KR100684825B1 - Organic electro luminescence display device and manufacturing method thereof - Google Patents

Abstract

The present invention relates to an organic light emitting display and a method of manufacturing the same. An organic electroluminescent display device according to the present invention includes an organic EL display including a display panel including a plurality of scanning lines, a plurality of data lines crossing the scanning lines, and a plurality of pixel circuits formed in a matrix shape by scanning lines and data lines The pixel circuit includes an organic EL element including an organic light emitting layer formed between first and second pixel electrode layers and between first and second pixel electrode layers and displaying an image corresponding to a current flowing between the first and second pixel electrode layers, And a driving circuit for controlling a current flowing between the first and second pixel electrode layers in response to the image signal applied to the plurality of data lines in response to the selection signal from the scanning line, The organic light emitting layer is formed so as to overlap the power supply line for supplying power to the driving circuit through the first insulating layer, It is formed so as not to overlap the line.

An organic EL display, an aperture ratio, an organic light emitting layer, a pixel electrode layer, a power supply line

Description

TECHNICAL FIELD [0001] The present invention relates to an organic electroluminescent display device,

Fig. 1 shows a voltage-writing type organic EL display device.

2 is a plan view showing a pixel circuit of the organic EL display device shown in Fig.

Fig. 3 shows a cross-sectional view of the A-A 'portion of the pixel circuit shown in Fig.

4 is a plan view schematically showing a pixel circuit according to an embodiment of the present invention.

5 is a plan view showing a pixel circuit according to an embodiment of the present invention.

6 is a cross-sectional view taken along line A-A 'of the pixel circuit shown in Fig.

Fig. 7 shows a cross-sectional view along the line A-A 'of the pixel circuit shown in Fig. 5 when the organic light emitting layer is formed to be as wide as possible.

8 illustrates a case where a pixel circuit according to an embodiment of the present invention is applied to a front emission display device.

9 shows a pixel circuit according to another embodiment of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device, and more particularly, to an electroluminescent (EL) display device having an improved aperture ratio.

2. Description of the Related Art In general, an organic EL display device is a display device for electrically exciting a fluorescent organic compound to emit light, and displays images by voltage writing or current writing of N X M organic light emitting cells. Such an organic light emitting cell has a structure of an anode, an organic thin film and a cathode layer. The organic thin film has a multilayer structure including an emitting layer (EML), an electron transport layer (ETL), and a hole transport layer (HTL) in order to improve the light emitting efficiency by improving the balance between electrons and holes. And further includes a separate electron injecting layer (EIL) and a hole injecting layer (HIL).

1 shows an organic EL display device.

1, the organic EL display device includes an organic EL display panel (hereinafter, referred to as a display panel) 100, a data driver 200, and a scan driver 300. [

The display panel 100 includes a plurality of data lines D1-Dm extending in the column direction, a plurality of scanning lines S1-Sn extending in the row direction, and a plurality of pixel circuits.

The pixel circuit includes a driving transistor 20 for controlling the current flowing through the organic EL element 40 and a driving transistor 20 for applying a voltage of the data line D1 to the gate of the driving transistor 20 in response to a selection signal from the scanning line S1 And a capacitor 30 connected between the gate and the source of the driving transistor. In addition, the source of the driving transistor 20 is connected to the power supply line 50 which transmits the power supply voltage V _DD .

The data driver 200 supplies data voltages to the data lines D1 to Dm and the scan driver 300 sequentially applies a selection signal for selecting the pixel circuits to the scan lines S1 to Sn.

FIG. 2 is a plan view showing a pixel circuit connected to the scan line S1 and the data line D1 in the organic EL display device shown in FIG. 1. FIG. 3 is a cross-sectional view taken along the line A-A 'in FIG.

2 and 3, the organic EL element 40 includes an organic light emitting layer 41 and a pixel electrode layer 42 such as ITO. Then, the organic EL element 40 is disposed apart from the power supply line 50.

The organic light emitting layer 41 is formed in the pixel region defined by the insulating layer forming the opening portion on the pixel electrode layer 42. [ That is, since the organic light emitting layer 41 is formed within the region where the pixel electrode layer 42 is formed, the region where the organic light emitting layer 41 is formed is limited by the pixel electrode layer 42. Therefore, the region where the organic light emitting layer 41 is formed is narrow, and the aperture ratio of the pixel circuit is lowered.

SUMMARY OF THE INVENTION The present invention has been made in order to improve the aperture ratio of an organic EL display device.

According to one aspect of the present invention, there is provided an organic EL display device including a plurality of scanning lines, a plurality of data lines crossing the scanning lines, and a plurality of data lines formed in a matrix by the scanning lines and the data lines. An organic EL display device comprising a display panel having a pixel circuit, wherein the pixel circuit includes first and second pixel electrode layers, and a second pixel electrode layer formed between the first and second pixel electrode layers and between the first and second pixel electrode layers An organic EL element including an organic light emitting layer for displaying an image in response to a current flowing between the first and second pixel electrode layers in response to an image signal applied to the plurality of data lines in response to a selection signal from the scanning line, Wherein the first pixel electrode layer of the organic EL element has a first insulating layer interposed therebetween The organic light emitting layer is formed to overlap the power supply line for supplying power to the driving circuit, and the organic light emitting layer is formed so as not to overlap with the power supply line.

In the organic EL display device according to one aspect of the present invention, the first pixel electrode layer includes a transparent electrode layer, and the second pixel electrode layer includes a metal layer.

In the organic EL display device according to one aspect of the present invention, the organic light emitting layer of the organic EL element is formed by a step between the power supply line and the stepped portion of the first insulating layer, a stepped portion of the first pixel electrode layer, And are spaced apart horizontally by an interval equal to or more than the sum of the intervals between the stepped portions of the layers.

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In the organic EL display device according to one aspect of the present invention, the pixel circuit includes an opening formed so as to cover at least a portion of at least an edge of the first pixel electrode layer of the organic EL element, And a second insulating layer.

In the organic EL display device according to one aspect of the present invention, the opening of the second insulating layer is formed by horizontally falling apart by a sum of the thicknesses of the power supply line and at least the first insulating layer and the first pixel electrode layer .

In the organic EL display device according to one aspect of the present invention, the first pixel electrode layer includes a metal layer, and the second pixel electrode layer includes a transparent electrode layer.

In the organic EL display device according to one aspect of the present invention, a planarization layer formed of an organic film is further formed under the first pixel electrode layer.

An organic EL display device according to another aspect of the present invention includes a display panel including a plurality of scanning lines, a plurality of data lines intersecting the scanning lines, and a plurality of pixel circuits formed in a matrix by the scanning lines and the data lines Wherein the pixel circuit includes a first pixel electrode layer and a second pixel electrode layer and an image formed between the first and second pixel electrode layers and corresponding to a current flowing between the first and second pixel electrode layers And a driving circuit for controlling a current flowing between the first and second pixel electrode layers in response to an image signal applied to the plurality of data lines in response to a selection signal from the scanning line, Wherein the first pixel electrode layer of the organic EL device is formed to overlap the scanning line with the first insulating layer interposed therebetween The.

A manufacturing method of an organic EL display device according to one aspect of the present invention is a manufacturing method of an organic EL display device including an organic EL element and a driving circuit for controlling a current flowing in the organic EL element, A first step of forming a power supply line for supplying power to the first electrode; A second step of forming a first insulating layer so that the power supply line is embedded; A third step of forming a first pixel electrode layer of the organic EL device on the first insulating layer and a part of the first pixel electrode layer overlapping the power supply line; A fourth step of forming a second insulating layer having an opening at a portion of the first pixel electrode layer not overlapped with the power supply line; A fifth step of forming an organic light emitting layer of the organic EL device in the opening; And a sixth step of forming a second pixel electrode layer on the organic light emitting layer.

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

In the drawings, the thickness is enlarged to clearly represent the layers and regions. Like parts are designated with like reference numerals throughout the specification. It will be understood that when an element such as a layer, film, region, plate, or the like is referred to as being "on" another portion, it includes not only the element directly over another element,

In the following description, the case where the present invention is applied to the back emission display will be mainly described. However, it is apparent to those skilled in the art that the concept of the present invention is not limited to a backlight display device, and can be applied to a front emission display device as described later.

4 is a plan view schematically showing a pixel circuit according to an embodiment of the present invention. 4, only one pixel circuit driven by the scanning line S1, the data line D1, and the power supply line 50 is shown for convenience of explanation.

4, the pixel circuit according to an embodiment of the present invention includes an organic EL element 40 for expressing an image corresponding to an amount of current to be applied, And a driving circuit (80).

The organic EL element 40 includes an organic light emitting layer, a pixel electrode layer 42 for forming an anode (ITO), and a pixel electrode layer (not shown) for forming a cathode.

The driving circuit 80 can be formed using a driving circuit of a voltage or current writing type. When a selection signal is applied from a scanning line, a current flowing in the organic EL element 40 is controlled in accordance with an image signal applied to the data line So that a desired image is displayed.

The pixel electrode layer 42 of the organic EL element 40 is formed so as to overlap with the power supply line 50 of the driving circuit 80 according to an embodiment of the present invention. In this case, since a constant power supply voltage is applied to the power supply line 50, variations in small data applied to the pixel electrode layer 42 do not substantially affect the power supply line 50. [

Therefore, when the pixel electrode layer 42 is formed to overlap with the power supply line 50, the organic light emitting layer 41 can be formed to be wider, and the aperture ratio of the organic EL display device can be improved.

5 is a plan view showing a pixel circuit according to an embodiment of the present invention.

5, the driving circuit 80 includes a driving transistor 20 for controlling the current flowing to the organic EL element 40 in accordance with the voltage applied to the gate, A switching transistor 10 for transferring the applied image signal to the driving transistor 20, and a capacitor 30.

Specifically, the gate electrode of the switching transistor 10 is formed by an electrode layer substantially the same as the scanning line S1, and the source region of the switching transistor 10 is electrically connected to the data line D1 by a contact hole . The drain region of the switching transistor 10 is elongated toward the driving transistor 20 and is electrically connected to the gate electrode of the driving transistor 20 by a contact hole.

The drain region of the driving transistor 20 is electrically connected to the power supply line 50 through a contact hole and the source region is electrically connected to the pixel electrode layer 42 of the organic EL element 40 by a contact hole.

At this time, an insulating layer is formed between the pixel electrode layer 42 of the organic EL element 40 and the power supply line 50 so that a part of the pixel electrode layer 42 overlaps the power supply line 50 with the insulating layer therebetween .

The capacitor 30 is formed by the power supply line 50 and the gate electrode of the driving transistor 20.

Thus, when the switching transistor 10 is turned on by the selection signal, the data voltage is transferred to the gate of the driving transistor 20, and a predetermined current is applied to the pixel electrode layer 42. The holes injected from the pixel electrode layer 42 are transferred to the light emitting layer via the major transport layer of the organic light emitting layer 41 and electrons are injected from the cathode electrode layer (not shown) via the electron transport layer of the organic light emitting layer 41 do. Electrons and holes recombine in the light emitting layer to generate excitons. As the excitons change from the excited state to the ground state, the fluorescent molecules of the light emitting layer emit light. At this time, the emitted light is emitted through the transparent pixel electrode layer 42, the insulating layer, and the substrate, thereby forming an image.

6 is a cross-sectional view taken along line A-A 'of the pixel circuit shown in Fig.

6, an organic EL display device according to an embodiment of the present invention includes a polycrystalline silicon layer 12 formed on a transparent insulating substrate 11, wherein the polycrystalline silicon layer 12 is formed An insulating film 15 made of silicon dioxide (SiO ₂ ), silicon nitride (SiNx) or the like is formed.

A gate electrode 16 made of aluminum (Al), chromium (Cr) or the like is formed in the lateral direction so as to cross the silicon layer 12 on the insulating film 15.

At this time, in the silicon layer 12, the portion located under the gate electrode 16 is not doped, and both portions of the silicon layer 12 are doped with an n-type impurity. And a drain region 14, and a non-doped region forms a channel region.

A source electrode 18 is formed on the source region 13 and is electrically connected to the data line D1 through the source electrode 18. [ A drain electrode 19 is formed on the drain region 14 and a drain electrode 19 is connected to the gate electrode of the second transistor 20.

The power supply line 50 is formed on the insulating film 15 and buried by the first insulating layer 17. The pixel electrode layer 42 of the organic EL element 40 is formed on the first insulating layer 17 between the transistor 10 and the power supply line 50. [ The pixel electrode layer 42 of the organic EL element 40 extends to a portion over the power supply line 50 and a second insulating layer 23 having an opening formed on the pixel electrode layer 42 is formed. At this time, the second insulating layer 23 is formed so as to cover at least a part of the edge of the pixel electrode layer 42.

When the organic light emitting display device according to an embodiment of the present invention is a backside light emitting display device, the opening of the second insulating layer 23 is formed at a portion where the pixel electrode layer 42 does not overlap the power supply line 50 And the organic light emitting layer 41 is formed in the opening of the second insulating layer 23. On the organic light emitting layer 41, a metal layer 21 for forming a cathode electrode is formed.

7 is a cross-sectional view taken along the line A-A 'in the case where the organic light emitting layer 42 is formed to be as wide as possible.

As shown in FIG. 7, the organic light emitting layer 41 can be formed so as to be maximally close to the power supply line 50 within a range that does not warp.

The distance between the step of the first insulating layer 17 and the power supply line 50 is b and the distance between the step of the pixel electrode layer 42 and the step of the first insulating layer 17 is a , The opening portion of the second insulating layer 23 is formed away from the power supply line 50 by a sum of at least a and b, and the aperture ratio of the organic EL display device is maximized.

As described above, by overlapping the pixel electrode layer 42 of the organic EL element 40 with the power supply line 50 and the insulating layer 17 interposed therebetween, the organic light emitting layer 41 can be formed to be wider, .

8 illustrates a case where a pixel circuit according to an embodiment of the present invention is applied to a front emission display device.

As shown in FIG. 8, when the concept of the present invention is applied to the front emission display device, the planarization layer 22 is formed on the first insulation layer 17, .

The planarizing film 22 may be formed of an organic film. The electrode layer 42 is formed of a metal layer capable of reflecting light, and the electrode layer 21 is formed of a transparent electrode layer. According to an embodiment of the present invention, the electrode layer 42 is formed to overlap with the power supply line 50 and the first insulating layer 17 therebetween.

9 shows a pixel circuit according to another embodiment of the present invention.

The pixel circuit according to another embodiment of the present invention is also characterized in that the pixel electrode layer 42 of the organic EL element 40 overlaps not only the power supply line 50 but also the scanning line S2, Which is different from the pixel circuit shown in FIG.

Specifically, since the positive voltage signal is applied to the scanning line during the selection time of the pixel circuit, a small voltage fluctuation by the pixel electrode layer 42 does not substantially affect the selection signal applied to the scanning line.

By overlapping the pixel electrode layer 42 of the organic EL element 40 with the signal line to which the constant voltage is applied, the light emitting region of the pixel circuit can be maximized and the aperture ratio of the organic electroluminescent display device can be increased.

In the pixel circuit according to another embodiment of the present invention, a second insulating layer having an opening is formed on the pixel electrode layer 42, and an organic light emitting layer 41 is formed on the opening. The openings of the second insulating layer are formed so as to be horizontally spaced at least by the sum of the distance between the stepped portion of the first insulating layer and the power supply line and the stepped portion of the pixel electrode layer 42 and the stepped portion of the first insulating layer .

In FIG. 9, the pixel electrode layer 42 is illustrated as overlapping the scanning line S2 of the next row, but it goes without saying that it may be overlapped with the current scanning line S1 in some embodiments. In addition, the pixel electrode layer 42 may be superposed only on the scanning line S2 without overlapping with the power supply line 50. [

In the foregoing, embodiments in which the concept of the present invention is optimally applied have been described. It will be apparent to those skilled in the art, however, that the concept of the present invention is not limited to the above embodiments, and that various modifications may be made without departing from the scope of the present invention.

Specifically, in the above description, the drive circuit includes a voltage-write-type circuit including only a driving transistor and a switching transistor, but the concept of the present invention is not limited to a specific pixel circuit, Alternatively, a drive circuit can be formed by a current write method.

In this case, the pixel electrode layer of the organic EL element may be a gate electrode or a source / drain electrode. In this case, the power source line may be a gate electrode or a source / drain electrode of the transistor. And an insulating layer.

Further, in the above description, the case where the driving transistor and the switching transistor are implemented by a transistor having an N-type channel has been described. However, the driving transistor and the switching transistor may include a first electrode, a second electrode, And all elements capable of controlling a current flowing from the second electrode to the third electrode according to a voltage applied to the electrode and the second electrode.

According to the present invention, by overlapping an electrode layer of an organic EL element with a signal line to which a constant voltage such as a scan line is applied, an organic light emitting layer can be formed in a wide area, and the aperture ratio of the organic EL display device can be improved.

Claims (23)

An organic EL (electroluminescent) display device comprising a display panel having a plurality of scanning lines, a plurality of data lines crossing the scanning lines, and a plurality of pixel circuits formed in a matrix by the scanning lines and the data lines In this case, The pixel circuit includes: An organic EL element including first and second pixel electrode layers and an organic light emitting layer formed between the first and second pixel electrode layers and displaying an image corresponding to a current flowing between the first and second pixel electrode layers, And a driving circuit for controlling a current flowing between the first and second pixel electrode layers in response to an image signal applied to the plurality of data lines in response to a selection signal from the scanning line / RTI > Wherein the first pixel electrode layer of the organic EL element is formed so as to overlap a power supply line for supplying power to the driving circuit with the first insulating layer therebetween and the organic light emitting layer is formed to overlap with the power supply line EL display device. The method according to claim 1, Wherein the first pixel electrode layer includes a transparent electrode layer, and the second pixel electrode layer includes a metal layer. delete 3. The method of claim 2, Wherein the organic light emitting layer of the organic EL element horizontally falls apart by a distance equal to or greater than a sum of the distance between the step of the power supply line and the first insulating layer, and the distance between the step of the first pixel electrode layer and the step of the first insulating layer And the organic EL display device. The method according to claim 1, Wherein the pixel circuit further includes a second insulating layer covering a part of an edge of the first pixel electrode layer of the organic EL element and including an opening formed so as not to overlap with the power supply line. 6. The method of claim 5, The opening portion of the second insulating layer is horizontally separated by an interval equal to or greater than a sum of the distance between the step of the power supply line and the first insulating layer and the distance between the step of the first pixel electrode layer and the step of the first insulating layer And the organic EL display device. The method according to claim 1, Wherein the first pixel electrode layer includes a metal layer, and the second pixel electrode layer includes a transparent electrode layer. 8. The method of claim 7, And a planarization layer formed of an organic film below the first pixel electrode layer. delete delete An organic EL display device comprising a display panel including a plurality of scanning lines, a plurality of data lines intersecting the scanning lines, and a plurality of pixel circuits formed in a matrix by the scanning lines and the data lines, The pixel circuit includes: An organic EL element including first and second pixel electrode layers and an organic light emitting layer formed between the first and second pixel electrode layers and displaying an image corresponding to a current flowing between the first and second pixel electrode layers, And a driving circuit for controlling a current flowing between the first and second pixel electrode layers in response to an image signal applied to the plurality of data lines in response to a selection signal from the scanning line, Wherein the first pixel electrode layer of the organic EL device is formed so as to overlap the scanning line with a first insulating layer interposed therebetween, the first pixel electrode layer includes a transparent electrode layer, and the second pixel electrode layer includes a metal layer And the organic light emitting layer of the organic EL device is formed so as not to overlap the scanning line. 12. The method of claim 11, The organic light emitting layer of the organic EL element is horizontally formed to be spaced by an interval equal to or greater than a sum of a distance between the step of the scan line and the first insulating layer and a step between the step of the first pixel electrode layer and the step of the first insulating layer And the organic EL display device. An organic EL display device comprising a display panel including a plurality of scanning lines, a plurality of data lines intersecting the scanning lines, and a plurality of pixel circuits formed in a matrix by the scanning lines and the data lines, The pixel circuit includes: An organic EL element including first and second pixel electrode layers and an organic light emitting layer formed between the first and second pixel electrode layers and displaying an image corresponding to a current flowing between the first and second pixel electrode layers, And a driving circuit for controlling a current flowing between the first and second pixel electrode layers in response to an image signal applied to the plurality of data lines in response to a selection signal from the scanning line, Wherein the first pixel electrode layer of the organic EL element is formed so as to overlap the scanning line with a first insulating layer interposed therebetween, the pixel circuit covers at least a part of at least an edge of the first pixel electrode layer of the organic EL element, And a second insulating layer including an opening formed so as not to overlap with the scanning line. 14. The method of claim 13, The opening portion of the second insulating layer is horizontally separated by an interval equal to or greater than a sum of the distance between the step of the power supply line and the first insulating layer and the distance between the step of the first pixel electrode layer and the step of the first insulating layer And the organic EL display device. delete delete An organic EL display device comprising a display panel including a plurality of scanning lines, a plurality of data lines intersecting the scanning lines, and a plurality of pixel circuits formed in a matrix by the scanning lines and the data lines, The pixel circuit includes: An organic EL element including first and second pixel electrode layers and an organic light emitting layer formed between the first and second pixel electrode layers and displaying an image corresponding to a current flowing between the first and second pixel electrode layers, And a driving circuit for controlling a current flowing between the first and second pixel electrode layers in response to an image signal applied to the plurality of data lines in response to a selection signal from the scanning line, Wherein the first pixel electrode layer of the organic EL element is formed so as to overlap the scanning line with a first insulating layer interposed therebetween, and the pixel circuit further comprises a power supply line for supplying power to the driving circuit, Wherein the first pixel electrode layer of the device is formed to overlap the power supply line with the third insulating layer interposed therebetween. 18. The method of claim 17, Wherein the third insulating layer is substantially the same layer as the first insulating layer. A manufacturing method of an organic EL display device including an organic EL element and a driving circuit for controlling a current flowing through the organic EL element, A first step of forming a power supply line for supplying power to the driving circuit; A second step of forming a first insulating layer so that the power supply line is embedded; A third step of forming a first pixel electrode layer of the organic EL device on the first insulating layer and a part of the first pixel electrode layer overlapping the power supply line; A fourth step of forming a second insulating layer having an opening at a portion of the first pixel electrode layer not overlapped with the power supply line; A fifth step of forming an organic light emitting layer of the organic EL device in the opening; And A sixth step of forming a second pixel electrode layer on the organic light emitting layer Wherein the organic EL display device is a display device. 20. The method of claim 19, Wherein the first pixel electrode layer is formed of a transparent electrode and the second pixel electrode layer is formed of a metal layer. 20. The method of claim 19, Wherein the organic light emitting layer of the organic EL element horizontally falls apart by a distance equal to or greater than a sum of the distance between the step of the power supply line and the first insulating layer, and the distance between the step of the first pixel electrode layer and the step of the first insulating layer Wherein the organic EL display device is formed on the substrate. 20. The method of claim 19, Wherein the second insulating layer is an insulating layer for defining a pixel region. 20. The method of claim 19, And forming a planarization layer formed of an organic film on the first insulating layer before the third step.

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