WO2005112516A1

WO2005112516A1 - Organic el device

Info

Publication number: WO2005112516A1
Application number: PCT/JP2005/008682
Authority: WO
Inventors: Toshio Negishi
Original assignee: Ulvac, Inc.
Priority date: 2004-05-17
Filing date: 2005-05-12
Publication date: 2005-11-24
Also published as: TW200607386A

Abstract

A long-lived organic EL device is provided. An organic EL device (10) has a water absorbing layer (17) disposed on a transparent electrode membrane (15). Since the water absorbing layer (17) is made of transparent water absorbing material such as MgO, there is no possibility that the light emitted from an organic layer (12) and passed through the transparent electrode membrane (15) will be absorbed by the water absorbing layer (17). Therefore, even if the water absorbing layer (17) is formed widely over a display range, the brightness of the device will not lower. Further, the moisture entering the organic EL device (10) is absorbed by this water absorbing layer (17), so that the organic layer (12) will never be moisture-deteriorated, prolonging the life of the device.

Description

Specification

Organic EL device

Technical field

[0001] The present invention relates to the field of organic EL devices.

Background art

[0002] Conventionally, display devices and light emitting devices using organic EL (Electro Luminescence) have been widely used, and it is required to extend the life of these devices. The main cause of the short life of the organic EL device is that moisture enters the element and the electrode is peeled off from the organic layer, thereby generating a light emission defective spot called a dark spot. Therefore, the life of the organic EL device can be extended by preventing water from entering the element.

[0003] In a bottom emission type organic EL device in which light is emitted from the organic EL layer and passes through the substrate and is emitted from the surface of the substrate, a cap is provided on the back side of the substrate to seal the organic layer. In addition, a desiccant is attached inside the cap to absorb moisture. (For example, see Figures 1 and 8 in Patent Document 1.)

However, when a TFT (Thin Film Transistor) is provided on the substrate side, the light emitted from the organic layer is absorbed by the TFT, so that the display area is reduced and the brightness of the device may be reduced.

[0004] Therefore, a top emission type organic EL device that emits light to the back surface side (cap side) of a substrate has been proposed. (See Patent Document 1, FIGS. 3 to 6 and Patent Document 2.)

In the top emission type, it is not necessary to emit light to the substrate side on which the TFT is provided, so that the light emitting area can be increased and the brightness of the device can be increased. Incidentally, in such a top emission type, the cap on the back surface needs to be formed of a transparent substrate.

[0005] However, in the top emission type, the inside of the cap is wide like the bottom emission type! (4) If a desiccant is set in the range, light is absorbed by the desiccant, so that the desiccant cannot be sufficiently set. Insufficient waterproof performance may shorten the life of the device compared to the bottom emission type.

Patent Document 1: JP-A-2000-173766 Patent Document 2: JP 2003-142254 A

Disclosure of the invention

Problems to be solved by the invention

[0006] The present invention has been made in order to solve the above-mentioned disadvantages of the related art, and an object thereof is to provide a top emission type organic EL device having high luminance and a long life. is there.

Means for solving the problem

[0007] In order to solve the above problems, the present invention provides a substrate, an active region disposed on the substrate, on which an electric element and a lower electrode film are formed, and an organic region disposed on the active region. A transparent electrode film disposed on the organic layer, and when the electric element is turned on, a current flows through the organic layer located between the lower electrode film and the transparent electrode film. An organic EL device configured to emit light in the portion of the organic layer where the current flows, wherein a water-absorbing layer mainly composed of a transparent water-absorbing substance is disposed on the transparent electrode film; The light emitted from the organic layer is transmitted through the transparent electrode film and the water-absorbing layer and emitted to the outside.

The present invention is an organic EL device, wherein the water-absorbing layer contains a water-absorbing substance that also has MgO power.

The present invention is an organic EL device, wherein the water absorbing layer is an organic EL device formed by sputtering.

The present invention is an organic EL device, wherein the water absorbing layer has a thickness of 5 nm or more and 20 nm or less.

The present invention is an organic EL device, wherein a transparent sealing layer is disposed on the water absorbing layer, and the water absorbing layer and the organic layer are surrounded by the sealing layer and the substrate. It is.

The present invention is the organic EL device, wherein the sealing layer contains one or both of silicon nitride and silicon nitride.

The present invention is an organic EL device, wherein a transparent container is disposed on the sealing layer, and the sealing layer, the water absorbing layer, and the organic layer are surrounded by the container and the substrate. Tayu Machine EL device.

The present invention is an organic EL device, wherein a desiccant is disposed between the container and the substrate and at a position outside the active region.

The invention's effect

[0008] In the present invention, the water-absorbing layer is made transparent, and light emitted from the organic layer is not absorbed by the water-absorbing layer but passes through, so that the water-absorbing layer can also be formed in the display range. Therefore, it is possible to arrange the water absorbing layer over a wide range without being restricted by the place where the water absorbing layer is provided unlike the conventional organic EL device, and the water entering the device is absorbed by the water absorbing layer. The layers are not degraded by moisture and the life of the device is extended. As described above, according to the present invention, even the top emission type has a sufficient water absorbing ability and high waterproofness! (4) An organic EL display device can be provided.

Brief Description of Drawings

[0009] [FIG. 1] (a) to (g): cross-sectional views illustrating an example of a process for manufacturing the organic EL device of the present invention [FIG. 2] cross-sectional views illustrating a cap

FIG. 3 is an enlarged sectional view of the organic EL device of the present invention.

Explanation of symbols

[0010] 10: Organic EL device 11: Substrate 12: Organic layer 15: Transparent electrode film 17: Water absorbing layer 18: Sealing layer 20: Active area 25: Transistor (electric element) 30… Cap (container)

BEST MODE FOR CARRYING OUT THE INVENTION

First, an example of a process for manufacturing the organic EL device of the present invention will be described in detail. In FIG. 1A, reference numeral 11 denotes a substrate, and an electric element and a lower electrode film, which will be described later, are formed on one surface of the substrate 11. Reference numeral 20 in FIG. 1A indicates an active region in which an electric element and a lower electrode film are formed.

Reference numeral 9 in FIG. 1 (a) indicates a mask used for forming an organic layer described later. As shown in FIG. L (a), the opening of the mask 9 is located on the active area 20. Then, the mask 9 is arranged on the substrate 11 so that the edge of the substrate 11 is covered with the mask 9. In that state, mask the substrate 11 9 Together with the inside of a first film forming apparatus (here, a vapor deposition apparatus).

[0013] A vacuum atmosphere is previously formed inside the first film forming apparatus, and while maintaining the vacuum atmosphere, the organic material disposed inside the first film forming apparatus is heated, and the organic material is heated. Generates steam.

The surface of the substrate 11 on which the mask 9 is disposed is held toward the organic material, and the vapor of the organic material passes through the opening of the mask 9, and the vapor that has passed through the opening of the mask 9 A film of organic material (organic layer 12) grows on the 20 surface (Fig. 1 (b)).

When the organic layer 12 has grown to a predetermined thickness, the substrate 11 is transported together with the mask 9 from the first film forming apparatus to a second film forming apparatus (here, a sputtering apparatus). A vacuum atmosphere is previously formed inside the second film forming apparatus, and a target made of a transparent conductive material is arranged in the vacuum atmosphere.

When a ground potential is applied to the substrate 11 and a negative voltage is applied to the target while maintaining a vacuum atmosphere inside the second film forming apparatus, the target is sputtered and sputtered particles are emitted from the target.

The substrate 11 has the surface on the side where the mask 9 is disposed facing the target, and among the sputter particles emitted from the target, the sputter particles that have passed through the opening of the mask 9 are organic layers. The transparent conductive material film (transparent electrode film 15) grows on the surface of the substrate 12 (FIG. 1 (c)). When the transparent electrode film 15 has grown to a predetermined thickness, the substrate 11 is carried together with the mask 9 from the second film forming apparatus to a third film forming apparatus (here, a vapor deposition apparatus).

A vacuum atmosphere is previously formed inside the third film forming apparatus, and a transparent water absorbing material (here, MgO) placed inside the third film forming apparatus is maintained while maintaining the vacuum atmosphere. Is heated to generate vapor of the water absorbing material.

The surface of the substrate 11 on which the mask 9 is disposed faces the water-absorbing material, and the vapor of the water-absorbing material passing through the opening reaches the surface of the transparent electrode film 15, A layer of water-absorbing material (water-absorbing layer 17) grows on the surface (Fig. 1 (d)).

When the water-absorbing layer 17 has grown to a predetermined film thickness, the substrate 11 is also carried out by the third film forming apparatus, and the mask 9 is removed from the substrate 11. In the case of CVD equipment). A vacuum atmosphere is previously formed inside the fourth film forming apparatus by vacuum evacuation, and while the vacuum evacuation is continued, the first raw material gas containing silicon is contained inside the fourth film forming apparatus ( Here, SiH gas) and a second source gas containing oxygen and nitrogen (here, O gas, N

4 2

H gas) is supplied together to form a film formation atmosphere at a predetermined pressure.

Three

Electrodes are arranged inside the fourth film forming apparatus. When a ground potential and a negative voltage are applied to the substrate 11 and the electrode while maintaining the film forming atmosphere, the first and second source gases are applied. Is generated, and an insulating film is formed on the surface of the substrate 11 as a reactant (silicon oxynitride, SiON) of the first and second source gases.

If the amount of silicon nitride in SiON is too large, the insulating film is colored. The supply amount of nitrogen-containing gas (NH gas) is so small that the insulating film becomes transparent. Board 1

Three

A transparent insulating film grows on 1. When the insulating film has grown to a predetermined thickness, the substrate 11 is unloaded from the fourth film forming apparatus.

FIG. 1E shows a state immediately after the insulating film 18 ′ having a predetermined thickness is formed. In this state, the insulating film 18 ′ is formed on the surface and side surfaces of the water absorbing layer 17 and the transparent electrode film 15. Side, the side of the organic layer 12, the periphery of the active region 20, and the portion of the surface of the substrate 11 outside the active region 20 in a continuous manner.

Next, when the portion of the insulating film 18 ′ located outside the active region 20 is removed by etching, the end of the substrate 11 is exposed. FIG. 1 (f) shows a state after the etching, and reference numeral 18 in the same figure denotes a sealing layer made of the insulating film 18 ′ remaining without being etched.

[0026] The sealing layer 18 is formed so as to continuously cover the periphery of the active region 20, the side surface of the organic layer 12, the side surface of the transparent electrode film 15, and the side surface and surface of the water absorbing layer 17, The organic layer 12, the transparent electrode film 15, and the water absorbing layer 17 are surrounded by the sealing layer 18 and the substrate 11, and are shielded from the outside.

[0027] Reference numeral 30 in FIG. 2 indicates a transparent container-shaped cap, and a plurality of ring-shaped grooves 37 to 39 are formed at an edge of the container opening of the cap. Here, the center of the ring of each groove 37-39 coincides with the center of the opening of the cap 30, and the inner diameter of each groove 37-39 is larger than the diameter of the opening of the cap 30. Therefore, the opening of the cap 30 is surrounded by the grooves 37-39. In order to attach the cap 30 to the substrate 11 described above, a ring-shaped adhesive resin 31 is arranged at least in the groove 37 located at the outermost periphery, and the groove 3 located inside the groove 37 located at the outermost periphery.

A ring-shaped desiccant 32 is placed on 8, 39 (Fig. 2).

[0029] Since the thickness of the ring of the adhesive resin 31 and the desiccant 32 is made larger than the depth of the grooves 37 to 39, the adhesive resin 31 and the desiccant 32 also reduce the surface force of the edge portion of the cap 30. It is protruding.

[0030] The inner diameter of the opening of the cap 30 is larger than the diameter of the sealing layer 18 described above, and the opening of the cap 30 faces the surface of the substrate 11 on the side where the sealing layer 18 is arranged. When the cap 30 is placed on the substrate 11, the sealing layer 18 is covered with the cap 30 and the adhesive resin 31 is formed. The desiccant 32 adheres to a portion of the substrate 11 outside the region where the sealing layer 18 is formed.

Here, the adhesive resin 31 contains an ultraviolet curable resin, and when the adhesive resin 31 is irradiated with ultraviolet light, the adhesive resin 31 is located outside the sealing layer 18 of the substrate 11. It cures in a state where it is in close contact with both the part and the cap 30.

Reference numeral 10 in FIG. 1G indicates the organic EL device in a state where the adhesive resin 31 is cured.

As described above, the adhesive resin 31 is cured in a state in which both the portion of the substrate 11 outside the sealing layer 18 and the cap 30 are in close contact with each other. It is surrounded by the cap 30 and the hardened adhesive resin 31.

[0033] The adhesive resin 31 is made of a resin having high waterproofness after curing, such as an acrylic resin. Further, the cap 30 is made of a highly waterproof substance such as glass, and the substrate 11 is also made of a highly waterproof substance such as a glass plate, so that the cured adhesive resin 31 and the cap 30 are used. It is difficult for the moisture of the external atmosphere to enter the space surrounded by the substrate 11 and the moisture of the external atmosphere, even if the moisture of the external atmosphere passes through the adhesive resin 31 and enters the space. Absorbed by a desiccant 32 located inside the 31 ring.

Accordingly, moisture hardly reaches the sealing layer 18 and the organic layer 12 surrounded by the sealing layer 18 and the substrate 11. Even if moisture enters the space surrounded by the sealing layer 18 and the substrate 11, the water absorbing layer 17 is disposed in that space, and the water is absorbed by the water absorbing layer 17, so that the organic layer 12 cannot be chemically degraded by moisture! Next, an example of a process in which the organic EL device 10 emits light will be described. FIG. 3 shows an enlarged cross-sectional view of the organic EL device 10. A plurality of lower electrode films 21 are arranged in a row in the active region 20, and at least one electric element (here, a transistor 25) is arranged near each lower electrode film 21! You.

Here, each transistor 25 has a gate electrode 22, a source electrode 23, a drain electrode 27, and a semiconductor layer 26, respectively. The gate electrode 22 is covered with the insulating thin film 24, the semiconductor layer 26 is disposed in close contact with the surface of the insulating thin film 24, and the source electrode 23 and the drain electrode 27 are in close contact with the semiconductor layer 26 while being separated from each other. Arranged!

[0037] A source line and a gate line (not shown) extend in the active region 20 while being insulated from each other. The source line is connected to a power supply circuit, and the gate line is connected to a control circuit. The source wiring is connected to the source electrode 23, the gate wiring is connected to the gate electrode 22, the voltage of the power supply circuit is applied to the source electrode 23, and the voltage from the control circuit is applied to the gate electrode 22. It's like that.

In order for the organic EL device 10 to emit light, a transistor 25 to be turned on is selected, and a source line and a gate line are connected so that a voltage is applied to the source electrode 23 and the gate electrode 22 of the selected transistor 25. When a voltage is applied to the transistor 25, the resistance value of the semiconductor layer 26 of the selected transistor 25 decreases, the source electrode 23 and the drain electrode 27 are electrically connected, and the transistor 25 is turned on.

Since the drain electrode 27 is connected to the lower electrode film 21, when the transistor 25 is turned on, the voltage of the drain electrode 27 is applied to the lower electrode film 21. Since the lower electrode films 21 are insulated from each other by the insulating layer 29, no electricity is transmitted from one lower electrode film 21 to the other lower electrode film 21, and the lower electrode films 21 connected to the conductive transistor 25 are not connected. Only the voltage is applied.

Since the above-mentioned organic layer 12 is in close contact with each lower electrode film 21 and the transparent electrode film 15, a positive voltage is applied to the selected lower electrode film 21 while a negative voltage is applied to the transparent electrode film 15. Then, a current flows to a portion of the organic layer 12 on the selected lower electrode film 21 to emit light.

As described above, the water absorbing layer 17 is mainly composed of a transparent water absorbing material, the sealing layer 18 is made of a transparent insulating material such as SiON, and the water absorbing layer 17 and the sealing layer 18 are High transparency Since it has optical properties, light emitted from the organic layer 12 passes through the transparent electrode film 15, the water absorbing layer 17, and the sealing layer 18.

[0042] The cap 30 is a force closely attached to the sealing layer 18, or if there is a space between the cap 30 and the sealing layer 18, no light-shielding substance is disposed in the space. Instead, the cap 30 is made transparent as described above, so that the light transmitted through the sealing layer 18 is transmitted through the cap 30 and is emitted to the outside.

In the organic EL device 10, by selecting the transistor 25 to be turned on, only a desired portion of the organic layer 12 emits light, and image information such as characters and figures can be displayed.

In general, members (wirings, electrodes, and the like) forming the transistor 25 are opaque, but light emitted from the organic layer 12 is not reflected on the substrate 11 side on which the transistor 25 is disposed, but on the transparent electrode film 15 side. The organic EL device 10 has high brightness because the light is emitted to the device.

If a reflective member having a reflective property is arranged on a member in the active region 20, for example, on the lower electrode film 21 or the insulating layer 29, radiation is emitted from the organic layer 12 toward the substrate 11 side. The reflected light is reflected by the reflection member and emitted to the transparent electrode film 15 side, so that the luminance of the organic EL device 10 can be further increased.

The substrate 11 is not particularly limited, and a transparent substrate exemplified by a glass substrate or another opaque substrate such as a ceramic substrate can be used. In the case of a so-called top emission type organic EL device 10 that emits light emitted from the organic layer 12 to the side opposite to the substrate 11 on which the transistor 25 is formed, the substrate 11 may not be transparent. If a transparent substrate is used for the substrate 11, light emitted from the organic layer 12 can be emitted to both the cap 30 side and the substrate 11 side.

The lower electrode film 21 and the transistor 25 formed in the active region 20 are not particularly limited. Although the above description has been made on the case where one transistor 25 is arranged for one lower electrode film 21, a plurality of transistors may be provided for one lower electrode film 21.

In the above, a so-called active matrix type organic EL device in which a plurality of lower electrode films 21 are arranged in a matrix and a transistor 25 is provided on each lower electrode film 21 has been described, but the present invention is not limited to this. A linear lower electrode film is arranged in the active area 20 substantially parallel to the active area 20 and a linear transparent electrode film is formed on the active area 20 so as to be orthogonal to the lower electrode film. The present invention also includes a so-called simple matrix organic EL device in which the organic layer 12 emits light at a position where the transparent electrode film and the lower electrode film cross each other. Also in this case, by providing a transparent water-absorbing layer on the transparent electrode film, it is possible to prevent water from entering the organic layer 12.

[0049] Although the case where the organic layer 12 has a single-layer structure has been described above, the organic layer is formed by laminating a plurality of layers such as a hole transport layer, a light emitting layer, and an electron transport layer in the thickness direction. The present invention also includes the case where a

Further, a plurality of lower electrode films 21 adjacent to each other are used as one set of light-emitting units, and an organic light-emitting device that emits light of different colors such as red, blue, green, etc. By providing the respective layers and selecting the lower electrode film 21 to which a voltage is applied, by causing the organic layer 12 of a desired color to emit light, image information can be displayed in color.

Further, even when the emission colors of the organic layers 12 are the same, color filters of different colors are provided on the organic layers 12 so that the organic layers 12 where the color filters of the desired colors are located emit light. Thus, the image information can be displayed in color.

Although the above description has been given of the case where the organic EL device is used as a display device for displaying image information, the present invention is not limited to this. If the organic layer 12 emits light over a wide area, it can be used as a light emitting device.

[0053] The type and thickness of the transparent electrode film 15 are not particularly limited either. For example, the transparent electrode film 15 contains any one metal material selected from the group consisting of Li, Ca, Mg, and Ag. A film formed with a thickness of lOnm or more and 15 nm or less (100 to 15θΑ), more preferably a thickness of 12 nm (120 A) can be used. In order to reduce the resistance value of the transparent electrode film 15, a transparent conductive film such as an InZnO film can be formed on the surface of the transparent electrode film 15 by vapor deposition.

The thickness of the water-absorbing layer 17 is not particularly limited, but if the thickness of the water-absorbing layer 17 is less than 5 nm, the water absorption is insufficient, and if it exceeds 20 nm, the light transmittance may decrease. Therefore, the thickness is preferably 5 nm or more and 20 nm or less.

The substance constituting the water-absorbing layer 17 is water-absorbing and is not particularly limited as long as it is a transparent water-absorbing material. The substance having a transmittance Z and a refractive index used for the cap 30 (eg, glass) It is more preferable to configure the same as the above. For example, if the cap 30 is made of glass In such a case, it is preferable to use a substance (for example, MgO or the like) having the same refractive index Z transmittance as that of glass and having water absorption. The method for forming the water-absorbing layer is not limited to the vapor deposition method, and the water-absorbing layer can be formed by another film-forming method such as a sputtering method.

When the water-absorbing layer 17 is formed by a sputtering method, the sputtering speed is set to 0.2 to 0.2 nmZ (lAZs to 2AZs) so as not to damage the transparent electrode film 15 and the organic layer 12.成膜

The shape of the water absorbing layer 17 is not particularly limited. If the water absorbing layer 17 has sufficient insulating properties and is made of an absorbing material having low chemical reactivity with the organic material of the organic layer 12, the side surface of the transparent electrode film 15 and the organic layer 12 A water absorbing layer 17 is formed to cover the side surface.

[0057] The material constituting the cap 30 is not particularly limited as long as it is a material that transmits light (particularly, visible light), and glass or transparent resin (for example, acrylic resin) can be used. Also, it is not necessary that the entire cap 30 be transparent, and at least the portion located on the active area 20 is transparent. Also, the shape of the cap 30 is not particularly limited.

In the above, the description has been given of the case where the water absorbing layer 17 and the sealing layer 18 are formed on the transparent electrode film 15. The order of forming these layers is not limited to this. Specifically, the sealing layer 18 may be formed on the transparent electrode film 15, and the water absorbing layer 17 may be formed on the sealing layer 18. Further, the sealing layer 18, the water absorbing layer 17, and the sealing layer 18 may be laminated on the transparent electrode film 15 in the order described. The number of the sealing layers 18 and the water absorbing layers 17 and the order of lamination are not particularly limited.

The material constituting the sealing layer 18 has a high translucency! If it is a material, it is not limited to SiON. It is also possible to use another material such as SiO. Especially the membrane method

2

It is not limited.

The sealing layer 18 may be a combination of SiON and SiO. Specifically, the transparent electrode film

2

Above 15, a first sealing layer mainly composed of SiON and a second sealing layer mainly composed of SiO

2

A layer and a water absorbing layer 17 containing MgO as a main component may be provided. The order of laminating the first and second sealing layers and the water absorbing layer 17 is not particularly limited.

When the MgO layer (water absorbing layer) is formed by sputtering, before the MgO layer is formed by sputtering. In addition, by forming the sealing layer 18 on the transparent electrode film 15, the influence of sputtering on the transparent electrode film 15 and the organic layer 12 can be suppressed.

The adhesive resin 31 for fixing the cap 30 to the substrate 11 is not limited to an acrylic resin, but may be, for example, urethane resin or epoxy resin as an ultraviolet curable resin. Further, the adhesive resin 31 is not limited to the ultraviolet curing type, and various types such as a thermosetting type can be used. Further, a resin obtained by adding other resins such as a thermoplastic resin and additives such as a filler, an ultraviolet absorber, an antioxidant, and a coloring agent to the adhesive resin 31 may be used. The shape and location of the desiccant 32 are not particularly limited.If it is outside the active area 20, for example, it can be installed on the inner side surface of the cap 30.

Claims

The scope of the claims

[1] a substrate,

An active region disposed on the substrate, on which an electric element and a lower electrode film are formed, and an organic layer disposed on the active region,

Having a transparent electrode film disposed on the organic layer,

When the electrical element is turned on, a current flows through the organic layer located between the lower electrode film and the transparent electrode film,

An organic EL device configured to emit light at a portion of the organic layer where the current flows, and

A water-absorbing layer mainly composed of a transparent water-absorbing substance is disposed on the transparent electrode film, and light emitted from the organic layer is emitted to the outside through the transparent electrode film and the water-absorbing layer. Organic EL device.

2. The organic EL device according to claim 1, wherein the water-absorbing layer contains a water-absorbing substance made of MgO.

3. The organic EL device according to claim 1, wherein the water absorbing layer is formed by sputtering.

4. The organic EL device according to claim 1, wherein the water absorbing layer has a thickness of 5 nm or more and 20 nm or less.

[5] A transparent sealing layer is disposed on the water absorbing layer,

The organic EL device according to claim 1, wherein the water absorbing layer and the organic layer are surrounded by the sealing layer and the substrate.

6. The organic EL device according to claim 5, wherein the sealing layer contains one or both of silicon nitride and silicon nitride.

[7] A transparent container is disposed on the sealing layer,

7. The organic EL device according to claim 5, wherein the sealing layer, the water absorbing layer, and the organic layer are surrounded by the container and the substrate.

8. The organic EL device according to claim 7, wherein a desiccant is disposed between the container and the substrate and outside the active area.