KR100600397B1 - Light emitting display - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting display device having a power line and an interference blocking means capable of preventing electrical interference transmitted from a power supply to a driving circuit. According to the present invention, there is provided a light emitting display device including an image display unit including a plurality of pixels, a scan driver supplying a scan signal to a scan line connected to the pixel, and a data line supplied with external power through a first power supply line and connected to the pixel. A driving circuit unit for supplying a data signal to the control unit and controlling the scan driver, a power supply unit supplying pixel power to a pixel power line connected to the pixel by receiving external power through a second power line, and first and second power lines And an interference blocking means electrically connected to and blocking electrical interference transmitted from the power supply to the drive circuit.

Light emitting display, power supply, driving circuit, ripple, power line, separation

Description

Light emitting display device             

1 is a block diagram of a light emitting display device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating driving signals supplied to pixels by a scan driver and a data driver of the light emitting display device illustrated in FIG. 1.

3 is a diagram illustrating an interference blocking unit of a light emitting display device according to an embodiment of the present invention.

4 is a circuit diagram of a pixel of the light emitting display device illustrated in FIG. 1.

5 is a schematic view of an implementation of a light emitting display device according to an embodiment of the present invention.

FIG. 6 is a schematic plan view of a flexible circuit board of the light emitting display device illustrated in FIG. 5.

FIG. 7 is a partially enlarged cross-sectional view taken along the line VII-VII of the flexible circuit board illustrated in FIG. 6.

8 is a schematic bottom view of the flexible circuit board of FIG. 6.

Explanation of symbols on the main parts of the drawings

100: light emitting display device 110: image display unit

120: pixel 130: scan driver

140: data driver 150: timing controller

160: driving circuit section 170: DC-DC converter

180: interference blocking unit 182: first power line

184: second power line

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting display device, and more particularly, to an organic light emitting display device including a power line capable of preventing electrical interference transmitted from a power supply unit to a driving circuit unit and interference blocking means.

Recently, various flat panel displays have been developed to reduce weight and volume, which are disadvantages of cathode ray tube displays. Such flat panel displays include, for example, liquid crystal displays (LCDs), plasma display panels (PDPs), field emission displays (FEDs), and electroluminescence (EL) displays. Device and the like.

Among them, a light emitting display device is a display device using a self-luminous element that emits light by itself, and has advantages of fast response speed and high luminous efficiency, luminance, and viewing angle. Such light emitting display devices are classified into inorganic light emitting display devices employing inorganic light emitting devices and organic light emitting display devices employing organic light emitting devices according to materials of light emitting layers. An organic light emitting display is a display device that electrically excites fluorescent or phosphorescent organic compounds and emits light. The organic light emitting diode display is configured by voltage programming or current programming of M * N organic EL devices (OLED or Organic Light Emitting Device, OLED). It is configured to display the brightness.

In addition, the above-described conventional light emitting display device includes an image display unit including a plurality of pixels and displaying a predetermined image, a driving circuit unit for driving the image display unit, and a power supply unit for supplying power to the image display unit and the driving circuit unit. . In this case, most light emitting display devices use a DC-DC converter as a power supply. The DC-DC converter basically uses a switching element to split a DC voltage or current into a square wave pulse that emerges, and then filters and generates a desired DC component.

Therefore, in the conventional light emitting display device, since the power supply unit and the driving circuit unit are commonly connected through one power line connected from an external power supply device to the light emitting display device, a switching element is required to generate a desired direct current in the power supply unit. In the on-off operation, the ripple generated from the power supply unit flows back through the power line and flows into the driving circuit unit, whereby an error may occur in the operation of the driving circuit unit.

As described above, in the conventional light emitting display device, electrical interference generated from the power supply unit is transmitted to the driving circuit unit, thereby preventing the driving circuit unit from operating normally. Here, ripple is defined as a peak-to-peak value of a voltage or a current in which an alternating current component that is not completely smooth in a desired direct current component is overlapped. The smaller the ripple factor of the alternating current component (ripple factor) relative to the average value of the direct current component, the closer to the desired direct current component, and the larger the ripple factor, the larger the ripple factor may have a relatively large influence on other electrically connected devices.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a light emitting display device which operates more stably and improves reliability by preventing electrical interference generated from a power supply unit from being transmitted to a driving circuit unit. will be.

In order to achieve the above object, according to an aspect of the present invention, an image display unit including a plurality of pixels, a scan driver for supplying a scan signal to a scan line connected to the pixel, and an external power supply through the first power line A driving circuit unit for supplying a data signal to a data line connected to the pixel and controlling the scan driver; a power supply unit supplying pixel power to a pixel power line connected to the pixel by receiving external power through a second power line; A light emitting display device is provided that includes an interference blocking means electrically connected to first and second power lines to block electrical interference from a power supply to a driving circuit.

Preferably, the light emitting display device further includes a first ground line and a second ground line electrically connected to the driving circuit unit and the power supply unit, respectively.

In addition, the first and second power lines and the first and second ground lines are formed on the flexible circuit board.

The interference blocking means also includes a capacitive capacitor connected between the first power line and the second power line.

The driving circuit portion also includes a data driver for supplying a data signal to the data line, and a timing controller for supplying control signals to the scan driver and the data driver.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, parts irrelevant to the present invention have been omitted for clarity, and like reference numerals denote like parts throughout the specification.

1 is a block diagram of a light emitting display device according to an embodiment of the present invention. FIG. 2 is a diagram illustrating driving signals supplied to pixels by a scan driver and a data driver of the light emitting display device illustrated in FIG. 1. 3 is a diagram illustrating an interference blocking unit of a light emitting display device according to an embodiment of the present invention.

1 and 2, the light emitting display device 100 displays an image by an active matrix driving method. This driving method can control each pixel individually to produce a desired luminance, and can display natural colors with excellent image quality. To this end, the light emitting display device 100 includes an image display unit 110, a scan driver 130, a driving circuit unit 160, a power supply unit 170, and an interference blocking unit 180.

The image display unit 110 includes n × m pixels 120. Here, n and m represent arbitrary natural numbers. Each pixel 120 includes a light emitting element and a pixel circuit for controlling the light emitting element (see FIG. 4). In addition, the image display unit 110 extends from the scan driver 130 in the horizontal direction of the image display unit 110 and has n scan lines S1, S2,..., Sn electrically connected to the pixel 120. The data driver 140 includes m data lines D1, D2, D3,..., And Dm extending in the vertical direction of the image display unit 110 and electrically connected to the pixel 120.

The scan driver 130 generates a scan signal and sequentially supplies the generated scan signal to the first scan line S1, the second scan line S2, and the n-th scan line Sn. In this case, pixels connected to each scan line S1, S2,..., Sn are sequentially selected in units of horizontal lines. In addition to the progressive scan method, the scan signal may include a single scan method, a dual scan method, an interlaced scan method, a combination thereof, or another scanning method in addition to the progressive scan method. 120).

The driving circuit unit 160 supplies a data signal to the plurality of pixels 120. In addition, the driving circuit unit 160 supplies the scan control signal SCS to the scan driver 130 to control the scan driver 130. Preferably, the driving circuit unit 160 is formed of the data driver 140 and the timing controller 150.

As illustrated in FIG. 2, the data driver 140 may supply the data signal DS to the pixels of the horizontal line when the scan signal is supplied to the scan lines S1, S2,..., Sn. The data signal is supplied to (D). Here, the data line D includes a first data line D1, a second data line D2, a third data line D3, and an m-th data line Dm. The data signal described above represents a data voltage. The data driver may be implemented as a data driver of a current driving method that supplies a data current according to the structure of the pixel circuit. In addition, the timing controller 150 supplies the data control signal DCS and the data signal Data to the data driver 140, and controls the data driver 140. In this case, the timing controller 150 may receive a synchronization signal from an external host device.

The power supply unit 170 generates the first pixel power source VDD and the second pixel power source VSS by using an external power source supplied from an external power supply device, and generates the first pixel power source VDD and the second pixel power source VSS. The pixel power source VSS is supplied to the pixel 120. The power supply unit 170 is preferably formed of a DC-DC converter. Therefore, hereinafter, the power supply unit 170 will be described as a DC-DC converter.

The interference blocking unit 180 may include first and second power lines 182 and second electrically connected to the driving circuit unit 160 and the DC-DC converter 170, respectively, from an external power supply device not shown in FIG. 1. And a power line 184. The first power line 182 transmits external power to the DC-DC converter 170 from an external power supply device, and the second power line 184 is external to the driving circuit unit 160 from an external power supply device. Deliver power.

In addition, the interference blocking unit 180 includes a first ground line and a second ground line electrically connected to the driving circuit unit 160 and the DC-DC converter 170 from an external power supply device, respectively (FIG. 7). References 522 and 524).

In this case, the first power line 182, the second power line 184, and / or the first ground line and the second ground line may be formed on the flexible circuit board connecting the external power supply device and the light emitting display device 100. (See reference numeral 500 of FIGS. 5-7). In this case, the DC-DC converter 170 and / or the driving circuit 160 may be formed on the flexible circuit board.

In addition, the interference blocking unit 180 may include an interference blocking unit 186 connected between the first power line 182 and the second power line 184 as shown in FIG. 3. For example, the interference blocking means 186 includes a capacitive capacitor. By such a configuration, the interference blocking unit 180 transmits noise transmitted from the DC-DC converter 170 to the driving circuit unit 160 through the first power line 182 and the second power line 184. Or reduce electrical interference such as ripple.

According to the above-described present invention, an interference interruption is formed by separating a power supply line and / or a grounding line which transmits power from an external power supply device to a power supply unit and a circuit driving unit in a light emitting display device, and forming a capacitive capacitor between the power supply lines. A light emitting display device having a portion is provided. With such a configuration, in the light emitting display device 100 according to the present invention, the influence of the ripple generated from the power supply unit 170 on the driving circuit unit 160 can be greatly reduced. Accordingly, the light emitting display device 100 may operate more stably, and the reliability of the light emitting display device 100 may be improved.

4 is a circuit diagram of a pixel of the light emitting display device illustrated in FIG. 1.

Referring to FIG. 4, the pixel 120 of the light emitting display device 100 according to an exemplary embodiment of the present invention represents basic components of the image display unit 110 displaying an image in the light emitting display device 100. An electroluminescent device (EL) and a pixel circuit 122 for controlling the light emitting element EL. In addition, the pixel 120 is connected to a power line for transmitting the first pixel power source VDD and the second pixel power source VSS, and is transferred through the scan signal and the data line Dm transmitted through the scan line Sn. A predetermined color and a predetermined level of light are emitted according to the data signal.

Specifically, the light emitting element EL of the pixel 120 includes an organic thin film and first and second electrodes formed on both surfaces of the organic thin film. Here, the first electrode represents an anode formed of a predetermined metal material, and the second electrode represents a cathode formed of a transparent electrode (Indium Tin Oxide, ITO) or the like. The second electrode may be commonly connected to the second electrode of another light emitting element in the light emitting display device.

Next, the pixel circuit 122 includes a first transistor M1, a capacitor C, and a second transistor M2. In the present exemplary embodiment, the first and second transistors M1 and M2 of the pixel circuit 122 may be implemented as thin film transistors, and each has a gate, a source, and a drain. Here, the first and second transistors M1 and M2 are formed of a P-type thin film transistor.

First, the second transistor M2 is a gate connected to the scan line Sn, a source connected to the data line Dm, and a drain commonly connected to the gate of the first transistor M1 and one electrode of the capacitor C. It is provided. As a result, the second transistor M2 samples the data signal applied to the data line Dm according to the scan signal applied to the scan line Sn.

The capacitor C includes one electrode commonly connected to the drain of the second transistor M2 and the gate of the first transistor M1, a power supply line transferring the first pixel power supply VDD, and a source of the first transistor M1. It is provided with a common electrode connected to. As a result, the capacitor C stores a predetermined voltage corresponding to the data signal transmitted through the data line Dm during the on period of the second transistor M2, and stores the predetermined voltage during the off period of the second transistor M2. The voltage between the gate and the source of transistor M1 is maintained at a stored voltage.

The first transistor M1 is common to the one electrode of the capacitor C and the gate connected to the drain of the second transistor M2, the power supply line for transmitting the first pixel power supply VDD, and the electrode of the capacitor C. And a drain connected to the light emitting element EL. As a result, the first transistor M1 operates as a current source for supplying a predetermined current to the light emitting element EL by a voltage stored in the capacitor C and applied between the gate and the source.

Next, an example of a light emitting display device according to an exemplary embodiment of the present invention will be described with reference to FIGS. 5 to 8. 5 is a view schematically illustrating an embodiment of a light emitting display device according to an embodiment of the present invention. FIG. 6 is a schematic plan view of a flexible circuit board of the light emitting display device illustrated in FIG. 5. FIG. 7 is a partially enlarged cross-sectional view taken along the line VII-VII of the flexible circuit board illustrated in FIG. 6. And FIG. 8 is a schematic bottom view of the flexible circuit board of FIG. 6.

5 to 8, the light emitting display device 300 includes an image display part 320, a scan driver 330, and a driver circuit part 340 formed on a predetermined substrate 310 such as a glass substrate or an insulating substrate. And a first pixel power line 350, a second pixel power line 360, and a pad unit 370. In addition, the light emitting display device 300 further includes a flexible circuit board 500 that electrically connects an external power supply or control unit with the light emitting display device 300.

Referring to FIG. 5, the image display unit 320 is disposed at approximately the center of the substrate 310, the scan driver 330 is disposed at the right side of the image display unit 320, and the driving circuit unit 340 is disposed at the image display unit 320. The pad unit 370 is disposed below the driving circuit unit 340 on the lower side of the image display unit 320. In addition, the first pixel power line 350 extends from the pad portion 370 disposed on the lower surface of the image display portion 320 to the upper surface of the image display portion 310 through the right edge of the substrate 310. In addition, the second pixel power line 360 is disposed on the left side of the image display unit 320. The pad portion 370 is connected to the flexible circuit board 500 by the power supply lines 512 and 514, the ground lines 522 and 524, and the signal lines 516 (see FIGS. 6 and 7). The flexible circuit board 500 is connected to the pad portion 370 and folded on the rear surface of the substrate 310, and as shown in FIG. 7, the base film 502, the conductive circuit pattern 504, and the insulating film 506. Is formed. In addition, the DC-DC converter 380 may be formed on the flexible circuit board 500 as illustrated in FIG. 8. In the flexible circuit board 500, some electrical elements 342 and 344, such as resistors, diodes, capacitors, and the like of the driving circuit unit 340 may be formed in the flexible circuit board 500.

As such, the light emitting display device 300 according to the present exemplary embodiment may include the first power line 512, the second power line 514, and the first ground line 522 formed on the flexible circuit board 500 from an external power supply device. And an external power source to the DC-DC converter and the driving circuit unit 340 independently and through the second ground line 524. At this time, an interference blocking means such as a capacitive capacitor is provided between the first power line 512 and the second power line 514 to substantially reduce the ripple generated from the power supply to the driving circuit. Such interference blocking means is preferably arranged between the power lines between the flexible circuit board and the external power supply (see FIG. 3).

Meanwhile, in the above-described embodiment, the scan driver 130 and / or the data driver 140 may be directly mounted on the substrate on which the image display unit 110 is formed, and the scan line, on the substrate on which the image display unit 110 is formed, It can be replaced by a driving circuit formed of the same layers as the data line and the transistor. On the other hand, the scan driver 130 and / or the data driver 140 may be formed in a chip on flexible board, or chip on film (COF) structure. In other words, the scan driver 130 and / or the data driver 140 may be mounted in the form of a chip or the like on flexible printed circuits (FPC) or a film that are bonded to and electrically connected to the substrate. .

In the above-described embodiment, the transistor in the pixel circuit has been described as a P-type transistor. However, the present invention is not limited to such a configuration, and the transistor in the pixel circuit can be implemented with an N-type transistor.

In the above-described embodiment, the case where one driving transistor M1 and one switching transistor M2 are included in the pixel circuit has been described. However, the present invention is not limited to such a configuration. For example, the pixel circuit according to the present invention may include at least two driving transistors and / or at least two switching transistors. In addition, the pixel circuit according to the present invention may be configured to include at least two light emitting elements connected to one driving transistor. In addition, the pixel circuit according to the present invention may be driven in a sequential driving manner in which two light emitting devices are sequentially driven during one horizontal period. In this case, the at least two light emitting devices may display different colors.

In addition, in the above-described embodiment, the pixel circuit is referred to as a basic pixel circuit of the voltage write method including the driving transistor M1 and the switching transistor M2. However, the present invention can be applied to a pixel write type pixel circuit including a transistor for compensating a threshold voltage of a driving transistor, a transistor for compensating a voltage drop, etc. in addition to the switching transistor and the driving transistor. Further, the present invention can be applied not only to the pixel circuit of the voltage write method but also to the pixel circuit of the current write method which supplies a data signal as a data current.

Further, in the above-described embodiment, while the transistor in the pixel circuit has been described as having a source, a drain, and a gate, each transistor has a first electrode representing a source or drain, a second electrode representing a drain or source, and a gate. It can be formed to. In other words, the MOS transistor in the above-described pixel circuit is mentioned as an example. Therefore, the pixel circuit of the present invention can be formed of other kinds of transistors in addition to the MOS transistors. For example, a first electrode, a second electrode, and a third electrode are provided, and the amount of current flowing from the second electrode to the third electrode can be controlled by a voltage applied between the first electrode and the second electrode. It can be implemented as an active element.

In addition, in the above-described embodiment, the second transistor M2 of the pixel circuit is an element for switching the electrodes on both sides in response to the scan signal, and may be implemented using several switching elements capable of performing the same function. have.

In addition, in the above-described embodiment, the light emitting device may include an inorganic light emitting device to form a light emitting layer using an inorganic material in addition to the organic light emitting device.

As mentioned above, although preferred embodiment of this invention was described in detail, this invention is not limited to the said embodiment, A various deformation | transformation by a person of ordinary skill in the art within the scope of the technical idea of this invention is carried out. This is possible.

According to the present invention, the electric interference generated from the power supply unit is not transmitted to the driving circuit unit, whereby the light emitting display device operates more stably and improves reliability.

Claims (5)

An image display unit including a plurality of pixels; A scan driver which supplies a scan signal to a scan line connected to the pixel; A driving circuit unit which receives external power through a first power line, supplies a data signal to a data line connected to the pixel, and controls the scan driver; A power supply unit receiving the external power through a second power line and supplying pixel power to a pixel power line connected to the pixel; And And interference blocking means electrically connected to the first and second power lines to block electrical interference from the power supply to the driving circuit. The method of claim 1, And a second ground line electrically connected to the driving circuit unit and the power supply unit, respectively. The method of claim 2, The first and second power lines and the first and second ground lines are formed on a flexible circuit board. The method of claim 3, The interference blocking means includes a capacitive capacitor connected between the first power line and the second power line. The method of claim 1, And the driving circuit unit includes a data driver supplying the data signal to the data line, and a timing controller supplying a control signal to the scan driver and the data driver.

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