KR100736574B1 - Light emitting device and method of driving the same - Google Patents

Abstract

A light emitting device and a method for driving the same are provided to enhance image quality by discharging data lines to a discharge level corresponding to a cathode voltage of pixels. A light emitting device includes data lines(D1~D6), scan lines(S1~S4), plural pixels(E11~E64), and a discharge unit(308). The data lines are arranged in a first direction. The scan lines are arranged in a second direction different from the first direction. The plural pixels are formed on the cross sections of the data and scan lines. The discharge unit discharges at least one data line to a first discharge level during a first sub-discharge time of a discharge time, and converts the first discharge level to a second discharge level during a second sub-discharge time of the discharge time.

Description

LIGHT EMITTING DEVICE AND METHOD OF DRIVING THE SAME}

1 is a block diagram showing a conventional light emitting device.

2A and 2B are circuit diagrams schematically illustrating the light emitting device of FIG. 1.

2C and 2D are timing diagrams illustrating a driving process of the light emitting device.

3A is a block diagram showing a light emitting device according to a first embodiment of the present invention.

3B is a diagram illustrating a discharge level graph according to the operation of the discharge unit of FIG. 3A.

4A and 4B are circuit diagrams schematically illustrating the light emitting device of FIG. 3A.

4C and 4D are timing diagrams illustrating a driving process of the light emitting device.

5 is a block diagram illustrating a light emitting device according to a second exemplary embodiment of the present invention.

6 is a block diagram showing a light emitting device according to a third embodiment of the present invention.

7 is a block diagram illustrating a light emitting device according to a fourth exemplary embodiment of the present invention.

The present invention relates to a light emitting device and a method of driving the same, and more particularly, to a light emitting device and a method of driving the cross-talk phenomenon (Cross-talk Phenomenon) and comb pattern does not occur.

The light emitting element generates light having a predetermined wavelength when a predetermined current or voltage is provided.

1 is a block diagram showing a conventional light emitting device.

Referring to FIG. 1, a conventional light emitting device includes a panel 100, a controller 102, a first scan driver 104, a second scan driver 106, a discharge unit 108, a precharge unit 110, and the like. The data driver 112 is included. For example, the light emitting device is an organic electroluminescent device.

The panel 100 includes a plurality of pixels E11 to E64 formed in light emitting regions where the data lines D1 to D6 and the scan lines S1 to S4 cross each other.

The control unit 102 receives the display data from an external device, and uses the received display data to control the scan drivers 104 and 106, the discharge unit 108, the precharge unit 110, and the data driver 112. Control the operation.

The first scan driver 104 transmits the first scan signals to some of the scan lines S1 to S4 (eg, S1 and S3). The second scan driver 106 transmits second scan signals to the remaining scan lines S2 and S4. As a result, the scan lines S1 to S4 are sequentially connected to ground.

The discharge unit 108 is connected to the data lines D1 to D6 through the switches SW1 to SW6. Referring to the discharge operation, the discharge unit 108 turns on the switches SW1 to SW6 during discharge, so that the data lines D1 to D6 are connected to the zener diode ZD. As a result, the data lines D1 to D6 are discharged to the zener voltage of the zener diode ZD.

The precharge unit 110 provides a precharge current corresponding to the display data to the discharged data lines D1 to D6 under the control of the controller 102.

The data driver 112 provides data currents corresponding to the display data to the precharged data lines D1 to D6 under the control of the controller 102. As a result, the pixels E11 to E64 emit light.

2A and 2B are schematic circuit diagrams illustrating the light emitting device of FIG. 1, and FIGS. 2C and 2D are timing diagrams illustrating a driving process of the light emitting device.

Hereinafter, the driving process of the light emitting device will be described in detail with reference to the cathode voltages VC11 to VC64.

The sizes of the cathode voltages VC11 to VC61 of the pixels E11 to E61 corresponding to the first scan line S1 will be compared.

As shown in FIG. 2A, the resistance between the eleventh pixel E11 and the ground is a scan resistor R _S , and the resistance between the twenty-first pixel E21 and the ground is R _S + R _P. In addition, the resistance between the thirty-first pixel E31 and the ground is R _S + 2R _P , and the resistance between the forty-first pixel E41 and the ground is R _S + 3R _P. In addition, the resistance between the 51st pixel E51 and the ground is R _S + 4R _P , and the resistance between the 61st pixel E61 and the ground is R _S + 5R _P.

Here, it is assumed that data currents I11 to I61 of the same magnitude are provided to the data lines D1 to D6 to emit the pixels E11 to E61 at the same luminance. In this case, the data currents I11 to I61 pass through the pixels E11 to E61 and the first scan line S1 and then flow to ground. Accordingly, the cathode voltages VC11 to VC61 of the pixels E11 to E61 have the same magnitude of the data currents I11 to I61, so that the corresponding resistances, that is, the resistances between the pixels E11 to E61 and the ground, are the same. It has a size proportional to Therefore, the 61st cathode voltage VC61, the 51st cathode voltage VC51, the 41st cathode voltage VC41, the 31st cathode voltage VC31, the 21st cathode voltage VC21, and the 11th cathode voltage VC11 in order. As its size is large.

Referring to FIG. 2B, the resistance between the twelfth pixel E12 and the ground is R _S + 5R _P , which is larger than the resistance between the eleventh pixel E11 and the ground. Here, the data current flowing in the first data line D1 when the first scan line S1 is connected to the ground and the data flowing in the first data line D1 when the second scan line S2 is connected to the ground Assume that the magnitude of the current is the same. In this case, since the cathode voltages VC11 and VC12 of the pixels E11 and E12 have a magnitude proportional to the corresponding resistance, the twelfth cathode voltage VC12 is greater than the eleventh cathode voltage VC11.

Hereinafter, a process of driving the light emitting device will be described in detail.

The switches SW1 to SW6 are turned on, and the scan lines S1 to S4 have a voltage V2 of the same magnitude as a voltage corresponding to a driving voltage of the light emitting element, for example, the maximum luminance of the data current. The branches are connected to non-light emitting sources. Accordingly, the pixels E11 to E64 do not emit light, and the data lines D1 to D6 are equally discharged to the zener voltage of the zener diode ZD during the first discharge time dcha1.

Then, after the switches SW1 to SW6 are turned off, the precharge current corresponding to the first display data is first precharge time pcha1 as shown in FIGS. 2C and 2D. Is provided to the data lines D1 to D6.

Subsequently, the first scan line S1 is connected to ground as shown in FIG. 2A, and the remaining scan lines S2 to S4 are connected to the non-light emitting source.

 Subsequently, data currents I11 to I61 corresponding to the first display data are provided to the data lines D1 to D6 during the first emission time t1 as shown in FIGS. 2C and 2D. As a result, the pixels E11 to E61 emit light for the first emission time t1.

Hereinafter, it is assumed that the 61st pixel E61 and the eleventh pixel E11 are preset to emit light with the same luminance. That is, data currents I11 and I61 having the same magnitude are provided to the first data line D1 and the sixth data line D6 during the first emission time t1.

First, during discharge, the data lines D1 and D6 are discharged at the same level of discharge level during the first discharge time dcha1 as shown in FIG. 2D, so that the data lines D1 and D6 are first free of charge. It is precharged to the same level, that is, to a predetermined precharge voltage, during the charge time pcha1.

Subsequently, data currents I11 and I61 of the same magnitude are provided to the first data line D1 and the sixth data line D6, respectively. In this case, since the pixels E11 to E61 are preset to emit light with the same luminance, the anode voltages VA11 and VA61 of the pixels E11 and E61 are corresponding cathode voltages VC11 and VC61 from the precharge voltage. And rises up to voltages having a predetermined level difference and then stabilizes. This is because the pixel emits light with luminance corresponding to the difference between its anode voltage and its cathode voltage. For example, if the cathode voltage VC11 of the pixel E11 is 1V and the cathode voltage VC61 of the pixel E61 is 2V, the pixel E61 when the anode voltage VA11 of the pixel E11 is stabilized to 6V. Anode voltage VA61 is stabilized to 7V. In this case, since the data lines D1 and D6 are precharged to the same level, for example, 3V, the anode voltage VA11 of the pixel E11 is stabilized after rising from 3V to 6V, but the anode of the pixel E61 is The voltage VA61 rises from 3V to 7V and then stabilizes. Therefore, the amount of charge consumed until the anode voltage VA61 of the pixel E61 is stabilized becomes larger than the amount of charge consumed until the anode voltage VA11 of the pixel E11 is stabilized, as shown in FIG. 2D. Thus, although pixels E11 and E61 are preset to emit light with the same brightness, pixel E61 emits light darker than pixel E11.

Hereinafter, the light emitting device driving process will be described in detail.

Scan lines D1 to D6 are connected to the non-light emitting source, and switches SW1 to SW6 are turned on. As a result, the data lines D1 to D6 are discharged to a predetermined discharge level during the second discharge time dcha2 as shown in FIG. 2C.

Subsequently, after the switches SW1 to SW6 are turned off, a precharge current corresponding to the second display data is provided to the data lines D1 to D6. Here, the second display data is data input after the first display data is input to the controller 102.

Subsequently, a second scan line S2 is connected to the ground, and the remaining scan lines S1, S3 and S4 are connected to the non-light emitting source.

Subsequently, data currents I12 to I62 corresponding to the second display data are provided to the data lines D1 to D6, so that the pixels E12 to E62 emit light for the second emission time t2. .

Hereinafter, it is assumed that the pixel E11 and the pixel E12 are set to emit light at the same luminance.

In this case, since the resistance between the pixel E12 and the ground is greater than the resistance between the pixel E11 and the ground, the cathode voltage VC12 of the pixel E12 is greater than the cathode voltage VC11 of the pixel E11, Therefore, the amount of charge consumed until the anode voltage VA12 of the pixel E12 is stabilized is greater than the amount of charge consumed until the anode voltage VA11 of the pixel E11 is stabilized. Therefore, the pixel E12 emits light darker than the pixel E11. The phenomenon in which pixels set to emit light with the same luminance emits light with different luminance is called a cross-talk phenomenon.

Hereinafter, the emission luminances of the pixels E11 to E61 corresponding to the first scan line S1 and the pixels E12 to E62 corresponding to the second scan line S2 will be compared.

Among the pixels E11 to E61 corresponding to the first scan line S1, the pixel E11 emits the brightest light among the pixels E11 to E61 as described above, and the pixel E61 emits the darkest light. . In addition, the pixels E12 of the pixels E12 to E62 corresponding to the second scan line S2 emit the darkest of the pixels E12 to E62, and the pixel E62 emits the brightest light. Therefore, the luminance difference between the pixels E11 and E12 corresponding to the first outermost data line D1 and the luminance difference between the pixels E61 and E62 corresponding to the second outermost data line D6 are different from each other. It was larger than the luminance difference of (E21 to E52), so that stripes were generated between the pixels E11 and E12 and between the pixels E61 and E62. The stripes generated between the scan lines arranged in different directions as described above are called comb marks.

An object of the present invention is to provide a light emitting device which does not generate a cross-talk phenomenon and a comb fringe, and a method of driving the same.

In order to achieve the above object, a light emitting device according to an exemplary embodiment of the present invention includes data lines, scan lines, a plurality of pixels, and a discharge unit. The data lines are arranged in a first direction, and the scan lines are arranged in a second direction different from the first direction. The pixels are formed in regions where the data lines and the scan lines intersect. The discharge unit discharges at least one data line to a first discharge level during a first sub discharge time during a discharge time, and changes the first discharge level to the second discharge level during a second sub discharge time during the discharge time. . Here, the second discharge level has a different size from the first discharge level.

The light emitting device according to the exemplary embodiment of the present invention includes data lines, scan lines, a plurality of pixels, and a discharge part. The data lines are arranged in a first direction, and the scan lines are arranged in a second direction different from the first direction. The pixels are formed in regions where the data lines and the scan lines intersect. The discharge unit discharges the data lines to first discharge levels by providing a first current to the data lines during a first sub discharge time during a discharge time, and the data lines during a second sub discharge time during the discharge time. Some of the second current is provided to discharge the data lines to the second discharge levels. Here, the first discharge levels have the same magnitude, and the second discharge levels each have a magnitude corresponding to the cathode voltage of the corresponding pixel.

According to an embodiment of the present invention, a method of driving a light emitting device including a plurality of pixels formed in light emitting regions where data lines and scan lines cross each other may be performed. Providing a first current to a data line to discharge the data line to a first discharge level; And providing a second current to the data line during a second sub discharge time of the discharge time to change the data line from the first discharge level to a second discharge level. Here, the second discharge level has a different size from the first discharge level.

The light emitting device according to the present invention and the method of driving the same discharge the data lines at a discharge level corresponding to the cathode voltage of the corresponding pixel, so that no cross-talk phenomenon and comb pattern are generated in the light emitting device.

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

3A is a block diagram illustrating a light emitting device according to a first exemplary embodiment of the present invention, and FIG. 3B is a diagram illustrating a discharge level graph according to the operation of the discharge unit of FIG.

Referring to FIG. 3A, the light emitting device of the present invention includes a panel 300, a controller 302, a first scan driver 304, a second scan driver 306, a discharge unit 308, and a precharge unit 310. And a data driver 312.

The light emitting device according to the preferred embodiment of the present invention includes an organic electroluminescent device (PDP), a plasma dispaly panel (PDP), a liquid crystal display (LCD), and the like. However, hereinafter, the organic EL device will be described as an example for convenience of description.

The panel 300 includes a plurality of pixels E11 to E64 formed in emission areas where the data lines D1 to D6 and the scan lines S1 to S4 cross each other.

Each pixel E11 to E64 includes an anode electrode layer, an organic material layer, and a cathode electrode layer sequentially formed on a substrate.

The controller 302 receives display data, for example, RGB data, from an external device, and scan scan units 304 and 306, a discharge unit 308, and a pre-cha using the received display data. The operations of the branch 310 and the data driver 312 are controlled. In addition, the controller 302 may store the received display data in its internal memory.

The first scan driver 304 transmits the first scan signals to some of the scan lines S1 to S4 (eg, S1 and S3). The second scan driver 306 transmits second scan signals to the remaining scan lines S2 and S4. As a result, the scan lines S1 to S4 are sequentially connected to a light emitting source, for example, ground.

The discharge unit 308 discharges the data lines D1 to D6 to a discharge level corresponding to the cathode voltage of the pixel, and includes a sub discharge unit 320 and a discharge level unit 322.

The discharge level unit 322 includes a plurality of switches SW1 to SW6 respectively connecting the data lines D1 to D6 and the sub discharge unit 320.

The sub discharge unit 320 discharges the data lines D1 to D6 to the first discharge level by providing a predetermined voltage to the data lines D1 to D6 during the first sub discharge time during the discharge time. Here, the switches SW1 to SW6 are turned on for the first sub discharge time.

Subsequently, the sub discharge unit 320 provides a predetermined voltage to the data lines D1 to D6 during the second sub discharge time of the discharge time. As a result, the data lines D1 to D6 are discharged at discharge levels between the first discharge level and the second discharge level as shown in FIG. 3B. That is, the data lines D1 to D6 are discharged at discharge levels having a constant slope (but may be a curve rather than a straight line) as shown in FIG. 3B. Here, the discharge levels are voltages corresponding to the cathode voltage of the pixel as described below.

In the above, the case where the second discharge level is larger than the first discharge level is taken as an example, but the second discharge level may be smaller than the first discharge level. Detailed description thereof will be described below with reference to the accompanying drawings.

The precharge unit 310 provides a precharge current corresponding to the display data to the discharged data lines D1 to D6 under the control of the controller 302.

The data driver 312 provides data signals corresponding to the display data and synchronized with the scan signals, that is, data currents, to the precharged data lines D1 to D6 under the control of the controller 302. As a result, the pixels E11 to E64 emit light.

Hereinafter, the light emitting device driving process of the present invention will be described in detail.

The first scan line S1 is connected to ground, and the remaining scan lines S2 to S4 have a voltage equal to a driving voltage of the light emitting element, for example, a voltage corresponding to the maximum luminance of the data current. It is connected to a non-light emitting source having a.

Then, first data currents corresponding to the first display data are provided to the data lines D1 to D6. In this case, the first data currents provided to the data lines D1 to D6 flow to the ground through the pixels E11 to E61 and the first scan line S1 corresponding to the data lines D1 to D6. . As a result, the pixels E11 to E61 corresponding to the first scan line S1 emit light.

The data lines D1 to D6 are then discharged to discharge levels corresponding to the cathode voltages of the pixels E11 to E41 during the first discharge time.

Subsequently, the data lines D1 to D6 are precharged to a level corresponding to the second display data input to the controller 302 after the first display data input.

Then, the second scan line S2 is connected to ground, and the remaining scan lines S1, S3, and S4 are connected to the non-light emitting source.

Subsequently, second data currents corresponding to the second display data are provided to the data lines D1 to D6. As a result, the pixels E12 to E62 corresponding to the second scan line S2 emit light.

Subsequently, the data lines D1 to D6 are discharged for the second discharge time.

The above light emission process is repeated up to the fourth scan line S4, and then the above light emission process is repeated again from the first scan line S1.

4A and 4B are schematic circuit diagrams illustrating the light emitting device of FIG. 3A, and FIGS. 4C and 4D are timing diagrams illustrating a driving process of the light emitting device.

Referring to FIG. 4A, the sub discharge unit 320 includes an op amp connected to a first voltage source having a first voltage V _H or a second voltage source having a second voltage V _L. Here, the second voltage V _L is smaller than the first voltage V _H.

Hereinafter, the driving process of the light emitting device will be described in detail with reference to the cathode voltages VC11 to VC64.

The sizes of the cathode voltages VC11 to VC61 of the pixels E11 to E61 corresponding to the first scan line S1 will be compared.

As shown in FIG. 4A, the resistance between the eleventh pixel E11 and the ground is a scan resistor R _S , and the resistance between the twenty-first pixel E21 and the ground is R _S + R _P. In addition, the resistance between the thirty-first pixel E31 and the ground is R _S + 2R _P , and the resistance between the forty-first pixel E41 and the ground is R _S + 3R _P. In addition, the resistance between the 51 st pixel E31 and the ground is R _S + 4R _P , and the resistance between the 61 st pixel E61 and the ground is R _S + 5R _P.

Here, it is assumed that data currents I11 to I61 of the same magnitude are provided to the data lines D1 to D6 to emit the pixels E11 to E61 at the same luminance. In this case, the data currents I11 to I61 pass through the pixels E11 to E61 and the first scan line S1 and then flow to ground. Accordingly, the cathode voltages VC11 to VC61 of the pixels E11 to E61 have the same magnitude of the data currents I11 to I61, so that the corresponding resistances, that is, the resistances between the pixels E11 to E61 and the ground, are the same. It has a size proportional to Therefore, the 61st cathode voltage VC61, the 51st cathode voltage VC51, the 41st cathode voltage VC41, the 31st cathode voltage VC31, the 21st cathode voltage VC21, and the 11th cathode voltage VC11 in order. As its size is large.

Referring to FIG. 4B, the resistance between the twelfth pixel E12 and the ground is R _S + 5R _P , which is larger than the resistance between the eleventh pixel E11 and the ground. Here, the data current flowing in the first data line D1 when the first scan line S1 is connected to the ground and the data flowing in the first data line D1 when the second scan line S2 is connected to the ground Assume that the magnitude of the current is the same. In this case, since the cathode voltages VC11 and VC12 of the pixels E11 and E12 have a magnitude proportional to the corresponding resistance, the twelfth cathode voltage VC12 is greater than the eleventh cathode voltage VC11.

Hereinafter, the light emitting device driving process will be described in detail.

The discharge unit 308 discharges the data lines D1 to D6.

Hereinafter, a process of discharging the data lines D1 to D6 will be described in detail. However, the scan lines S1 to S4 are connected to the non-light emitting source having the voltage V2 during the first discharge time dcha1, and the first scan line S1 is connected to the ground during the first light emission time t1. .

As a first example, the switches SW1, SW2, SW3, SW4, SW5, SW6, and SW8 are turned on during the first sub discharge time of the first discharge time dcha1.

Subsequently, the discharge unit 308 provides the first output voltage corresponding to the second voltage V _L to the data lines D1 to D6, so that the data lines D1 to D6 are connected to the first output voltage. Is discharged to a first discharge level corresponding to.

Subsequently, the switches SW1 to SW6 remain on, the switch SW8 is turned off, and the switch SW7 is turned on during the second sub discharge time of the first discharge time dcha1. .

Subsequently, the discharge unit 308 provides a second output voltage corresponding to the first voltage V _H to the data lines D1 to D6. However, in this case, the switches SW1 to SW6 are sequentially turned off in the direction of the first data line D1 to the sixth data line D6 in units of N (an integer greater than or equal to 1, preferably 1). . For example, when N is 1, the switch is sequentially turned off from the first switch SW1 to the sixth switch SW6. Accordingly, the data lines D1 to D6 are discharged to discharge levels having a slope as shown in FIG. 3B, that is, to discharge levels corresponding to the cathode voltages of the pixels E11 to E61.

According to an exemplary embodiment of the present invention, the discharge unit 308 corresponds to the second voltage V _L such that the data lines D1 to D6 are discharged at discharge levels having a slope as shown in FIG. 3B. The second current corresponding to the first current and the first voltage V _H is provided to the data lines D1 to D6 in the same manner as described above.

As a second example, the switches SW1, SW2, SW3, SW4, SW5, SW6, and SW7 are turned on during the first sub discharge time of the first discharge time dcha1.

Subsequently, the discharge unit 308 provides a second output voltage corresponding to the first voltage V _H to the data lines D1 to D6, so that the data lines D1 to D6 are connected to the second output voltage. Is discharged to a second discharge level corresponding to.

Subsequently, the switches SW1 to SW6 remain on, the switch SW7 is turned off, and the switch SW8 is turned on during the second sub discharge time of the first discharge time dcha1. .

Subsequently, the discharge unit 308 provides the first output voltage corresponding to the second voltage V _L to the data lines D1 to D6. However, in this case, the switches SW1 to SW6 are sequentially turned off in the direction from the sixth data line D6 to the first data line D1 in units of N (an integer greater than or equal to 1, preferably 1). . For example, when N is 1, the switch is sequentially turned off from the sixth switch SW6 to the first switch SW1. Accordingly, the data lines D1 to D6 are discharged to discharge levels having a slope as shown in FIG. 3B, that is, to discharge levels corresponding to the cathode voltages of the pixels E11 to E61. However, in the above case, since the sixty-first cathode voltage VC61 is greater than the eleventh cathode voltage VC11, the second discharge level is greater than the first discharge level.

Hereinafter, it is assumed that the 61st pixel E61 and the eleventh pixel E11 are preset to emit light with the same luminance. That is, data currents I11 and I61 having the same magnitude are provided to the first data line D1 and the sixth data line D6 during the first emission time t1.

In this case, since the sixty-first cathode voltage VC61 is greater than the eleventh cathode voltage VC11, the sixth data line D6 is connected to the first data line D during the first discharge time dcha1 as shown in FIG. 4D. The discharge is discharged to a discharge level larger than D1), so the sixth data line D6 is precharged to a precharge voltage larger than the first data line D1.

Subsequently, the first scan line S1 is connected to ground, and the remaining scan lines S2 to S4 are connected to the non-light emitting source. Thereafter, data currents I11 and I61 of the same magnitude corresponding to the first display data are respectively provided to the first data line D1 and the sixth data line D6. In this case, since the pixels E11 to E61 are preset to emit light with the same luminance, the anode voltages VA11 and VA61 of the pixels E11 and E61 are corresponding cathode voltages VC11 and VC61 from the precharge voltage. And rises up to voltages having a predetermined level difference and then stabilizes. This is because the pixel emits light with luminance corresponding to the difference between its anode voltage and its cathode voltage. For example, if the cathode voltage VC11 of the pixel E11 is 1V and the cathode voltage VC61 of the pixel E61 is 2V, the pixel E61 when the anode voltage VA11 of the pixel E11 is stabilized to 6V. Anode voltage VA61 is stabilized to 7V. In this case, since the data line D6 is precharged to a higher precharge voltage than the data line D1, the anode voltage VA11 of the pixel E11 rises from the first precharge voltage, for example, from 3V to 6V. It is stabilized, and the anode voltage VA61 of the pixel E61 is stabilized after rising from a second precharge voltage higher than the first precharge voltage, for example, 4V to 7V. That is, the anode voltages VA11 and VA61 of the pixels E11 and E61 are stabilized after rising by the same rising width, that is, 3V, as shown in FIG. 4D. Therefore, the amount of charge consumed until the anode voltage VA61 of the pixel E61 is stabilized is substantially the same as the amount of charge consumed until the anode voltage VA11 of the pixel E11 is stabilized. Therefore, when the pixels E11 and E61 are preset to emit light with the same brightness, the pixel E61 has the same brightness VA61-VC61 as the brightness VA11-VC11 of the pixel E11. Therefore, the pixels E11 and E61 emit light with the same brightness.

Hereinafter, the light emitting device driving process will be described in detail.

The discharge unit 308 discharges the data lines D1 to D6 during the second discharge time dcha2.

Hereinafter, the discharge process will be described in detail.

As a first example, the switches SW1, SW2, SW3, SW4, SW5, SW6, and SW8 are turned on during the first sub discharge time of the second discharge time dcha2.

Subsequently, the discharge unit 308 provides a first output voltage corresponding to the second voltage V _L to the data lines D1 to D6, and the data lines D1 to D6 are connected to the first output voltage. Discharged to a corresponding first discharge level.

Subsequently, during the second sub discharge time of the discharge time, the switches SW1 to SW6 remain on, the switch SW8 is turned off, and the switch SW7 is turned on.

Subsequently, the discharge unit 308 provides a second output voltage corresponding to the first voltage V _H to the data lines D1 to D6. However, in this case, the switches SW1 to SW6 are turned off in the direction from the sixth data line D6 to the first data line D1 in units of N (an integer greater than or equal to 1, preferably 1). That is, when N is 1, the switch is sequentially turned off from the sixth switch SW6 to the first switch SW1. Thus, the data lines D1 to D6 are discharged at discharge levels between the first discharge level and the second discharge level. However, the discharge levels become larger toward the data line D1.

As a second example, the switches SW1, SW2, SW3, SW4, SW5, SW6, and SW7 are turned on during the first sub discharge time of the second discharge time dcha2.

Subsequently, the discharge unit 308 provides a second output voltage corresponding to the first voltage V _H to the data lines D1 to D6, and the data lines D1 to D6 are connected to the second output voltage. Discharged to a corresponding second discharge level.

Subsequently, during the second sub discharge time of the second discharge time dcha2, the switches SW1 to SW6 remain on, the switch SW7 is turned off, and the switch SW8 is turned on. .

Subsequently, the discharge unit 308 provides the first output voltage corresponding to the second voltage V _L to the data lines D1 to D6. However, in this case, the switches SW1 to SW6 are sequentially turned off in a direction from the first data line D1 to the sixth data line D6 in units of N (an integer greater than or equal to 1, preferably 1). . For example, when N is 1, the switch is sequentially turned off from the first switch SW1 to the sixth switch SW6. Thus, the data lines D1 to D6 are discharged at discharge levels between the first discharge level and the second discharge level. However, the discharge levels become larger toward the data line D1.

In other words, each of the data lines D1 to D6 is discharged to a discharge level corresponding to the cathode voltage of the corresponding pixels E12 to E62.

Hereinafter, discharge levels corresponding to the eleventh pixel E11 and the twelfth pixel E12 will be compared.

Since the cathode voltage VC12 of the twelfth pixel E12 is greater than the cathode voltage VC11 of the eleventh pixel E11, the first data line D1 has a first discharge time dcha1 as shown in FIG. 4C. Is discharged at a higher discharge level during the second discharge time dcha2.

Subsequently, a precharge current corresponding to the second display data is provided to the data lines D1 to D6. Here, the second display data is data input after the first display data is input to the controller 302.

Subsequently, a second scan line S2 is connected to the ground, and the remaining scan lines S1, S3, and S4 are connected to the non-light emitting source.

Subsequently, data currents I12 to I62 corresponding to the second display data are provided to the data lines D1 to D6.

In this case, although the cathode voltage VC12 of the pixel E12 is greater than the cathode voltage VC11 of the pixel E11, the precharge voltage corresponding to the pixel E12 corresponds to the precharge corresponding to the pixel E11. Since the voltage is larger than the voltage, the amount of charge consumed until the anode voltage VA12 of the pixel E12 is stabilized is substantially the same as the amount of charge consumed until the anode voltage VA11 of the pixel E11 is stabilized, as shown in FIG. 4C. Do. Therefore, when the pixel E12 and the pixel E11 are preset to emit light with the same luminance, the pixel E12 may obtain luminances VA12-VC12 having substantially the same magnitude as the luminance VA11-VC11 of the pixel E11. Glow with

That is, in the light emitting element driving method of the present invention, unlike the conventional light emitting element driving method, the discharge voltage and the precharge voltage of the data line are changed according to the cathode voltage of the pixel. Thus, when pixels are preset to emit light with the same brightness, the pixels emit light with the same brightness regardless of their cathode voltages.

That is, the cross-talk phenomenon and the comb-tooth pattern do not occur in the panel 300 included in the light emitting device of the present invention.

5 is a block diagram illustrating a light emitting device according to a second exemplary embodiment of the present invention.

Referring to FIG. 5, the light emitting device of the present invention includes a panel 500, a controller 502, a first scan driver 504, a second scan driver 506, a discharge unit 508, and a precharge unit 510. And a data driver 512.

Since the remaining components except for the discharge unit 508 are the same as those of the first embodiment, the description thereof will be omitted.

The discharge unit 508 includes a sub discharge unit 520, a switching unit 522, and a discharge level unit 524.

The discharge level unit 524 includes a plurality of switches SW1 to SW12.

The sub discharge unit 520 provides a current to the data lines D1 to D6.

The switching unit 522 includes switches SW15 and SW16.

Hereinafter, the operation of the discharge unit 508 according to the discharge process will be described in detail.

First, when the input terminal of the operational amplifier is connected to the first voltage source having the first voltage V _H , the switch SW15 and the switches SW1, SW3, SW5, SW7, SW9 and SW11 are turned on, and the rest The switches SW2, SW4, SW6, SW8, SW10, SW12 and SW16 are turned off. In this case, the resistors R _D1 between the data lines D1 to D6 have first resistance values.

On the other hand, when the input terminal of the op amp is connected to a second voltage source having a second voltage V _L , the switches SW2, SW4, SW6, SW8, SW10, SW12 and SW16 are turned on and the switches (SW1, SW3, SW5, SW7, SW9, SW11, and SW15) are turned off. In this case, the resistors R _D2 between the data lines D1 to D6 have second resistance values different from the first resistance values. Preferably, the second resistance value is greater than the first resistance value. This is to ensure sufficient time for the discharge levels corresponding to the data lines D1 to D6 to have a constant slope as shown in FIG. 3B.

Since the discharging process is similar to the discharging process of the first embodiment, the following description is omitted.

6 is a block diagram showing a light emitting device according to a third embodiment of the present invention.

Referring to FIG. 6, the light emitting device of the present invention includes a panel 600, a controller 602, a first scan driver 604, a second scan driver 606, a discharge unit 608, and a precharge unit 610. And a data driver 612.

Since the remaining components except for the discharge unit 608 perform the same functions as the components of the first embodiment, a description thereof will be omitted.

The discharge unit 608 includes a first sub discharge unit 620, a second sub discharge unit 622, and a discharge level unit 624.

The first sub discharge unit 620 discharges the data lines D1 to D6 equally to a predetermined discharge voltage. For example, as illustrated in FIG. 6, the first sub discharge unit 620 discharges the data lines D1 to D6 to the zener voltage of the zener diode ZD using the zener diode ZD.

Since the second sub-discharge unit 622 and the discharge level unit 624 are the same as the components of the first embodiment, a description thereof will be omitted.

Hereinafter, the light emitting device of the first embodiment and the light emitting device of the third embodiment will be compared.

In the first embodiment, the light emitting device compensates for the cathode voltages VC11 to VC64 of the pixels E11 to E64 using only the current output from the op amp, so that the power consumption of the light emitting device is large. However, in the third embodiment, the light emitting device discharges the data lines D1 to D6 to a predetermined discharge voltage by using the zener diode ZD, and then compensates the cathode voltages VC11 to VC64 using the op amp. Therefore, the light emitting element of the third embodiment has lower power consumption than the light emitting element of the first embodiment.

7 is a block diagram illustrating a light emitting device according to a fourth exemplary embodiment of the present invention.

Referring to FIG. 7, the light emitting device of the present invention includes a panel 700, a controller 702, a scan driver 704, a discharge unit 706, a precharge unit 708, and a data driver 710.

Since the components of the light emitting device perform functions similar to those of the first embodiment, a description thereof will be omitted.

In the light emitting device of the fourth embodiment, the scan driver 704 is formed in one direction of the panel 700 as shown in FIG. 7, unlike in other embodiments in which the scan drivers are formed in both directions.

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

As described above, the light emitting device according to the present invention and the method of driving the same discharge the data lines at a discharge level corresponding to the cathode voltage of the corresponding pixel, so that no cross-talk phenomenon and the comb pattern are not generated in the light emitting device. There is an advantage.

Claims (23)

Data lines arranged in a first direction; Scan lines arranged in a second direction different from the first direction; A plurality of pixels formed in regions where the data lines and the scan lines cross each other; And A discharge unit configured to discharge at least one data line to a first discharge level during a first sub discharge time during a discharge time, and to change the first discharge level to the second discharge level during a second sub discharge time during the discharge time; But And the second discharge level is different from the first discharge level. The light emitting device of claim 1, wherein the second discharge level is set according to a cathode voltage of a pixel corresponding to the data line. The method of claim 1, wherein the discharge unit, Providing a first output voltage corresponding to the first discharge level to the data line during the first sub discharge time, and a second output voltage corresponding to the second discharge level to the data line during the second sub discharge time Sub discharge unit for providing; And And a discharge level unit for switching a connection between the data line and the sub discharge unit. The method of claim 3, wherein the sub discharge unit comprises an op amp, And the input terminal of the operational amplifier is connected to a first voltage source having a first voltage or a second voltage source having a second voltage different from the first voltage. The method of claim 1, wherein the discharge unit, Providing a first output voltage corresponding to the first discharge level to the data lines during the first sub discharge time, and a second corresponding to the second discharge level to the data lines during the second sub discharge time. A sub discharge unit providing an output voltage; And And a discharge level unit having a plurality of switches for respectively switching the connection of the data lines and the sub discharge unit. The method of claim 5, wherein the switches connect the data lines and the sub discharge unit during the first sub discharge time, and are sequentially turned off in units of N (an integer of 1 or more) during the second sub discharge time. Light emitting element, characterized in that. 7. The method of claim 6, wherein the cathode voltage of the pixel corresponding to the first outermost data line of the data lines is greater than the cathode voltage of the pixel corresponding to the second outermost data line and the first discharge level is the second discharge. And when the level is smaller than the level, the switches are sequentially turned off in units of N from the second outermost data line toward the first outermost data line during the second sub discharge time. 7. The method of claim 6, wherein the cathode voltage of the pixel corresponding to the first outermost data line of the data lines is greater than the cathode voltage of the pixel corresponding to the second outermost data line and the first discharge level is the second discharge. And the switches are sequentially turned off in units of N in the direction from the first outermost data line to the second outermost data line during the second sub discharge time. The method of claim 5, wherein the sub discharge unit comprises an op amp, And the input terminal of the operational amplifier is connected to a first voltage source having a first voltage or a second voltage source having a second voltage different from the first voltage. The method of claim 1, wherein the discharge unit, Providing a first output voltage corresponding to the first discharge level to the data lines during the first sub discharge time, and a second corresponding to the second discharge level to the data lines during the second sub discharge time. A sub discharge unit providing an output voltage; And A plurality of first switches connecting the data lines and the sub discharge unit during the first sub discharge time and a plurality of second switches connecting the data lines and the sub discharge unit during the second sub discharge time; A light emitting device comprising a discharge level portion. The method of claim 10, wherein the resistances between the data lines have first resistance values when the first switches connect the sub discharge part and the data lines, and the second switches have the first resistance values. And the resistances between the data lines when connecting the lines have second resistance values different from the first resistance value. The light emitting device of claim 11, wherein the second resistance value is greater than the first resistance value. The method of claim 1, wherein the discharge unit, A first sub discharge unit configured to discharge the data line to a predetermined discharge level; And Providing a first output voltage corresponding to the first discharge level to the data line during the first sub discharge time, and a second output voltage corresponding to the second discharge level to the data line during the second sub discharge time Light emitting device comprising a second sub discharge unit for providing a. The method of claim 13, wherein the first sub discharge unit, A Zener diode connected to the data line, The second sub discharge unit, And an op amp whose input terminal is connected to a first voltage source having a first voltage or a second voltage source having a second voltage different from the first voltage. The method of claim 1, wherein the light emitting element, A scan driver to transmit scan signals to the scan lines; And And a data driver for transmitting data signals to the data lines. The method of claim 1, wherein the light emitting element, A first scan driver to transmit first scan signals to some of the scan lines; A second scan driver to transmit second scan signals to the remaining scan lines; And And a data driver for transmitting data signals to the data lines. The light emitting device of claim 1, wherein the light emitting device is an organic electroluminescent device. Data lines arranged in a first direction; Scan lines arranged in a second direction different from the first direction; A plurality of pixels formed in regions where the data lines and the scan lines cross each other; And Providing a first output voltage to the data lines during a first sub discharge time during a discharge time to discharge the data lines to first discharge levels, and supplying the data lines to a second sub discharge time during the discharge time. A discharge unit configured to provide a second output voltage to discharge the data lines to second discharge levels, And the first discharge levels have the same magnitude, and the second discharge levels have a magnitude corresponding to the cathode voltage of the corresponding pixel, respectively. The method of claim 18, wherein the discharge unit, A first sub discharge unit configured to discharge the data line to a predetermined discharge level; And And a second sub discharge unit configured to provide the first output voltage to the data lines during the first sub discharge time, and to provide the second output voltage to the data lines during the second sub discharge time. An organic electroluminescent element. A method of driving a light emitting device including a plurality of pixels formed in light emitting regions where data lines and scan lines cross each other, Discharging said data line to a first discharge level by providing a first output voltage to at least one data line during a first sub discharge time of a discharge time; And Providing a second output voltage to the data line during a second sub discharge time of the discharge time to change the data line from the first discharge level to a second discharge level, And the second discharge level is different from the first discharge level. 21. The method of claim 20, wherein the second discharge level has a level corresponding to a cathode voltage of a corresponding pixel. The method of claim 20, wherein the light emitting device driving method, And discharging the data line to a predetermined discharge level using a zener diode. The method of claim 20, wherein the light emitting device driving method, Providing scan signals to the scan lines; And And providing data currents to the data lines in synchronization with the scan signals.

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