erase signal V _E is applied, this time is referred to as a light emission sustain time.

Here, the address section and the erase section of each subfield may be the same for each subfield.

The light emission section is a period for determining the gray scale weight in each subfield. For example, the gray scale weight of each subfield is 2 ⁿ by setting the gray scale weight of the first subfield SF1 to 2 ⁰ and the gray scale weight of the second subfield to 2 ¹ , where n = The gray scale weight of each subfield may be determined to increase at a ratio of 0, 1, 2, 3, 4, and 5).

As such, by adjusting the light emission holding time in the light emitting period of each subfield according to the gray scale weight in the light emitting period of each subfield, it is possible to realize the grayscale of various images.

The organic light emitting display uses a plurality of frames to display an image of 1 second. For example, 60 frames are used to display an image of 1 second.

Here, the case where one frame is composed of six subfields has been illustrated and described. However, the number of subfields constituting one frame may be variously changed.

Further, although the subfields are arranged in increasing order of the gray scale weight in one frame, the subfields may be arranged in the order of decreasing gray scale weight in one frame, or regardless of the gray weight. Subfields may be arranged.

4 is a diagram illustrating a configuration example of one frame of an image of an organic light emitting display device according to an exemplary embodiment of the present invention.

Referring to FIG. 4, the organic light emitting diode display according to an exemplary embodiment of the present invention applies an erasing signal V _E at different points in time to each of the red, green, and blue subpixels 120 to display the red, green, and blue subpixels. Each may have a different light emission holding time.

That is, in the case of the blue subpixel, the data signal is applied in response to the scan signal Vs in one subfield to start light emission, and then until the erase signal V _E is applied to stop light emission. The emission sustain time of is longer than that of the red subpixel and the green subpixel.

In addition, the emission sustain time of the red subpixel is shorter than the emission sustain time of the blue subpixel and the green subpixel.

In other words, in one subfield, the erase signal V _E is applied in the order of the red subpixel, the green subpixel, and the blue subpixel in order to reduce the emission sustain time to red, green, and blue. This is different for each subpixel.

The reason why the light emission holding time is different for each of the red, green, and blue subpixels is to supply the same power voltage to the red, green, and blue subpixels, so as to reduce the variation of the light emission characteristics according to the characteristics of the light emitting layer to achieve white balance. .

That is, according to the related art, power sources of different sizes are supplied according to characteristics of light emitting layers of red, green, and blue subpixels. In general, the light emitting characteristics of the light emitting layer of the blue subpixels are lower than those of the light emitting layers of the red and green subpixels. In order.

However, the organic electroluminescent display according to the exemplary embodiment of the present invention supplies the same power supply voltage Vdd to the red, green, and blue subpixels, and the variation of the light emission characteristics with respect to the material properties of the light emitting layer is red, green, and blue. The white balance can be adjusted by compensating the application time of the erase signal V _E differently, that is, by varying the emission sustain time.

In this case, the same power supply voltage Vdd is supplied to the red, green, and blue subpixels, and the application time of the erase signal V _E is changed for each of the red, green, and blue subpixels, but is not limited thereto.

That is, the same power supply voltage may be supplied to the subpixels of at least two colors among the red, green, blue, and white subpixels, and the viewpoint of the erase signal V _E applied to the subpixels to which the same power supply voltage is supplied may be different. It is.

For example, if the same power supply voltage is supplied to the blue and red subpixels, only the timing of the erase signal V _E applied to the blue and red subpixels may be different.

Accordingly, the total cost of the organic light emitting display device can be reduced by reducing the number of power supply voltage sources, and the white balance for realizing pure white can be adjusted.

In addition, since the magnitude of the power supply voltage is supplied to the red and green subpixels in the same manner as that of the conventional blue subpixels, the luminance of the red and green subpixels is reduced due to the reduction of the emission time. You can compensate.

Although the light emission sustaining time of the blue subpixel is the longest and the light emission sustaining time of the red subpixel is illustrated as being the shortest, the present invention is not limited thereto. That is, when the material properties of the light emitting layer of the green subpixel are deteriorated according to the material properties of the light emitting layer, the light emission holding time of the green subpixel can be longest. The light emission holding time of the subpixel can also be shortest.

5 is a block diagram illustrating a driving circuit of an organic light emitting display device according to another exemplary embodiment of the present invention.

Here, among the features of the organic light emitting display according to another exemplary embodiment of the present invention, features substantially the same as those of the organic light emitting display according to the exemplary embodiment of the present invention described with reference to FIG. 1 will be described. Omit it.

Referring to FIG. 5, a driving circuit of an organic light emitting display device according to another exemplary embodiment of the present invention may include a gamma unit 210, a gain adjusting unit 220, a halftone correcting unit 230, and a subfield mapping unit 240. ), A data alignment unit 250, and a driver 260.

Here, the pixel circuit unit may include a plurality of red, green, and blue subpixels, and may further include a white subpixel 120 in some cases.

Hereinafter, for convenience of description, the pixel circuit unit is illustrated and described as including the red, green, and blue subpixels 120.

The gamma part 210 gamma-corrects the image signals of red (R), green (G), and blue (B) input through pre-stored gamma data, thereby adjusting the red (R), green (G), and blue (B) colors. The luminance value according to the gray value of the image signal is gamma-converted to suit the image implementation of the organic light emitting display device, and the gamma-converted image signals of red (R), green (G), and blue (B) are white-balanced on the output screen. Output to the gain adjusting unit 220 for the adjustment of.

The gain adjusting unit 220 corrects the gains of the gamma-converted red (R), green (G), and blue (B) image signals differently and outputs the gains to the halftone correcting unit 230.

Here, the gain value for gain correction of the blue (B) video signal may be the largest and the gain value for gain correction of the red (R) video signal may be the smallest.

In general, since the material of the light emitting layer of the blue subpixel is inferior to the material of the light emitting layer of the red and green subpixels, the gain of the image signal of the blue (B) is maximized, and the material of the light emitting layer of the red subpixel is light emitting. Since the gain is the best, the gain of the video signal of red (R) is minimized so that the gain of the video signals can be adjusted.

However, the present invention is not limited thereto, and the gains of the image signals of red (R), green (G), and blue (B) may be adjusted according to the material properties of the light emitting layers of the red, green, and blue subpixels.

Here, although the same power supply voltage Vdd is supplied to the red, green, and blue subpixels, and the gains of the blue, green, and blue image signals are corrected differently for each color, the present invention is not limited thereto.

That is, the same power supply voltage may be supplied to at least two color subpixels of the red, green, and blue subpixels, and the gain of the image signal of the color corresponding to the subpixel to which the same power supply voltage is supplied may be differently corrected.

For example, if the same power supply voltage is supplied to the blue and red subpixels, the gain of the index blue and red image signals corresponding to the blue and red subpixels may be differently corrected.

The halftone correction unit 230 finely adjusts the luminance values of the image signals of red (R), green (G), and blue (B) gain-corrected through image dithering or error diffusion, and adjusts the adjusted red (R). The video signals of the green (G) and blue (B) signals are output to the subfield mapping unit 240.

The subfield mapping unit 240 performs subfield mapping of the input red (R), green (G), and blue (B) image signals by using a preset subfield pattern, and the mapped red (R) and green (G) signals. ), A blue (B) image data signal is output to the data alignment unit 250.

For example, when one frame includes a total of six subfields, the gray scale weight of the image adjusted by the above-described gain adjusting unit 220 among the first subfield SF1 to the sixth subfield SF6 is adjusted. Map by selecting one or more subfields.

The data aligning unit 250 outputs a data signal for each subfield so as to display the mapped image data signals of red (R), green (G), and blue (B) on the organic electroluminescent display, and the driving unit 260. Will output

The driver 260 displays an image by supplying data aligned red (R), green (G), and blue (B) image data signals to the red, green, and blue subpixels of the pixel circuit unit.

6 is a diagram illustrating a configuration example of one frame of an image of an organic light emitting display device according to another exemplary embodiment of the present invention.

Referring to FIG. 6, the gain adjusting unit 220 of the organic light emitting display according to another exemplary embodiment may vary the gain of the image signals of red (R), green (G), and blue (B) for each color. After the correction, the image is output by supplying the data signals output through the halftone corrector 230, the subfield mapping unit 240, the data alignment unit 250, and the driver 260 to the red, green, and blue subpixels. An example is implemented.

For example, as described with reference to FIG. 3, it is assumed that one frame is implemented with six subfields, and that 16 grays of 64 grays are displayed.

First, in the case of a blue subpixel, when the gain adjusting unit 220 corrects gain by setting the gain of the blue (B) video signal to 1, 16, which is a value obtained by multiplying 16 gray, which is an input video signal, by 1 The grayscale is output, and the subfield mapping unit 240 maps the first subfield SF1, the second subfield SF2, the third subfield SF3, and the fourth subfield SF4. The first subfield SF1, the second subfield SF2, the third subfield SF3, and the fourth subfield SF4 emit light through the data aligning unit 250 and the driving unit 260. ON) to express 16 gray levels.

Next, in the case of a red sub-pixel, when the gain is adjusted by setting the gain of the red (R) video signal to 0.8125 (Gain), the gain adjusting unit 220 adjusts the gain of the input video signal to 16 gray scales (0.8 gray). 13 grays, which are values multiplied by a gain, are output, and when the first subfield SF1, the third subfield SF3, and the fourth subfield SF4 are mapped by the subfield mapping unit 240, The first subfield SF1, the third subfield SF3, and the fourth subfield SF4 are turned on through the data aligning unit 250 and the driving unit 260 to represent 13 gray levels. Done.

Next, in the case of the green subpixel, when the gain is adjusted by setting the gain of the green (G) video signal to 0.875 (Gain), the gain adjusting unit 220 adjusts the gain of the input video signal to 16 gray scales to 0.875 (Gray). 14 gray, which is a value multiplied by Gain, is output, and when the second subfield SF2, the third subfield SF3, and the fourth subfield SF4 are mapped by the subfield mapping unit 240, The second subfield SF1, the third subfield SF3, and the fourth subfield SF4 are turned on through the data aligning unit 250 and the driving unit 260 to express 14 gray levels. Done.

As such, by supplying the same power supply voltages to the red, green, and blue subpixels, the white balance can be adjusted by reducing the variation in emission characteristics. In addition, since the power supply voltage is supplied to the red and green subpixels in the same manner as the power supply voltage supplied to the conventional blue subpixels, loss of luminance of the red and green subpixels due to the gain adjustment is compensated for. Can be.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains can understand that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. will be. Therefore, the above-described embodiments are to be understood as illustrative and not restrictive in all respects, and the scope of the present invention is indicated by the appended claims rather than the detailed description, and the meaning and scope of the claims and All changes or modifications derived from the equivalent concept should be interpreted as being included in the scope of the present invention.

The organic light emitting display device according to the embodiment of the present invention made as described above has an effect of reducing the manufacturing cost and achieving white balance.

Claims (11)

In an organic light emitting display device which displays an image by dividing one frame into a plurality of subfields, A pixel circuit unit including subpixels of at least three colors of red, green, blue, and white subpixels; A power supply unit supplying a same power voltage to at least two color subpixels of the subpixels; And A driver configured to apply a scan signal, a data signal, and an erase signal to each subpixel of the pixel circuit unit; And the driving unit applies the erase signal to different sub-pixels of the sub-pixels to which the same power voltage is supplied. The method of claim 1, The erasing signal applied to the blue subpixel is applied later than the erasing signal applied to the red and green subpixels. The method of claim 1, And an erase signal applied to the red subpixel before the erase signal applied to the blue and green subpixels. The method of claim 1, The pixel circuit unit A first transistor configured to transfer the data signal in response to the scan signal; A capacitor for storing the data signal; A second transistor generating a driving current corresponding to the data signal; A third transistor for transferring said erase signal for canceling said data signal stored in said capacitor; And a light emitting diode emitting light corresponding to a driving current generated by the second transistor. The method of claim 1, And the driving unit applies the erase signal at different times for each of the red, green, and blue subpixels. An organic electroluminescent display device which displays an image by dividing one frame into a plurality of subfields. A pixel circuit unit including subpixels of at least three colors of red, green, blue, and white subpixels; A gain adjusting unit which corrects gains of image signals of at least two colors of red, green, blue, and white differently for each color; A driver supplying a data signal corresponding to the gain corrected image signals to the pixel circuit unit; And And a power supply unit supplying the same power voltage to the subpixels of the color corresponding to the gain-corrected image signals. The method of claim 6, The gain of the red image signal is smaller than the gain of the green and blue image signals. The method of claim 6, The gain of the blue image signal is greater than the gain of the red and green image signals. The method of claim 6, The organic light emitting display device A subfield mapping unit for mapping the data signals corresponding to the gain-corrected image signals to each subfield; And And a data alignment unit for rearranging the data signals mapped in the subfield mapping unit in units of frames and outputting the data signals to the driving unit. The method of claim 6, The pixel circuit unit A first transistor configured to transfer the data signal in response to a scan signal; A capacitor for storing the data signal; A second transistor generating a driving current corresponding to the data signal; A third transistor configured to transfer an erase signal to erase the data signal stored in the capacitor; And And a light emitting diode emitting light corresponding to a driving current generated by the second transistor. The method of claim 6, The gain adjusting unit corrects gain of red, green, and blue image signals differently for each color.

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