KR20060077898A - Organic electro luminescence device and the fabrication method thereof - Google Patents

Abstract

The present invention relates to an organic electroluminescent device, and more particularly, to a dual panel type organic electroluminescent device and a method of manufacturing the same.

The present invention forms an organic electroluminescent layer having a uniform thickness by further forming a second buffer layer protruding to the organic electroluminescent layer region below the first buffer layer below the partition in the organic electroluminescent device to improve device characteristics and improve image quality. There is an advantage.

Dual panel, buffer, peening, organic light emitting layer, bulkhead

Description

Organic electroluminescent device and its manufacturing method {Organic Electro luminescence Device and the fabrication method

1 is a view showing a basic pixel structure of a general active matrix organic electroluminescent device.

Figure 2 is a schematic cross-sectional view of a conventional bottom emission organic electroluminescent device.

3 is an enlarged cross-sectional view of one subpixel area of the FIG. 2 bottom emission type organic light emitting display device;

4 is a schematic cross-sectional view of an organic light emitting display device of a dual panel type.

FIG. 5 is a detailed cross-sectional view of a specific portion A of FIG. 4. FIG.

6 is a schematic cross-sectional view of an organic light emitting display device of the dual panel type according to the first embodiment of the present invention.

FIG. 7 is a detailed cross-sectional view of a specific portion B of FIG. 6.

8 and 9 are sectional views showing a modified structure of the first embodiment of the present invention.

10A to 10G are cross-sectional views illustrating a process of manufacturing the organic light emitting display device according to the present invention.

11 is a schematic cross-sectional view of an organic light emitting display device of a dual panel type according to a second embodiment of the present invention.

12 is a detailed cross-sectional view of a specific portion C of FIG. 11.

<Description of Signs of Major Parts of Drawings>

533, 633: First buffer 535, 637: Second buffer

537: third buffer 634: auxiliary bulkhead

635: bulkhead

The present invention relates to an organic electroluminescent device, and more particularly, to a dual panel type organic electroluminescent device and a method of manufacturing the same.

One of the new flat panel displays (FPDs), organic light emitting diodes are self-luminous, so they have better viewing angles, contrast, etc. than liquid crystal displays. Do.

In addition, since it is possible to drive DC low voltage, fast response speed, and all solid, it is strong against external shock, wide use temperature range, and especially inexpensive in terms of manufacturing cost.

In particular, unlike the liquid crystal display device or the plasma display panel (PDP), the deposition and encapsulation equipments can be referred to in the manufacturing process of the organic light emitting device, and the process is very simple.

In the related art, a passive matrix having no separate switching device has been mainly used as a driving method of the organic light emitting device.

However, in the passive matrix method, since the scan lines and the signal lines are configured to form a device in a matrix form, the scanning lines are sequentially driven over time in order to drive each pixel, thereby requiring the average luminance. In order to indicate, the instantaneous luminance is equal to the average luminance multiplied by the number of lines.

However, in the active matrix method, a thin film transistor, which is a switching element for turning on / off a pixel, is positioned for each subpixel, and the first electrode connected to the thin film transistor is The second electrode, which is turned on / off in subpixel units and faces the first electrode, becomes a common electrode.

In the active matrix method, a voltage applied to a pixel is charged in a storage capacitor (C _ST ), so that power is applied until the next frame signal is applied, thereby relating to the number of scan lines. Run continuously for one screen without

Therefore, according to the active matrix method, since the same luminance is applied even when a low current is applied, it has the advantage of low power consumption, high definition, and large size.

Hereinafter, the basic structure and operation characteristics of the active matrix organic electroluminescent device will be described in detail with reference to the accompanying drawings.

1 is a view showing a basic pixel structure of a general active matrix organic electroluminescent device.

As shown, the scan line 2 is formed in the first direction, is formed in the second direction crossing the first direction, and the signal line 3 and the power supply line spaced apart from each other by a predetermined distance. (4) is formed to define one subpixel area.

At the intersection of the scan line 2 and the signal line 3, a switching TFT 5 as an addressing element is formed, and the switching TFT 5 and the power supply line 4 are formed. A driving capacitor C _ST 6 is connected to the driving capacitor C _ST 6, which is connected to the storage capacitor C _ST 6 and the power supply line 4, and is a driving thin film transistor 7 that is a current source element. Is formed, and is connected to the driving thin film transistor 7 to form an organic luminescent diode 8.

When the organic light emitting diode 8 supplies current to the organic light emitting material in a forward direction, a P (positive) -N (negative) junction between an anode electrode, which is a hole providing layer, and a cathode electrode, which is an electron providing layer, is applied. Since the electron and the hole move and recombine with each other through the junction, they have less energy than when the electron and the hole are separated, and thus, the principle of emitting light due to the difference in energy generated at this time is used.

The organic light emitting diode is classified into a top emission type and a bottom emission type according to a traveling direction of light emitted from the organic light emitting diode.

Hereinafter, FIG. 2 is a schematic cross-sectional view of a conventional bottom emission type organic light emitting display device, and is illustrated based on one pixel area including red, green, and blue subpixels.

As illustrated, the first and second substrates 10 and 30 are disposed to face each other, and the edge portions of the first and second substrates 10 and 30 are sealed by a seal pattern 40. The thin film transistor T is formed on the transparent substrate 1 of the first substrate 10 for each subpixel, and is connected to the thin film transistor T to form the first electrode 12. Red, green, and blue colors are disposed on the transistor T and the first electrode 12 to be connected to the thin film transistor T so as to correspond to the first electrode 12. An organic light emitting layer 14 including a light emitting material is formed, and a second electrode 16 is formed on the organic light emitting layer 14.

The first and second electrodes 12 and 16 serve to apply an electric field to the organic light emitting layer 14.

The second electrode 16 and the second substrate 30 are spaced apart from each other by the seal pattern 40 described above, and although not shown in the drawing, the inner surface of the second substrate 30 may be formed from the outside. A moisture absorbent (not shown) that absorbs the incoming moisture and a semipermeable tape (not shown) for adhesion between the moisture absorbent and the second substrate 30 are included.

For example, when the first electrode 12 is an anode and the second electrode 16 is a cathode in a bottom emission structure, the first electrode 12 is selected from a transparent conductive material, and the second electrode 16 is formed. ) Is selected from a metal material having a low work function, and under these conditions, the organic light emitting layer 14 is formed from a layer in contact with the first electrode 12, a hole injection layer 14a, a hole transport layer 14b; A transporting layer), an emission layer 14c, and an electron transporting layer 14d are formed in this order.

In this case, the light emitting layer 14c has a structure in which light emitting materials for implementing red, green, and blue colors are sequentially disposed for each subpixel.

FIG. 3 is an enlarged cross-sectional view of one subpixel area of the FIG. 2 bottom emission type organic electroluminescent device.

As illustrated, the semiconductor layer 62, the gate electrode 68, the source and drain electrodes 80 and 82 are sequentially formed on the transparent substrate 1 to form a thin film transistor region, and the source and drain electrodes 80, The power electrode 72 and the organic light emitting diode E formed in the power supply line (not shown) are respectively connected to 82.

In addition, the capacitor electrode 64 is positioned with an insulator interposed between the power electrode 72 and a lower portion of the power electrode 72, and the corresponding region forms a storage capacitor region.

Elements formed in the thin film transistor region and the storage capacitor region other than the organic light emitting diode E form the array element A.

The organic light emitting diode E includes a first electrode 12 and a second electrode 16 facing each other with the organic light emitting layer 14 interposed therebetween. The organic light emitting diode E is positioned in a light emitting area for emitting self-emitting light to the outside.

As described above, the conventional organic light emitting display device has a structure in which the array device A and the organic light emitting diode E are stacked on the same substrate.

As described above, the conventional bottom emission type organic light emitting diode device is manufactured by bonding an array device and a substrate on which an organic light emitting diode is formed and a separate substrate for encapsulation. In this case, since the product of the yield of the array device and the yield of the organic light emitting diode determines the yield of the organic light emitting diode, the overall organic process of the organic light emitting diode structure yields the overall process yield by the organic electroluminescent diode process. There was a problem that is greatly limited. For example, even if the array element is well formed, when the organic electroluminescent layer using the thin film of about 1000 mW is defective by foreign matter or other factors, the organic electroluminescent element is determined to be a poor grade. .

This results in a loss of overall costs and material costs that were required to manufacture the array device of good quality, there was a problem that the production yield is lowered.

In addition, the bottom emission method has a high degree of freedom and stability due to the encapsulation process, and has a problem in that it is difficult to be applied to a high resolution product due to the limitation of the aperture ratio. The top emission method is easy to design a thin film transistor and improves the aperture ratio It is advantageous in terms of product life, but in the conventional top emission type structure, since the material selection range is narrow as the cathode is normally positioned on the organic light emitting layer, the transmittance is limited to reduce the light efficiency and minimize the decrease in the light transmittance. In order to configure a thin film type protective film, there is a problem that does not sufficiently block the outside air.

The present invention provides an organic electroluminescent device for improving device characteristics by forming an organic electroluminescent layer having a uniform thickness by further forming a second buffer layer protruding to the organic electroluminescent layer region under the first buffer layer below the barrier rib in the organic electroluminescent device. And a method for producing the same.

In order to achieve the above object, a first embodiment of an organic light emitting display device according to the present invention includes: first and second substrates spaced apart from each other by a predetermined distance; An array element having at least one thin film transistor formed on the first substrate in units of subpixels; A first electrode formed on an inner surface of the second substrate; A third buffer formed in an outer region partitioning each subfill cell on the first electrode; A first buffer formed on the third buffer; A second buffer formed in an area including a stepped portion of the first buffer above the third buffer; An undercut structure region formed by removing a first buffer region which does not overlap with the second buffer; An organic light emitting layer formed in each of the sub-pixels in a region partitioned by the second buffer; A second electrode formed on a second substrate on which the organic light emitting layer is formed; And a conductive spacer electrically connecting the thin film transistor on the first substrate and the second electrode on the second substrate corresponding to each subpixel.

The third buffer is characterized in that formed to a thickness of less than 1㎛.

The third buffer is characterized in that the protruded 0.5 ~ 10㎛ from the second buffer.

The third buffer and the first buffer is characterized in that formed from different materials.

And the third buffer is removed from the undercut structure region.

The first buffer is formed in an area including a stepped portion of the third buffer.

A metal wire may be further included between the first electrode and the third buffer.

In addition, in order to achieve the above object, a second embodiment of the organic light emitting display device according to the present invention comprises: first and second substrates spaced apart from each other by a predetermined distance; An array element having at least one thin film transistor formed on the first substrate in units of subpixels; A first electrode formed on an inner surface of the second substrate; A second buffer formed in an outer region partitioning each subfill cell on the first electrode; A first buffer formed on the second buffer; A partition wall formed on the first buffer; An organic light emitting layer formed in a region partitioned by the first buffer in each subpixel; A second electrode formed on a second substrate on which the organic light emitting layer is formed; And a conductive spacer electrically connecting the thin film transistor on the first substrate and the second electrode on the second substrate corresponding to each subpixel.

The second buffer is characterized in that formed to a thickness of less than 1㎛.

The second buffer is characterized in that formed by protruding 0.5 ~ 10㎛ from the first buffer.

It further comprises an auxiliary partition formed on both sides of the partition wall in the upper portion of the first buffer.

The second buffer may be formed to protrude from 0.5 to 10 μm from the auxiliary partition wall.

In addition, in order to achieve the above object, a first embodiment of the method of manufacturing an organic light emitting display device according to the present invention includes forming an array device having at least one thin film transistor formed in a subpixel unit on an inner surface of a first substrate. Steps; Forming a first electrode on the transparent substrate of the second substrate; Forming a third buffer in an outer region of a subpixel that divides each subpixel among the upper regions of the first electrode; Forming a first buffer on the third buffer; Forming a second buffer in an area including a stepped portion of the first buffer; Removing the first buffer region that does not overlap the second buffer to form an undercut structure; Forming an organic EL layer in each of the sub-pixels in a region partitioned by the second partition wall; Forming a second electrode on a second substrate on which the organic light emitting layer is formed; It characterized in that it comprises a step of bonding the first and second substrates.

In addition, in order to achieve the above object, according to a second embodiment of the method of manufacturing an organic light emitting display device, an array device having at least one thin film transistor formed in subpixel units on an inner surface of a first substrate is formed. Steps; Forming a first electrode on the transparent substrate of the second substrate; Forming a second buffer in an outer region of a subpixel that divides each subpixel among the upper regions of the first electrode; Forming a first buffer on the second buffer; Forming a partition on the first buffer; Forming an organic light emitting layer in each of the sub-pixels in a region partitioned by the partition wall; Forming a second electrode on a second substrate on which the organic light emitting layer is formed; It characterized in that it comprises a step of bonding the first and second substrates.

Prior to the description of the present invention, a dual panel type organic light emitting display device will be described.

FIG. 4 is a schematic cross-sectional view of an organic light emitting display device of a dual panel type, and is illustrated based on an adjacent subpixel area for convenience of description.

As shown in the drawing, the dual panel type organic light emitting diodes are arranged with first and second substrates 110 and 130 spaced apart from each other by a predetermined distance, and an array is formed on an inner surface of the transparent substrate 100 of the first substrate 110. The device 120 is formed, and the organic light emitting diode device E is formed on the inner surface of the transparent substrate 101 of the second substrate 130.

In addition, edge portions of the first and second substrates 110 and 130 are sealed by a seal pattern 140.

The organic light emitting diode device E includes a first electrode 132 used as a common electrode on a substrate, and first and second buffer layers 133 and 135 positioned at a boundary between subpixels under the first electrode 132. ) And an organic light emitting layer 136 is formed in regions within the first and second buffer layers 133 and 135, and the second electrode 138 having a pattern separated in units of subpixels by the first and second buffer layers is formed. It is formed in order.

The organic light emitting layer 136 has a structure in which a first carrier transfer layer 136a, a light emitting layer 136b, and a second carrier transfer layer 136c are stacked in this order, and the first and second carrier transfer layers 136a are stacked. , 136c serves to inject and transport electrons or holes into the light emitting layer 136b.

The first and second carrier transfer layers 136a and 136c are defined according to the arrangement of the anode and the cathode. For example, the emission layer 136b is selected from a polymer material, and the first electrode 132 is an anode. When the second electrode 138 is formed of a cathode, the first carrier transfer layer 136a which is in contact with the first electrode 132 has a structure in which a hole injection layer and a hole transport layer are sequentially stacked. The second carrier transport layer 136c in contact with the second electrode 138 has a structure in which an electron injection layer and an electron transport layer are sequentially stacked.

The array device A is a device including a polysilicon thin film transistor T. In order to supply current to the organic light emitting diode device E, the second electrode 138 and the thin film are provided in subpixel units. A columnar spacer 114 is positioned at a position connecting the transistor T, and a predetermined metal 113 is formed at an outer portion of the spacer, and the predetermined metal 113 is formed of the thin film transistor T. It is electrically connected to the drain electrode 112.

In addition, the organic light emitting layer 136 may be formed of a high molecular material or a low molecular material. When the low molecular material is formed by a vacuum deposition method, a high molecular material is formed by an inkjet method.

Unlike the liquid crystal display spacer, the conductive spacer 114 is intended to electrically connect two substrates as well as a cell gap retention function. The conductive spacer 114 has a predetermined height in a columnar shape in a section between the two substrates. Have

That is, the conductive spacer 114 may include the drain electrode 112 of the thin film transistor T provided in the sub-pixel unit on the first substrate 110 and the second electrode 138 provided in the second substrate 130. It serves to electrically connect, which is composed of a metal coated on a columnar spacer formed of an organic insulating film or the like. The conductive spacers 114 as described above bond the pixels of the first and second substrates 110 and 130 one-to-one to allow current to flow through the conductive spacers 114.

When the connection between the conductive spacer 114 and the thin film transistor T is described in more detail, a protective layer having a drain contact hole 122 partially exposing the drain electrode 112 in a region covering the thin film transistor T. 124 is formed, and the conductive spacer 114 is positioned on the passivation layer 124 by being connected to the drain electrode 112 through the drain contact hole 122.

Here, the thin film transistor T corresponds to a driving thin film transistor connected to the organic light emitting diode E.

The metal forming the outside of the conductive spacer 114 is selected from a conductive material, and preferably selected from a metal material having ductility and low specific resistance.

In addition, the light emission from the organic light emitting layer 136 is characterized in that the upper light emitting method for emitting toward the second substrate 130.

Accordingly, the first electrode 132 may be selected from a transparent material having transparency, and the second electrode 138 may be selected from an opaque metal material.

Although not shown in the drawings, the array element 120 includes a scan line, a signal line and a power supply line that intersect the scan line, and are spaced apart from each other by a predetermined distance, a switching thin film transistor positioned at a point where the scan line and the signal line cross, and a storage capacitor. It includes more.

Such a dual panel type organic electroluminescent device has an array element and an organic electroluminescent diode element formed on different substrates, and thus can be compared with the case of forming an existing array element and an organic electroluminescent diode element on the same substrate. At this time, the organic electroluminescent diode device is not affected by the yield of the array device, and thus it may exhibit good characteristics in terms of production management of each device.

In addition, if the screen is implemented in the upper light emission method under the above-described conditions, it is possible to design a thin film transistor without minding the aperture ratio, thereby increasing the array process efficiency, providing a high aperture ratio / high resolution product, and providing a dual panel ( Since the organic light emitting diode device is formed as a dual panel type, it is possible to effectively block outside air than the conventional top emitting method, thereby increasing the stability of the product.

In addition, since the thin film transistor design generated in the conventional lower light emitting device product is configured on a substrate separate from the organic light emitting diode device, the degree of freedom in the arrangement of the thin film transistor can be obtained sufficiently. Since the first electrode is formed on the transparent substrate, the first electrode has an advantage of increasing the degree of freedom for the first electrode as compared with the structure of forming the first electrode on the array element.

In the dual panel type organic electroluminescent device, when the organic electroluminescent layer 136 is formed of a polymer material, it is formed by an inkjet method as described above.

In this case, when the organic light emitting layer 136 is formed of an inkjet polymer material, the ink prevents overflow of the outside of the buffer, and the polymer material is limited within the light emitting area in the buffer to define the profile and thickness of the film. There is a difficulty to control.

In the dual panel type organic light emitting device structure shown in the foregoing, the second buffer 135 has a round tapered shape, and thus, the polymer ink forming the organic light emitting layer 136 is the second tape of the round tapered shape. Since a pinning phenomenon that rises along the side surface is generated, the thickness of the organic light emitting layer film is non-uniform, which causes problems such as light emission and causes a poor quality such as deterioration.

FIG. 5 is a detailed cross-sectional view of a specific portion A of FIG. 4, which will be described in more detail with reference to FIG. 5.

Referring to FIG. 5, the first buffer 133 and the second buffer 135 formed on the first electrode 132 of the second substrate 130 of the dual panel type organic electroluminescent device shown in FIG. The organic light emitting layer 136 is formed in the internal regions of the buffers 133 and 135 to partition light emitting regions within each subpixel.

The polymer ink constituting the organic light emitting layer 136 is easily formed along the side surface X of the second buffer 135, and thus blackening due to overflow between each subpixel and connection of the second electrode 138. In addition, light emission unevenness occurs due to difficulty in controlling thickness of the organic light emitting layer 136 film, which results in poor quality of the organic light emitting device.

The present invention was created to overcome the above problems and will be described in more detail with reference to the accompanying drawings.

<First Embodiment>

FIG. 6 is a schematic cross-sectional view of an organic light emitting display device of a dual panel type according to a first embodiment of the present invention, and FIG. 7 is a detailed cross-sectional view of a specific portion B of FIG. 6.

However, the same reference numerals are used for the same components as in FIG. 4, and descriptions of the same components will be omitted.

The present invention provides a dual panel type organic light emitting display device comprising: a first buffer 533 formed in an outer region dividing each subpixel, and a second buffer formed in a round tapered shape in an area including a stepped portion of the first buffer. 535 is provided, and a second buffer 535 formed between the first and second buffers and the first electrode is provided, and the exposed first buffer is removed 534 by an under cut structure. The second electrode 138 can be separated for each subpixel, and the organic electroluminescent layer 136 made of a polymer material can be uniformly formed.

In this case, the second buffer 535 is formed in a region including a stepped portion of the first buffer 533, that is, formed in a well type surrounding the region in which the organic light emitting layer 136 is formed. It consists of a round tapered shape.

In addition, the third buffer 537 is formed to protrude toward the organic light emitting layer area from the second buffer having a round tapered shape.

The third buffer 537 has a thickness of 1 μm or less, and protrudes 0.5 to 10 μm from the end of the second buffer 535.

In addition, regions of the first buffer 533 and the third buffer 537 that do not overlap with the second buffer 535 are removed 534 by an undercut structure by a hydrophobization process or an etching process, and the removed undercut is removed. Each adjacent subpixel may be separated by the structure.

That is, the second electrode formed on the organic light emitting layer of each subpixel by the undercut structure 534 is formed by being separated for each subpixel without being connected between the subpixels, thereby providing a conventional inverse tapered partition wall. If not, it will be able to perform the role of the partition.

In addition, since the second electrode is formed in contact with the first electrode of the first buffer region exposed by the undercut process, the resistance value of the first electrode can be reduced.

6 and 7, in the organic light emitting display device according to the present invention, the first electrode 132 of the organic light emitting diode E is formed on the transparent substrate 101 of the second substrate 530. The third buffer 537 is formed on the entire surface and is formed in a predetermined region of the upper portion of the first electrode 132, that is, an outer region of the subpixel that divides each subpixel. A first buffer 533 is formed on the third buffer 537, and a second buffer 535 is formed in an area including a stepped portion of the first buffer 533.

However, an area of the first buffer 533 that is not overlapped with the second buffer 535, that is, an area of the exposed first buffer 533 is removed 534 by an undercut structure. In other words, at least one side of the first buffer 533 is formed in a gap form of about 0.1 to 3 μm into the second buffer 535.

In addition, the third buffer 357 is formed to protrude from the round tapered second buffer 535 toward the organic light emitting layer 136 region, and the third buffer 537 has a thickness of 1 μm or less. At the end of the second buffer 535, 0.5 to 10 μm protrude.

In addition, the first buffer 533 and the second buffer 535 are formed of different materials, and the second buffer 535 surrounds a region in which the organic light emitting layer 136 is formed. It is formed as a round tapered shape.

The third buffer 357 is formed of a material that is not etched during the surface treatment process for hydrophilization of the first electrode 132 and hydrophobization of the buffer.

Therefore, in the dual panel type organic light emitting device structure according to the present invention, the third buffer 537 protruding into the organic light emitting layer 136 minimizes the pinning phenomenon caused by the rounded tapered second buffer 353. It serves to make the thickness of the film of the organic light emitting layer 136 uniform, which in turn improves the image quality of the organic light emitting device.

According to the structure of the present invention, the organic light emitting layer forming region in each subpixel is partitioned by the second buffer 535.

In addition, the undercut structure region 534 inside the first buffer serves to separate the second electrode 138 formed in each subpixel for each subpixel.

That is, according to the present invention, the second electrode formed on the organic light emitting layer of each subpixel by the undercut structure region 534 is formed by being separated for each subpixel without being connected between the subpixels. Even if a reverse tapered partition is not provided, the partition can serve as the partition.

In addition, since the second electrode 138 is formed on the first electrode 132 of the first buffer region exposed by the undercut process, the resistance value of the first electrode 132 may be reduced.

Therefore, in the first exemplary embodiment according to the present invention, the third buffer 537 is formed under the first and second buffers 533 and 535 and is also formed in the undercut structure region 534. As shown in FIG. 6, a low resistance bus line 549 is further formed in the undercut structure region 534 to reduce the wiring resistance of the first electrode 132 to reduce the resistance value of the first electrode 132. You may.

That is, after the low resistance bus line 549 is formed on the first electrode 532 in the undercut structure region 534 and the third buffer 537 is formed, the first and second buffers 533, By forming the 535, the wiring resistance of the first electrode 132 may be reduced without forming the first electrode 132 and the second electrode 138 in contact with each other.

In addition, as shown in FIG. 9, the second electrode 138 is disposed on the first electrode 132 of the first buffer region exposed by being undercut by preventing the third buffer from being formed in the undercut structure region. By being in contact with each other, the resistance value of the first electrode 132 can be reduced.

In this case, the third buffer 357 is formed to protrude from the round tapered second buffer 535 toward the area of the organic light emitting layer 136, and the third buffer 537 has a thickness of 1 μm or less. At the end of the second buffer 535, 0.5 to 10 μm protrude.

In addition, the first buffer 533 and the second buffer 535 are formed of different materials, and the second buffer 535 surrounds a region in which the organic light emitting layer 136 is formed. It is formed as a round tapered shape.

The third buffer 357 is formed of a material that is not etched during the surface treatment process for hydrophilization of the first electrode 132 and hydrophobization of the buffer.

On the other hand, the second buffer 535 can obtain the shielding effect of the ink (sttraction) by the stepped portion of the first buffer (533).

As a result, by forming the second buffer 535 in the region including the stepped portion of the first buffer, blackening phenomenon due to overflow between each subpixel and connection of the second electrode 138, control of thickness control of the organic light emitting layer film It is possible to overcome the problem of light emission unevenness due to the difficulty, thereby improving the image quality of the organic light emitting device.

In addition, an organic light emitting layer 136 is formed in a region partitioned by the second buffer 535 for each subpixel, and a second electrode 138 is formed on a second substrate including the organic light emitting layer 136. Is formed.

In addition, the third buffer 537 serves to minimize the pinning phenomenon caused by the round tapered second buffer 353, thereby making the thickness of the film of the organic light emitting layer 136 uniform. The image quality of the light emitting device is improved.

The organic electroluminescent layer 136 is formed of a polymer material, and the second electrode 138 is divided by each subpixel by the undercut structure region 534 of the first buffer. It serves as an electrode.

In addition, since the conductive spacer 114 is formed of a metal material, the conductive spacer 114 is in an electrically connected state with the second electrode 138.

In addition, the array element 120 formed on the first substrate 110 is a device including a driving thin film transistor T, and supplies a current to the organic light emitting diode E formed on the second substrate 530. To this end, the conductive spacer 114 is electrically connected to the drain electrode 112 of the driving thin film transistor T provided in each subpixel.

This is only an embodiment of the present invention, various structures other than the above structure can be applied to the present invention.

10A to 10G are cross-sectional views illustrating a process of manufacturing the organic light emitting display device according to the present invention. However, this is illustrated based on the cross-sectional view shown in FIG.

Referring first to FIG. 10A, an array element is formed on a first substrate.

For example, when the thin film transistor T constituting the array device 120 is a polysilicon thin film transistor, as shown in the drawing, the step of forming a semiconductor layer and a capacitor electrode on the transparent substrate 100; Forming a gate electrode, a source, and a drain electrode on the semiconductor layer, and forming a power electrode on the capacitor electrode and connected to the source electrode.

In addition, a passivation layer 124 having a drain contact hole 122 exposing a part of the drain electrode 112 is formed in an area covering the thin film transistor T, and a drain contact hole is formed on the passivation layer 124. The drain electrode 112 is exposed through 122.

The drain electrode is in contact with the conductive spacer 114 to be formed on the second substrate later, and thus serves to electrically connect the first substrate and the second substrate. However, an electrical connection pattern connected to the drain electrode 112 may be formed so that the electrical connection pattern is in contact with the conductive spacer 114.

The conductive spacer 114 is preferably formed on the first substrate after the array element on the first substrate is formed.

Next, as shown in FIG. 10B, the first electrode 132 of the organic light emitting diode is formed on the transparent substrate 101 of the second substrate.

In this case, the first electrode 132 is preferably an indium tin oxide (ITO) electrode as a transparent conductive material.

A third buffer 537 is formed in a predetermined region of the upper portion of the first electrode 132, that is, an outer region of the subpixel that divides each subpixel.

The third buffer 537 may be formed to a thickness of 1 μm or less.

Here, the low resistance wiring may be further formed under the third buffer to reduce the wiring resistance on the first electrode before the third buffer is formed.

Metals such as chromium (Cr) and molybdenum (Mo) may be used as the low resistance wiring.

Next, as shown in FIG. 10C, a first buffer 533 and a second buffer 535 are formed on the third buffer 537.

The first buffer 533 is formed, and the second buffer 535 is formed in an area including the stepped portion of the first buffer 533.

The third buffer 537 protrudes 0.5 to 10 μm from the end of the second buffer 535 toward the organic light emitting layer region.

In this case, the first buffer 533 and the second buffer 535 is characterized by being formed of different materials, the third buffer 537 is the hydrophobization process of the first electrode 132 and the buffer hydrophobicity It is formed of a material that is not etched during the surface treatment for treatment.

Hereinafter, the first buffer 533 is formed using a silicon nitride film (SiNx) or a silicon oxide film (SiO ₂ ) as an example.

Here, since the second buffer 535 is formed in a region including the stepped portion of the first buffer 533, the second buffer 535 is formed in a wall type surrounding the region in which the organic light emitting layer is formed. Accordingly, the light emitting area of each subpixel is defined by the second buffer 535.

In addition, the second buffer 535 is formed in a round tapered shape, and thus the second taper of the round tapered shape is further formed in an area including the stepped portion of the first buffer, thereby reducing the number of side surfaces. Through this process, it is possible to overcome the problem that the polymer ink constituting the organic light emitting layer is deflected into the stepped portion of the first buffer.

In this case, the non-uniformity of the organic light emitting layer may be minimized by the third buffer formed under the second buffer by the pinning phenomenon due to the round tapered shape of the second buffer.

Next, as shown in FIG. 10D, the first buffer region that does not overlap the second buffer, that is, the region of the exposed first buffer, is removed 534 with an under cut structure.

That is, a structure is formed in which at least one side of the first buffer 533 is in a gap form of about 0.1 to 3 μm into the second buffer.

The undercut structure 534 may be formed through various processes. However, in the exemplary embodiment of the present invention, the first buffer 533 may be formed of silicon nitride (SiNx) or silicon oxide (SiO ₂ ). Explain. However, in this case, the second buffer 535 is preferably formed of an organic material or an inorganic material composed of a material different from the first buffer 533.

In addition, the third buffer 537 is formed of a material different from the first buffer 533 so as not to be etched in the etching process of the first buffer 533 for forming the undercut structure 534. In this case, however, the case in which the first buffer 533 is made of a silicon nitride film (SiNx) or a silicon oxide film (SiO ₂ ) has been described as an example. Thus, the third buffer 537 may be formed of an organic material or the first buffer 533. It is preferably formed of a mineral composed of a material different from).

First, when the first buffer 533 is formed of a silicon nitride film (SiNx), the undercut structure region 534 is automatically formed in the exposed first buffer region by performing a hydrophobization process on the second buffer. Is formed.

That is, as the CF ₄ hydrophobic treatment proceeds after the O ₂ surface treatment, the first buffer formed of the silicon nitride film (SiNx) has its exposed surface removed by the CF ₄ to form an undercut structure as shown. Will be.

In addition, when the first buffer is made of silicon oxide (SiO ₂ ), the undercut structure region 534 is formed in the exposed first buffer region through a separate wet etching process.

That is, by wet etching the surface of the first buffer exposed without overlapping with the second buffer, it is possible to form the undercut structure as shown.

Next, as shown in FIG. 10E, an organic light emitting layer 136 is formed in the region defined by the second buffer 535 in each subpixel.

In this case, the third buffer 537 is formed to protrude toward the organic light emitting layer 136 forming region under the second buffer 535.

The organic electroluminescent layer 136 is formed of a polymer material. Assuming that the first electrode is an anode and the second electrode is a cathode, the hole transport layer 136a and the light emitting layer 136b. ), And the electron transport layer 136c is sequentially stacked, and the hole / electron transport layers 136a and 136c inject holes or electrons into the light emitting layer 136b, and It is responsible for transporting. However, the organic light emitting layer 136 may be formed of a low molecular material.

At this time, the hole transport layer 136a which is in contact with the first electrode has a structure in which a hole injection layer and a hole transport layer are stacked in order, and the electron transport layer 136c which is in contact with the second electrode is later referred to as an electron injection layer, The electron transport layer may be formed of a stacked structure in order.

In this case, the organic light emitting layer 136 may be formed by an inkjet method, and the third buffer 537 serves to minimize a pinning phenomenon by the second buffer 353 having a round tapered shape. The thickness of the electroluminescent layer 136 film is made uniform, which in turn improves the image quality of the organic electroluminescent device.

That is, although the second buffer has a round tapered shape to form a sharp step toward the side of the organic light emitting layer, the third buffer is formed toward the organic light emitting layer area to reduce the step difference and reduce the round tapered shape of the second buffer. Accordingly, the phenomenon in which the organic electroluminescent material is pinned can be minimized.

Accordingly, the third buffer 357 is formed to protrude from the round tapered second buffer 535 toward the organic light emitting layer 136 region, and the third buffer 537 has a thickness of 1 μm or less. At the end of the second buffer 535, 0.5 to 10 μm protrude.

Subsequently, as shown in FIG. 10F, when the organic light emitting layer 136 is formed in the light emitting region formed by the second buffer 535, the second electrode 138 of the organic light emitting diode is formed thereon. .

Since the second electrode 138 is divided for each subpixel by the undercut forming regions 534 and 535, the second electrode 138 serves as a pixel electrode, and the conductive spacer 114 is formed of a metal material. , And is in an electrically connected state with the second electrode 138.

In addition, the second electrode 138 is preferably selected from a metal having a low work function, and examples thereof include aluminum (Al).

Thereafter, as shown in FIG. 10G, when the first and second substrates 110 and 530 are bonded to each other and encapsulated, the first and second substrates 110 and 530 are electrically connected to each other. The second electrode 138 of the organic light emitting diode formed on the second substrate 530 and the drain electrode 112 of the driving thin film transistor T formed on the first substrate 410 are electrically connected to each other.

Second Embodiment

FIG. 11 is a schematic cross-sectional view of an organic light emitting display device of a dual panel type, and is illustrated based on one pixel area for convenience of description.

As illustrated, the dual panel type organic electroluminescent device has first and second substrates 210 and 230 disposed to be spaced apart from each other by a predetermined distance, and an array is formed on an inner surface of the transparent substrate 200 of the first substrate 210. The device 220 is formed, and the organic light emitting diode device E is formed on the inner surface of the transparent substrate 201 of the second substrate 230.

In addition, edge portions of the first and second substrates 210 and 230 are sealed by a seal pattern 240.

The organic light emitting diode E includes a first electrode 232 used as a common electrode, a partition wall 234 positioned at a boundary between subpixels below the first electrode 232, and a partition wall ( In the region 234, the organic light emitting layer 236 and the second electrode 238 are sequentially formed in a pattern separated by subpixel units.

The first electrode 232 is preferably an indium tin oxide (ITO) electrode as a transparent conductive material.

In addition, the organic light emitting layer 236 formed in each subpixel is partitioned, and the first buffer and the first buffer 232 and the second electrode 238 are overcome by the conductive spacer 214 to overcome the short circuit. Second buffers 633 and 637 are formed.

The second buffer is formed between the first buffer 633 and the first electrode 232, and the second buffer 637 is formed to protrude 0.5 to 10 μm from the end of the first buffer 633. do.

The second buffer 637 is preferably formed to a thickness of 1 μm or less.

A partition 635 is formed on the first buffer 633. The partition 635 serves to separate adjacent subpixels. As illustrated, the first buffer 633 is formed. It is formed in a reverse taper shape on the phase.

In addition, both sides of the partition wall 635 formed on the first buffer 633 are provided with auxiliary tapered walls 634 having a round tapered shape spaced apart from each other by a predetermined interval.

The round tapered auxiliary partition wall 634 is for preventing the pinning of the ink and the deflection of the ink due to the formation of the organic light emitting layer.

However, even when the auxiliary barrier rib 634 is formed, the polymer ink forming the organic electroluminescent layer 236 may form a round tapered auxiliary barrier rib when the organic electroluminescent layer is formed by ink jetting. Since the phenomenon of pinning occurs at 634, a light emission unevenness may occur due to difficulty in controlling the thickness of the organic light emitting layer film, which results in a poor quality of the organic light emitting device.

Accordingly, the second buffer 637 protrudes 0.5 to 10 μm from the end of the first buffer 633 toward the area of the organic light emitting layer 236, and the thickness of the second buffer 637 is 1 μm or less, thereby minimizing such defects. can do.

In addition, the organic light emitting layer 236 may be formed of a high molecular material or a low molecular material. When the low molecular material is formed by a vacuum deposition method, a high molecular material is formed by an inkjet method.

In addition, the array element 220 is a device including a thin film transistor T. In order to supply current to the organic light emitting diode E, the second electrode 238 and the thin film transistor T in subpixel units. ), A columnar conductive spacer 214 is positioned at a position connecting the c).

The conductive spacer 214 electrically connects the drain electrode 212 of the thin film transistor T provided in the sub-pixel unit on the first substrate 210 and the second electrode 238 provided in the second substrate 230. It serves as a connection, which is composed of a metal coated on a columnar spacer formed of an organic insulating film or the like. The conductive spacer 214 as described above bonds the pixels of the first and second substrates 210 and 230 one-to-one to allow current to flow therethrough.

Here, the thin film transistor T corresponds to a driving thin film transistor connected to the organic light emitting diode E.

The metal forming the outside of the conductive spacer 214 is selected from a conductive material, and preferably selected from a metal material that is ductile and has a low specific resistance.

In addition, the light emission from the organic light emitting layer 236 is characterized in that the top emission method for emitting the light toward the second substrate 230.

Accordingly, the first electrode 232 may be selected from a transparent material having transparency, and the second electrode 238 may be selected from an opaque metal material.

FIG. 12 is a detailed cross-sectional view of the specific portion C of FIG. 11, which will be described in more detail with reference to FIG. 12.

Referring to FIG. 12, a second buffer 637 is formed on the first electrode 232 of the second substrate 230 of the dual panel type organic light emitting display illustrated in FIG. 11, and the second buffer 637 is formed. ) Is formed on the first buffer 633.

The second buffer 637 has a thickness of 1 μm or less, and protrudes 0.5 to 10 μm from the end of the first buffer 633.

In addition, the first buffer 633 and the second buffer 637 serve to partition light emitting regions in each subpixel, and an organic light emitting layer 236 is formed in an inner region of the first buffer 633. .

In addition, an inverse tapered partition wall 635 is formed in an upper region of the first buffer 633, and an auxiliary partition wall 634 having a round taper shape is formed at both sides of the partition wall 635.

Accordingly, the polymer ink constituting the organic electroluminescent layer 236 is easily deflected into the reverse tapered partition side surface X, and thus flows easily due to the overflow between the subpixels and the connection of the second electrode 238. Light emission unevenness occurs due to blackening and difficulty in controlling thickness control of the organic light emitting layer 236 film, which results in poor quality, such as deterioration of the quality of the organic light emitting device.

Accordingly, an attempt was made to prevent a defect caused by the reverse tapered partition 635 by forming a round tapered auxiliary partition 634 on both sides of the partition on the first buffer 633. When the first buffer 633 to be determined has a thickness of 1 μm or more, pinning of the polymer ink occurs, and the organic light emitting layer 236 is unevenly formed, and the first buffer 633 is 1 μm or less. There is a fear that the inter-pixel overflow of the polymer ink may occur.

On the other hand, in the present invention, by forming the second buffer 637 protrudes 0.5 to 10 μm from the end of the first buffer 633, it is possible to prevent the pinning phenomenon of the polymer material ink.

In addition, the second buffer 637 is formed to a thickness of 1 μm or less so that the second buffer 637 may have a uniform thickness when the organic light emitting layer 236 is formed.

The first buffer 633 and the second buffer 637 also serve to partition an area of each subpixel and define an area in which the organic light emitting layer 236 is formed, and the organic light emitting layer 236. In each of these subpixels, it is formed within the area defined by the buffer.

As described above, the organic light emitting display device according to the present invention is not limited to the above embodiments, and may be applied to organic light emitting display devices having various structures, and having ordinary skill in the art within the technical idea of the present invention. It is apparent that the deformation and improvement can be made by.

According to the present invention, by further forming a buffer protruding into the organic electroluminescent layer region, the organic electroluminescent layer can be obtained as a film having a uniform thickness on the effective electrode, thereby improving the image quality.

In addition, since the second taper having a round tapered shape is formed in a region including the stepped portion of the buffer, there is an advantage in that the organic electroluminescent layer made of a polymer material can be uniformly formed.

In addition, by removing the stepped portion of the buffer in the inkjet process of the polymer material, there is an advantage that the jetting directionality margin can be widened by reducing the pinning phenomenon during the inkjet process.

Claims (38)

First and second substrates spaced apart from each other by a predetermined distance; An array element having at least one thin film transistor formed on the first substrate in units of subpixels; A first electrode formed on an inner surface of the second substrate; A third buffer formed in an outer region partitioning each subfill cell on the first electrode; A first buffer formed on the third buffer; A second buffer formed in an area including a stepped portion of the first buffer above the third buffer; An undercut structure region formed by removing a first buffer region which does not overlap with the second buffer; An organic light emitting layer formed in each of the sub-pixels in a region partitioned by the second buffer; A second electrode formed on a second substrate on which the organic light emitting layer is formed; And a conductive spacer electrically connecting the thin film transistor on the first substrate and the second electrode on the second substrate corresponding to each subpixel. The method of claim 1, The third buffer is an organic light emitting device, characterized in that formed in a thickness of less than 1㎛. The method of claim 1, The third buffer is an organic light emitting device, characterized in that formed by protruding from the 0.5 to 10㎛. The method of claim 1, And the third buffer and the first buffer are formed of different materials. The method of claim 1, The first buffer and the second buffer is an organic light emitting device, characterized in that formed of different materials. The method of claim 1, The second buffer is an organic light emitting device, characterized in that formed in a round tapered shape. The method of claim 1, And the third buffer is removed from the undercut structure region. The method of claim 1, The first buffer is an organic light emitting device, characterized in that formed in the region including the step portion of the third buffer. The method of claim 1, The organic light emitting device of claim 1, further comprising a metal wiring between the first electrode and the third buffer. The method of claim 1, The metal wiring is an organic light emitting device, characterized in that the chromium, molybdenum-based metal. First and second substrates spaced apart from each other by a predetermined distance; An array element having at least one thin film transistor formed on the first substrate in units of subpixels; A first electrode formed on an inner surface of the second substrate; A second buffer formed in an outer region partitioning each subfill cell on the first electrode; A first buffer formed on the second buffer; A partition wall formed on the first buffer; An organic light emitting layer formed in a region partitioned by the first buffer in each subpixel; A second electrode formed on a second substrate on which the organic light emitting layer is formed; And a conductive spacer electrically connecting the thin film transistor on the first substrate and the second electrode on the second substrate corresponding to each subpixel. The method of claim 11, The second buffer is an organic light emitting display device, characterized in that formed in a thickness of less than 1㎛. The method of claim 11, The second buffer is an organic light emitting display device, characterized in that formed by protruding from 0.5 ~ 10㎛. The method of claim 11, The organic light emitting device of claim 1, further comprising auxiliary partitions formed on both sides of the partition wall on the first buffer. The method of claim 14, The auxiliary partition wall has an organic light emitting device, characterized in that the round tapered shape. The method of claim 14, The auxiliary barrier rib is formed in an area including a stepped portion of the first buffer. The method of claim 14, The organic light emitting device, characterized in that the second buffer protrudes from 0.5 to 10㎛ from the auxiliary partition. The method of claim 11, The partition wall is an organic light emitting device, characterized in that the inverse tapered shape. The method of claim 11, The first buffer is an organic light emitting display device, characterized in that formed in the region including the step portion of the second buffer. Forming an array device having at least one thin film transistor formed in a subpixel unit on an inner surface of the first substrate; Forming a first electrode on the transparent substrate of the second substrate; Forming a third buffer in an outer region of a subpixel that divides each subpixel among the upper regions of the first electrode; Forming a first buffer on the third buffer; Forming a second buffer in an area including a stepped portion of the first buffer; Removing the first buffer region that does not overlap the second buffer to form an undercut structure; Forming an organic EL layer in each of the sub-pixels in a region partitioned by the second partition wall; Forming a second electrode on a second substrate on which the organic light emitting layer is formed; A method of manufacturing an organic light emitting display device, characterized in that the step of bonding the first and second substrates. The method of claim 20, And forming a conductive spacer electrically connecting the thin film transistor on the first substrate and the second electrode on the second substrate for each sub-pixel. The method of claim 20, The second buffer is a method of manufacturing an organic light emitting device, characterized in that formed in a round tapered shape. The method of claim 20, The third buffer is a method of manufacturing an organic light emitting device, characterized in that formed in a thickness of less than 1㎛. The method of claim 20, The third buffer is a method of manufacturing an organic light emitting device, characterized in that formed by protruding from the 0.5 to 10㎛. The method of claim 20, The third buffer and the first buffer manufacturing method of the organic light emitting device, characterized in that formed of different materials. The method of claim 20, The first buffer and the second buffer is a method of manufacturing an organic light emitting device, characterized in that formed from different materials. The method of claim 20, Before the step of forming the third buffer in the outer region of the subpixel partitioning each subpixel of the upper region of the first electrode, The method of manufacturing an organic light emitting display device further comprising the step of forming a metal wiring under the third buffer. The method of claim 20, And said third buffer is not formed in said undercut region. Forming an array device having at least one thin film transistor formed in a subpixel unit on an inner surface of the first substrate; Forming a first electrode on the transparent substrate of the second substrate; Forming a second buffer in an outer region of a subpixel that divides each subpixel among the upper regions of the first electrode; Forming a first buffer on the second buffer; Forming a partition on the first buffer; Forming an organic light emitting layer in each of the sub-pixels in a region partitioned by the partition wall; Forming a second electrode on a second substrate on which the organic light emitting layer is formed; The method of manufacturing an organic light emitting display device comprising the step of bonding the first and second substrates. The method of claim 29, And forming a conductive spacer electrically connecting the thin film transistor on the first substrate and the second electrode on the second substrate for each sub-pixel. The method of claim 29, A method of manufacturing an organic light emitting display device, characterized in that auxiliary barrier ribs are further formed on both sides of the barrier rib on the second buffer. The method of claim 31, wherein The auxiliary partition wall is a manufacturing method of an organic light emitting device, characterized in that formed in a round tapered shape. The method of claim 29, The second buffer is a method of manufacturing an organic light emitting display device, characterized in that formed in a thickness of less than 1㎛. The method of claim 29, The second buffer is a method of manufacturing an organic light emitting device, characterized in that formed to protrude from 0.5 to 10㎛ from the first buffer. The method of claim 31, wherein The auxiliary barrier rib is formed in an area including a stepped portion of the first buffer. The method of claim 31, wherein And the second buffer is formed to protrude from 0.5 to 10 μm from the auxiliary partition wall. The method of claim 29, The partition wall is a manufacturing method of an organic light emitting device, characterized in that formed in the reverse tapered shape. In the 29th, And the first buffer is formed in a region including a stepped portion of the second buffer.

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