KR100600884B1 - Organic Electo Luminescence Device for preventing a voltage overflow - Google Patents

Abstract

An organic light emitting display device including an ELVDD power generator and a power detector to prevent an overpower voltage generated from a power supply unit from being input into a panel unit. The organic light emitting device uses an ELVDD power generator and a power detector to prevent the organic light emitting device of the panel unit from being damaged.

Description

Organic Electo Luminescence Device for preventing a voltage overflow             

1 is a block diagram schematically illustrating an organic light emitting device according to the related art.

2 is a block diagram schematically illustrating an organic light emitting display device according to a preferred embodiment of the present invention.

3 is a block diagram illustrating an ELVDD power generator and a power detector of an organic light emitting device according to an exemplary embodiment of the present invention.

4 is a circuit diagram illustrating an ELVDD power generator and a power detector of an organic light emitting device according to a preferred embodiment of the present invention.

5 is another circuit diagram illustrating an ELVDD power generator and a power detector of an organic light emitting device according to an exemplary embodiment of the present invention.

The present invention relates to an organic light emitting device, and more particularly, to an organic light emitting device that prevents an overpower voltage generated from a power supply unit from being input into a panel unit, so that the organic light emitting device of the panel unit is not damaged. will be.

In general, an organic EL device is a flat self-emission display that emits light by applying an electric field to a phosphor coated on a glass substrate or a transparent organic film. Electroluminescence refers to a phenomenon of emitting light when an electric field is applied to a phosphor made of a semiconductor.

Recently, liquid crystal displays (LCDs) and organic light emitting diodes (OLEDs) are used in portable information devices due to their light weight and thinness. The organic light emitting device is attracting attention as a next-generation flat panel display because it has superior luminance and viewing angle characteristics as compared to the liquid crystal display.

In general, in an active matrix organic light emitting device (AMOLED), one pixel includes R, G, and B unit pixels, and each R, G, and B unit pixel includes an EL element. Each EL element has an R, G, B organic light emitting layer interposed between the anode electrode and the cathode electrode to emit light from the R, G, B organic light emitting layer compared to the voltage applied to the anode electrode and the cathode electrode.

1 is a block diagram schematically illustrating an organic light emitting device according to the related art.

Referring to FIG. 1, the conventional organic light emitting device 100 includes a power supply unit 110, a memory unit (SSRAM / ROM: 120), a program unit (FPGA: 130), a buffer unit (Buffer: 140), and a driver (Driver). : 150) and a panel unit (Panel: 160).

First, the power supply unit 110 receives source power from a power supply source, steps down, and divides the source power for each internal circuit to deliver a power voltage.

That is, the power supply unit 110 divides the source power into a memory unit 120, a program unit 130, a buffer unit 140, a driving unit 150, and a panel unit 160, and changes the source power to a power supply voltage. It is designed to deliver to the circuit.

Here, the embedded circuits are collectively named as the memory unit 120, the program unit 130, the buffer unit 140, the driving unit 150, and the panel unit 160.

Next, the memory unit 120 is composed of a RAM and a ROM, which stands for Ramdon Access Memory, also called a random access memory. When the power supply voltage is turned off, the stored contents are erased. In addition, ROM stands for Read Only Memory, which is a read-only memory, and its contents remain even when the power supply voltage is turned off. In particular, as the data processing speed of the RAM continues to increase in the organic light emitting device 100 recently, data stored in the memory unit 120 is quickly transferred to the program unit 130.

Next, the program unit (Field Programmable Gate Array) 130 receiving data from the memory unit 120 transmits a command signal and an address signal to the memory unit 120 according to program logic already implanted. signal). That is, the address of the memory unit 120 is designated according to the input command signal and the address signal, and data corresponding to the address is output to the program unit 130. Therefore, the data received by the program unit 130 is processed by the program logic and transferred to the buffer unit 140.

Hereinafter, data processed and output according to the above-described process will be referred to as a program signal.

Next, the buffer unit 140 is a storage place for storing temporary information, and is used to compensate for a difference in time or information flow rate that occurs when the information is transmitted from one device to another. In addition, the buffer unit 140 is a kind of register, and since it is an internal circuit that makes an address buffer for the transmission of an address, the program signal is temporarily transmitted from the program unit 130 to transmit the program signal. After compensating and adjusting the time, the program signal is transmitted to the driver 150.

Next, the driver 150 amplifies the program signal input from the program unit 130 by using a driving transistor mounted on the driver 150. That is, the driving unit 150 extends the program signal and transfers the program signal to the panel unit 160 so that the organic light emitting diode of the panel unit 170 can be displayed smoothly.

Finally, the program signal amplified by the driving unit 150 is input to the organic light emitting element in the panel unit 160 and displayed.

Problems related to the conventional organic EL device related to the present invention and overcome by the present invention are as follows.

When the power supply unit supplies a power supply voltage to the organic light emitting diode of the panel unit, the organic light emitting diode is damaged due to an overvoltage.

In order to solve this problem, the ELVDD power generation unit and the power sensing unit must be designed so that the organic light emitting diode of the panel unit is not damaged by the overvoltage transmitted from the power unit in the intermediate line connected to the power unit and the panel unit.

SUMMARY OF THE INVENTION An object of the present invention is to provide an organic light emitting device having an ELVDD power generation unit and a power detection unit to prevent an overpower voltage generated from a power supply unit from being input to a panel unit.

The present invention for achieving the above object is a data driver for applying a data signal to a plurality of data lines arranged in the first direction; A scan driver for applying a selection signal to the plurality of selection scan lines arranged in a second direction; And a predetermined screen is displayed by using a plurality of organic light emitting elements that emit light corresponding to data currents or data voltages applied to a plurality of unit pixels connected to the data line and the selection scan line. An ELVDD power generation unit disposed between a power supply unit supplying a power supply voltage to the panel unit and a panel unit including the organic light emitting device, and generating ELVDD power supplied to the panel unit; And a power detector including an overvoltage detector for detecting an overvoltage of the ELVDD power and a photo coupler for generating a resonance control signal for controlling an operation of the ELVDD power generator.

In addition, the present invention for achieving the above object, ELVDD power generation unit for generating an ELVDD power supply; An overvoltage detector configured to detect whether the ELVDD power is overvoltage; And a photo coupler for receiving the output of the overvoltage detector and generating a resonance control signal for controlling the operation of the ELVDD power generator.

Hereinafter, described in detail with reference to the accompanying drawings of the present invention.

2 is a block diagram schematically illustrating an organic light emitting display device according to a preferred embodiment of the present invention.

Referring to FIG. 2, the organic light emitting device 200 includes a power supply unit 210, an ELVDD power generator unit 220, a power detection unit 230, a memory unit SSRAM / ROM. 240, a program unit (FPGA: 250), a buffer unit (Buffer: 260), a driver unit (270), and a panel unit (Panel: 280).

The power supply unit 210 receives source power from a power supply source and divides the source power for each internal circuit to transfer a power voltage.

However, the embedded circuit may include the ELVDD power generator 220, the power detector 230, the memory unit 240, the program unit 250, the buffer unit 260, the driver 270, and the panel unit 280. Named generically.

Accordingly, the power supply unit 210 supplies a predetermined power voltage to the ELVDD power generation unit 220, the power detection unit 230, the memory unit 240, the program unit 250, and the buffer unit 260. In addition, the driver 270 applies a power supply voltage Vdata and Vsel to drive the data signal and the control signal. The panel unit 280 is supplied with a power supply voltage Vdd and Vcat so that the organic light emitting diode emits light.

Next, the ELVDD power generation unit 220 and the power supply unit 210 so as not to damage the organic light emitting device in the panel unit 210 due to the overvoltage ELVDD transmitted from the power supply unit 210 to the panel unit 280. As an embedded circuit provided in the middle line of the panel unit 280, the ELVDD power generation unit 220 cuts off the overvoltage ELVDD and supplies the normal ELVDD power to the panel unit 280.

Next, the power detection unit 230 is an internal circuit provided in an intermediate line connected to the ELVDD power generation unit 220 and the panel unit 280, and the power detection unit 230 is the ELVDD voltage generation unit ( The ELVDD power output from 220 is monitored in real time. That is, when the ELVDD power is excessively applied from the ELVDD voltage generator 220 to the panel unit 280, the power detector 230 inputs the ELVDD power so that it is not transmitted to the panel unit 280. And generates a resonance control signal. In addition, the power detector 230 controls the ELVDD power generator 220 by feeding back the resonance control signal to the ELVDD power generator 220.

Next, the memory unit 240 is composed of a RAM and a ROM, which stands for Ramdon Access Memory, also called a random access memory. When the power supply voltage is turned off, the stored contents are erased. In addition, ROM is an abbreviation of Read Only Memory, which is a read only memory, and its contents remain even when the power supply voltage is turned off. In particular, recently, as the data processing speed of the RAM continues to increase in the organic light emitting device 200, data stored in the memory unit 240 is quickly transferred to the program unit 250.

Next, the program unit 250 that receives data from the memory unit 240 applies a command signal and an address signal to the memory unit 240 according to the program logic already implanted. . That is, the address of the memory unit 240 is designated according to the input command signal and the address signal, and data corresponding to the address is output to the program unit 250. Accordingly, the data received by the program unit 230 is processed by the program logic and transferred to the buffer unit 240.

Hereinafter, data processed and output according to the above-described process will be referred to as a program signal.

Next, the buffer unit 260 is a storage place for storing temporary information, and is used to compensate for a difference in time or information flow rate that occurs when information is transmitted from one device to another. In addition, since the buffer unit 260 is a kind of register, a built-in circuit for making an address buffer to transmit an address, and temporarily stores the program signal input from the program unit 250 to compensate for the flow rate. After adjusting, the program signal is transmitted to the driver 270.

However, it should be noted that the buffer unit 260 is not an internal circuit that is essentially provided in the organic light emitting device 200.

Next, the driver 270 amplifies the program signal input from the program unit 250 by using a driving transistor mounted on the driver 270. That is, the driving unit 270 extends the program signal and transmits the program signal to the panel unit 280 to smoothly emit the organic light emitting diode of the panel unit 280.

Finally, the program signal amplified by the driver 250 is input to the organic light emitting diode in the panel 280 to emit light.

3 is a block diagram illustrating an ELVDD power generator and a power detector of an organic light emitting device according to an exemplary embodiment of the present invention.

Referring to FIG. 3, first, the ELVDD voltage generator 220 of the organic light emitting device 200 includes a resonance circuit 300 and a transformer 310. That is, when the ELVDD voltage generator 220 excessively applies the power voltage transmitted from the power supply unit 210 to the panel unit 280, the organic light emitting diode in the panel unit 280 may be overpowered. Do not damage it. In addition, the ELVDD voltage generator 220 receives a resonance control signal detected from the power detector 230 to block the overpower voltage to the panel unit 280 in advance.

In more detail, the resonant circuit 300 provided in the ELVDD voltage generator 220 may electrically resonate a resonance phenomenon generated when the free vibration frequency and the external force frequency generated by reversible conversion between different energies are very close. As a circuit which arises, it is also called a tuning circuit.

In addition, the resonant circuit 300 is electrically resonated at a specific frequency determined by the values of the coils and capacitors in the electric circuit of the coils and capacitors, and the electrical properties of the coils and capacitors are apparently dissipated so that some quantum inherent It becomes a circuit of electric resistance delivery.

That is, the resonant circuit 300 refers to a circuit that is freely converted between the electrostatic energy of the capacitor (C) and the electromagnetic energy of the inductance (L), the capacitor (C) and the inductance (L) is a series resonant circuit in series and a parallel resonant circuit in parallel. In addition, all the resonance frequencies f0 are represented by [Equation 1].

That is, the unit of the resonant frequency is represented by the inductance L is represented by H (Henry) and the capacitor C is represented by F (farad), the impedance of the external force of the resonant frequency is 0 in series and infinity in parallel. . Therefore, a large current flows at a small voltage in series and a large voltage is obtained at a small current in parallel. In addition, in a tuning circuit such as a radio, a weak current input from an antenna can be selectively brought into a large voltage by writing parallel and adjusting a constant of LC to a frequency of radio waves to be received.

Accordingly, the resonant circuit 300 of the ELVDD voltage generator 220 adjusts the power supply voltage input from the power supply unit 210 to generate a resonance voltage that is greater than the power supply voltage to the transformer 310. To pass. In addition, when the power supply voltage delivered to the panel unit 280 is an overpower voltage, the resonant circuit 300 blocks the overpower voltage according to the resonance control signal transmitted from the power detector 230.

Next, the transformer 310 provided in the ELVDD voltage generator 220 may also be generally referred to as a transformer.

Generally, the transformer includes a power transformer connected to a transmission and distribution line and a coupling transformer used in an electronic circuit. The power transformer can change the voltage applied to the AC circuit, so the power does not change. In addition, the power transformer has a primary winding connected to a power source and a secondary winding connected to a load are wound with the same iron core.

In addition, the iron core is assembled to the required thickness by overlapping the magnetic material of silicon steel sheet, permalloy and ferrite having a thickness of 0.35 mm.

Accordingly, the transformer 310 converts the resonance voltage received from the resonance circuit 300 into ELVDD power, which is a power required for the organic light emitting diode of the panel 280 to emit light. Transfer to the organic electroluminescent device of.

Subsequently, the power detector 230 of the organic light emitting device includes a photo coupler 320 and an overvoltage detector 330. That is, the power detector 230 is connected between the ELVDD power generator 220 and the panel unit 280 to output the ELVDD power output from the transformer 230 of the ELVDD voltage generator 220 in real time. Watch.

If the ELVDD power is excessively applied to the panel unit 280, the organic light emitting diode of the panel unit 280 is damaged. Accordingly, the power detector 230 detects an overvoltage ELVDD power, which is an ELVDD power excessively applied to the panel unit 280, and generates the resonance control signal so that the overvoltage ELVDD power is not transmitted to the panel unit 280. do. That is, the resonance control signal is fed back to the resonance circuit 300 of the ELVDD power generator 220.

4 is a circuit diagram illustrating an ELVDD power generator and a power detector of an organic light emitting device according to a preferred embodiment of the present invention.

Referring to FIG. 4, the power detector 230 includes an overvoltage detector 330 and a photo coupler 320.

The overvoltage detector 230 has at least one zener diode and an overvoltage control transistor Q1. At least one zener diode is disposed between the input terminal of the panel unit 280 and the base terminal of the overvoltage control transistor Q1. In FIG. 4, although two zener diodes ZD1 and ZD2 are connected in series and a resistor is interposed between the zener diode and the base terminal, the number of zener diodes can be changed according to the embodiment. It may be arranged appropriately. The number of Zener diodes connected in series can be changed according to the sensed overvoltage level.

In addition, a resistor R2 and a capacitor C1 are disposed between the base terminal and the emitter terminal of the overvoltage control transistor Q1.

When the ELVDD power output of the transformer 310 exceeds the sum of the threshold voltages of the zener diodes ZD1 and ZD2, that is, the overvoltage ELVDD power supply is greater than the sum of the threshold voltages of the zener diodes ZD1 and ZD2. If large, the two Zener diodes ZD1 and ZD2 are turned on, the current flows through the resistors R1 and R2 by the turn-on of the Zener diodes ZD1 and ZD2. The voltage of the base terminal of the control transistor Q1 increases, and the transistor Q1 is turned on as the voltage of the base terminal of the transistor Q1 rises, and the photo coupler 320 provided in the power detector 230 is Recognizing an overvoltage ELVDD power transmitted from the transformer 310 to the panel unit 280, the photodiode, which is a display element provided in the photo coupler 320, is turned on and emits light.

However, when the ELVDD power transmitted from the transformer 310 to the panel unit 280 is applied to the normal ELVDD power, the photodiode of the photo coupler 310 is turned off and the photodiode does not emit light.

In addition, as the overvoltage control transistor Q1 provided in the overvoltage detector 230 is turned on by the overvoltage ELVDD power source, the light emitting diode is turned on. In addition, the bipolar junction transistor Q2 disposed in the photo coupler 320 is turned on by the turn-on of the light emitting diode to generate a resonance control signal. That is, the resonance control signal is input to control the resonant circuit operation of the ELVDD power generator 220, and the resonance circuit 300 in which the resonance control signal is received is output from the ELVDD power generator 220. The overvoltage ELVDD power is blocked from being transferred to the organic light emitting diode of the panel unit 280.

5 is another circuit diagram illustrating an ELVDD power generator and a power detector of an organic light emitting device according to an exemplary embodiment of the present invention.

Referring to FIG. 5, the overvoltage detector 330 of the power detector 230 includes at least one field effect transistor Q1, Q2 .. Qn and an overvoltage control transistor Q′1. At least one field effect transistor Q1, Q2 .. Qn is disposed between the input terminal of the panel portion 280 and the gate terminal of the overvoltage control transistor Q'1. In FIG. 5, n field effect transistors Q1 and Q2... Qn have a diode connection and are connected in series, and a resistor R1 is interposed between the gate terminals of the overvoltage control transistor Q'1. The number of field effect transistors can be changed, and the resistor R1 can also be disposed appropriately. The number of field effect transistors connected in series can be appropriately changed depending on the sensed overvoltage level.

In addition, a resistor R2 and a capacitor C1 are disposed between the gate terminal and the source terminal of the overvoltage control transistor Q'1.

When the ELVDD power supply, which is the output of the transformer 310, exceeds the sum of the threshold voltages of the field effect transistors Q1, Q2 .. Qn, that is, the overvoltage ELVDD power supply is the field effect transistors Q1, Q2 .. Qn. If greater than the sum of the threshold voltages of the n field effect transistors Q1, Q2 .. Qn are turned on. A current flows in the resistors R1 and R2 by the turn-on of the field effect transistors Q1, Q2 .. Qn. The voltage at the gate terminal of the overvoltage control transistor Q'1 is increased by the current flowing through the resistor R1. The transistor Q'1 is turned on as the voltage of the gate terminal of the transistor Q'1 increases. In addition, the photo coupler 320 provided in the power detector 230 recognizes the overvoltage ELVDD power transferred from the transformer 310 to the panel unit 280 and is a display device provided in the photo coupler 320. The photodiode is turned on and emits light.

However, when the ELVDD power transmitted from the transformer 310 to the panel unit 280 is applied to the normal ELVDD power, the photodiode of the photo coupler 320 is turned off and the photodiode does not emit light.

In addition, as the overvoltage control transistor Q'1 provided in the overvoltage detector 330 is turned on by the overvoltage ELVDD power source, the light emitting diode is turned on. In addition, the field effect transistor Q ′ 2 disposed in the photo coupler 320 is turned on by the turn-on of the light emitting diode to generate a resonance control signal. That is, the resonance control signal is input to control the operation of the resonant circuit of the ELVDD power generator 220, and the resonant circuit receiving the resonance control signal is an overvoltage ELVDD power output from the ELVDD power generator 220. The panel is blocked from being transferred to the organic light emitting diode of the panel unit 280.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

According to the present invention described above, the ELVDD power generation unit and the power detection unit of the organic light emitting device to prevent the over-power voltage generated from the power supply unit to be input to the panel in advance to prevent damage to the organic light emitting device of the panel unit It works.

Claims (20)

A data driver for applying a data signal to the plurality of data lines arranged in the first direction; A scan driver for applying a selection signal to the plurality of selection scan lines arranged in a second direction; And An organic electroluminescent device in which a predetermined screen is displayed using a plurality of organic electroluminescent elements that emit light corresponding to data currents or data voltages applied to a plurality of unit pixels connected to the data line and the selection scan line. An ELVDD power generation unit disposed between a power supply unit supplying a power voltage to each circuit unit and a panel unit including the organic light emitting device, and generating an ELVDD power supply to the panel unit; And And a power detector including an overvoltage detector for detecting an overvoltage of the ELVDD power and a photo coupler for generating a resonance control signal for controlling an operation of the ELVDD power generator. The method of claim 1, wherein the overvoltage detector, At least one zener diode turned on by an overvoltage ELVDD power input above a threshold voltage; A resistor for generating a voltage according to a current flowing at the Zener diode turn-on; And       And a transistor connected in parallel with the zener diode and whose turn-on operation is controlled according to the voltage generated by the resistor. The organic light emitting device of claim 2, wherein the transistor is a bipolar junction transistor. The method of claim 1, wherein the overvoltage detector, At least one diode coupled transistor turned on by an overvoltage ELVDD power input above a threshold voltage; A resistor for generating a voltage according to a current flowing during the diode-connected transistor turn-on; And And a field effect transistor connected in parallel with the diode-connected transistor and whose turn-on operation is controlled according to a voltage generated from the resistor. The organic light emitting device of claim 4, wherein the diode-connected transistor is a field effect transistor. The method of claim 1, wherein the photo coupler, A photodiode operating according to an output of the overvoltage detector; And       And a resonant circuit control transistor for controlling the resonant circuit in accordance with the operation of the photodiode.        7. The bipolar junction of claim 6, wherein the resonant circuit control transistor is bipolar junction. An organic light emitting device comprising a transistor or a field effect transistor. 7. The organic light emitting device of claim 6, wherein the photo coupler transfers the overvoltage ELVDD power in a feedback form to a resonant circuit of the ELVDD power generation unit. The method of claim 1, wherein the ELVDD power generation unit, A resonant circuit which generates a resonant voltage and cuts off the overvoltage ELVDD power delivered from the power detector; And       And a transformer for receiving the resonance voltage generated from the resonance circuit and converting the resonance voltage into an ELVDD power supply to the panel unit.      10. The organic light emitting device of claim 9, wherein the ELVDD power generator cuts off the overvoltage ELVDD power transmitted from the power detector and supplies normal ELVDD power applied from the power supply to the panel unit. An ELVDD power generator for generating an ELVDD power; An overvoltage detector configured to detect whether the ELVDD power is overvoltage; And And a photo coupler for receiving the output of the overvoltage detector and generating a resonance control signal for controlling the operation of the ELVDD power generator. The method of claim 11, wherein the overvoltage detector, At least one zener diode turned on by an overvoltage ELVDD power input above a threshold voltage; A resistor for generating a voltage according to a current flowing at the Zener diode turn-on; And       Is connected in parallel with the zener diode and according to the voltage generated by the resistor A power supply device for an organic light emitting device, characterized in that it comprises a transistor for which the turn-on operation is controlled. 13. The power supply voltage supply device of an organic light emitting device according to claim 12, wherein the transistor is a bipolar junction transistor. The method of claim 11, wherein the overvoltage detector, At least one diode coupled transistor turned on by an overvoltage ELVDD power input above a threshold voltage; A resistor for generating a voltage according to a current flowing during the diode-connected transistor turn-on; And And a field effect transistor connected in parallel with the diode-connected transistor and whose turn-on operation is controlled according to the voltage generated by the resistor. 15. The power supply voltage supplying device according to claim 14, wherein the transistor is a field effect transistor. The method of claim 11, wherein the photo coupler, A photodiode operating according to an output of the overvoltage detector; And And a resonant circuit control transistor for controlling the resonant circuit in accordance with the operation of the photodiode. 17. The power supply voltage supply apparatus of claim 16, wherein the resonant circuit control transistor is a bipolar junction transistor or a field effect transistor. 17. The power supply device of claim 16, wherein the photo coupler transfers the overvoltage ELVDD power in a feedback form to a resonant circuit of the ELVDD power generation unit.        The method of claim 11, wherein the ELVDD power generation unit, A resonant circuit which generates a resonant voltage and cuts off the overvoltage ELVDD power delivered from the power detector; And       And a transformer for receiving the resonant voltage generated from the resonant circuit and converting the resonant voltage to the ELVDD power supplied to the panel unit.     20. The power supply voltage of the organic light emitting device of claim 19, wherein the ELVDD power generation unit cuts off the overvoltage ELVDD power transmitted from the power detection unit and supplies normal ELVDD power applied from the power supply to the panel unit. Feeder.

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