KR20020031882A - driving contol circuit in light device and method of the same - Google Patents

Abstract

PURPOSE: A driving control circuit of a light emitting device and a method thereof are provided, which control to accelerate a response characteristics of the device and at the same time minimize a power loss according to the transportation of charges by reducing an influence due to a junction capacitance. CONSTITUTION: The driving control circuit comprises data lines from D1 to Dm, scan lines from S1 to Sn, a light emitting device part(15) from p(1,1) to p(m,n), a data driving circuit(1) applying data value to the data lines, a scan driving circuit(2) applying a current to the scan line sequentially, and a light emission control circuit(3) controlling the data driving circuit and the scan driving circuit. The scan driving circuit comprises a power supply VP(8) and a ground GND(14), and a number of scan driving switches(21-2n) switching a number of scan signals to the power supply voltage VP in sequence one by one and switching other ports to the ground GND. The data driving circuit comprises a power supply VD(4) and a ground GND(14), data driving switches(71-7m) to switch the constant current sources connected to the power supply voltage VD to the data lines, and a power supply VT(5) between the power VD and a ground GND. And the on/off control the scan driving switches and the data driving switches of the driving circuit are controlled by the light emission control circuit.

Description

Driving control circuit and method of the light emitting device {driving contol circuit in light device and method of the same}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device, and more particularly, to a driving control circuit and a method for controlling a light emitting device by controlling an amount of charge inside the device in a driving circuit of a light emitting device controlled by a current.

Recently, the development of the flat panel display has made a quantum leap.

In particular, light emitting device (LED) arrays are becoming increasingly popular as image sources in direct displays or virtual displays.

LEDs can generate a relatively large amount of light, which means that displays in LED arrays can be used in a variety of ambient conditions.

In addition, the application of organic LED arrays is increasing in small size products, especially portable electronic products such as portable small pagers, cellular phones and portable phones.

Organic LED arrays generate enough light for use as displays in a wide range of ambient light conditions, from low or low light levels to bright light environments.

Furthermore, organic LEDs can be manufactured relatively inexpensively and can range from very small sizes (less than 1 inch) to fairly large sizes (tens of inches).

It also provides a very wide viewing angle.

In general, the organic LED is composed of a primary electrode layer, an electron transport layer, a light emitting layer, a hole transport layer, a secondary electrode layer, the light can be emitted in both directions or in one direction of the electrode.

And the most efficient LEDs have one electrode layer that is transparent to the light emitted, and one of the most widely used transparent electrodes is indium tin oxide (ITO), which is like a glass plate. It is deposited on a transparent substrate.

At this time, the main problem of LED, especially organic LED, is the connection capacitance, which is a problem of power consumption due to large driving power and response speed.

The connection capacitance is a capacitance inside the device composed of a material and an electrode, and a capacitance by column and row electrodes of an array structure.

And what makes these two problems more serious is that the organic EL element is not driven by voltage like LCD but is driven by current.

In detail, as shown in Fig. 1, the initial current supplied when driving the organic EL element in the array structure is used to charge the connection capacitance.

Referring to FIG. 1, the power supply VD (10V) is switched and applied to a light emitting device to emit light corresponding to a sequentially changing scan signal for one frame, and the ground GND (0V) is applied to other light emitting devices.

Accordingly, as the number of arrays of light emitting elements increases or the number of devices increases, the connection capacitance increases, so that more current must be supplied to the devices to initially charge each light emitting element.

In addition, the charging time (RC time) of the capacitance is affected not only by the magnitude of the capacitance but also by the resistance connected to the capacitance, so that the response speed of the device is significantly affected by the increase in the resistance.

And since the transparent electrode layer has a high resistance material, such a problem is further increased.

Therefore, the high resistance electrode layer and the connecting capacitance of the organic LED are an obstacle to making the organic LED into a large array structure.

Therefore, the present invention has been made to solve the above problems, and the object of the present invention is to reduce the influence of the connection capacitance to quickly control the response characteristics of the device and to minimize the loss of power due to the movement of charge.

Figure 1a is a drive control circuit of a light emitting device according to the prior art

1b is a drive control timing diagram of a light emitting device according to the prior art.

2A to 5A are first drive control circuits of the light emitting device according to the present invention.

2B to 5B are first driving control timing diagrams of a light emitting device according to the present invention.

6A to 9A illustrate a second drive control circuit of the light emitting device according to the present invention.

6B to 9B are second drive control timing diagrams of the light emitting device according to the present invention.

* Explanation of symbols for main parts of the drawings

1: Data driving circuit 1 ₁ to 1 _m : Constant current source

2: scan drive circuit 2 ₁ ~ 2 _n : scan drive switch

3: light emission control circuit 4, 5, 8: power supply

6, 14: Ground 7 ₁ ~ 7 _m : Data drive switch

15: light emitting element

A characteristic of the driving control circuit of the light emitting device according to the present invention for achieving the above object is a first power source, ground, a second power source which is a value between the first power source and the ground connected to a constant current source, and the first, and A data driver configured as a first switch for switching a second power supply and a ground, a scan driver configured as a third power source, a ground, and a second switch for switching a third power source and a ground, and controlling the first switch and the second switch And a light emitting element unit having an array structure for selectively emitting light with a current applied through the first switch and the second switch.

Another feature of the invention is characterized by having a VT power supply which is a value between the VC power supply and the GND power supply connected to the constant current source on the data line side.

The driving control method of the light emitting device according to the present invention for achieving the above object is one frame by sequentially switching so that one scan line of the plurality of scan lines is connected to the ground and the other scan lines are all connected to the power source Connecting each of the plurality of scan lines to the ground for at least one scan time, and dividing the data time into a plurality of time domains during the one scan time. And selectively switching the first power supply and the ground, and connecting to a second power supply having a value between the first power supply and the ground for the other time domain.

Another feature of the invention is characterized in that a specific time domain in which the data line is connected to VC or GND via a constant current source and another time domain connected to VT, which is a value between VC and GND, can be adjusted within one scan time. .

An operation according to a feature of the invention has a plurality of power supplies on the data line side, each of which divides the time of data into a plurality of time domains, and the data line is connected to the first power supply via a constant current source or to ground during a particular time domain. In addition, during other time domains, the second power supply may be connected to a second power supply having a value between the first power supply and the ground to quickly control the response characteristics of the device and to minimize the loss of power consumption.

Other objects, features and advantages of the present invention will become apparent from the detailed description of the embodiments with reference to the accompanying drawings.

A preferred embodiment of a drive control circuit for a light emitting device according to the present invention will be described with reference to the accompanying drawings.

First embodiment

2 to 5 show a driving circuit of the first embodiment according to the present invention.

This drive circuit then switches the data drive switch to VT (5) which is a value between the power supply VD (4) and ground GND (6) before the next scan starts.

2A to 5A, data lines D1 to Dm, scan lines S1 to Sn, light emitting element portions 15 to p (1,1) to p (m, n), and the data lines Light emission control for controlling the data driving circuit 1 for applying a data value, the scan driving circuit 2 for sequentially applying current to the scan line, and the data driving circuit 1 and the scan driving circuit 2. It consists of the circuit 3.

The scan driving circuit 2 switches the power supply VP 8 and the ground GND 14 and a plurality of scan signals sequentially to the Vp 8 (eg, 10 V) one by one, and the other terminals are all ground GND ( 14) (for example, it consists of a plurality of scan driving switch (2 ₁ ~ 2 _n) for switching to 0V).

In addition, the data driving circuit 1 is configured to selectively switch the constant current source 1 ₁ to 1 _m connected to the power supply VD 4 and ground GND 6 and the power supply VD 4 from the data lines D 1 to D m. is composed of: a data driving switch (7 ₁ ~ 7 _m), and a power supply VD (4) and GND (6) the power value of VT (5) (5V for example) between.

At this time, the on / off adjustment of the scan driving switches 2 ₁ to 2 _n of the scan driving circuit 2 and the data driving switches 7 ₁ to 7 _m of the data driving circuit is performed by the light emission control circuit 3. Is controlled by

2B to 5B are timing diagrams showing data waveforms and scan waveforms input to the light emitting element unit 15 shown in FIGS. 2A to 5A.

2B-5B, T (11) is one scan time, T1 (12) is the time that the data line is connected to the VD (4) power supply or ground GND (6), and T2 (13) is the data line. This is the time connected to the VT (5) power supply.

The operation of the driving control circuit of the light emitting device according to the present invention configured as described above will be described in detail with reference to the accompanying drawings.

The operation described below is based on P (1,1) and P (m, 1) of the light emitting element section 15 when scan line S1 is selected as ground GND 14 and all other scan lines are selected as VP (8). When the light emitting elements P (2,2) and P (2, m) emit light when the light emitting element 2) and the next scan line S2 are selected as the ground GND 14 and all other scans are selected as the VP (8). Is described as an example.

First, referring to FIGS. 2A and 2B, the first scan line is connected to the ground GND 14 and selected as 0 V, and all other scan lines are connected to the power supply VP 8.

Therefore, a reverse voltage of 10 V is applied from each scan line S2 to Sn through a scan drive switch of 2 ₂ to 2 _n .

The constant current sources 1 ₁ and 1 _m are connected to the data lines D1 and Dm through the data driving switches 7 ₁ and 7 _m , respectively, and all other data lines except for the D1 and Dm are connected to 0V.

Thus Figure 2a, 2b emits light only the constant current source ₁₁ and a positive voltage higher than the voltage capable of emitting light in T1 (12) hours from the 1 _m is a P (1,1) and P (1, m) element.

0 V is applied from P (2,1) to P (m, 1), P (1,2) to P (1, n), and P (m, 2) to P (m, n). All other devices do not emit light with a reverse voltage applied.

The light emitting element shown in FIG. 2A is charged from the top to the bottom shown in the figure.

3A and 3B, the scan driving circuit maintains 0 V in the same manner as in FIGS. 2A and 2B, and the scan driving switches from 2 ₂ to 2 _n are connected to the VP (8) power supply to S2 to Sn. The VP (8) power supply is applied to the scan line of.

And the data drive circuit connects all data drive switches 7 ₁ to 7 _m to the VT (5) power supply.

At this time, each light emitting device is charged in the direction shown in the drawing, and in this state, the value of the VT (5) power supply and the T2 (13) time have a value that is less than the value of the current required for the device to emit light. .

Therefore, the conventional light emitting device is switched from the ground 0V (power supply 10V) to the power supply 10V (ground 0V) at the time of turning on / off at one time. The power supply is maintained at a level such that 5V does not emit light, and the light emitting element is switched from 5V to ground 0V or to a power supply 10V when the light emitting element is turned on / off.

As a result, the response speed of the light emitting device driven from off to on can be controlled quickly. In addition, since the separate power consumption driving power according to the fast response speed is used only for a very short time, T2 (2), Only drive power is needed.

Thus, as shown in FIGS. 3A and 3B, in the first scan selected as the light emitting device, p (1,1) and p (1, m) discharge the charge to the value of the VT (5) power source and the other connected to the first scan. The devices charge the charge to the value of the VT (5) power supply.

Here, the devices connected to the scan lines of 2 ₂ to 2 _n except the first scan line and the data lines of D1 and Dm connected to the constant current source through the data drive switches 1 ₁ and 1 _m are connected to VT (5) at the voltage VP (8). Charge the charge corresponding to the voltage minus the voltage.

The light emitting device connected to the scan lines 2 ₂ to 2 _n except for the first scan line and the remaining data lines except D1 and Dm connected to the ground through the remaining data driving switches except for 1 ₁ and 1 _m are VP (8). Discharge the charge corresponding to the voltage minus the VT (5) voltage.

In this state, the light emitting device connected to the first scan 21 has a charge of VT (5) in the positive direction, and all light emitting devices connected to the scan except the first scan have a VP (8) voltage in the negative direction. Has the charge corresponding to the voltage minus VT (5).

4A shows a case where the second scan line is selected to ground GND (0V) and all other scan lines are connected to the VP 8.

4A and 4B, the scan line S2 is selected and the constant current sources 1 ₂ and 1 _m are selected to the data lines D2 and Dm through the data drive switches 7 ₂ and 7 _m .

In this case, since the present invention changes from 5V to 10V, rather than the conventional change from 0V to 10V, the driving control circuit charges the elements p (2,2) and p (2, m) at a fast current and accordingly The light emitting element unit 15 emits light in a short time.

In other words, in FIG. 4A, since the charged charge is small in the state of FIG. 3A, the parasitic capacitance is rapidly charged.

At this time, a reverse voltage of 10V is applied to each scan line except S2 through all other scan drive switches except scan drive switch 2 ₂ .

The constant current sources 1 ₂ and 1 _m are connected to the data lines D2 and Dm through the data driving switches 7 ₂ and 7 _m , respectively. All other data lines except for the data lines D2 and Dm are connected to the ground GND (6) (eg, 0V).

Therefore, FIGS. 4A and 4B show only p (2,2) and p (2, m) devices having positive voltages capable of emitting light within the time T1 (12) from the constant current sources 1 ₂ and 1 _m . The device does not emit light by applying reverse voltage or 0V as shown in Figs. 4A and 4B.

4A and 4B, the light emitting device unit 15 is charged in the direction shown in the drawing.

5A and 5B, the second scan line maintains the ground GND (0V) similarly to FIGS. 4A and 4B, and the other scan lines except for the second scan line are connected to the VP (8) power source. All data drive switches from 7 ₁ to 7 _m are connected to the VT (5) supply.

At this time, the device is charged in the direction shown in the drawing, and in this state, the value of the VT (5) power source and the T2 (13) time have the value of the state in which the device does not emit light as in FIGS. 3A and 3B.

In the selected second scan of the bladder, p (2,2) and p (2, m) discharge the charge to the value of the VT (5) supply, and the other devices connected to the second scan to the value of the VT (5) supply. Charge the charge.

Here, the light emitting devices connected to the scan lines except for the second scan line and the data lines of D2 and Dm connected to the constant current source through the data driving switches 1 ₂ and 1 _m are obtained by subtracting the VT (5) voltage from the VP (8) voltage. Charge the charge corresponding to the voltage.

And a constant current source 1 ₂ and 1 _m, respectively connected to the light emitting element to the other scan lines other than the rest of the data lines and second scan lines, excluding D2 and Dm that was connected to ground via the data driving switch VT (5 in the voltage VP (8) Discharge the charge corresponding to the voltage minus the voltage.

In this state, the light emitting devices connected in the second scan 22 have a charge equal to the VT (5) voltage in the bipolar direction, and all the light emitting devices connected in the scan except the second scan 22 are VP in the negative direction. It has a charge corresponding to the voltage of (8) minus the VT (8) voltage.

As described above, the first drive control circuit is first used for T1 (12) time when the scan is selected as 0V and the remaining scan lines are connected to VP (8) (e.g. 10V) as shown in Figs. 2A and 2B. The device in which the data line is connected to the constant current source charges the charge as much as the voltage of VS (9) (10V) in the direction of bipolarity, and the charge is discharged so that the device in which the data line is connected to the ground becomes 0V.

All scans connected to the VP (8) power supply and the data line connected to the constant current source, except for the scan selected as 0V, are applied to the VS (9) (example: 10V) voltage at the VP (8) (example: 10V) voltage. All devices connected to the VP (8) (e.g. 10V) power source and the data line connected to 0V on the data line are discharged as much as the voltage of VP (8) (e.g. 10V) except the scan selected as 0V. Charge the charge.

3A and 3B, when one scan is selected as 0V and the other scan line is connected to VP (8) (e.g. 10V), all data lines are VT (5) (e.g. 5V) for the time T2 (13). It is connected to the power source.

At this time, all the scan-side devices connected to 0V are charged or discharged with the electric charge corresponding to the voltage of VT (5) (eg 5V) in the direction of bipolarity. In the direction of negative polarity, the battery is charged or discharged with a charge corresponding to a voltage obtained by subtracting the VT (5) (eg 5V) voltage from the VP (8) (eg 10V) voltage.

Second embodiment

6 to 9 are views illustrating a second driving circuit of the present invention.

The difference between the second driving circuit and the first driving circuit according to the first embodiment is that the first driving circuit maintains the T2 time for a predetermined time before driving the light emitting device, whereas the second driving circuit maintains the T2 time for the light emitting device. It is maintained for a predetermined time after the operation of.

That is, first, when the next scan is selected and then the next scan is selected, the data drive switch is set to VT (5) which is a value between VD (4) and GND (6).

6 to 9, the circuit includes a data line from D1 to Dm, a scan line from S1 to Sn, a light emitting element unit 15 from p (1,1) to p (m, n), and the data line. A data driving circuit 1 for applying a data value, a scan driving circuit 2 for sequentially applying current to the scan line, and a light emission control circuit for controlling the data driving circuit 1 and the scan driving circuit 2. It consists of (3).

Each terminal of the scan drive switches 2 ₁ to 2 _n has one terminal connected to Vp (6) (e.g., 10V) and the other terminal connected to ground voltage (e.g., 0V).

The data driving circuit 1 includes a power supply VD (e.g. 10V) 4, a ground GND (e.g. 0V) 6, a constant current source 1 ₁ to 1 _m connected to the power supply VD 4, And a data drive switch 71 to 7m for selecting each of the data lines D1 to Dm, and a power supply VT 5 (for example, 5 V) that is a value between the power supply VD 4 and the ground GND 6.

The scan drive circuit 2 further includes a power supply VP 8 (e.g., 10V), a ground GND 14 (e.g., 0V), and a scan drive switch 2 for selecting each of a plurality of scan lines S1 to Sn. ₁ to 2 _n ).

On / off adjustment of the scan drive switches 2 ₁ to 2 _n and the data drive switches 7 ₁ to 7 _m is controlled by the light emission control circuit 3.

6B to 9B illustrate input data waveforms and scan waveforms.

Here, during one scan time T (11), T1 (12) is the time that the data line is connected to the VD power supply 4 or ground GND (6), and T2 (13) means that the data line is VT (5) (e.g., 5V) It is the time connected to the power.

The operation of the light emitting device by the second driving circuit will be described with reference to FIGS. 6 to 9 as follows.

The operation described below is performed when the light emitting elements P (1,1) and P (m, 1) emit light when the scan line S1 is selected as the ground GND 14 and all other scan lines are selected as the VP (8). As an example, when the light emitting elements P (2,2) and P (2, m) emit light when the next scan line S2 is selected as the ground GND 14 and all other scans are selected as VP (8). Explain.

Referring to FIG. 6, the light emitting device unit 15 selects 0V as the first scan line in the scan driving circuit ₂ , and all other scan lines from S2 to Sn are VP through the scan driving switches 2 ₂ to 2 _n . (8) Connect to the power supply.

And the data drive circuit 1 connects all the data drive switches 71 to 7m to the VT (5) power supply.

At this time, the device is charged in the direction shown in FIG. 6A. In this state, the value of the VT (5) power supply and the T2 (13) time have the value of the state in which the device does not emit light.

In the first scan line selected as the light emitting element, p (1,1) and p (1, m) discharge the charge to the value of the VT (5) power supply, and the other light emitting elements connected to the first scan line are VT (5) Charge the charge to the value of the power supply.

Here, the light emitting elements connected to the data lines of D1 and Dm connected to the constant current source through the data driving switches 1 ₁ and 1 _m and the scan lines of 2 ₂ to 2 _n except the first scan line are respectively VT at the voltage of VP (8). (5) Charge the electric charge corresponding to the voltage minus the voltage.

The devices connected to the scan lines of 2 ₂ to 2 _n except the first scan line and the remaining data line except D1 and Dm, which were connected to ground through the data drive switch except 1 ₁ and 1 _m , respectively, are VP (8). The charge corresponding to the voltage minus the VT (5) voltage is discharged.

In this state, the device connected to the first scan 21 has a charge of VT (5) in the positive direction, and all devices connected to the scan except the first scan are VT at the voltage VP (8) in the negative direction. (5) It has a charge corresponding to the voltage minus the voltage.

Next, as shown in FIGS. 7A and 7B, the first scan line maintains 0V and a reverse voltage VP 8 is applied to each scan line from S2 to Sn through all other scan drive switches from 2 ₂ to 2 _n .

The constant current sources 1 ₁ and 1 _m are connected to the data lines D1 and Dm through the data driving switches 7 ₁ and 7 _m , respectively, and all other data lines except the D1 and Dm are connected to the ground GND 6.

Therefore, FIG. 7 emits only p (1,1) and p (1, m) devices to which positive voltages greater than the voltage capable of emitting light within the time T1 (11) from the constant current sources 1 ₁ and 1 _m emit light. The device does not emit light by applying reverse voltage or 0V.

In this state, the light emitting element is charged in the direction shown in Fig. 7A.

8A and 8B, when the second scan line selects the ground GND 14 and the other scan lines except for the second scan line are connected to the VP (8) power supply, All data drive switches ₁ to 7 _m are connected to the VT (5) supply.

At this time, the light emitting device is charged in the direction shown in FIG. 8A, and in this state, the value of the VT (5) power supply and the T2 (13) time have the value of the state in which the light emitting device does not emit light.

That is, in the second scan selected as the light emitting device, p (2,2) and p (2, m) charge or discharge the charge to the value of the VT (5) power supply, and the other devices connected to the second scan are VT (5 Charge or discharge the charge with the value of the power supply.

Here, the light emitting devices connected to the data lines of D2 and Dm connected to the constant current source using the data driving switches 1 ₂ and 1 _m and the scan lines except for the second scan line, respectively, have a VT (5) voltage at the VP (8) voltage. Charge the voltage corresponding to the subtracted voltage.

The light emitting devices connected to the remaining data lines except D2 and Dm connected to the ground through the constant current sources 1 ₂ and 1 _m and the remaining scan lines except the second scan line were subtracted from the voltage of VP (8) by the voltage of VT (5). Discharge the charge corresponding to the voltage.

In this state, the light emitting device connected to the second scan line 22 has a charge equal to the VT (5) voltage in the bipolar direction, and all light emitting devices connected to the scan except the second scan are VP (8) in the negative direction. The voltage has a charge corresponding to the voltage minus the VT (5) voltage.

Subsequently, as shown in FIGS. 9A and 9B, the second scan line maintains 0 V and the reverse voltage VP 8 is applied to each scan line through all the other scan drive switches, and the data drive circuit is a constant current source 1 ₂ and 1 _m. Is connected to data lines D2 and Dm via data drive switches 7 ₂ and 7 _m , respectively.

All other data lines except for D2 and Dm are connected to ground GND 6 (0V).

Therefore, FIGS. 9A and 9B show only the p (2,2) and p (2, m) devices to which positive voltages greater than the voltage capable of emitting light within the T1 (12) time from the constant current sources 1 ₂ and 1 _m are applied. All other devices do not emit light with a reverse voltage or 0V applied.

In this case, the light emitting device is charged in the direction shown in FIG. 9A.

As such, according to the second drive circuit, when one scan is selected as ground GND (14) (0V) and the other scan line is connected to VP (8) (e.g .: 10V), all data lines are stored for T2 (13) time. VT (5) (e.g. 5V) is connected to the power supply.

Therefore, all devices on the scan side connected to ground GND (14) (0V) are charged with a charge corresponding to the voltage of VT (5) (e.g. 5V) in the direction of bipolarity and selected as VP (8) (e.g. 10V). All other scan-side devices are charged or discharged in the negative direction with a charge corresponding to the voltage minus the VT (5) (eg 5V) voltage from the VP (8) (eg 10V) voltage.

When scan is selected as ground GND (14) (0V) and the rest of the scan line is connected to VS (8) (e.g. 10V), the device with the data line connected to the constant current source for the time T1 (12) is in the bipolar direction. Charge as much as VS (9) (example: 10V).

Then, the device in which the data line is connected to the ground GND 6 discharges the charge so as to be 0V.

In addition, the light emitting elements connected to the remaining scan line connected to the VP (8) power supply (eg, 10V) and the data line connected to the constant current source except for the scan line selected as the ground GND 14 (0V) are connected to the VP (8) power supply (eg, Charge is discharged by the voltage minus VS (9) (e.g. 10V).

The other scan line connected to the VP (8) power supply (except the scan line selected as ground GND (14) (0V)) and the data line connected to the ground GND (6) (0V) are respectively connected to VP (8). Charge (10V)

The driving control circuit of the light emitting device according to the present invention as described above has the following effects.

First, when the data is turned on / off by maintaining the VT value, which is a value between VC and GND, for a predetermined time to reduce the influence of the connection capacitance, it is possible to quickly control the response characteristics of the device and to thereby lose power consumption Can be minimized.

Second, it can be applied to all products that use LEDs, especially for products that require fast response and low power at the same time.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

Claims (5)

A data driver comprising a first power source connected to a constant current source, a ground, a second power source having a value between the first power source and ground, and a first switch for switching the first and second power sources and ground; A scan driver including a third power source, ground, and a second switch for switching the third power source and ground; A light emission control unit controlling the first switch and the second switch; And a light emitting element portion having an array structure for selectively emitting light with current applied through the first switch and the second switch. The method of claim 1, The value of the second power supply is a drive control circuit of the light emitting element, characterized in that the value smaller than the power required to emit light. Connecting one of the plurality of scan lines to the ground and the other one of the plurality of scan lines to the ground in order to connect each of the plurality of scan lines to the ground for at least one scan time for one frame; The data time is divided into a plurality of time domains during the one scan time, and the first power source and the ground are selectively switched during the on / off period of the light emitting element unit during some time domains, and the first power source and the ground during the other time domains. And connecting to a second power supply having a value of between. The method of claim 3, wherein And the plurality of time domains can be adjusted within one scan time. The method of claim 4, wherein The value of the second power supply is a drive control circuit of the light emitting element, characterized in that the value smaller than the power required to emit light.