KR100625993B1 - Organic electro-luminescent display device comprising test point lines - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electroluminescent display, comprising: an organic electroluminescent panel having a switching thin film transistor in each pixel, and receiving a gate control signal and applying the gate control signal to a scan line to switch the thin film transistors. A display unit generating an application signal to drive a gate of the thin film transistor, a control unit generating a gate control signal to drive each gate of the thin film transistors of the organic light emitting panel, and connected between the control unit and the display unit, And a signal line unit for transmitting the gate control signal output from the control unit to a display unit, wherein the signal line unit includes means for controlling or observing signals in the display unit for generating the gate application signal. do.

Description

Organic electroluminescent display device comprising test point lines

1 is a block diagram of an active matrix organic electroluminescent display.

2 is a plan view illustrating a structure of a panel of an active matrix organic electroluminescent display.

3 is a cross-sectional view of the pixel portion seen from line II of FIG. 2.

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

5 is a schematic diagram schematically showing a coupling relationship between a gate driver and a level shifter.

FIG. 6 is a waveform diagram illustrating a gate control signal, a scan line selection signal, and a scan line applying signal in a gate driver and a level shifter, which can be controlled or observed in test point lines according to an exemplary embodiment of the present invention.

<Explanation of symbols for main parts of the drawings>

1: organic electroluminescent display, 50: image processing unit,

100: main circuit section, 110: control section,

200: display unit, 210: display panel,

220: gate driver, 222: flip-flop,

224: AND gate (logical circuit section), 230: level shifter,

232: current buffer, 240: data driver,

TFTsw: thin film transistor for switches,

TFTdr: thin film transistor for driving current,

Cst: charging capacitor,

OLED: organic electroluminescent device,

TP1, TP2, TP3: test point,

TPL1, TPL2, TPL3: test point line,

GSP: gate start pulse signal,

GSC: gate shift clock signal,

GOE: Gate Output Enable Signal

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electroluminescent display, and more particularly, by providing a test point at an important node inside a display unit of a display device and providing a test point line at a signal line between the display unit and the control unit. An organic electroluminescent display device useful for inspection or inspection of a product after sale.

In general, electroluminescent displays are self-luminous displays that electrically excite fluorescent organic compounds to emit light, which can be driven at low voltage, are easy to thin, and are pointed out as problems in liquid crystal display devices such as wide viewing angle and fast response speed. It is attracting attention as the next generation display that can solve the shortcomings. The electroluminescent display may be classified into an inorganic electroluminescent display and an organic electroluminescent display according to whether a material forming the light emitting layer is an inorganic material or an organic material.

Meanwhile, in the organic light emitting display device, an organic film having a predetermined pattern is formed on glass or other transparent insulating substrate, and electrode layers are formed on upper and lower portions of the organic film. The organic film consists of organic compounds. In the organic light emitting display device configured as described above, as the anode and cathode voltages are applied to the electrodes, holes injected from the electrode to which the anode voltage is applied are moved to the light emitting layer via the hole transport layer, and the electrons have a cathode voltage. It is injected from the applied electrode into the light emitting layer via the electron transport layer. In this light emitting layer, electrons and holes recombine to produce excitons, and as the excitons change from the excited state to the ground state, the fluorescent molecules in the light emitting layer emit light to form an image.

Among such organic light emitting display devices, an active matrix active matrix (AM) type organic light emitting display device includes at least two thin film transistors (hereinafter, referred to as TFTs) for each pixel. These thin film transistors are used as switching elements for controlling the operation of each pixel and current driving elements for driving the pixels. The thin film transistor has a semiconductor active layer having a drain region and a source region doped with a high concentration of impurities on a substrate, and a channel region formed between the drain region and the source region, the gate insulating film formed on the semiconductor active layer, and the active layer. And a gate electrode formed on the gate insulating film above the channel region, and a drain electrode and a source electrode connected through the contact hole with the drain region, the source region and the interlayer insulating film therebetween.

1 is a block diagram of an active matrix organic electroluminescent display 1.

Referring to FIG. 1, a typical organic electroluminescent display 1 includes an image processor 50, a controller 110, an organic electroluminescent display panel 210, a gate driver 220, a level shifter 230, and data. Driver 240. The image processing unit 50 converts an external analog image signal into a digital signal, and internal image signals, for example, 8-bit red (R), green (G) and blue (B) image data, clock signals, vertical and horizontal, respectively. Generate sync signals.

The controller 110 generates a gate control signal (gate start pulse GSP, gate shift clock GSC, gate output enable GOE) and a data control signal according to an internal image signal from the image processor 50. . The gate driver 220 generates a selection signal for selecting a scan line (scan line) from the gate control signals GSP, GSC, and GOE from the controller 110, that is, a gate selection pulse. The level shifter 230 adaptively changes the voltage of the gate selection pulse received from each output line of the gate driver to the gate on / off voltage of the switching thin film transistor of each pixel portion of the display panel 210.

Meanwhile, the data driver 240 latches the digital image data of red (R), green (G), and blue (B) in synchronization with the data control signal, corrects the latched data according to the gamma voltage, and then A display data signal for converting the image data into analog data to supply the data line DL by one line is generated, and the display data signals corresponding to the same scan line are applied to the source lines of the display panel 210.

FIG. 2 is a plan view illustrating a pixel portion of an active matrix organic electroluminescent display, and FIG. 3 is a cross-sectional view of the I-I.

First, as shown in FIG. 2, the organic light emitting display has a plurality of subpixels. A single subpixel is surrounded by a scan line (Scan), a data line (Data), and a driving line (Vdd). Each subpixel is most simply a switching TFT (TFTsw) for switching and a driving TFT (TFTdr) for current driving. ), At least two thin film transistors, one capacitor Cst, and one organic light emitting diode OLED. The number of thin film transistors and capacitors as described above is not necessarily limited thereto, and of course, a larger number of thin film transistors and capacitors may be provided.

The switching TFT TFTsw is driven by a scanning signal applied to the scan line Scan to transfer a data signal applied to the data line Data. The driving TFT TFTdr is transferred to the organic light emitting diode OLED through the driving line Vdd according to the data signal transmitted through the switching TFT TFTsw, that is, the voltage difference Vgs between the gate and the source. Determine the amount of current flowing in. The capacitor Cst stores a data signal transmitted through the switching TFT TFTsw for one frame.

FIG. 3 illustrates a cross-sectional view of the pixel portion of the active matrix organic electroluminescent display. As shown in FIG. 3, a buffer layer 11 is formed on a first substrate 10 made of glass. The thin film transistor TFT and the organic light emitting diode OLED are formed thereon.

Such an active matrix organic light emitting display device is generally formed as follows. First, the semiconductor active layer 21 of a predetermined pattern is provided on the buffer layer 11 of the substrate 10. The gate insulating film 12 is provided on the upper surface of the semiconductor active layer 21 by SiO _{2 or the} like, and the gate electrode 22 is formed on the predetermined region above the gate insulating film 12 by a conductive film such as MoW or Al / Cu. The gate electrode 22 is connected to a scan line (not shown) for applying a TFT on / off signal. An inter-insulator 13 is formed on the gate electrode 22, and the source / drain electrodes 23 contact the source region and the drain region of the semiconductor active layer 21 through contact holes. Is formed. A passivation film 14 made of SiO ₂ , SiNx, or the like is formed on the source / drain electrode 23, and a planarization film (eg, acrylic, polyimide, BCB, or the like) is formed on the passivation film 14. 15) is formed.

In the passivation film 14 and the planarization film 15, via holes 14a and 15a are formed which are connected to the source / drain electrodes 23 by photolithography or perforation. The first electrode layer 31 serving as the anode electrode is formed on the planarization film 15, so that the first electrode layer 31 is electrically connected to the source / drain electrodes 23. A pixel define layer 16 is formed of an organic material to cover the first electrode layer 31. After the predetermined opening 16a is formed in the pixel definition film 16, the organic layer 32 is formed in the region defined by the opening 16a. The organic layer 32 includes a light emitting layer. Then, the second electrode layer 33 serving as the cathode is formed to cover the organic layer 32. The organic layer 32 emits light through the injection of holes and electrons at portions of the first electrode layer 31 and the second electrode layer 33 that face each other.

Meanwhile, the image processor 50 and the controller 110 are typically disposed on the main circuit board 100, whereas the gate driver 220, the level shifter 230, the data driver 240, and the like are displayed in the display panel ( The display unit 200 is disposed on the display unit 200 formed of one module coupled to 210.

However, during the manufacturing process, it is often difficult to determine whether the input / output signals such as the gate driver 220 and the level shifter 230 disposed on the display unit 200 are correct. Moreover, this problem also occurs in post-sale inspection of the product.

Accordingly, there is a need for a means for controlling or observing signals in a display for generating a gate application signal of an organic electroluminescent display.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art, and provides a means for easily controlling or observing signals in a display for generating a gate application signal in a display of an organic electroluminescent display. The purpose is to.

The present invention for achieving the above object,

An organic electroluminescent panel having a thin film transistor for switching is provided to each pixel, and receives a gate control signal, generates an application signal to be applied to a scan line to switch each thin film transistor, and drives the gate of the thin film transistor. With display part to say,

A controller for generating a gate control signal to drive the gates of the thin film transistors of the organic light emitting panel;

A signal line unit connected between the control unit and the display unit to transmit the gate control signal output from the control unit to a display unit;

The signal line unit provides an organic light emitting display device having means for controlling or observing signals in the display unit for generating the gate application signal.

Means for controlling or observing signals in the display unit are at least one test point line provided in the signal line unit.

In this case, the gate control signal output from the controller is selected such that a gate start pulse, a gate shift clock having a predetermined pulse width for shifting the gate start pulse to a plurality of flip-flops, and an output pulse of the flip-flop do not overlap. And a gate output enable signal.

The display unit receives the gate control signal and sequentially applies the application signal to the scan lines connected to the gates of the thin film transistors at intervals of one horizontal period.

A shift register receiving the gate start pulse and shifting the gate start pulse in each flip-flop corresponding to each scan line according to the gate shift clock; A gate driver connected to an output terminal of each flip-flop of said shift register, said gate driver having a logic circuit portion for controlling said pulse signal to be applied to said scan line in accordance with said gate output enable signal;

And a level shifter for converting output signals of the gate driver into on / off voltages of the scan line and outputting them as an application signal of the scan line.

According to another feature of the invention, the signal line unit may include a first test point line for controlling or observing the gate control signal. The first test point line is connected to a node through which a gate control signal flows between the controller and the gate driver, and the gate control signal is applied or output.

According to another feature of the invention, the signal line unit may include a second test point line for controlling or observing a pulse signal between the gate driver and the level shifter. The second test point line is connected to a node through which a scan line selection signal flows between the gate driver and the level shifter so that the scan line selection signal is applied or output.

According to another aspect of the present invention, the signal line unit may include a third test point line for controlling or observing a scan line applying signal output from the level shifter. The third test point line is connected to a node through which a scan line applying signal output from the level shifter flows, and the scan line applying signal is applied or output.

Hereinafter, an organic light emitting display device according to an embodiment of the present invention will be described with reference to the accompanying drawings.

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

As shown in FIG. 4, the controller 110 is disposed on the main circuit board 100, while the gate driver 220, the level shifter 230, the data driver 240, and the display panel 210 are disposed on the main circuit board 100. The signal line unit 300 is disposed on the display unit 200 and transmits a control signal and an image data signal from the control unit to the display unit 200 between the control unit 110 and the display unit 200.

The main circuit board 100 including the control unit 110 includes an image processing unit 50, a power supply unit (not shown), and a user input console (not shown) in addition to the control unit 110. Typically, the display unit 200 includes an organic electroluminescent display panel 210 on the front side and integrated circuits such as a gate driver 220, a level shifter 230, and a data driver 240 on the back side. It consists of a circuit board.

On the other hand, typically, the signal line unit 300 is made of a flexible printed circuit (FPC), is configured to be flexible so that it can be easily bent in a small space.

Flexible wiring circuit boards (FPCs) are developed due to the miniaturization and light weight of electronic products that require wiring. They are excellent in workability, and have high heat resistance, bending resistance, and chemical resistance, so that organic light emitting display devices, cameras, computers and peripherals, It is widely used in mobile phones, audio-visual equipment, camcorders, printers, military equipment, satellite equipment, and medical equipment. Flexible wiring circuit boards can be three-dimensional wiring alone, it is possible to reduce the size and weight of the device, and has a high durability against repeated bending. In addition, high density wiring of 0.2m / m per pitch is light, there is no wiring error, assembly is good, reliability is high, and continuous production method is possible.

The control unit 110 controls the gate control signal (gate start pulse (GSP), gate according to the internal image signals (red (R), green (G) and blue (B) image data, clock signals, vertical and horizontal synchronization signals)). Generates a shift clock (GSC), a gate output enable (GOE) and a data control signal.

Among the gate control signals output from the controller, the gate start pulse GSP is a signal for controlling the start and end points of the gate signal among one vertical synchronization signal, and is a start signal for sequentially applying a selection pulse to the scan line. In addition, the gate shift clock GSC is a signal for indicating the time of gate on / off of the thin film transistor TFTsw and is a signal for sequentially shifting the gate start pulse GSP, and the gate output enable GOE. Is a signal that selects the output pulses of the shifted gate start pulses (GSP) not to overlap and serves to control the output of the gate driver.

5 is a schematic diagram schematically showing a coupling relationship between a gate driver and a level shifter. 4 and 5, the gate driver 220 may select a scan signal (ie, a gate selection pulse) for selecting a scan line (scan line) from the gate control signals GSP, GSC, and GOE from the controller 110. Generates. To this end, the gate driver 220 has a shift register 222 which sequentially generates scan pulses in response to a gate start pulse GSP and a gate shift clock GSC signal input from the controller 110. Is composed of a plurality of flip-flops (F / F) connected in series. In order to sequentially shift the gate start pulse GSP to the plurality of flip-flops F / F, the gate shift clock GSC is connected to the plurality of flip-flops F / F in parallel. Therefore, after the gate start pulse GSP is first applied and input to the first flip-flop, whenever the gate shift clock GSC is applied, the gate start pulse GSP is sequentially moved one line to the right. Done.

In addition, in the logic circuit unit 224, in order to select the output pulses of the flip-flops F / F so as not to overlap each other (see FIG. 6), a gate output enable (GOE) signal is provided for each flip-flop (F / F). Is coupled to the output terminal of and AND gate 224. Therefore, the scan line selection signal, which is the output value of the AND gate 224, is output from each output line of the gate driver 220.

The level shifter 230 adaptively changes the voltage of the scan line selection signal input from each output line of the gate driver 220 to the gate on / off voltage of the switching thin film transistor of each pixel portion of the display panel 210. ) Is installed at the output terminal of each logic circuit unit 224, and a current buffer 232 for amplifying the current in consideration of the load of the scan line GL may be installed at the output terminal of each level shifter 230 as necessary. . Each output terminal is connected to a scan line of the display panel 210. The pixel voltage signal on the data line DL is transferred to the current driving thin film transistor TFTdr and the charging capacitor Cst by the switching thin film transistor TFTsw of each subpixel in response to a scan pulse which is an applied signal output from each output terminal. And a current is supplied to the organic light emitting diode OLED through the current driving thin film transistor TFTdr according to the charging voltage of the charging capacitor Cst to generate light emission.

FIG. 6 illustrates a gate control signal and a scan line selection signal of the gate driver 220 and the level shifter 230 shown in FIG. 5, which may be controlled or observed in the test point lines, according to an exemplary embodiment. And a waveform diagram showing a scan line application signal.

Referring to FIG. 6, the gate start pulse GSP is shifted by the gate shift clock GSC, and one period of the gate shift clock GSC at the output terminal of each flip-flop F / F in the shift register 222. As many output signals are shifted sequentially. In this case, each output signal is separated by a gate output enable (GOE) signal without being overlapped, and is amplified by the gate on / off voltage of the switching thin film transistor TFTsw through the level shifter 230 and then the current buffer 232. Output via

As shown in the waveform diagram of FIG. 6, when a gate control signal such as GSP, GSC, or GOE is applied to the gate driver 220, a predetermined pulse is recognized by recognizing 'H' of the GSP at the rising edge or the falling edge of the GSC. Generate an output with 'H' equal to one cycle of GSC having widths GSC1, GSC2, GSC3, .... However, the output signal is input to the AND gate 224 together with the signal width of the GOE, and some outputs of one cycle of the GSC having a predetermined pulse width are disabled by the GOE, and a plurality of flip-flops (F / The output signal of F) is converted into a signal having a pulse width (GOE1, GOE2, GOE3, ...) so as not to overlap, and then amplified by the gate on / off voltage in the level shifter 230, and then output to the scan line. do.

In the display device according to the present invention, test points for controlling or observing signals between circuit parts in the display part 200 are designated, and the control part 110 and the display part 200 of the main circuit part 100 are connected to each other. A line connected to the test points is installed in the signal line unit 300.

For example, the test point may be installed in a node capable of controlling or observing gate control signals GOE, GSP, and GSC input from the controller 110 to the gate driver 220. In addition, the test point may be installed at a node capable of controlling or observing a scan line selection signal between the gate driver 220 and the level shifter 230.

In addition, the test point may be installed at a node capable of controlling or observing a gate applying signal output from the level shifter 230 to the scan line.

Each line connected to the test point, that is, the test point line, extends from the display unit 200 to the signal line unit 300 so that the display unit 200 can be easily tested during the product manufacturing process or after the product sale. do. For example, when a test point for controlling or observing the gate control signals GSP, GSC, and GOE is designated as the first test point TP1, the signal line unit 300 connected to the first test point may be used. By measuring the output waveform of the first test point line, it is possible to determine whether the gate control signal from the controller 110 is appropriate. A plurality of first test points may exist according to the number of gate control signals.

In the waveform diagram of FIG. 6, the signal applied or observed at TPL1 is the same as the gate control signals GSP, GSC, GOE, and the signal applied or observed at TPL2 is the inverse of the gate output enable (GOE) signal, and TPL3. The signal applied or observed to is the same as the gate application signal.

In one embodiment, the gate control signals GSP, GSC, and GOE are applied to the first test point line TPL1, the scan line select signal is applied to the second test point line TPL2, and the third test point line TPL3. The gate applying signal can be applied to control the waveform, or can be observed.

For example, the display unit 200 is controlled by applying the gate control signals SP, GSC, and GOE of FIG. 6 to the first test point line TP1 of the signal line unit 300 connected to the first test point. At the same time, if a node input from the gate driver 220 to the level shifter 230 is designated as the second test point TP2, the scan line selection signal is appropriate by observing the waveform of the second test point line. I can figure out.

In addition, using the second test point line TPL2 connected to the second test point TP2 as a control point, for example, an inverted scan line selection signal having the same width as that of the GOE waveform of FIG. 6 may be applied. At the same time, it is possible to observe the scan line applying signal from the third test point line TPL3 using the third test point TP3 connected to the output terminal of each level shifter 230 as an observation point.

Then, using the third test point TP3 connected to the output terminal of the level shifter 230 as a control point, a gate applying signal input to each scan line is directly applied from the third test point line TPL3 to display each of the display panel. It is possible to observe whether the pixel is operating correctly.

As mentioned above, although this invention was demonstrated based on the most preferable embodiment, the said Example is only for helping understanding of this invention, The content of this invention is not limited to it. Additions, reductions, changes, modifications, etc. of some components of the composition of the present invention fall within the scope of the present invention as long as they belong to the technical idea of the present invention defined by the appended claims.

According to the display device according to the present invention, a test point line is provided at an important node inside the display unit of the display device and a test point line is provided in the signal line section between the display unit and the control unit, which is useful for product inspection during the product manufacturing process. It is also useful for inspecting products after sale. In particular, the signals in the display unit for generating the gate application signal in the display unit of the organic light emitting display device can be easily controlled or observed.                     

Moreover, the test point lines can be installed on a flexible printed circuit board which is a connection medium between the main circuit section and the display section, so that it is possible to inspect the product without disassembling the display device.

Claims (9)

An organic electroluminescent panel having a thin film transistor for switching is provided to each pixel, and receives a gate control signal, generates an application signal to be applied to a scan line to switch each thin film transistor, and drives the gate of the thin film transistor. With display part to say, A controller for generating a gate control signal to drive the gates of the thin film transistors of the organic light emitting panel; A signal line unit connected between the control unit and the display unit to transmit the gate control signal output from the control unit to a display unit; And the signal line unit has means for controlling or observing signals in the display unit for generating the gate application signal. The method of claim 1, The gate control signal output from the control unit selects a gate start pulse, a gate shift clock having a predetermined pulse width to shift the gate start pulse to a plurality of flip flops, and an output pulse of the flip flop so as not to overlap. An organic electroluminescent display comprising a gate output enable signal. The method of claim 2, The display unit, A shift register receiving the gate start pulse and shifting the gate start pulse in each flip-flop corresponding to each scan line according to the gate shift clock; A gate driver connected to an output terminal of each flip-flop of the shift register, the gate driver having a logic circuit portion controlling the pulse signal to be applied to the scan line according to the gate output enable signal; And And a level shifter configured to change output signals of the gate driver to on / off voltages of the scan line and output the signal as an application signal of the scan line. The method of claim 3, wherein And the signal line unit is a means for controlling or observing signals in the display unit, and includes a first test point line for controlling or observing the gate control signal. The method of claim 4, wherein And the first test point line is connected to a node through which a gate control signal flows between the controller and the gate driver so that the gate control signal is applied or output. The method of claim 3, wherein The signal line unit may be a means for controlling or observing signals in the display unit and including a second test point line for controlling or observing a scan line selection signal between the gate driver and the level shifter. Organic electroluminescent display. The method of claim 6, And the second test point line is connected to a node through which a scan line selection signal flows between the gate driver and the level shifter so that the scan line selection signal is applied or output. The method of claim 3, wherein The signal line unit is a means for controlling or observing signals in the display unit, and includes a third test point line for controlling or observing a scan line applying signal output from the level shifter. Light emitting display. The method of claim 8, And the third test point line is connected to a node through which a scan line applying signal output from the level shifter flows, and the scan line applying signal is applied or output.

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