KR100752340B1 - Light-emitting device and method of driving the same - Google Patents

Abstract

The present invention relates to a light emitting device that does not generate a cross-talk phenomenon. The light emitting device 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 includes at least one discharge auxiliary element, and discharges the at least one data line to a discharge voltage corresponding to the cathode voltage of the corresponding pixel. Here, the discharge assistance element controls a discharge rate for discharging the data line to the discharge voltage. In the light emitting device, since the discharge voltages change according to the cathode voltages, no cross-talk phenomenon occurs.

Cross-talk phenomenon, light emitting element, cathode voltage

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.

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

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

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

5 is a circuit diagram showing a light emitting device according to a second preferred embodiment of the present invention.

6 is a block diagram showing a light emitting device according to a third 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) 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, the 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 data. The drive unit 112 is included.

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 control unit 102 receives display data from an external device and uses the received display data to control the scan driving units 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 D4 through the switches SW1 to SW4. Referring to the discharge operation, the discharge unit 108 turns on the switches SW1 to SW4 during discharge, so that the data lines D1 to D4 are connected to the zener diode ZD. As a result, the data lines D1 to D4 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 D4 under the control of the controller 102.

The data driver 112 provides data signals corresponding to the display data, that is, data current, to the precharged data lines D1 to D4 under the control of the controller 102. As a result, the pixels E11 to E44 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 VC44.

The cathode voltages VC11 to VC41 of the pixels E11 to E41 corresponding to the first scan line S1 will be described as an example of the cathode voltages VC11 to VC44 for convenience of description.

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.

Here, it is assumed that data currents I11 to I41 of the same magnitude are provided to the data lines D1 to D4 in order to emit the pixels E11 to E41 at the same luminance. In this case, the data currents I11 to I41 flow to the ground after passing through the pixels E11 to E41 and the first scan line S1. Accordingly, the cathode voltages VC11 to VC41 of the pixels E11 to E41 have the same magnitude of the data currents I11 to I41, so that the corresponding resistances, that is, the resistances between the pixels E11 to E41 and the ground, are the same. It has a size proportional to Therefore, the magnitude thereof is large in order of the forty-first cathode voltage VC41, the thirty-first cathode voltage VC31, the twenty-first cathode voltage VC21, and the eleventh cathode voltage VC11.

Referring to FIG. 2B, the resistance between the twelfth pixel E12 and the ground is R _S + 3R _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 SW4 included in the discharge unit 108 are turned on, so that the data lines D1 to D4 discharge to a predetermined discharge voltage during the first discharge time dcha1. do. In this case, the scan lines S1 to S4 are connected to a non-light emitting source having a voltage V2 of the same size as a voltage corresponding to a driving voltage of the light emitting element, for example, the maximum luminance of the data current.

Then, after the switches SW1 to SW4 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 D4.

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, I21, I31 and I41 corresponding to the first display data are provided to the data lines D1 to D4. As a result, the pixels E11 to E41 emit light for the first emission time t1.

Hereinafter, it is assumed that the forty-first pixel E41 and the eleventh pixel E11 are preset to emit light with the same luminance. That is, data currents I11 and I41 having the same magnitude are provided to the first data line D1 and the fourth data line D4 during the first emission time t1.

First, during discharge, the data lines D1 and D4 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 D4 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 I41 of the same magnitude are provided to the first data line D1 and the fourth data line D4, respectively. In this case, since the pixels E11 to E41 are preset to emit light with the same luminance, the anode voltages VA11 and VA41 of the pixels E11 and E41 are corresponding cathode voltages VC11 and VC41 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, when the cathode voltage VC11 of the pixel E11 is 1V and the cathode voltage VC41 of the pixel E41 is 2V, the pixel E41 when the anode voltage VA11 of the pixel E11 is stabilized to 6V. Anode voltage VA41 is stabilized to 7V. In this case, since the data lines D1 and D4 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 E41 is The voltage VA41 rises from 3V to 7V and then stabilizes. Therefore, the amount of charge consumed until the anode voltage VA41 of the pixel E41 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 E41 are preset to emit light with the same brightness, pixel E41 emits light darker than pixel E11.

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

Scan lines S1 to S4 are connected to the non-light emitting source, and switches SW1 to SW4 are turned on. As a result, the data lines D1 to D4 are discharged to a predetermined discharge voltage during the second discharge time dcha2 as shown in FIG. 2C.

Subsequently, after the switches SW1 to SW4 are turned off, a precharge current corresponding to the second display data is provided to the data lines D1 to D4. 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 as shown in FIG. 2B, and the remaining scan lines S1, S3 and S4 are connected to the non-light emitting source.

Subsequently, data currents I12, I22, I32 and I42 corresponding to the second display data are provided to the data lines D1 to D4, so that the pixels E12 to E42 are provided at the second emission time t2. Flashes.

Hereinafter, it is assumed that the eleventh pixel E11 and the twelfth pixel E12 are designed to emit light with the same luminance. That is, the data currents I11 and I12 having the same magnitude are provided to the eleventh pixel E11 and the twelfth pixel E12.

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.

An object of the present invention is to provide a light emitting device that does not generate a cross-talk phenomenon and a method of constructing 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 includes at least one discharge auxiliary element, and discharges the at least one data line to a discharge voltage corresponding to the cathode voltage of the corresponding pixel. Here, the discharge assistance element controls a discharge rate for discharging the data line to the discharge voltage.

According to a preferred 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 include a first outermost one of the outermost data lines of the data lines. Providing a first voltage to an outer data line; And providing a second voltage to a second outermost data line of the outermost data lines. Here, at least one data line is discharged to a discharge voltage corresponding to the cathode voltage of the corresponding pixel according to the provided voltages, and the discharge rate during the discharge is controlled by a discharge auxiliary device connected to the data line.

According to another exemplary 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 include a first data line corresponding to a first pixel. Discharging for a discharging time; Discharging a second data line corresponding to the second pixel for a second discharge time; Providing a first data current to the discharged first data line; And providing a second data current to the discharged second data line. Here, the magnitude between the voltage at the end point of the first discharge time in the change waveform of the voltage of the first data line and the voltage at the end point of the second discharge time in the change waveform of the voltage of the second data line. The difference corresponds to the magnitude difference of the cathode voltages of the pixels, the at least one cathode voltage having a value corresponding to the resistance of the corresponding scan line, and the discharge rate during discharge is controlled.

In the light emitting device and the method of driving the same according to the present invention, since the discharge voltages change according to the cathode voltages, no cross-talk phenomenon occurs.

In addition, in the light emitting device and the method of driving the same according to the present invention, since the scan line resistance is increased, power consumption may be reduced.

Hereinafter, exemplary embodiments of a light emitting device and a method of driving the same according to the present invention will be described in detail with reference to the accompanying drawings.

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

Referring to FIG. 3, 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 E44 formed in emission areas where the data lines D1 to D4 and the scan lines S1 to S4 cross each other.

When the light emitting device is the organic electroluminescent device, each of the pixels E11 to E44 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 outside, and scan scan units 304 and 306, a discharge unit 308, and a precharge unit using the received display data. The operation of the 310 and the data driver 312 is controlled. In addition, the controller 302 may store the received display data in an external memory or an internal thereof.

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 having a low scan driving voltage, preferably to ground. Hereinafter, the light emitting source is assumed to be grounded.

The discharge unit 308 discharges at least one data line to a discharge voltage corresponding to the cathode voltage of the pixel, and preferably, the data lines D1 to D4 are connected to the cathode voltages of the pixels E11 to E44. Discharge up to the corresponding discharge voltages. Here, the cathode voltages are values corresponding to the resistance of the scan line corresponding to the corresponding pixels (hereinafter referred to as "scan line resistance") if the magnitudes of the data currents provided to the data lines D1 to D4 are the same. Have

The discharge unit 308 includes a first sub discharge unit 320, a second sub discharge unit 322, and a discharge auxiliary unit 324.

As illustrated in FIG. 3, the first sub-discharge unit 320 is connected to the first outermost data line D1 of the outermost data lines D1 and D4 of the data lines D1 to D4 and discharged. The first voltage is provided to the first outermost data line D1.

The second sub discharge part 322 is connected to the second outermost data line D4 among the outermost data lines D1 and D4 and provides a second voltage to the second outermost data line D4.

According to an embodiment of the present invention, the second voltage has a different magnitude from the first voltage.

The discharge assistant 324 promotes discharge. Detailed descriptions of the sub discharge parts 320 and 322 and the discharge assistant part 324 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 D4 under the control of the controller 302.

The data driver 312 provides data signals corresponding to the display data, that is, data current, to the precharged data lines D1 to D4 under the control of the controller 302. As a result, the pixels E11 to E44 emit light.

Hereinafter, the light emitting device driving process of the present invention will be described in detail. However, it is assumed that a plurality of display data are sequentially input to the controller 302.

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, a first data current corresponding to the first display data is provided to the data lines D1 to D4. In this case, the first data current passes through the data lines D1 to D4 and the corresponding pixels E11 to E41 and then flows to the ground through the first scan line S1. As a result, the pixels E11 to E41 corresponding to the first scan line S1 emit light.

Subsequently, the data lines D1 to D4 are discharged to discharge voltages corresponding to the cathode voltages of the pixels E11 to E41 during the discharge time.

Subsequently, the data lines D1 to D4 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, a second data current corresponding to the second display data is provided to the data lines D1 to D4. As a result, the pixels E12 to E42 corresponding to the second scan line S2 emit light.

Subsequently, the data lines D1 to D4 are discharged during the 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. 3, and FIGS. 4C and 4D are timing diagrams illustrating a driving process of the light emitting device.

Referring to FIG. 4A, the first sub discharge unit 320 may include a first switch SW1, a first digital-analog converter 402 (first DAC), and a first OP Amp. , 404).

The second sub discharge unit 322 includes a second switch SW2, a second DAC 408, and a second op amp 410.

The discharge assistant 324 includes at least one discharge assistant, for example, a third op amp, connected to the data line. Preferably, the third op amps are connected to the data lines D1 to D4, respectively.

Hereinafter, the driving process of the light emitting device will be described in detail with reference to the cathode voltages VC11 to VC44.

The sizes of the cathode voltages VC11 to VC41 of the pixels E11 to E44 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, that is, the scan line resistance is the scan resistance R _S , and the scan line resistance between the twenty-first pixel E21 and the ground is R _S + R _P. In addition, the scan line resistance between the thirty-first pixel E31 and the ground is R _S + 2R _P , and the scan line resistance between the forty-first pixel E41 and the ground is R _S + 3R _P.

Here, it is assumed that data currents I11 to I41 of the same magnitude are provided to the data lines D1 to D4 in order to emit the pixels E11 to E41 at the same luminance. In this case, the data currents I11 to I41 flow to the ground after passing through the pixels E11 to E41 and the first scan line S1. Accordingly, the cathode voltages VC11 to VC41 of the pixels E11 to E41 have the same magnitude of the data currents I11 to I41, so that the corresponding resistances, that is, the resistances between the pixels E11 to E41 and the ground, are the same. It has a size proportional to Therefore, the magnitude thereof is large in order of the forty-first cathode voltage VC41, the thirty-first cathode voltage VC31, the twenty-first cathode voltage VC21, and the eleventh cathode voltage VC11.

Referring to FIG. 4B, the resistance between the twelfth pixel E12 and the ground is R _S + 3R _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 D4.

Hereinafter, a process of discharging the data lines D1 to D4 will be described in detail.

The switches SW1 to SW5 are turned on, and the scan lines S1 to S4 are connected to the non-light emitting source. Therefore, the pixels E11 to E44 do not emit light.

Subsequently, the first DAC 402 outputs a first level voltage according to the first external voltage V3 input from the outside, and the output first level voltage is input to the first op amp 404. In addition, the second DAC 408 outputs a second level voltage according to the second external voltage V4 input from the outside, and the output second level voltage is input to the second op amp 410.

Subsequently, the first op amp 404 provides a first op amp output voltage to the first outermost data line D1 according to the input first level voltage, so that the first outermost data line D1 is provided. Has a first voltage. In addition, the second op amp 410 provides a second op amp output voltage to the second outermost data line D4 according to the input second level voltage, so that the second outermost data line D4 is Has a second voltage. Here, according to one embodiment of the present invention, the second voltage has a different magnitude from the first voltage. In the above case, since the forty-first cathode voltage VC41 is greater than the eleventh cathode voltage VC11, the second voltage is greater than the first voltage.

As such, when the first outermost data line D1 has the first voltage and the second outermost data line D4 has the second voltage, the data lines D1 to D4 are resistors R _d . Have voltages of sequential magnitude depending on the voltage distribution by. That is, the data lines D1 to D4 are discharged to different discharge levels during discharge. Preferably, the data lines D1 to D4 are discharged at discharge levels corresponding to the cathode voltages of the corresponding pixels.

According to another preferred embodiment of the present invention, the op amps 404 and 410 can respectively output predetermined currents such that the data lines D1 to D4 are discharged at discharge levels corresponding to the cathode voltages of the corresponding pixels. have.

Hereinafter, it is assumed that the forty-first pixel E41 and the eleventh pixel E11 are preset to emit light with the same luminance. That is, data currents I11 and I41 having the same magnitude are provided to the first data line D1 and the fourth data line D4 during the first emission time t1.

In this case, since the forty-first cathode voltage VC41 is greater than the eleventh cathode voltage VC11, the fourth data line D4 is the first data line D during the first discharge time dcha1 as shown in FIG. 4D. Discharge up to a discharge voltage greater than In this case, the light emitting device of the present invention improves the discharge rate by using the third op amps as described below.

Subsequently, the data lines D1 to D4 are precharged during the first precharge time pcha1. In this case, since the fourth data line D4 is discharged to a discharge voltage larger than the first data line D1, the fourth data line D4 is precharged to a precharge voltage larger than the first data line D1. do.

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 I41 of the same magnitude corresponding to the first display data are respectively provided to the first data line D1 and the fourth data line D4. In this case, since the pixels E11 to E41 are preset to emit light with the same luminance, the anode voltages VA11 and VA41 of the pixels E11 and E41 are corresponding cathode voltages VC11 and VC41 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, when the cathode voltage VC11 of the pixel E11 is 1V and the cathode voltage VC41 of the pixel E41 is 2V, the pixel E41 when the anode voltage VA11 of the pixel E11 is stabilized to 6V. Anode voltage VA41 is stabilized to 7V. In this case, since the data line D4 is precharged to a precharge voltage higher 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 VA41 of the pixel E41 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 VA41 of the pixels E11 and E41 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 VA41 of the pixel E41 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 E41 are preset to emit light with the same luminance, the pixel E41 has the same luminance VA41-VC41 as the luminance VA11-VC11 of the pixel E11. Thus, the pixels E11 and E41 emit light with the same brightness.

Although not described above, the twenty-first pixel E21 and the thirty-first pixel E31 operate in the same manner as above. Therefore, when the eleventh to 41th pixels E11 to E41 are preset to emit light with the same brightness, the pixels E11 to E41 emit light with substantially the same brightness.

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

Subsequently, scan lines D1 to D4 are connected to the non-light emitting source, and switches SW1 to SW5 are turned on.

Subsequently, the first sub discharge unit 320 provides a third op amp output voltage to the first outermost data line D1, so that the first outermost data line D1 has a third voltage. The second sub discharge part 322 provides a fourth op amp output voltage to the second outermost data line D4, so that the second outermost data line D4 has a fourth voltage. Here, since the twelfth cathode voltage VC12 is greater than the forty-second cathode voltage VC42, the third voltage is preset to have a value greater than the fourth voltage. Thus, the data lines D1 to D4 are discharged to discharge voltages having sequential magnitudes.

Hereinafter, discharge voltages 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 may have a first discharge time as shown in FIG. 4C. It is discharged to a higher discharge voltage during the second discharge time dcha2 than dcha1).

Subsequently, a precharge current corresponding to the second display data is provided to the data lines D1 to D4. 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, I22, I32 and I42 corresponding to the second display data are provided to the data lines D1 to D4. 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. Here, the data currents I11 and I12 have the same magnitude. 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. Therefore, when pixels are preset to emit light with the same brightness, the pixels emit light with the same brightness regardless of their cathode voltages. Therefore, the cross-talk phenomenon does not occur in the panel 300 included in the light emitting device of the present invention.

Hereinafter, the role of the discharge assistant 324 will be described in detail.

The discharge assistants 324a to 324d include switches SW3 to SW6 and third op amps, which are discharge assist devices, respectively, as shown in FIGS. 4A and 4B.

The switches SW3 to SW6 are turned on upon discharging.

The third op amps provide the corresponding data lines with voltages formed according to the voltages and resistors R _d provided from the op amps 404 and 410, so that the data lines D1 to D4 are corresponding pixels. Discharged at discharge levels corresponding to their cathode voltages. That is, the third op amps may control a time at which the data lines are discharged to the discharge levels, that is, a discharge rate.

In the light emitting device according to the exemplary embodiment of the present invention, the resistance R _d (hereinafter referred to as “data line resistance”) between the data lines D1 to D4 is set to be large, and the reason for such setting is described above, for example. would.

The case where the resistance R _d between the data lines without the third op amp and the data line is 100 Ω (not shown) is compared with the case where the resistance R _d between the data lines with the third op amp is 1 kΩ. However, let the magnitude difference between the second voltage and the first voltage be 1V.

When the resistance between the data lines R _d is 100Ω, the current flowing through the line corresponding to the resistance between the data lines R _d is 1V / 100Ω = 10 mA. On the other hand, the data line between the resistor (R _d) the current flowing through the line corresponding to the data line between the case of 1kΩ resistor (R _d) is 1V / 1kΩ = 1㎃. Therefore, setting the resistance R _d between the data lines with the third op amp larger than the case where the resistance R _{d with the} data op line without the third op amp is smaller than the case where the resistance R _d is set to be smaller. Is reduced. However, as the resistance R _d between the data lines increases, the time for discharging the data lines D1 to D4 to desired discharge levels, that is, the discharge time may increase, but the light emitting device of the present invention is illustrated in FIG. 4A. As described above, the third op amps serving as buffers are used to shorten the time for discharging the data lines D1 to D4 to desired discharge levels, that is, the discharge time. Therefore, the light emitting device of the present invention can improve the discharge rate and power consumption characteristics.

In the light emitting device according to another embodiment of the present invention, the data lines D1 to D4 are discharged to a predetermined level by using a Zener diode, for example, and then to the desired discharge voltage using the op amps 404 and 410. Can be discharged. Therefore, the power consumption can be reduced in the light emitting device than in the light emitting device of the first embodiment which controls the discharge voltage level using only the current output from the op amps 404 and 410.

5 is a circuit diagram showing a light emitting device according to a second preferred embodiment of the present invention.

Referring to FIG. 5, the light emitting device of the present invention further includes at least one third sub discharge part 500 than the light emitting device of the first embodiment.

The third sub discharge unit 500 is connected to one data line except for the outermost data lines D1 and D4 among the data lines D1 to D4, and provides a predetermined voltage to the corresponding data line during discharge.

In the first embodiment, when the data currents flowing through the data lines D1 to D4 are the same, the cathode voltages corresponding to one scan line are changed to sequential magnitudes. Thus, the light emitting device compensates for the cathode voltages using the two sub discharge parts 320 and 322, so that when the data lines D1 to D4 discharge, they discharge at discharge levels corresponding to the cathode voltages of the corresponding pixels. It became. However, the cathode voltages may not be sufficiently compensated by only the two sub discharge parts 320 and 322. Thus, the light emitting device of the second embodiment further includes at least one third sub discharge unit 500 corresponding to the data lines D1 to D4 to sufficiently compensate the cathode voltages.

The third sub discharge part 500 according to an embodiment of the present invention includes a third switch SW3, a third DAC 504, and a third op amp 502. The same elements as in the embodiment are 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 scan driver 604, a discharge unit 606, a precharge unit 608, and a data driver 610. 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, unlike the other embodiments in which the scan drivers are formed in both directions, the scan driver 604 is formed in one direction of the panel 600 as shown in FIG. 6.

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, in the light emitting device and the method of driving the same according to the present invention, since the discharge voltages change according to the cathode voltages, there is an advantage that no cross-talk phenomenon occurs.

In addition, in the light emitting device and the method of driving the same according to the present invention, since the resistance R _d between the data lines is increased, the power consumption is reduced.

Claims (12)

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 having at least one discharge auxiliary element and discharging at least one data line to a discharge voltage corresponding to a cathode voltage of a corresponding pixel; And the discharge assisting element controls a discharge rate at which the data line is discharged to the discharge voltage. The method of claim 1, wherein the discharge unit, A first sub-discharge unit connected to a first outermost data line of the outermost data lines of the data lines and providing a first voltage to the first outermost data line during discharge; And And a second sub discharge part connected to a second outermost data line of the outermost data lines and providing a second voltage to the second outermost data line. The method of claim 2, wherein the discharge unit, And a third sub discharge part connected to any one of the data lines except for the outermost data lines and providing a third voltage to the data lines. The method of claim 3, wherein at least one of the sub-discharge units is An operational amplifier whose output is connected to a corresponding data line; And And a digital-to-analog converter (DAC) connected to an input of the op amp. The light emitting device of claim 2, wherein the second voltage has a different magnitude from that of the first voltage. The light emitting device of claim 1, wherein the discharge auxiliary device comprises an OP Amp. 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 configured to provide a data current 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 applying a data current to the data lines. The light emitting device of claim 1, wherein the discharge auxiliary devices are connected to the data lines, respectively. 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, Providing a first voltage to a first outermost data line of the outermost data lines of the data lines; And Providing a second voltage to a second outermost data line of the outermost data lines, At least one data line is discharged to a discharge voltage corresponding to a cathode voltage of a corresponding pixel according to the provided voltages, and the discharge rate is controlled by a discharge auxiliary device connected to the data line. Way. The method of claim 10, wherein the discharge assisting element is an operational amplifier. 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 a first data line corresponding to the first pixel for a first discharge time; Discharging a second data line corresponding to the second pixel for a second discharge time; Providing a first data current to the discharged first data line; And Providing a second data current to the discharged second data line, wherein The magnitude difference between the voltage at the end point of the first discharge time in the change waveform of the voltage of the first data line and the voltage at the end point of the second discharge time in the change waveform of the voltage of the second data line is And at least one cathode voltage has a value corresponding to a resistance of a corresponding scan line, and a discharge rate is controlled during discharge.

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