KR100656837B1 - Organic EL device and method for driving same - Google Patents

Abstract

The present invention relates to an organic electroluminescent device whose discharge level varies depending on the gradation. The organic electroluminescent device including a plurality of pixels formed in light emitting regions where data lines and scan lines intersect includes a data storage unit and a discharge unit. The data storage unit stores first RGB data and second RGB data sequentially input from the outside. The discharging unit discharges the data lines to a discharge level corresponding to the second Algibi data using the first and second Algibi data provided from the data storage unit. In the organic electroluminescent device, when the pixels emit light at low gray levels, the data lines are discharged at a higher discharge level than when the pixels emit light at high gray levels, so that the pixels emit desired luminance and power consumption may be reduced.

Organic electroluminescent element, discharge, precharge

Description

Organic electroluminescent device and method of driving the same {ORGANIC ELECTROLUMINESCENT DEVICEE AND METHOD OF DRIVING THE SAME}

1A is a diagram illustrating a conventional organic EL device.

1B is a timing diagram illustrating a conventional scan signal and data current.

2 is a block diagram illustrating an organic EL device according to an exemplary embodiment of the present invention.

3 is a timing diagram illustrating a scan signal and a data current according to an exemplary embodiment of the present invention.

4 is a flowchart illustrating a process of driving an organic light emitting diode according to an exemplary embodiment of the present invention.

The present invention relates to an organic electroluminescent device and a method for driving the same, and more particularly, to an organic electroluminescent device for varying the discharge level according to the gray scale and a method for driving the same.

The organic electroluminescent device is a device which emits light by using an organic material contained therein.

FIG. 1A is a block diagram illustrating a conventional organic EL device, and FIG. 1B is a timing diagram illustrating a conventional scan signal and a data current.

Referring to FIG. 1A, a conventional organic EL device includes a panel 100, a scan driver 102, a data storage unit 104, a discharge unit 106, a precharge unit 108, and a data driver 110. Include.

The panel 100 includes a plurality of pixels E11 to E44 formed in light emitting regions where the data lines D1 to D4 and the scan lines S1 to S4 cross each other.

The scan driver 102 sequentially transmits scan signals to the pixels E11 to E44 through the scan lines S1 to S4.

The data storage unit 104 sequentially stores the RGB data input from the outside in the latches included therein.

Hereinafter, it is assumed that the first and second AlgiBee data are sequentially input to the data storage unit 104, and the driving process of the organic EL device will be described in detail with reference to FIG. 1B.

Referring to FIGS. 1A and 1B, the precharge unit 108 may receive a first precharge current corresponding to the first ALG ratio data provided from the data storage unit 104 as illustrated in FIG. 1B. It is applied to the data lines D1 to D4 for a time pcha1. In this case, since the gray level corresponding to the first ALG ratio data is a high gray level (80%), the first precharge current is sufficiently overshooted during the first precharge time pcha1 as shown in FIG. 1B. overshooting). Therefore, the pixels E11 to E44 emit light with 80% gray level from the start point T2 of the low logic region of the second scan signal SP2.

Subsequently, the data driver 110 receives the first data current (80% gray scale) corresponding to the first Algibee data transmitted from the data storage unit 104 through the data lines D1 to D4. To E44).

Subsequently, the discharge unit 106 moves the data lines D1 to D4 to the predetermined discharge level DL1 during the second discharge time dcha2 according to the first ALG ratio data transmitted from the data storage unit 104. Discharge. Here, the discharge level DL1 is always constant regardless of the light emission gray level of the pixels E11 to E44.

Subsequently, the precharge unit 108 transmits a second precharge current corresponding to the second ALG ratio data provided from the data storage unit 104 to the data lines D1 to D4 during the second precharge time pcha2. Is authorized.

Subsequently, the data driver 110 transmits the second data current (20% gray scale) corresponding to the second Algivy data transmitted from the data storage unit 104 through the data lines D1 to D4. To E44). In this case, since the gradation corresponding to the second Algi ratio data is low gradation (20%), the second precharge current is not sufficiently overshooted, so that pixels E11 to E44 are connected to A of FIG. 1B. As shown in FIG. 3, the light emits with a 20% gray level after the start point T3 of the low logic region of the third scan signal SP3. Therefore, in the conventional organic EL device, the pixels E11 to E44 did not emit light with the desired luminance, and power had to be increased to emit the desired luminance. As a result, the power consumption of the conventional organic EL device has increased.

SUMMARY OF THE INVENTION An object of the present invention is to provide an organic electroluminescent device capable of emitting pixels at a desired luminance regardless of the gradation and a method of driving the same.

In order to achieve the above object, an organic electroluminescent device including a plurality of pixels formed in light emitting regions where data lines and scan lines cross each other according to an exemplary embodiment of the present invention includes a data storage unit and a discharge unit. Contains wealth. The data storage unit stores first RGB data and second RGB data sequentially input from the outside. The discharging unit discharges the data lines to a discharge level corresponding to the second Algibi data using the first and second Algibi data provided from the data storage unit.

A method of driving an organic electroluminescent device including a plurality of pixels formed in light emitting regions where data lines and scan lines intersect according to an exemplary embodiment of the present invention corresponds to first algibi data input from an external source. Applying a first data current to the data lines; And discharging the applied data lines to a discharge level corresponding to the second Algivy data by using the first Algivy data and second Algivy data input immediately after the first Algivy data. .

In the organic electroluminescent device according to the present invention, when the pixels emit light at low gradation, the data lines are discharged at a higher discharge level than when the pixels emit light at high gradation, so that the pixels emit desired luminance and power consumption can be reduced. have.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the organic electroluminescent device and a method for driving the same according to the present invention.

2 is a block diagram illustrating an organic EL device according to an exemplary embodiment of the present invention, and FIG. 3 is a timing diagram illustrating a scan signal and a data current according to an exemplary embodiment of the present invention.

Referring to FIG. 2, the organic electroluminescent device of the present invention includes a panel 200, a scan driver 202, a data storage unit 204, a discharge unit 206, a precharge unit 208, and a data driver 210. It includes.

The panel 200 includes a plurality of pixels E11 to E44 formed in emission areas where the data lines D1 to D4 and the scan lines S1 to S4 cross each other. Here, each of the pixels E11 to E44 includes an anode electrode layer, an organic material layer, and a cathode electrode layer sequentially stacked on a substrate, and a predetermined voltage is applied to the anode electrode layer and a negative voltage is applied to the cathode electrode layer. Generates light of the wavelength.

The scan driver 202 sequentially provides the scan signals to the pixels E11 to E44 through the scan lines S1 to S4.

The data storage unit 204 stores RGB data (RGB data) sequentially input from the outside in latches included therein.

In the following description, it is assumed that the first and second Algivy data are sequentially input to the data storage unit 204.

The precharge unit 208 receives the first and second ALGBI data from the data storage unit 204, and transmits first precharge currents corresponding to the received first ALGBI data to the data lines D1 to D4. ) Is applied.

The data driver 210 provides a first data current corresponding to the first ALGE ratio data transmitted from the data storage unit 204 to the data lines D1 to D4 to which the first precharge current is applied.

The discharge unit 206 includes a gray scale detection unit 212 and a discharge execution unit 214.

The gray scale detection unit 212 receives the second AlgiBi data from the data storage unit 204, detects a gray scale corresponding to the received second AlgiBi data, and discharges information about the detected gray scales. Send to 214.

The discharge execution unit 214 determines whether the detected gray level is a high gray level (for example, 50% or more gray level) through the transmitted gray level information. When the detected gradation is a high gradation, for example, when the gradation corresponding to the first algibi data is 50% and the gradation corresponding to the second algibi data is 80%, as shown in FIG. The discharge execution unit 214 discharges the data lines D1 to D4 provided with the first data current to the fixed first discharge level DL1 according to the first ALG ratio data transmitted from the data storage unit 204. Let's do it. However, the discharge execution unit 214 discharges the data lines D1 to D4 to the first discharge level DL1 regardless of the gray level. However, when the detected gradation is low gradation, for example, as shown in FIG. 3, the gradation corresponding to the first algibi data is 80% and the gradation corresponding to the second algibi data is 20%. In this case, the discharge execution unit 214 discharges the data lines D1 to D4 to the second discharge level DL2 according to the first ALG ratio data. However, the discharge execution unit 214 discharges the data lines D1 to D4 to the discharge level corresponding to the gray level. For example, when the detected gray scale is 40%, the discharge execution unit 214 moves the data lines D1 to D4 to a discharge level larger than the first discharge level DL1 and smaller than the second discharge level DL2. Discharge. In this case, the discharge execution unit 214 according to the embodiment of the present invention controls the discharge times dcha1 and dcha2 to discharge the data lines D1 to D4 to the discharge levels DL1 and DL2. Of course, the discharge execution unit 214 may discharge the data lines D1 to D4 to the discharge levels DL1 and DL2 by controlling the discharge amount for the same time.

The precharge unit 208 applies a second precharge current corresponding to the received second ALGE ratio data to the discharged data lines D1 to D4.

The data driver 210 provides a second data current corresponding to the second ALGE ratio data transmitted from the data storage unit 204 to the data lines D1 to D4 to which the second precharge current is applied.

Hereinafter, the conventional organic electroluminescent element and the organic electroluminescent element of the present invention will be compared.

In the conventional organic EL device, since the discharge level is always the same regardless of the gray level, when the gray level corresponding to the second ALG ratio data is low gray level, the desired level is displayed in the low logic region of the scan signal as shown in FIG. Current less than the data current is provided to the data lines D1 to D4. Therefore, the conventional organic EL device emits light with a lower brightness than the desired brightness, so that the power is increased to emit light with the desired brightness.

On the other hand, in the organic electroluminescent device of the present invention, since the discharge level is changed according to the gray level corresponding to the second Algi ratio data, even when the gray level corresponding to the second Algi ratio data is low gray level, B of FIG. As shown in FIG. 2, desired data current is provided to the data lines D1 to D4 in the low logic region of the scan signal. Therefore, the organic electroluminescent element of the present invention does not need to increase power unlike conventional, so power consumption is reduced.

4 is a flowchart illustrating a process of driving an organic light emitting diode according to an exemplary embodiment of the present invention.

Referring to FIG. 4, the data driver 210 provides a first data current corresponding to the first Algibee data to the pixels E11 to E44 through the data lines D1 to D4 (S400).

Subsequently, the gray scale detection unit 212 detects a gray scale corresponding to the second ALG ratio data (S402).

Subsequently, it is determined whether the detected grayscale corresponds to high grayscale (S404).

When the detected grayscale corresponds to a high grayscale, the discharge execution unit 214 discharges the data lines D1 to D4 to a fixed first discharge level D1 (S406).

On the other hand, when the detected grayscale corresponds to the low grayscale, the discharge execution unit 214 discharges the data lines D1 to D4 to a discharge level corresponding to the detected grayscale (S408).

Subsequently, the precharge unit 208 applies a precharge current corresponding to the second ALG ratio data to the data lines D1 to D4 (S410).

Subsequently, the data driver 210 provides a second data current corresponding to the second Algivy data to the pixels E11 to E44 through the data lines D1 to D4 (S412).

Preferred embodiments of the present invention described above are disclosed for purposes of illustration, and those skilled in the art having ordinary knowledge of the present invention will be able to make various modifications, changes, additions within the spirit and scope of the present invention, such modifications, changes and Additions should be considered to be within the scope of the following claims.

As described above, in the organic electroluminescent device according to the present invention, when the pixels emit light with low gradation, the data lines are discharged at a higher discharge level than when the pixels emit light with high gradation, so that the pixels emit light with a desired luminance. Therefore, the power consumption of the organic EL device is reduced.

Claims (11)

An organic electroluminescent device comprising a plurality of pixels formed in light emitting regions where data lines and scan lines intersect. A data storage for storing first RGB data and second RGB data sequentially input from the outside; And And a discharge unit for discharging the data lines to a discharge level corresponding to the second AlgiBee data using the first and second AlgiBee data provided from the data storage unit. 2. The organic electroluminescence of claim 1, wherein the discharge part discharges the data lines up to a discharge level corresponding to the second Algibi data when the second AlgiBee data is data corresponding to a low gray level. device. The organic electroluminescent device according to claim 2, wherein the discharge unit adjusts the discharge level by controlling a discharge time. The organic electroluminescent device according to claim 2, wherein the discharge part discharges the data lines to a predetermined level irrespective of the gray level when the second ALG ratio data is data corresponding to a high gray level. The method of claim 1, wherein the discharge unit, A gray level detector for detecting a gray level of a data current corresponding to the second ALG ratio data according to the second ALG ratio data provided from the data storage unit; And And a discharge execution unit for discharging the data lines to a discharge level corresponding to the second AlgiBi data by using the gray level detected by the gradation detector and the first ALGBI data provided from the data storage unit. Organic electroluminescent device. The method of claim 1, wherein the organic electroluminescent device, A scan driver configured to provide scan signals to the scan lines; A precharge unit configured to receive the first and second AlgiBee data from the data storage unit and to provide the data lines with first and second precharge currents corresponding to the received first and second AlGeeBee data; And A data driver configured to receive the first and second AlgiBee data from the data storage and to provide the data lines with first and second data currents corresponding to the received first and second AlGeeBee data; An organic electroluminescent device, characterized in that. A method of driving an organic electroluminescent device comprising a plurality of pixels formed in light emitting regions where data lines and scan lines intersect. Applying a first data current corresponding to first algibi data input from the outside to the data lines; And Discharging the applied data lines to a discharge level corresponding to the second Algibi data using the first Algibi data and second Algibi data input immediately after the first Algibi data. An organic electroluminescent element driving method. The method of claim 7, wherein the discharging step, Detecting a gray level of a second data current corresponding to the second ALG ratio data; And And discharging the data lines to the discharge level according to the detected gray level and the first ALG ratio data. The method of claim 8, wherein the discharge to the discharge level, When the detected gray level is a high gray level, discharging the data lines to a predetermined discharge level regardless of the gray level; And And discharging the data lines to a discharge level corresponding to the gray level when the detected gray level is a low gray level. The method of claim 9, wherein the data lines are discharged to a discharge level corresponding to the gray level by adjusting a discharge time. The method of claim 7, wherein the organic electroluminescent device driving method, Applying a precharge current corresponding to the second ALG ratio data to the discharged data lines; And And providing a second data current corresponding to the second Algivy data to the data lines to which the precharge current is applied.

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