KR100646990B1 - Luminescent device and method of driving the same - Google Patents

Abstract

A light emitting element and a driving method thereof are provided to restrict cross-talk by applying precharge current from the light emitting element to data lines in consideration of cathode voltage of pixels. A light emitting element having plural pixels(E11~E44) formed in emission regions where data lines(D1~D4) and scan lines(S1~S4) cross each other includes a precharge degree control unit(406) for transmitting a precharge control signal according to display data input from the outside and a precharging unit(408) for applying precharge current corresponding to the resistance of the scan lines and the display data, to the data lines according to the precharge control signal transmitted from the precharge degree control unit. The amount of the precharge current corresponds to the sum of cathode voltage of the corresponding pixel and voltage corresponding to the display data.

Description

LIGHT EMITTING DEVICE AND METHOD FOR DRIVING THE SAME

1 is a block diagram illustrating a light emitting device according to a first exemplary embodiment.

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

2C is a timing diagram illustrating a light emission process of the pixels of FIGS. 2A and 2B.

3 is a block diagram illustrating a light emitting device according to a second exemplary embodiment.

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

5A is a circuit diagram illustrating a driving process of the light emitting device of FIG. 4 according to an exemplary embodiment of the present invention.

5B is a circuit diagram illustrating a driving process of the light emitting device of FIG. 4 according to another exemplary embodiment of the present invention.

5C is a timing diagram illustrating a light emission process of the pixels of FIGS. 5A and 5B.

6 is a circuit diagram illustrating a light emitting process of the light emitting device of FIG. 4 according to another exemplary embodiment of the present invention.

7 is a block diagram illustrating a light emitting device according to a second 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 that does not generate a cross-talk phenomenon and a method of driving the same.

1 is a block diagram illustrating a light emitting device according to a first exemplary embodiment.

Referring to FIG. 1, a conventional light emitting device includes a panel 100, a scan driver 102, a data storage 104, a precharge unit 106, and a data driver 108.

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 is formed in one direction of the panel 100 and sequentially transmits scan signals to the scan lines S1 to S4.

The data storage unit 104 stores display data input from the outside, for example, ALGBI data (RGB data), in latches included therein. Subsequently, the data storage unit 104 transmits the stored display data to the precharge unit 106 and the data driver 108.

The precharge unit 408 applies a precharge current corresponding to the display data transmitted from the data storage unit 104 to the data lines D1 to D4.

The data driver 108 applies a data current corresponding to the display data transmitted from the data storage unit 104 to the data lines D1 to D4.

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

Hereinafter, the resistance R _S between the outermost pixel and the ground is 10 Ω, the resistance R _P between the pixels is 2 Ω, and the 41st pixel E41 and the 42nd pixel E42 each have a 3A data current. Assume that it is designed to emit light with the same luminance. In addition, the eleventh, 21, and 31 pixels E11, E21, and E31 do not emit light, and the twelfth, 22, and 32 pixels E12, E22, and E32 emit light with luminance corresponding to 1A data current.

First, the light emission process of the pixels E11 to E41 corresponding to the first scan line S1 will be described in detail.

Referring to FIG. 2A, the precharge unit 106 applies a precharge current corresponding to the display data to the eleventh through 41 pixels E11 through E41. As a result, the charge corresponding to the V2 voltage (default precharge voltage) is charged to the forty-first pixel E41 during the first precharge time pcha1 as shown in FIG. 2C.

Subsequently, eleventh to 41th data currents I11 to I41 which are 0, 0, 0, and 3A, respectively, are applied to the data lines D1 to D4. In this case, the anode voltage VA41 of the forty-first pixel E41 is raised to the voltage V3 corresponding to the sum of the forty-first cathode voltage VC41 and 4V corresponding to the 3A data current for the time T1, and then the voltage V3. Stabilized. In this case, the 48-V cathode voltage VC41 is a product of the total current flowing through the first scan line S1 (sum of 0, 0, 0 and 3A) and the scan line resistance (sum of 10, 2, 2 and 2 Ω). Therefore, V3 is 52V. Therefore, the forty-first pixel E41 emits light with luminance corresponding to 4V (anode voltage VA41-forty-first cathode voltage VC41).

Referring to FIG. 2B, the precharge unit 106 applies a precharge current corresponding to the display data to the twelfth to 42th pixels E12 to E42. As a result, the charge corresponding to the V2 voltage (default precharge voltage) is charged in the 42nd pixel E42 during the second precharge time pcha2 as shown in FIG. 2C. That is, since the forty-first and forty-eighth pixels E41 and E42 are designed to emit light with the same brightness, charges corresponding to the voltage V2 are charged in the forty-first and forty-eighth pixels E41 and E42.

Subsequently, 12th to 42nd data currents I12 to I42 which are 2, 2, 2 and 3A, respectively, are applied to the data lines D1 to D4. In this case, the anode voltage VA42 of the forty-second pixel E42 is increased to a voltage V4 corresponding to the sum of the forty-second cathode voltage VC42 and 4V corresponding to 3A for the time T2 and then stabilized to V4. Here, the 96-volt voltage (VC42) is 96V, which is the product of the total current (sum of 1, 1, 1 and 3A) flowing in the second scan line S2 and the scan line resistance (sum of 10, 2, 2 and 2Ω) Therefore, V4 is 100V.

In other words, the difference between the stabilized anode voltage VA42 and the precharge voltage V2 of the 42nd pixel E42 is greater than the difference between the stabilized anode voltage VA41 and the precharge voltage V2 of the 41st pixel E42. , So T2 is greater than T1. Therefore, as shown in FIG. 2C, the amount of charge consumed while rising to the stabilized anode voltages VA42 in the 42nd pixel E42 increases to the stabilized anode voltages VA41 in the 41st pixel E41. Is greater than the amount of charge consumed during the process. Therefore, the forty-second pixel E42 emits light with a lower luminance even though it is designed to emit light with the same luminance as the forty-first pixel E41. This phenomenon is called cross-talk phenomenon.

3 is a block diagram illustrating a light emitting device according to a second exemplary embodiment.

Referring to FIG. 3, a conventional light emitting device includes a panel 300, a first scan driver 302, a second scan driver 304, a data storage 306, a precharge unit 308, and a data driver 310. ).

Since the remaining components except for the first scan driver 302 and the second scan driver 304 perform the same functions as the components of the first embodiment, a description thereof will be omitted.

The first scan driver 302 transmits first scan signals to portions S1 and S3 of the scan lines S1 to S3 in one direction of the panel 300.

The second scan driver 304 transmits the second scan signals to the remaining scan lines S2 and S4 in the other direction of the panel 300.

Even in the case of the light emitting element of the second embodiment, the time taken to rise to the stabilized anode voltages between the pixels that should emit light with the same brightness as in the light emitting element of the first embodiment is different, so that it crosses the panel 300. Torque phenomenon occurs. Since the light emission operation process of the second embodiment is similar to the light emission operation process of the first embodiment, a detailed description thereof will be omitted.

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 driving the same.

In order to achieve the above object, a light emitting 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 may include a precharge amount control unit and a precharge unit. Contains wealth. The precharge amount control unit transmits a precharge control signal according to display data input from the outside. The precharge unit applies a precharge current corresponding to the display data and the resistance of the scan lines to the data lines according to a precharge control signal transmitted from the precharge amount control unit.

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 intersect is provided. Calculating an amount of precharge current using a resistance; And applying a precharge current corresponding to the calculated amount to the data lines.

In the light emitting device and the method of driving the light emitting device according to the present invention, since the precharge current is applied to the data lines in consideration of the cathode voltages of the pixels, no cross-talk phenomenon occurs in the panel.

Hereinafter, with reference to the accompanying drawings will be described in detail preferred embodiments of the cross-talk preventing light emitting device and a method for driving the same according to the present invention.

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

Referring to FIG. 4, the light emitting device of the present invention includes a panel 400, a scan driver 402, a data storage unit 404, a precharge amount control unit 406, a precharge unit 408, and a data driver 410. It includes. Here, the light emitting device according to an embodiment of the present invention is an organic electroluminescent device.

The panel 400 includes a plurality of pixels E11 to E44 that are formed in emission areas where the data lines D1 to D4 and the scan lines S1 to S4 intersect.

The scan driver 402 is formed in one direction of the panel 400 and sequentially transmits scan signals to the scan lines S1 to S4.

The data storage unit 404 stores display data input from the outside, for example, ALGBI data (RGB data), in latches included therein. Subsequently, the data storage unit 404 transmits the stored display data to the precharge amount control unit 406 and the data driver 410.

The precharge amount control unit 406 calculates the amount of precharge current to be applied to the data lines D1 to D4 according to the display data transmitted from the data storage unit 404, and has a preload information having information on the calculated amount. The charge control signal is transmitted to the precharge unit 408.

The precharge unit 408 applies the precharge current corresponding to the calculated amount to the data lines D1 to D4 according to the precharge control signal transmitted from the precharge amount control unit 406. The precharge unit 408 according to an embodiment of the present invention includes a digital-to-analog converter (DAC), and generates a multi-level precharge current using the DAC.

A detailed description of the operations of the precharge amount control unit 406 and the precharge unit 408 will be given below with reference to the accompanying drawings.

The data driver 410 applies a data current corresponding to the display data transmitted from the data storage unit 404 to the data lines D1 to D4. As a result, the pixels E11 to E44 emit light of a predetermined wavelength.

5A is a circuit diagram illustrating a driving process of the light emitting device of FIG. 4 according to an exemplary embodiment of the present invention, and FIG. 5B is a circuit diagram illustrating a driving process of the light emitting device of FIG. 4 according to another exemplary embodiment of the present invention. to be. 5C is a timing diagram illustrating a light emission process of the pixels of FIGS. 5A and 5B.

Hereinafter, the resistance R _S between the outermost pixel and the ground is 10 Ω, the resistance R _P between the pixels is 2 Ω, and the 41st pixel E41 and the 42nd pixel E42 each have a 3A data current. Assume that it is designed to emit light with the same luminance. In addition, the eleventh, 21, and 31 pixels E11, E21, and E31 do not emit light, and the twelfth, 22, and 32 pixels E12, E22, and E32 emit light with luminance corresponding to 1A data current.

First, the light emission process of the pixels E11 to E41 corresponding to the first scan line S1 will be described in detail.

Referring to FIG. 5A, the precharge amount control unit 406 uses information about the resistors R _S and R _P stored therein and the display data transmitted from the data storage unit 404 to display the forty-first cathode voltage ( VC41) is calculated. That is, the precharge amount control unit 406 detects through the display data that the 11 th to 41 th data currents I11 to I41 are 0, 0, 0, and 3A, respectively, and the total flows through the first scan line S1. The forty-first cathode voltage (V41 = 48V) is calculated by multiplying the current (sum of 0, 0, 0 and 3A) by the scan line resistance (sum of 10, 2, 2 and 2Ω).

Subsequently, the precharge amount control unit 406 transmits a precharge control signal having the calculated information on the forty-first cathode voltage VC41 to the precharge unit 408.

Subsequently, the precharge unit 408 supplies the precharge current through the fourth data line D4 during the first precharge time pcha1 as shown in FIG. 5C according to the transmitted precharge control signal. Applied to pixel E41. As a result, a charge corresponding to the sum 49V of the forty-first cathode voltages VC41 and 48V and the default precharge voltage (for example, 1V) is charged in the forty-first pixel E41. Here, the default precharge voltage is a voltage corresponding to the precharge current when the forty-first cathode voltage VC41 is 0V and the forty-first data current is 3A.

Subsequently, the data driver 410 receives the eleventh to 41th data currents I11 to I41 corresponding to the display data transmitted from the data storage unit 404 during the low logic time of the first scan signal PS1. It is applied to (D1 to D4). As a result, the anode voltage VA41 of the forty-first pixel E41 is stabilized to 52V after T1 time from the end of the precharge as shown in FIG. 5C. Therefore, the forty-first pixel E41 emits light with luminance corresponding to 4V (52V to 48V).

Hereinafter, a light emission process of the pixels E12 to E42 corresponding to the second scan line S2 will be described in detail.

Referring to FIG. 5B, the precharge amount control unit 406 uses the information about the resistors R _S and R _P stored therein and the display data transmitted from the data storage unit 404 to display the 42nd cathode voltage ( VC42) is calculated. That is, the precharge amount control unit 406 determines through the display data that the twelfth to forty-second data currents I12 to I42 are 1, 1, 1, and 3A, respectively, and the total flows through the second scan line S2. The 42nd cathode voltage (VC41 = 96V) is calculated by multiplying the current (sum of 1, 1, 1 and 3A) by the scan line resistance (sum of 10, 2, 2 and 2Ω).

Subsequently, the precharge amount control unit 406 transmits a precharge control signal having the calculated information on the 42nd cathode voltage VC42 to the precharge unit 408.

Subsequently, the precharge unit 408 supplies the precharge current through the fourth data line D4 during the second precharge time pcha2 as shown in FIG. 5C according to the transmitted precharge control signal. Applied to the pixel E42. As a result, a charge corresponding to the sum 97V of the 42nd cathode voltages VC42 and 96V and the default precharge voltage (for example, 1V) is charged in the 42nd pixel E42. Here, the default precharge voltage is a voltage corresponding to the precharge current when the 42nd cathode voltage VC42 is 0V and the 42nd data current is 3A.

Subsequently, the data driver 410 receives the 12th to 42nd data currents I12 to I42 corresponding to the display data transmitted from the data storage unit 404 during the low logic time of the second scan signal PS2. It is applied to (D1 to D4). In order for the 42nd pixel E42 to emit light with a luminance corresponding to 4V, the 42nd cathode voltage VC42 is 96V. Therefore, as shown in FIG. 5C, the 42nd anode voltage VA42 must be increased to 100V. In this case, since the precharge voltage V4 corresponding to the forty-second pixel E42 is 97V, only 3V needs to be increased in the same manner as the forty-first pixel E41. Accordingly, the 42nd anode voltage VA42 may be stabilized to 100V after the T1 time from the end of the precharge similarly to the forty-first pixel E41.

In short, in the light emitting device of the present invention, since the forty-first pixel E41 and the forty-second pixel E42 are equally stabilized after T1 hours from the end of the precharge, they are consumed during the light emitting time dt1 and dt2 unlike in the conventional light emitting device. The amount of charge that is made is the same. Therefore, the forty-first pixel E41 and the forty-second pixel E42 emit light with the same luminance, so that the cross-talk phenomenon does not occur in the light emitting device of the present invention, unlike the conventional light emitting device.

6 is a circuit diagram illustrating a light emitting process of the light emitting device of FIG. 4 according to another exemplary embodiment of the present invention.

The precharge voltage will be generalized with reference to FIG. 6.

Although not mentioned in the first embodiment, as illustrated in FIG. 6, the pixels include pixels corresponding to red light, pixels corresponding to green light, and pixels corresponding to blue light.

The precharge voltage corresponding to red (V _{PRE - CHARGE - RED} (n)) is V _CR (n) + V _{default - PRECHARGE -RED} (D _R (n)), and the precharge voltage (V _PRE corresponding to green). _{- CHARGE -} a _GREEN (n)) is _{V CG (n) + V default} -PRECHARGE-GREEN (D G (n)). In addition, the precharge voltage V _{PRE -CHARGE-BLUE} (n) corresponding to blue is V _CB (n) + V _{default - PRECHARGE -BLUE} (D _B (n)). _{Here, V CF (n), V} CG (n) and V _CB (n) are cathode voltages corresponding to red, green and blue _{pixels, V default - PRECHARGE -RED (D} R (n)), V default - _{PRECHARGE -GREEN} (D _G (n)) and V _{default - PRECHARGE -BLUE} (D _B (n)) are precharge voltages corresponding to red, green, and blue display data when the cathode voltage is 0V.

That is, the light emitting device of the present invention applies the precharge current to the data lines D1 to D4 in consideration of the cathode voltage. The formula for obtaining the cathode voltage has been described with reference to FIGS. 5A to 5C, and thus will be omitted.

The light emitting device according to another embodiment of the present invention is a plasma display panel (PDP) and a liquid crystal display (LCD), and in these devices, the precharge current is applied to the data lines in consideration of the cathode voltage of the pixel. do.

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

Referring to FIG. 7, the light emitting device of the present invention includes a panel 700, a first scan driver 702, a second scan driver 704, a data storage unit 706, a precharge amount control unit 708, and a precar. A branch 710 and a data driver 712 are included.

The remaining components except for the first scan driver 702 and the second scan driver 704 perform the same functions as the components of the first embodiment, and thus descriptions thereof will be omitted.

The first scan driver 702 transmits first scan signals to portions S1 and S3 of the scan lines S1 to S3 in one direction of the panel 700.

The second scan driver 704 transmits the second scan signals to the remaining scan lines S2 and S4 in the other direction of the panel 700.

Also in the light emitting device of the second embodiment, the precharge current is applied to the data lines D1 to D4 during the precharge time in consideration of the cathode voltage. Since the light emitting operation of the light emitting device of the second embodiment is similar to the first embodiment, a detailed description of the light emitting operation will be omitted below.

Preferred embodiments of the invention described above are disclosed for purposes of illustration, and those skilled in the art having ordinary knowledge of the present invention will be capable of 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 light emitting device and the method of driving the light emitting device according to the present invention, since the precharge current is applied to the data lines in consideration of the cathode voltages of the pixels, there is an advantage that the cross-talk phenomenon does not occur in the panel.

Claims (8)

A light emitting device comprising a plurality of pixels formed in light emitting regions where data lines and scan lines cross each other. A precharge amount control unit which transmits a precharge control signal according to display data input from the outside; And And a precharge unit configured to apply a precharge current corresponding to the display data and the resistance of the scan lines to the data lines according to a precharge control signal transmitted from the precharge amount control unit. The light emitting device of claim 1, wherein the amount of precharge current is an amount of current corresponding to a sum of a cathode voltage of a corresponding pixel and a voltage corresponding to the display data. The method of claim 1, wherein the light emitting element, And a scan driver for transmitting scan signals to the scan lines in one direction. 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 in one direction; And And a second scan driver for transmitting second scan signals to the remaining scan lines in the other direction. The light emitting device of claim 1, wherein the precharge unit comprises a digital-to-analog converter (DAC). The light emitting device of claim 1, wherein the precharge amount control unit stores the line resistance of the scan lines and calculates the amount of the precharge current based on the line resistance and the display data. 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, Calculating an amount of precharge current using display data input from an external device and line resistances of the scan lines; And And applying a precharge current corresponding to the calculated amount to the data lines. 8. The method of claim 7, wherein the amount of precharge current is an amount of current corresponding to the sum of the cathode voltage of the pixel and the voltage corresponding to the display data.

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