KR100645715B1 - OLED display device and manufacturing method thereof - Google Patents

Abstract

The present invention relates to an organic light emitting display device and a method of manufacturing the same. An organic light emitting display device according to the present invention includes a substrate in which a plurality of pixels are defined, a thin film transistor formed for each pixel on the substrate, and a thin film transistor. An organic light emitting device including a first electrode layer in contact with a drain electrode, an organic layer formed on the first electrode layer, and a second electrode layer formed on the organic layer, and the organic light emitting device to protect the organic light emitting device from ultraviolet rays. Ultraviolet light transmission prevention film formed on the upper portion of the light emitting device, and comprises a sealing portion formed on the UV transmission prevention film.

According to the present invention, when the encapsulation into a thin film by CVD or PVD method using plasma can prevent the organic layer of the organic light emitting device is affected by ultraviolet light, thereby extending the life of the organic film to improve the product quality It can work.

Description

Organic light emitting display device and method for manufacturing same {ORGANIC LIGHT EMITTING DISPLAY AND FABRICATING METHOD THEREOF}

1 is a cross-sectional view showing an example of a conventional active matrix (AM) organic light emitting display device;

2 is a cross-sectional view showing an example of a conventional encapsulated organic light emitting display device;

3 is a cross-sectional view showing another example of a conventional encapsulated organic light emitting display device;

4 is a cross-sectional view illustrating an organic light emitting display device encapsulated according to the present invention;

5A through 5F are cross-sectional views illustrating a method of manufacturing an organic light emitting diode display according to an exemplary embodiment of the present invention;

♣ Explanation of symbols for the main parts of the drawing ♣

1: substrate 21: first electrode layer

23 organic layer 24 second electrode layer

31 ultraviolet ray preventing film 32 sealing part

The present invention relates to an organic light emitting display device and a method of manufacturing the same, and more particularly, to an organic light emitting display device and a method for manufacturing the organic light emitting device that can protect the organic light emitting element from ultraviolet rays when encapsulated by CVD or PVD method using plasma. It is about.

In general, the organic light emitting device injects electrons and holes into the light emitting layer from the electron injection electrode and the hole injection electrode, respectively, so that the exciton of the injected electrons and holes may fall from the excited state to the ground state. When the device emits light.

1 is a cross-sectional view illustrating an example of a conventional active matrix (AM) organic light emitting display device, in which a buffer layer 11 is formed on a substrate 1, and the buffer layer 11 is disposed above the buffer layer 11. TFT is provided. Here, the TFT is not necessarily possible with the structure shown in Fig. 1, and the number and structure thereof can be variously modified.

The TFT has an active layer 12 formed on the buffer layer 11, a gate insulating film 13 formed on the active layer 12, and a gate electrode 14 on the gate insulating film 13. The active layer 12 may be formed of an amorphous silicon thin film or a polycrystalline silicon thin film. This semiconductor active layer has source and drain regions doped with N-type or P-type impurities at a high concentration.

The gate insulating layer 13 is formed on the active layer 12 by SiO _2, and the gate electrode 14 is formed as a conductive layer on a predetermined region above the gate insulating layer 13. The gate electrode 14 is connected to a gate line for applying a TFT on / off signal. The region where the gate electrode 14 is formed corresponds to the channel region of the active layer 12.

An inter-insulator 15 is formed on the gate electrode 14, and the source and drain regions of the active layer 12 are connected to the source electrode 16 and the drain electrode 17 through contact holes. It is formed to be in contact with. A passivation film 18 made of SiO ₂ or the like is formed on the source and drain electrodes 16 and 17, and a planarization layer 19 made of acryl, polyimide, etc. is formed on the passivation film 18. It is.

Although not shown in the drawings, at least one capacitor is connected to the TFT.

On the other hand, the organic light emitting diode OLED is connected to the drain electrode 17, and is connected to the first electrode layer 21 serving as an anode of the organic light emitting diode OLED. The first electrode layer 21 is formed on the passivation film 18, and an insulating planarization layer 19 is formed thereon, and after forming a predetermined opening in the planarization layer 19, An organic light emitting diode (OLED) is formed.

The organic light emitting diode emits red, green, and blue light according to a current to display predetermined image information. The organic light emitting diode is connected to the drain electrode 17 of the TFT and receives positive power from the first electrode layer ( 21 and the second electrode layer 24 provided to cover all the pixels to supply negative power, and the organic layer 23 disposed between the first electrode layer 21 and the second electrode layer 24 to emit light. It is composed.

In the case of the bottom emission type, the first electrode layer 21 may be formed of a transparent electrode such as ITO, and in the case of the top emission type, the second electrode layer 24 may be provided as a transparent electrode. In this case, the second electrode layer 24 may be formed by forming a thin semi-permeable thin film made of metal such as Mg-Ag, and then depositing transparent ITO thereon. The second electrode layer 24 does not necessarily have to be entirely deposited, and of course, may be formed in various patterns.

In the above-described configuration, since the organic layer 23 is easily deteriorated when exposed, the organic layer 23 must be encapsulated to block moisture.

FIG. 2 is a cross-sectional view illustrating an example of an organic light emitting display device encapsulated by a first method, which is illustrated as an encapsulation of a single organic light emitting device for convenience.

As shown, the organic light emitting device must be encapsulated to protect it from external influences. In order to encapsulate, a metal can or a glass plate 26 is attached to the upper edge of the substrate 1 using an adhesive 27 in an inert gas (ex: N ₂ ) atmosphere which is not reactive. There is a way.

At this time, the adhesive 27 is bonded by a method of curing by irradiation with ultraviolet (UV). The inner side of the metal case or glass plate 26 constitutes a hygroscopic agent 25 made of barium oxide (BaO) or calcium oxide (CaO). The moisture absorbent 25 is a means for removing moisture that has penetrated between the metal case or the glass plate 26 and the substrate 1.

3 is a schematic cross-sectional view showing an organic light emitting device encapsulated according to a second conventional method.

As illustrated, the protective layer 29 is formed by depositing or applying an inorganic insulating material or an organic insulating material at a low temperature to the remaining areas except for the driving wiring unit (not shown) formed in the peripheral area of the substrate 1. The organic light emitting device is encapsulated using the above-described metal case or glass plate 26 using an adhesive on the substrate 1 on which the protective layer 29 is formed.

In the organic light emitting device having the above-described configuration, the characteristics of the polymer organic film including the organic layer 23 are very important, and product defects should be prevented from occurring due to deterioration or chemical modification of the organic film.

In the organic light emitting device having the configuration shown in FIG. 2, only the edges of the pixels need to be treated with ultraviolet (UV) light. However, when the mask is used, the organic light emitting device does not affect the organic light emitting device due to the ultraviolet light. In the case of the organic light emitting device, when the protective layer 29 is formed of UV curable resin and cured, UV light passes through the lower transparent second electrode layer 24 and is irradiated to the polymer organic film including the organic layer 23.

In this case, some polymers deteriorate when the ultraviolet rays are irradiated, causing substitution reactions in double bond sites, etc., thereby reducing the electroluminescent properties of organic materials and shortening their lifetime.

In particular, thin film encapsulation is necessary to realize thinner, lighter, and flexible OLEDs. Chemical vapor deposition (CVD) or physical vapor deposition (PVD) may be mentioned.

However, when plasma is used during CVD or PVD deposition, the organic light emitting device (hereinafter referred to as EL device) is affected. This effect causes a great damage to the organic layer and the EL device as described above.

Therefore, when thin film encapsulation using plasma, there is a need for an alternative that can prevent the EL element from the influence of ultraviolet rays.

Accordingly, the present invention has been made to solve the above-mentioned conventional problems, and the organic light emitting display device in which the organic layer of the EL device is not affected by ultraviolet rays when the thin film encapsulation is performed by CVD or PVD using plasma. And its manufacturing method.

In order to achieve the above object, in the present invention, a substrate in which a plurality of pixels are defined, a thin film transistor formed for each pixel on the substrate, a first electrode layer in contact with a drain electrode of the thin film transistor, and the first electrode layer An organic light emitting element including an organic layer formed on an upper portion of the organic layer, a second electrode layer formed on the organic layer, an ultraviolet light blocking layer formed on the organic light emitting element to protect the organic light emitting element from ultraviolet rays, and the ultraviolet ray An organic light emitting display device including an encapsulation part formed on an anti-transmission layer is provided.

Herein, the ultraviolet ray preventing film is a calcium oxide (CaO) film formed by depositing calcium in an oxygen atmosphere.

In addition, the UV transmission prevention film may be any one selected from the group of materials absorbing the wavelength of 400nm or less, and when the second electrode layer is formed as a transparent electrode, it is preferable to select from a transparent material group, the first electrode layer is When formed as a transparent electrode it can be selected from the group of opaque materials.

In addition, the seal is characterized in that formed by chemical vapor deposition (CVD) or physical vapor deposition (PVD) method using a plasma.

According to an aspect of the present invention, there is provided a method of manufacturing an organic light emitting display device, the method including: forming at least one thin film transistor on a substrate, a first electrode layer in contact with a drain electrode of the thin film transistor, and the first electrode layer Forming an organic light emitting device including an organic layer formed on an upper portion of the organic layer and a second electrode layer formed on the organic layer, forming an ultraviolet light blocking layer on the organic light emitting device, and an upper portion of the ultraviolet light blocking layer Forming a seal in the.

In this case, the forming of the UV transmission prevention film may include depositing calcium on the organic light emitting device and supplying plasma gas to the calcium.

Preferably, the plasma gas is oxygen, and the forming of the sealing part is preferably performed by chemical vapor deposition (CVD) or physical vapor deposition (PVD) using plasma.

Hereinafter, an organic light emitting diode display and a manufacturing method according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 4, in the organic light emitting diode display of the present invention, a buffer layer 11 is formed on a substrate 1 on which a plurality of pixels are defined, and a TFT is provided over the buffer layer 11.

The TFT has an active layer 12 formed on the buffer layer 11, a gate insulating film 13 formed on the active layer 12, and a gate electrode 14 on the gate insulating film 13.

An inter-insulator 15 is formed on the gate electrode 14, and the source and drain regions of the active layer 12 are connected to the source electrode 16 and the drain electrode 17 through contact holes. It is formed to be in contact with. A passivation film 18 made of SiO ₂ or the like is formed on the source and drain electrodes 16 and 17, and a planarization layer 19 made of acryl, polyimide, etc. is formed on the passivation film 18. It is.

Although not shown in the drawings, at least one capacitor is connected to the TFT.

On the other hand, an organic light emitting diode (OLED) is connected to the drain electrode 17, the organic light emitting element is connected to the drain electrode 17 of the TFT and the first electrode layer 21 receives a positive power therefrom, And a second electrode layer 24 provided to cover all the pixels to supply negative power, and an organic layer 23 disposed between the first electrode layer 21 and the second electrode layer 24 to emit light.

An ultraviolet ray preventing layer 31 is formed on the second electrode layer 24 to protect the organic light emitting element from ultraviolet rays. The ultraviolet ray preventing layer 31 serves to prevent ultraviolet rays from reaching the organic layer 23 of the organic light emitting device by blocking (absorbing) ultraviolet rays, and selecting any one selected from a group of substances absorbing a wavelength of 400 nm or less. can do.

In general, the ultraviolet ray is composed of a wavelength ranging from about 397 to 10 nm, and the wavelength range above is visible light, so that the ultraviolet ray absorbing film having a wavelength of 400 nm or less and the visible ray having a wavelength longer than that can be passed. Applicable to (31).

In this case, when the organic light emitting diode display is a top emission type, the ultraviolet ray preventing layer 31 together with the second electrode layer 24 should be transparent. Therefore, when the second electrode layer 24 is formed of a transparent electrode, it is preferable that the ultraviolet ray preventing layer 31 select a transparent material from among a group of materials absorbing a wavelength of 400 nm or less.

The present invention proposes calcium oxide (CaO) formed by depositing calcium in an oxygen atmosphere with the ultraviolet ray preventing layer 31.

That is, in the case of front emission, after depositing calcium on the second electrode layer 24 and supplying oxygen in the plasma carrier gas on the calcium, the layer on which calcium is deposited reacts with oxygen to change to calcium oxide (CaO). It becomes gradually transparent so that it is possible to form a transparent ultraviolet transmission prevention film 31.

The reaction scheme at this time is as follows.

In addition, the UV transmission preventing film 31 may be formed by depositing calcium and treating UV with irradiation in an oxygen atmosphere.

In the organic light emitting diode display of the present invention, the transparent UV ray preventing layer 31 is formed on the second electrode layer 24 so that visible light passes but ultraviolet rays are absorbed, thereby protecting the organic layer 23 from ultraviolet rays. The device can be protected.

In this case, since the ultraviolet ray preventing film 31 is provided to prevent the ultraviolet rays irradiated upon UV curing from entering the organic layer 23, it is preferable that the ultraviolet ray preventing layer 31 is formed to a thickness that can block ultraviolet rays. In the above-described configuration of the organic light emitting display device, it is preferable that the thickness of the ultraviolet ray preventing layer 31 has a value in the range of 3 to 30 nm.

In addition, even in the case of the back light emission, a protective film is required. In this case, since the ultraviolet ray preventing layer 31 may be opaque, it is possible to make the ultraviolet ray preventing layer 31 an opaque material.

On the other hand, a sealing portion 32 is formed on the ultraviolet transmission prevention film 31.

As described above, the sealing part 32 is encapsulated to prevent exposure of the organic layer 23 and to block moisture, and in the present invention, in order to realize encapsulation of the thin film, the sealing part ( 32) Chemical Vapor Deposition (CVD) or Physical Vapor Deposition (PVD) is applied to form a transparent and dense film at low temperature during film formation.

That is, by thin film encapsulation using chemical vapor deposition (CVD) or physical vapor deposition (PVD) using plasma, a thinner, lighter and more flexible OLED can be realized.

As described above, the present invention can form encapsulation by forming the sealing portion 32 in a chemical vapor deposition (CVD) or physical vapor deposition (PVD) method using plasma, while providing calcium in an oxygen atmosphere on the EL element. The UV transmission prevention film 31 formed by depositing or UV curing in an oxygen atmosphere prevents the EL device from being affected by ultraviolet light, thereby protecting the EL device from ultraviolet light.

In constructing the organic light emitting device according to the present invention by using the above-described configuration, it can be applied to not only an active matrix organic light emitting device but also a passive matrix organic light emitting device.

A manufacturing process of the organic light emitting diode display according to the present invention will now be described with reference to FIGS. 5A to 5F.

First, as shown in FIG. 5A, the buffer layer 11 is formed on the substrate 1, and the thin film transistor T is formed on the buffer layer 11.

The thin film transistor has an active layer 12 formed on the buffer layer 11, a gate insulating layer 13 formed on the active layer 12, and a gate electrode 14 formed on the gate insulating layer 13. The active layer 12 may be formed of an amorphous silicon thin film or a polycrystalline silicon thin film. This semiconductor active layer has source and drain regions doped with N-type or P-type impurities at a high concentration.

The active layer 12 deposits amorphous silicon (a-Si: H) on the substrate 1, crystallizes it by a predetermined method, and then patterns it.

Next, one of the inorganic insulating material groups including silicon oxide (SiO ₂ ) and silicon nitride (SiNx) is deposited on the entire surface of the substrate 1 on which the active layer 12 is formed. 13).

Next, a conductive metal is deposited on the gate insulating layer 13 and then patterned to form a gate electrode 14.

Next, an insulating material is deposited on the entire surface of the substrate 1 on which the gate electrode 14 is formed to form an interlayer insulating film 15, which is a second insulating film, and then patterned. The source electrode 16 and the drain are contacted through contact holes. The electrode 17 is formed.

Next, as illustrated in FIG. 5B, one selected from the group of organic insulating materials is coated on the entire surface of the substrate 1 on which the source electrode 16 and the drain electrode 17 are formed, and then patterned to form the drain electrode ( A passivation film 18 which is a third insulating film exposing a part of 17) is formed.

Next, the first electrode layer 21 is formed on the entire surface of the substrate 1 on which the passivation film 18 is formed.

Next, as shown in FIG. 5C, the organic layer 23 is formed on the upper surface of the substrate 1 on which the first electrode layer 21 is formed.

Next, a conductive metal having a low work function such as aluminum (Al), calcium (Ca), and magnesium (Mg) is deposited on the entire surface of the substrate 1 on which the organic layer 23 composed of the multilayer is formed, and the pattern is formed. The second electrode layer 24 is formed to form an organic light emitting diode OLED.

Next, as shown in FIG. 5D, the calcium layer 30 is formed by depositing calcium on the surface of the substrate 1 on which the second electrode layer 24 is formed to form an ultraviolet ray preventing layer.

Next, as shown in FIG. 5E, oxygen (O ₂ ) is supplied as a plasma gas to the substrate 1 having the calcium layer 30 attached thereto.

As such, when oxygen in the plasma carrier gas is supplied to the calcium layer 30 on which the calcium is deposited, the layer on which the calcium is deposited is changed into calcium oxide as it is changed to calcium oxide, thereby becoming more transparent. ) Is formed.

At this time, by controlling the amount of oxygen, the time at which calcium becomes transparent and the UV curing time, the EL device can be transparent and processed without the influence of ultraviolet rays.

Subsequently, as shown in FIG. 5F, the sealing part 32 is formed on the upper part of the ultraviolet ray preventing layer 31 by chemical vapor deposition (CVD) or physical vapor deposition (PVD) using plasma to form a transparent and dense material. To form a film.

As described above, the present invention prevents the EL device from being affected by ultraviolet light through the transparent electrode on the upper surface when encapsulating the thin film by chemical vapor deposition (CVD) or physical vapor deposition (PVD) using plasma. To protect against

Although the technical spirit of the present invention has been described in detail according to the above-described preferred embodiments, it should be noted that the above-described embodiment is for the purpose of description and not of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention.

As described above, according to the present invention, the EL device forms an ultraviolet ray preventing layer on the EL device while the thin film encapsulation is implemented by chemical vapor deposition (CVD) or physical vapor deposition (PVD) using plasma. It is possible to protect the EL element from ultraviolet rays by blocking the influence from the

Therefore, since the EL element can be prevented from being affected by ultraviolet rays, there is an effect of extending the life of the EL element and improving the quality of the product.

Claims (10)

A substrate in which a plurality of pixels are defined; A thin film transistor formed on each of the pixels on the substrate; An organic light emitting device including a first electrode layer in contact with a drain electrode of the thin film transistor, an organic layer formed on the first electrode layer, and a second electrode layer formed on the organic layer; An ultraviolet ray preventing layer formed on the organic light emitting element to protect the organic light emitting element from ultraviolet rays; And It includes a sealing portion formed on top of the UV transmission prevention film, And the ultraviolet ray preventing layer is a calcium oxide (CaO) film formed by depositing calcium in an oxygen atmosphere. delete The method of claim 1, The thickness of the UV light blocking layer is an organic light emitting display device, characterized in that the range of about 3 ~ 30nm. The method of claim 1, And the UV light blocking layer is any one selected from a group of materials absorbing a wavelength of 400 nm or less. The method of claim 4, wherein When the second electrode layer is formed of a transparent electrode, the UV light blocking layer is any one selected from a group of transparent materials. The method of claim 1, And the sealing part is formed by chemical vapor deposition (CVD) or physical vapor deposition (PVD) using plasma. Forming at least one thin film transistor on the substrate; Forming an organic light emitting device including a first electrode layer in contact with a drain electrode of the thin film transistor, an organic layer formed on the first electrode layer, and a second electrode layer formed on the organic layer; Depositing calcium on the organic light emitting device; Supplying a plasma gas to the calcium to form an ultraviolet ray preventing layer on the organic light emitting device; And Forming a seal on the UV transmission barrier; Method of manufacturing an organic light emitting display device comprising a. delete The method of claim 7, wherein And wherein the plasma gas is oxygen. The method of claim 7, wherein The forming of the encapsulation part may be performed by chemical vapor deposition (CVD) or physical vapor deposition (PVD) using plasma.

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