KR100469347B1 - Electroluminescent display panel - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroluminescent display panel capable of realizing a high resolution display by controlling the operation of an electroluminescent element. Each unit pixel may include: a first switching element for switching a data signal of a voltage source by an activation signal applied to the gate line, a capacitor for storing a voltage of the data signal transferred through the first switching element, and the capacitor A second switching element which is switched by the voltage of the data signal stored in the switch to switch the power supply voltage, an electroluminescent unit which emits light by the power supply voltage through the second switching element, and before the current frame operation, Low on the capacitor of the previous frame by the activation signal By discharging the electrical charges, which is characterized in that it comprises a suppressing emission of a certain amount of time off (OFF) of the EL unit.

Description

EL display panel {ELECTROLUMINESCENT DISPLAY PANEL}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroluminescent display panel, and more particularly, to an electroluminescent display panel capable of realizing a high resolution display by controlling the operation of the electroluminescent element.

Electroluminescen devices are faster in response to light-receiving devices such as liquid crystal display devices (LCDs) and have excellent brightness because they are self-luminous, and are simple to manufacture in production due to their simple structure and light weight. It is attracting attention as the next generation flat panel display device. The electroluminescent devices have a variety of uses, such as LCD backlights, portable terminals, car navigation systems (CNS), notebook computers, and wall-mounted TVs.

The electroluminescent display is largely divided into an inorganic light emitting device and an organic light emitting device according to the material used, wherein the organic light emitting device is a pair of electrons and holes when the charge is injected into the organic thin film layer formed between the electron injection electrode and the hole injection electrode After accomplishing this, it is an element that emits light while extinguishing. An inorganic light emitting element is an element that emits electrons, which are accelerated by a high electric field, to strike and excite the light emitter, and the excited light emitter falls to a ground state.

Hereinafter, a conventional electroluminescent display panel will be described with reference to the accompanying drawings.

1 is a circuit diagram of a unit pixel of a conventional electroluminescent display panel.

As illustrated, the unit pixel of the electroluminescent display panel is connected to the source line SL and controlled by a signal applied to the gate line GL to switch the data signal, and the first switching element 11. A capacitor 15 connected to an output terminal of the first switching element 11 and a second terminal to a power supply voltage terminal Vdd to charge a data voltage transferred through the first switching element 11; And a second switching element 19 connected between the power supply voltage terminal Vdd and the electroluminescent element 20 and switched by a voltage induced at the first terminal of the capacitor. Here, the first and second switching elements are composed of PMOS transistors.

Referring to the operation of the conventional electroluminescent display panel having the above configuration is as follows.

When the activation signal is applied to the gate line GL and the data voltage is applied to the source line SL in the unit pixel, the second switching element is charged while charging the capacitor 15 through the first switching element 11. By turning on (19), the electroluminescent device 20 emits light for a predetermined time.

Subsequently, even when the gate signal controlling the first switching element 11 is cut, the data voltage stored in the capacitor 15 is discharged, thereby continuously turning on the second switching element 19 to continuously emit the electroluminescent element. do.

However, the electroluminescent display panel according to the prior art has the following problems.

Pixel source lines disposed in the entire area of the electroluminescent display panel have resistance components, and parasitic capacitors are formed between the gate lines and the source lines. When a data voltage corresponding to the source line SL is applied in the current frame after the previous frame operation, it takes a long time to store the data voltage corresponding to the signal in the capacitor 15. As a result, as shown in FIG. 2, after the previous frame 1f operation, the blurring phenomenon occurs on the screen during the current frame 2f operation, making it difficult to manufacture a high-resolution electroluminescent display panel.

Accordingly, the present invention has been made to solve the above problems, and in a certain period before the current frame operation, to discharge the charge stored in the capacitor of the previous frame to emit the electroluminescent element for a predetermined time It is an object of the present invention to provide a high-resolution electroluminescent display panel that allows the capacitor to quickly charge and display the corresponding data voltage in the current frame.

1 is a circuit diagram of a unit pixel of a conventional electroluminescent display panel.

2 is a timing diagram for explaining a problem of a conventional electroluminescent display panel.

3 is a circuit diagram of an electroluminescent display panel according to a first embodiment of the present invention.

4 and 5 are operation timing diagrams of FIG.

6 is an overall configuration diagram of an electroluminescent display including unit pixels of FIG. 3.

7 is a circuit diagram according to a second embodiment of the present invention.

8 is an operation timing diagram of FIG. 6.

9 is an overall configuration diagram of an electroluminescent display including unit pixels of FIG. 7.

10 to 15 are circuit diagrams according to third to eighth embodiments of the present invention.

Explanation of symbols on the main parts of the drawings

100: first switching circuit 110: capacitor

120: second switching circuit 130: electroluminescent unit

140: light emission inhibiting unit 150: third switching circuit

200: drive system 203: system interface unit

205: timing controller 207: source driver

209: gate driver 210: electroluminescent display panel

213: gamma power supply unit 220: light emission control unit

In the electroluminescent display panel of the present invention for achieving the above object, in the electroluminescent display panel consisting of each unit pixel defined by a plurality of gate lines and source lines are arranged intersected, each unit pixel is applied to the gate line A first switching element for switching the data signal of the voltage source by an activation signal, a capacitor for storing a voltage of the data signal transmitted through the first switching element, and a voltage of the data signal stored in the capacitor A second switching element for switching a voltage, an electroluminescent unit for emitting light by a power supply voltage through the second switching element, and a storage signal in the capacitor of the previous frame by an activation signal of a front gate line before the current frame operation The electroluminescent unit is turned off for a predetermined time by discharging And a light emission suppressing unit to be turned off.

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

3 is a circuit diagram of an electroluminescent display panel according to a first embodiment of the present invention, FIGS. 4 and 5 are timing diagrams of an operation of FIG. 3, and FIG. 6 is an entire electroluminescent display including unit pixels of FIG. 3. 7 is a circuit diagram according to a second embodiment of the present invention, and FIG. 8 is an operation timing diagram of FIG. 6. 9 is an overall configuration diagram of an electroluminescent display including unit pixels of FIG. 7, and FIGS. 10 to 15 are circuit diagrams according to third to eighth embodiments of the present invention.

First, as shown in FIG. 3, each unit pixel defined by a plurality of gate lines GL and a source line SL that are intersected is provided. One unit pixel is shown in the drawing.

The electroluminescent display panel of the present invention is controlled by an activation signal applied to the gate line (GL) on the unit pixel to switch the data signal of the voltage source, and the first terminal is a first terminal A capacitor 110 connected to an output terminal of the switching device 100 and a second terminal connected to a power supply voltage terminal VDD to store a voltage of a data signal transmitted through the first switching device 100, and the power supply voltage; A second switching element 120 connected to a stage and switched by a voltage of a data signal stored in the capacitor 110 to switch a power supply voltage, and emit light by a power supply voltage through the second switching element 120. The electroluminescent unit 130 and the electric charge stored in the capacitor 110 of the previous frame are discharged by the activation signal of the front gate line GL before the current frame operation. It includes a light emission suppressing unit 140 to turn off (130) in a predetermined section.

The first and second switching elements 100 and 120 and the light emission suppressing unit 140 are each composed of PMOS transistors P1, P2, and P3, and the light emission suppressing unit 140 is formed of the capacitor 110. A light emission control driver connected in parallel with the capacitor 110 between the first terminal and the second terminal to apply a predetermined pulse of a low level before each activation signal is applied to the plurality of gate lines. The enable signal generated by (not shown) prevents the discharge voltage of the capacitor 110 from being transmitted to the electroluminescent unit 130.

The operation of the electroluminescent display panel having unit pixels having the above configuration will be described with reference to the timing chart.

That is, as shown in FIGS. 4 and 5, before the current frame operation, that is, before the gate signal is activated, the light emission control driver (not shown) is erased by the light emission control unit 140 disposed across the capacitor 110. When the signal E is outputted, the voltage charged in the capacitor 110 of the previous frame is completely discharged, and the electroluminescent unit 130 can no longer emit light by the light emission suppressing unit 140.

Then, during the current frame operation, that is, when an activation signal is applied to the gate line GL and a data voltage is applied to the source line SL, the voltage of the data signal is converted through the first switching element 100 into a capacitor ( 110, the electroluminescent unit 130 emits light through the power supply voltage terminal VDD by turning on the second switching element 120 by the voltage of the data signal stored in the capacitor 110. Make it work.

As shown in FIG. 5, after the previous frame 1f operation and before the current frame 2f operation, the data voltage stored in the capacitor 110 in the previous frame 1f for a predetermined period is completely By preventing the light emission of the electroluminescent unit 130 by discharging, the blurring phenomenon on the screen may be suppressed to improve image quality.

Here, when it is assumed that the time from when the electroluminescent unit 130 emits light to the output of the erase signal E before the next frame is t1, the electroluminescent unit 130 is adjusted by adjusting the t1. The brightness can be adjusted by adjusting the light emission time. In addition, when the electroluminescent unit 130 needs to be driven in a low power mode, the t1 time is shortened, thereby effectively driving the low power mode while balancing the overall gray balance.

Looking at the overall configuration of the electroluminescent display panel consisting of unit pixels having the above structure as follows.

As shown in FIG. 6, the electroluminescent display includes an R (Red), G (Green), and B (Blue) signals that are display data signals input from the driving system 200. The system interface unit 203 to be applied to the timing controller unit for receiving a data signal from the system interface unit 203 and generating various control signals and data so that the electroluminescent display panel 210 can be stably driven. 205 and a source driver 207 for converting a data signal from the timing controller 205 into an analog signal and applying a voltage to each source line SL of the electroluminescent display panel 210, and a timing controller unit ( A gate driver 209 for inputting a display control signal received from 205 to apply a pulse voltage to each gate line, and receiving power from the driving system 200. A power unit 211 for applying power required for the unit, a gamma power supply unit 213 for generating a reference voltage for digital / analog conversion of the source driving unit 207 by receiving the power branched from the power unit 211; And a light emission control driver 220 controlled by the timing controller 205 to control the light emission control unit 140 to turn off the electroluminescent unit 130 in the above-described unit pixel in a predetermined section. .

Next, FIG. 7 illustrates a second embodiment according to the present invention, in which an erase signal E, which is an enable signal of the light emission suppressing unit 140, is formed at the front end of the plurality of gate lines GL (N). The signal is activated by the gate line GL (N-1). This does not require a light emission control driver (not shown) for controlling the light emission control unit 140 described in FIG. 4, and initializes the capacitor 110 by controlling the light emission control unit 140 by itself.

An operation thereof will be described with reference to FIG. 8 as follows.

As shown, when the previous gate line GL (N-1) is activated, a video signal is stored in a pixel connected to the line. Next, the pixel connected to the gate line GL (N) drives the light emission suppressing unit 140 to completely discharge and initialize the data voltage stored in the capacitor 110 of the previous frame as described with reference to FIG. 4. Next, when the gate line GL (N) is activated and a data voltage is applied to the source line SL, the second switching is performed while charging the data voltage to the capacitor 110 through the first switching element 100. The device 120 is turned on so that the electroluminescent unit 130 emits light for a predetermined time through the power supply voltage terminal VDD.

FIG. 9 is an overall configuration diagram of an electroluminescent display panel formed of unit pixels illustrated in FIG. 7, in which the light emission control driver 220 is omitted in the electroluminescent display illustrated in FIG. 6. That is, since the erase signal E, which is the enable signal of the light emission suppressing unit 140, is activated by the gate line GL (N-1) of the preceding stage among the plurality of gate lines GL (N), the signal of FIG. The illustrated light emission suppression driver 220 is not necessary.

10 is a circuit diagram for explaining a third embodiment according to the present invention. The operation timing diagram for this is the same as FIG.

As shown, the light emission suppressing unit 140 is connected between the output terminal of the first switching device 100 and the output terminal of the second switching device 120. This is because the light emission control driver (not shown) outputs the erase signal E to the light emission control unit 140 configured at both ends of the capacitor 110 before the current frame operation, that is, before the gate signal is activated. ) Is driven to initialize the data voltage stored in the capacitor 110 of the previous frame to a value near the threshold voltage of the second switching element 120, thereby preventing the electroluminescent unit 130 from emitting light.

Then, in the current frame operation, that is, when the gate line GL is activated and a video signal having a data voltage, for example, a low luminance, is applied to the source line SL, in the conventional structure, the capacitor is charged with a voltage. Although it takes a long time, in the structure according to the embodiment of the present invention, the data voltage can be quickly charged to the capacitor 110, thereby making a high resolution electroluminescent display panel.

11 is a circuit diagram for explaining the fourth embodiment of the present invention. The operation timing for this is the same as in FIG.

As shown, the fourth embodiment of the present invention combines the embodiment described in Figs. That is, the emission suppression unit 140 is connected between the output terminal of the first switching element 100 and the output terminal of the second switching element 120, and the erase signal E which is an enable signal of the emission suppression unit 140. ) Is a signal activated by the gate line GL (N-1) of the preceding stage among the plurality of gate lines GL (N).

12 to 15 show a third switching for switching between the second switching element 120 and the electroluminescent unit 130 by the enable signal on the electroluminescent display panel constructed in the first to fourth embodiments described above. The fifth to eighth embodiments that further include the element 150 are illustrated. The third switching element 150 is preferably formed of an NMOS transistor and is turned off when the light emission suppressing unit 140 is driven, and is turned on when the light emission suppressing unit 140 is not driven, thereby causing the electroluminescent unit 130 to be turned on. ) Can be controlled more effectively.

On the other hand, the present invention described above is not limited to the above-described embodiment and the accompanying drawings, it is possible that various substitutions, modifications and changes within the scope without departing from the technical spirit of the present invention. It will be apparent to those of ordinary skill in Esau.

According to the electroluminescent display panel and the driving method thereof according to the present invention described above has the following advantages.

After the operation of the previous frame 1f, before the operation of the current frame 2f, the data voltage stored in the capacitor 110 in the previous frame 1f is completely discharged for a predetermined period to prevent light emission of the electroluminescent unit 130. As a result, blurring on the screen can be suppressed to improve image quality.

In addition, the brightness can be adjusted by adjusting the light emission time of the electroluminescent unit 130 by adjusting t1, which is the time until the erase signal E before the next frame is output. In addition, when the electroluminescent unit 130 needs to be driven in a low power mode, the t1 time is shortened, thereby effectively driving the low power mode while balancing the overall gray balance.

In addition, when a video signal having a low luminance is applied in the current frame, a high-resolution electroluminescent display panel may be manufactured to enable a capacitor to quickly charge and display a corresponding data voltage.

Claims (8)

In the electroluminescent display panel forming each unit pixel defined by a plurality of gate lines and source lines arranged to cross each other, each unit pixel is A first switching element for switching a data signal of a voltage source by an activation signal applied to the gate line; A capacitor for storing a voltage of the data signal transferred through the first switching element; A second switching element switched by the voltage of the data signal stored in the capacitor to switch the power supply voltage; An electroluminescence unit for emitting light by a power supply voltage through the second switching element; And a light emission suppressing unit configured to discharge the electric charge stored in the capacitor of the previous frame by the activation signal of the front gate line before the current frame operation to turn off the electroluminescent unit for a predetermined time. panel. The method of claim 1, And the first switching element, the second switching element, and the light emission inhibiting part are configured of a PMOS transistor. The method of claim 1, The light emitting suppressing unit is an electroluminescent display panel, characterized in that connected in parallel with the capacitor. The method of claim 1, And the light emission suppressing unit is connected between an output terminal of the first switching element and an output terminal of the second switching element. delete delete The method of claim 1, And a third switching device configured to switch between the second switching device and the electroluminescent part by an activation signal of the front gate line. The method of claim 7, wherein And said third switching element comprises an NMOS transistor.