KR100512900B1 - Organic Electroluminescent Device and Method for Fabricating the same - Google Patents

Abstract

According to the organic light emitting device according to the present invention, firstly, since the array device and the organic light emitting diode device are formed on different substrates, the production yield and production management efficiency can be improved, and the product life can be increased. Because it is a top emission type, it is easy to design thin film transistor and realize high opening ratio / high resolution. Third, the thickness of the absorbent can be reduced, so that a more compact product can be provided. The manufacturing cost can be reduced and the manufacturing cost can be reduced. Fifth, since the moisture absorption pattern is formed inside the seal pattern forming part which can penetrate the moisture, the moisture penetration can be effectively blocked, thereby improving the reliability of the device. Has the advantage.

Description

Organic electroluminescent device and method of manufacturing the same {Organic Electroluminescent Device and Method for Fabricating the same}

The present invention relates to an organic electroluminescent device, and more particularly to an encapsulation structure of the organic electroluminescent device.

One of the new flat panel displays (FPDs), the organic light emitting display device is self-luminous and thus has a better viewing angle and contrast than the liquid crystal display device. Is also advantageous. 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 equipment are all 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, a scanning line is formed in a first direction, and a signal line and a power supply line are formed in a second direction crossing the first direction and spaced apart from each other by a predetermined distance. Define the subpixel area.

A switching TFT, which is an addressing element, is formed at the intersection of the scan line and the signal line, and is connected to the switching thin film transistor and the power supply line to form a storage capacitor C _ST . A driving thin film transistor, which is connected to the storage capacitor C _ST and a power supply line, is formed, and the driving thin film transistor is connected to the driving thin film transistor to form an organic electroluminescent diode.

When the organic light emitting diode is supplied with a current in the forward direction, the organic light emitting diode has a positive (N) junction between the anode electrode, which is a hole providing layer, and the cathode electrode, which is an electron providing layer. Electrons and holes recombine with each other as they move through the part, and thus have a smaller energy than when the electrons and holes are separated, thereby utilizing the principle of emitting light due to the energy difference generated.

Hereinafter, FIG. 2 is a cross-sectional view of a conventional organic light emitting display device, and is shown based on an encapsulation structure.

As shown in the drawing, the first and second substrates 10 and 50 are arranged to be spaced apart from each other by a subpixel unit, which is the minimum unit for implementing the screen, and the sub-pixel unit is disposed on the inner surface of the first substrate 10. An array element layer 30 including a plurality of formed thin film transistors T is formed, and the first electrode 32 is connected to the thin film transistor T on the array element layer 30 to form a subpixel unit. The organic light emitting layer 34 is formed on the first electrode 32 to emit red, green, and blue colors in subpixel units, and the second electrode 38 is formed on the entire upper surface of the organic light emitting layer 36. ) Is formed.

The organic light emitting layer 36 interposed between the first and second electrodes 32 and 38 and the first and second electrodes 32 and 38 forms an organic light emitting diode device (E).

In addition, the second substrate 50 is used as an encapsulation substrate, and a recess 52 is formed at an inner central portion of the second substrate 50, and moisture from the outside is formed in the recess 52. A moisture absorbent 54 for blocking absorption and protecting the organic light emitting diode element E is enclosed.

The inner surface of the second substrate 50 in which the moisture absorbent 54 is enclosed and the second electrode 38 are importantly spaced apart from each other.

The edges of the first and second substrates 10 and 50 are encapsulated by the seal pattern 70.

As described above, according to the organic light emitting device having the existing encapsulation structure, there are the following problems.

First, since the inside of the encapsulation substrate is etched to encapsulate the absorbent, the substrate is easily broken at the portion where the absorbent is encapsulated.

Second, moisture is easily penetrated through the interface between the substrate and the seal pattern.

The present invention has been made to solve the above problems, and an object of the present invention is to provide an organic electroluminescent device which can improve productivity, reduce the thickness of the device, and ensure reliability.

To this end, the present invention intends to encapsulate two substrates of an organic light emitting display device using a seal pattern and a moisture absorption pattern as a double pattern structure. At this time, it is important that the moisture absorption pattern is located inside the seal pattern.

In still another object of the present invention, an array device and an organic light emitting display device are formed on different substrates, and the aforementioned dual panel type organic light emitting display device connects the array device and the organic light emitting display device through a separate electrical connection pattern. One moisture absorption pattern structure is to be applied.

In more detail, an organic electroluminescent device is typically manufactured by bonding an array element and a substrate on which an organic electroluminescent diode is formed and a separate encapsulation substrate. In this case, the yield and organic field of the array element are obtained. Since the product of the yield of the light emitting diode determines the yield of the organic electroluminescent device, there is a problem that the overall process yield is greatly limited by the organic electroluminescent diode process corresponding to the latter process. 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 a good array element, and a disadvantage in 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 of difficulty in applying to a high resolution product due to the limitation of the aperture ratio, and the top emission method is easy to design a thin film transistor and improves the aperture ratio. In terms of product life, it is advantageous in the above-mentioned top light emitting structure because the material selection range is narrow as the cathode is generally located on the organic light emitting layer, so that the light transmittance is limited and the light transmittance is minimized. In order to configure a thin film type protective film, there was a disadvantage in that it does not sufficiently block outside air.

However, according to the dual panel type organic light emitting diode, since the array element and the organic light emitting diode element are formed on different substrates, it is possible to improve production yield and production management efficiency, increase product life, and Since the screen is implemented by the light emitting method, it is easy to design the thin film transistor and has the advantage that the high aperture ratio / high resolution can be realized.

In order to achieve the above object, in the first aspect of the present invention, a plurality of thin film transistors formed in units of subpixels are formed on an inner surface of a first substrate in which a sub-pixel region, which is a minimum unit for implementing a screen, is defined An array element layer comprising a film transistor; An organic light emitting diode device comprising a first electrode connected to the thin film transistor on the array element layer, an organic light emitting layer and a second electrode sequentially formed on the first electrode; A second substrate which is an encapsulation substrate spaced apart from the organic light emitting diode device by a predetermined distance; And a double pattern including a seal pattern and a moisture absorption pattern encapsulating edge portions of the first and second substrates, wherein the moisture absorption pattern is positioned inside the seal pattern.

According to a second aspect of the present invention, a subpixel area, which is a minimum unit for implementing a screen, is defined and includes first and second substrates spaced apart from each other by a predetermined distance; An array element layer including a plurality of thin film transistors formed in subpixel units on an inner surface of the first substrate; An electrical connection pattern connected to the thin film transistor on the array element layer; A first electrode formed on the entire inner surface of the second substrate, an organic light emitting layer formed under the first electrode, and a second electrode formed in a subpixel unit under the organic light emitting layer; An organic light emitting diode device connected thereto; And a double pattern including a seal pattern and a moisture absorption pattern encapsulating the edges of the first and second substrates, wherein the moisture absorption pattern provides an organic light emitting device positioned inside the seal pattern.

The seal pattern and the moisture absorption pattern according to the first and second aspects of the present invention are disposed in close contact with each other, and have a pattern structure corresponding to each other, and the seal pattern and the moisture absorption pattern are dispensed using a nozzle. ), Wherein the moisture absorption pattern is formed by a dispensing method using a nozzle filled with a gel type moisture absorbent, and the material forming the seal pattern is a UV (ultra violet) curing agent. do.

According to a third aspect of the present invention, there is provided a method, comprising: forming an array device layer having a plurality of thin film transistors positioned in subpixel units on a first substrate on which a subpixel region is defined; Forming an organic light emitting diode device on the array device layer, the organic light emitting diode device being connected to the thin film transistor; Providing a second substrate that is an encapsulation substrate; Simultaneously forming a double pattern including a seal pattern and a moisture absorption pattern at an edge portion of one of the first and second substrates; And encapsulating the first and second substrates using the dual pattern, wherein the moisture absorption pattern is formed inside the seal pattern.

In a fourth aspect of the invention, there is provided a method, comprising: providing first and second substrates on which subpixel regions are defined; Forming an array device layer on the first substrate, the array device layer having a plurality of thin film transistors positioned in subpixel units; Forming an electrical connection pattern connected to the thin film transistor on the array element layer; Forming an organic light emitting diode device on the second substrate; Forming a double pattern including a seal pattern and a moisture absorption pattern at an edge portion of one of the first and second substrates; And encapsulating the first and second substrates in the dual pattern, wherein the organic light emitting diode device is connected to an electrical connection pattern, and the moisture absorption pattern is formed inside the seal pattern. Provided is a method of manufacturing an electroluminescent device.

In the forming of the organic electroluminescent layer according to the third and fourth aspects of the present invention, forming a first electrode on the entire display area of the second substrate and forming an organic electroluminescent layer on the first electrode. And forming a second electrode in subpixel units on the organic light emitting layer, wherein the thin film transistor includes a switching thin film transistor and a driving thin film transistor, and is connected to the organic light emitting diode device. The transistor corresponds to a driving thin film transistor, and the forming of the double pattern includes dispensing by using a first nozzle filled with a seal pattern material and a second nozzle filled with a moisture absorption pattern material. Forming a double pattern on the edge of any one of the substrate, the moisture absorption pattern material is a gel-type moisture absorbent, the seal pattern The material is a UV curing agent, characterized in that to form the seal pattern and the moisture absorption pattern in close contact with each other.

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

Example 1

In the present embodiment, an encapsulation seal pattern in an organic electroluminescent device having a structure in which an array element and an organic light emitting diode element are sequentially formed on the same substrate and encapsulated using a separate encapsulation substrate. In the manufacturing process, the moisture absorption pattern is simultaneously produced in the inner portion in contact with the seal pattern.

3 is a cross-sectional view of a general structure organic light emitting display device according to a first embodiment of the present invention.

As illustrated, an array element layer 150 including a plurality of thin film transistors T formed in units of subpixels is formed on an inner surface of the first substrate 110 in which a subpixel region is defined. The organic light emitting diode device E is connected to the thin film transistor T at an upper portion thereof.

In more detail, a buffer layer 112 is formed on an inner surface of the first substrate 110, and on both sides of the active region I and the active region II in subpixel units on the buffer layer 112. The semiconductor layer 114 in which the source region II and the drain region II are positioned is formed, and the gate insulating layer 116 and the gate electrode 118 are sequentially formed on the semiconductor layer 114. The interlayer insulating layer 124 having a source contact hole 120 and a drain contact hole 122 exposing the source region II and the drain region II, respectively, is disposed on the entire surface of the substrate covering the gate electrode 118. The semiconductor layer (not shown) is formed on the interlayer insulating layer 124 and is connected to the source region II of the semiconductor layer 114 through the source contact hole 120 and the drain contact hole 122. Each of the drain electrodes 128 connected to the drain region III of the 114 is formed. A first protective layer 129 is formed on the front surface of the substrate covering the electrode 126 and the drain electrode 128, and has a drain contact hole 122 that partially exposes the drain electrode 128. A first electrode 130 connected to the drain electrode 128 is formed on the layer 129 through the drain contact hole 122, and a main region of the first electrode 130 is formed on the first electrode 130. A second protective layer 134 is formed in an area covering the edge of the first electrode 130, and an upper portion of the second protective layer 134 is formed through the opening 132. The first carrier transfer layer 136 is formed to be connected to the first electrode 130, and the red, green, and blue light emitting layers 138a, 138b, and 138c are sequentially formed on the first carrier transfer layer 136 in subpixel units. The second carrier transfer layer 140 is repeatedly arranged on the red, green, and blue light emitting layers 138a, 138b, and 138c, and the second carrier The second electrode 142 is formed on the entire upper surface of the transfer layer 140.

The red, green, and blue light emitting layers 138a, 138b, and 138c interposed between the first and second carrier transfer layers 136 and 140 and the first and second carrier transfer layers 136 and 140 are organic electroluminescent layers 141. The first and second electrodes 130 and 142 and the organic light emitting layer 141 interposed between the first and second electrodes 130 and 142 form an organic light emitting diode device (E).

In addition, a second substrate 160, which is an encapsulation substrate, is disposed to face the first substrate 110 and to be spaced apart from the organic light emitting diode device E by a predetermined distance, and the first and second substrates 110 are disposed. The edge portion is encapsulated by the seal pattern 170 and the moisture absorption pattern 180. In this case, the seal pattern 170 and the moisture absorption pattern 180 form a double pattern in close contact with each other, the moisture absorption pattern 180 is characterized in that located inside the seal pattern 170.

Although not shown in the drawings, in order to form the seal pattern 170 and the moisture absorption pattern 180 in a double pattern structure, for example, a first nozzle filled with a UV (ultra violet) curing agent material forming a seal pattern, and a gel type A method of simultaneously dispensing a UV curing agent material and a gel type moisture absorbent on a substrate from a second nozzle filled with a moisture absorbent may be used.

At this time, substantial encapsulation is made in the seal pattern 170, and the moisture absorption pattern 180 prevents moisture from penetrating into the seal pattern portion, and the moisture absorption pattern 180 is formed in the seal pattern 170 region. Compared with the structure encapsulated in the existing encapsulation substrate, the device thickness can be reduced, and a separate recess is not formed in the encapsulation substrate, thereby effectively reducing the failure of the encapsulation substrate.

Example 2

This embodiment is an embodiment in which the encapsulation structure according to the present invention is applied to a dual panel type organic electroluminescent device.

FIG. 4 is a cross-sectional view of a dual panel type organic light emitting display device according to a second embodiment of the present invention, and the specific stacked structure of the array device may be briefly described since the first embodiment may be applied.

As illustrated, the first and second substrates 210 and 250 in which the subpixel regions are defined are disposed to face each other, and a plurality of thin film transistors T formed in subpixel units on the inner surface of the first substrate 210. The array element layer 240 including the () is formed, and the connection electrode 242 is formed on the array element layer 240 by being connected to the thin film transistor T.

In addition, an electrical connection pattern 244 made of a conductive material having a columnar shape is formed on the connection electrode 242.

In addition, a first electrode 252 is formed on the entire inner surface of the second substrate 250, and an insulating film 254 and a partition wall 256 are sequentially formed at the boundary of each subpixel under the first electrode 252. The organic light emitting layer 258 and the second electrode 260, which are automatically separated by the partition wall 256 in units of subpixels, are sequentially formed below the partition wall 256.

Although not shown in detail in the drawings, the organic light emitting layer 258 is a red, green, blue light emitting layer that is sequentially arranged in a sub-pixel unit and the red, green, blue light emitting layer is located in the upper and lower layers It consists of one and two carrier transport layers.

In this case, the lower surface of the second electrode 250 and the upper surface of the aforementioned electrical connection pattern 244 are in contact with each other.

The organic light emitting layer 258 interposed between the first and second electrodes 252 and 260 and the first and second electrodes 252 and 260 forms an organic light emitting diode device (E).

In the present invention, in addition to the barrier rib structure described above for realizing full color, a patterning process using a shadow mask or a structure including only a light emitting layer of monochromatic light may be applied to the organic light emitting layer including a separate color conversion layer. have.

The edges of the first and second substrates 210 and 250 are encapsulated by a double pattern of the seal pattern 260 and the moisture absorption pattern 270.

At this time, the actual encapsulation is made in the seal pattern 260, the moisture absorption pattern 270 prevents moisture from penetrating into the seal pattern portion, the moisture absorption pattern 270 is formed in the area of the seal pattern 260 Compared with the structure encapsulated in the existing encapsulation substrate, the device thickness can be reduced, and a separate recess is not formed in the encapsulation substrate, thereby effectively reducing the failure of the encapsulation substrate.

The dual panel type organic light emitting display device is characterized in that it is implemented in a top light emitting method as shown by the arrow.

The organic light emitting diode includes at least one switching thin film transistor and a driving thin film transistor in subpixel units, and the thin film transistor T in the drawing corresponds to a driving thin film transistor for supplying current to the organic light emitting diode device. .

FIG. 5 is a process flowchart illustrating a step of manufacturing an organic light emitting display device according to the present invention, and will be described based on an encapsulation process based on a general structure organic light emitting display device.

In ST1, an array element layer is formed on a first substrate on which a subpixel region is defined.

In this step, a plurality of thin film transistors are formed on the first substrate in subpixel units, wherein the thin film transistors include a switching thin film transistor used as a switching element, and a driving thin film for driving an organic light emitting diode device. It includes a transistor.

In step ST2, an organic light emitting diode device connected to a driving thin film transistor among the thin film transistors is formed.

The organic light emitting diode device includes a first electrode patterned in units of subpixels, a second electrode formed on the entire surface of the substrate, and an organic light emitting layer interposed between the first and second electrodes.

In ST3, a step of encapsulating a first substrate on which the organic light emitting diode device is formed is performed using a second substrate, which is an encapsulation substrate, and in this step, an edge of one of the first and second substrates is used. Forming a double pattern in which the seal pattern and the moisture absorption pattern is in close contact with each other, the first and second substrates are encapsulated by the double pattern.

In more detail, as an example, the first nozzle filled with the seal pattern material and the second nozzle filled with the gel-type moisture absorbent are simultaneously dispensed to the edge of the first substrate, so that the two materials on the first substrate are mutually separated. It is formed to form a double pattern formed in close contact.

In this case, it is important that the second nozzle is positioned inside the first nozzle so that a moisture absorption pattern is formed at the inner part of the seal pattern.

In addition, although not shown in the drawings, in the process of manufacturing a dual panel type organic light emitting display device according to the present invention, forming an array element layer and an electrical connection pattern on a first substrate in turn, and an organic light emitting diode on a second substrate Forming a device and forming a double pattern in which a seal pattern and a moisture absorption pattern are in close contact with each other at an edge of one of the first and second substrates, and encapsulating the first and second substrates by the double pattern. Including the step of migration.

However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.

For example, in the drawings according to the first and second embodiments, a structure in which two pixels consisting of red, green, and blue subpixels are arranged as an example for convenience of description is described, but the actual structure has a structure in which a plurality of pixels are configured.

As described above, the dual panel type organic electroluminescent device encapsulating the seal pattern and the moisture absorption pattern according to the present invention as a double pattern structure configured to be in close contact with each other has the following effects.

First, since the array device and the organic light emitting diode device are formed on different substrates, production yield and production management efficiency can be improved, and product life can be increased.

Second, because of the top emission method, it is easy to design a thin film transistor and high aperture ratio / high resolution can be realized.

Third, it is possible to reduce the thickness occupied by the moisture absorbent, thereby providing a more compact product.

Fourth, it is possible to reduce the manufacturing process by reducing the process of encapsulating the absorbent separately.

Fifth, since a moisture absorption pattern is formed in the seal pattern forming part through which moisture can penetrate, the moisture penetration pattern can be effectively blocked, thereby improving reliability of the device.

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

2 is a cross-sectional view of a conventional organic light emitting display device.

3 is a cross-sectional view of a general structure organic electroluminescent device according to a first embodiment of the present invention.

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

5 is a process flowchart showing step by step a manufacturing process of an organic light emitting display device according to the present invention;

<Explanation of symbols for main parts of the drawings>

110: first substrate 130: first electrode

141: organic light emitting layer 142: second electrode

160: second substrate 170: seal pattern

180: moisture absorption pattern E: organic light emitting diode device

T: thin film transistor

Claims (15)

delete First and second substrates each having a sub-pixel area defined as a minimum unit for implementing a screen, and spaced apart from each other by a predetermined distance; An array device layer including a plurality of thin film transistors formed on a sub-pixel unit on an inner surface of the first substrate; An electrical connection pattern connected to the thin film transistor on the array element layer; A first electrode formed on the entire inner surface of the second substrate, an organic electroluminescent layer formed by repeating red, green, and blue sequentially on the lower part of the first electrode and separated in subpixel units, and each organic formed separately in the subpixel unit An organic light emitting diode device formed of a second electrode separated by subpixels under the electroluminescent layer and connected to the electrical connection pattern; And a double pattern comprising a seal pattern and a moisture absorption pattern encapsulating the edges of the first and second substrates, wherein the moisture absorption pattern is positioned inside the seal pattern. The method of claim 2, The seal pattern and the moisture absorption pattern are positioned in close contact with each other, the organic light emitting device consisting of a pattern structure corresponding to each other. The method of claim 2, The seal pattern and the moisture absorption pattern are organic electroluminescent elements formed by a dispensing method using a nozzle. The method of claim 4, wherein An organic electroluminescent device formed by a dispensing method using a nozzle filled with the moisture absorption pattern and a gel type moisture absorbent. The method of claim 4, wherein The material constituting the seal pattern is an organic light emitting device UV (ultra violet) curing agent. delete Providing first and second substrates on which subpixel regions are defined; Forming an array device layer on the first substrate, the array device layer having a plurality of thin film transistors positioned in subpixel units; Forming an electrical connection pattern connected to the thin film transistor on the array element layer; Forming a first electrode on an entire surface of the display area on the second substrate, forming a red, green, and blue organic electroluminescent layer that is formed on each of the subpixels on the first electrode and is sequentially repeated; Forming an organic light emitting diode device in which a second electrode is formed in subpixel units on the organic light emitting layer separately formed for each subpixel; Forming a double pattern consisting of a seal pattern and a moisture absorption pattern by simultaneously applying a seal pattern material and a moisture absorption pattern material to an edge portion of one of the first and second substrates; Encapsulating the first and second substrates in the dual pattern The method of claim 1, wherein the organic light emitting diode is connected to an electrical connection pattern, and the moisture absorption pattern is formed inside the seal pattern. The method of claim 8, And forming a barrier rib at a boundary of each subpixel over the first electrode before the forming of the organic light emitting layer. The method of claim 8, The thin film transistor includes a switching thin film transistor and a driving thin film transistor, and the thin film transistor connected to the organic light emitting diode device is a method of manufacturing an organic light emitting device corresponding to a driving thin film transistor. The method of claim 8, The forming of the double pattern may include dispensing the first nozzle filled with the seal pattern material and the second nozzle filled with the moisture absorption pattern material to form an edge portion of one of the first and second substrates. Method of manufacturing an organic electroluminescent device which is a step of forming a double pattern. The method of claim 11, The moisture absorption pattern material is a gel-type moisture absorbent manufacturing method of an organic light emitting device. The method of claim 11, The seal pattern material is a UV curing agent manufacturing method of an organic light emitting device. The method of claim 8, The method of manufacturing an organic light emitting display device to form the seal pattern and the moisture absorption pattern in close contact with each other. The method of claim 1, The organic electroluminescent device is formed by separating the respective subpixels by the partition wall provided at the boundary of each subpixel.