Organic light emitting display device

An organic light emitting display device includes a substrate; an organic light emitting unit formed on the substrate; and a sealing unit which seals the organic light emitting unit, wherein the sealing unit is formed by alternately stacking at least one first thin film and at least one second thin film, the first thin film being formed to surround a portion of the second thin film.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No. 10-2008-0038252, filed on Apr. 24, 2008 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to an organic light emitting display device, and more particularly, to an organic light emitting display device capable of preventing penetration of vapor such as moisture or oxygen.

2. Description of the Related Art

Organic light emitting display (OLED) devices using OLED elements typically have faster response speeds than liquid crystal display (LCD) devices, which are currently in wide commercial use, and thus, can provide excellent images of rapid motion. Furthermore, OLED devices are emissive, have wide viewing angles, and have high brightness. Thus, OLED devices are expected to be next generation display devices.

An OLED element includes a pixel electrode and a facing electrode facing each other, and a light emitting layer including an organic material interposed between the pixel electrode and the facing electrode. The OLED element is sensitive to moisture, oxygen, and light. Accordingly, if the OLED element is exposed to moisture, oxygen, and light, the OLED element can be easily degraded. In addition, when moisture or oxygen diffuses into and entered into an organic material layer, an electrochemical charge transfer reaction occurs on the interface between the electrode and the organic material layer, thereby generating an oxide. Also, the oxide separates the organic material layer and the pixel electrode or the facing electrode, causing a phenomenon such as dark spot, thereby reducing the life of the OLED element. Since the OLED element has a relatively low threshold for thermal damage, when temperature increases to from about 30° C. to about 60° C., the life of the OLED element is shortened by approximately 20 times. Therefore, a sealing technology is generally used in the OLED element to prevent external moisture, oxygen, and light from entering the OLED element.

SUMMARY OF THE INVENTION

Some embodiments provide an organic light emitting display (OLED) device capable of preventing penetration of vapor such as moisture or oxygen from the outside.

Some embodiments provide an organic light emitting display with improved resistance to damage and/or infiltration by water vapor and/or oxygen. Embodiments of the organic light emitting display comprise a substrate, an organic light emitting unit disposed on the substrate, and a sealing unit disposed on the organic light emitting unit, which together with the substrate, encapsulate the organic light emitting unit. The sealing unit comprises a first set of films comprising at least one first thin film, and a second set of films comprising at least one second thin film. The thin films of the first set of films and the second set of films alternate or are interleaved. In some embodiments, a first thin film covers and surrounds a second thin film. In some embodiments, the second thin film is disposed over and covers the organic display unit. Some embodiments further comprise at least one getter layer disposed on a portion of a first thin film that is substantially not over the organic light emitting unit.

Accordingly an aspect provides an organic light emitting display device including: a substrate; an organic light emitting unit formed on the substrate; and a sealing unit which seals the organic light emitting unit, wherein the sealing unit is formed by alternately stacking at least one first thin film and at least one second thin film, the first thin film being formed to surround a portion of the second thin film.

The first thin film may be formed to be wider than the second thin film.

Each of the stacked first thin film may be formed to have the same width.

Each of the stacked second thin film may be formed to have the same width.

The first thin film may be formed of an inorganic material.

The second thin film may be formed of an organic material.

Another aspect provides an organic light emitting display device including: a substrate; an organic light emitting unit formed on the substrate; a sealing unit which seals the organic light emitting unit, wherein the sealing unit is formed by alternately stacking at least one first thin film and at least one second thin film, the first thin film being formed to surround a portion of the second thin film; and a getter layer formed on the first thin film, instead of forming on a region corresponding to the upper portion of the organic light emitting unit.

The getter layer may be formed of a reactive metal.

The getter layer may be formed of metal oxide.

The first thin film may be formed to be wider than the second thin film.

Each of the stacked first thin film may be formed to have the same width.

Each of the stacked second thin film may be formed to have the same width.

The first thin film may be formed of an inorganic material.

The second thin film may be formed of an organic material.

Some embodiments provide an organic light emitting display device comprising: a substrate; an organic light emitting unit disposed on the substrate; and a sealing unit disposed over the organic light emitting unit and at least a portion of the substrate, thereby sealing the organic light emitting unit therein, wherein the sealing unit comprises at least one first thin film and at least one second thin film alternately stacked, the first thin film surrounding at least a portion of the second thin film.

In some embodiments, the at least one first thin film is wider than the at least one second thin film.

Some embodiments comprise a plurality of stacked first thin films, wherein each of the stacked first thin films has substantially the same width. Some embodiments comprise a plurality of stacked second thin films, wherein each of the stacked second thin films has substantially the same width.

In some embodiments, the at least one first thin film comprises an inorganic material. In some embodiments, the at least one second thin film comprises an organic material.

Some embodiments further comprise a getter layer disposed on the at least one first thin film, wherein the getter layer is substantially not disposed over the organic light emitting unit. In some embodiments, the getter layer comprises a reactive metal. In some embodiments, the getter layer comprises metal oxide.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

Hereinafter, certain embodiments and features thereof will be described more fully with reference to the accompanying drawings, in which exemplary embodiments are shown. The disclosure may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concepts thereof to those skilled in the art. In the drawings, like reference numerals denote like elements, and the sizes and thicknesses of layers and regions are exaggerated for clarity.

FIG. 1is a cross-sectional diagram schematically illustrating an embodiment of an organic light emitting display device100, andFIG. 2is a perspective plan view schematically illustrating the organic light emitting display device100ofFIG. 1.

Referring toFIGS. 1 and 2, the organic light emitting display device100includes a substrate101, an organic light emitting unit102, and a sealing unit110. The organic light emitting unit102formed of an organic light emitting element is disposed on the substrate101. The substrate101may comprise glass or plastic, such as acrylic. The substrate101is not limited thereto and may comprise metal. In addition, a buffer layer (not shown) may be further disposed on the substrate101.

The organic light emitting unit102may further include a plurality of organic light emitting elements. The organic light emitting elements of the organic light emitting unit102includes a pixel electrode and a facing electrode facing each other, and an intermediate layer including a light emitting layer interposed between the pixel electrode and the facing electrode. The pixel electrode may be a transparent electrode or a reflection electrode. If the pixel electrode is a transparent electrode, the pixel electrode can comprise ITO, IZO, ZnO, or In2O3, and if the pixel electrode is a reflection electrode, the pixel electrode can include a reflection film formed of Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, or a compound thereof and a film comprising ITO, IZO, ZnO, or In2O3disposed on the reflection film. The facing electrode can also be a transparent electrode or a reflection electrode. If the facing electrode is a transparent electrode, the facing electrode can include a film comprising Li, Ca, LiF/Ca, LiF/Al, Al, Mg, or a compound thereof facing the intermediate layer and interposed between the pixel electrode and the facing electrode, and an auxiliary electrode or a bus electrode line disposed on the film, comprising the transparent electrode material, such as ITO, IZO, ZnO, or In2O3. If the facing electrode is a reflection electrode, the facing electrode can comprise Li, Ca, LiF/Ca, LiF/Al, Al, Mg, or a compound thereof. The intermediate layer interposed between the pixel electrode and the facing electrode can comprise a lower molecular weight organic material or a polymer organic material. If the intermediate layer is formed of a lower molecular weight organic material, the intermediate layer may comprise a stack comprising a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL), or an electron injection layer (EIL) in a single structure or a composite structure, and may comprise various organic materials such as copper phthalocyanine (CuPc), N,N′-di(naphthalene-1-yl)-N,N′-diphenylbenzidine (NPB), or tris-8-hydroxyquinoline aluminum (Alq3). The intermediate layer comprising a lower molecular weight organic material may be formed by a vacuum evaporation method using masks. If the intermediate layer comprises a polymer organic material, the intermediate layer may comprise an HTL and an EML, in which the HTL can comprise a polymer organic material such as poly-(2,4)-ethylene-dihydroxy thiophene (PEDOT), and the EML can comprise a polymer organic material such as poly-phenylenevinylene (PPV), or polyfluorene.

The sealing unit110seals the organic light emitting unit102. The sealing unit110may be formed by alternately stacking a first thin film111and a second thin film112, the first thin film111comprising separate films111a,111b, and111cand the second thin film112comprising separate films112aand112b. The first thin film111may surround a portion of the second thin film112. That is, the second thin films112aand112bare respectively interposed between the first thin films111a,111b, and111cand the second thin films112aand112bare completely surrounded by the first thin films111a,111b, and111c. Referring toFIGS. 1 and 2, the first thin film111aseals the organic light emitting unit102. The second thin film112ais formed on the first thin film111a. The second thin film112acompletely covers a region corresponding to the upper portion of the organic light emitting unit102and covers a portion of the first thin film111a. The width d2of the second thin film112ais greater than a width d1of the organic light emitting unit102and is smaller than a width d3of the first thin film111a.

The first thin film111bcompletely covers the second thin film112a. In addition, the second thin film112bis disposed on the first thin film111b. The second thin film112bcompletely covers the organic light emitting unit102and covers a portion of the first thin film111b. The first thin film111ccompletely covers the second thin film112b.

The sealing unit110may comprise at least two thin films111and112, and the total number of the thin films111a,111b,111c,112a, and112bforming the sealing unit110is an odd number. The thin film that directly covers the organic light emitting unit102is the first thin film111a. The first thin film111ais disposed on the organic light emitting unit102, and the first thin film111and the second thin film112are alternately stacked, so that only first thin film is disposed on the most outer portion of the organic light emitting unit102.

The first thin films111a,111b, and111cmay be formed by using various general methods of forming a thin film, for example, sputtering, chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), and/or plasma enhanced chemical vapor deposition (PECVD). In some embodiments, each of the first thin films is independently from about 0.02 μm to about 0.2 μm thick.

When the first thin films111a,111b, and111care formed by using above methods, shadow masks each having the same size may be used. That is, one shadow mask may be used to form the plurality of the first thin films111a,111b, and111c. Thus, the sizes, that is, the widths, of the first thin films111a,111b, and111care all the same. Since one shadow mask is used to form the plurality of the first thin films111a,111b, and111c, a manufacturing cost of the organic light emitting display device100is reduced. Moreover, since one shadow mask is used to form the stack of the plurality of the first thin films111a,111b, and111c, an align margin of each of the first thin films111a,111b, and111cis reduced and thus a dead space w over which the sealing unit110covers a region other than the organic light emitting unit102may be reduced.

The first thin film111may comprise inorganic materials, for example, metal oxide, metal nitride, metal oxynitride, and/or metal carbide. The first thin film111comprising an inorganic material prevents gas, such as oxygen and moisture, from contacting the organic light emitting unit102. As described above, the first thin film111completely seals the organic light emitting unit102and thus moisture or oxygen is prevented from penetrating from the outside, thereby protecting the organic light emitting unit102.

The second thin films112aand112bmay be formed by using various general methods of forming a thin film, for example, sputtering, CVD, PECVD, and/or PECVD, as for the first thin films111a,111b, and111c. In some embodiments, each of the second thin films is independently from about 0.1 μm to about 2 μm thick.

The plurality of the second thin films112aand112bmay be formed by using one shadow mask. Accordingly, both the second thin films112aand112bhave the same width d2. As described above, since one shadow mask is used to form the plurality of the second thin films112aand112b, a manufacturing cost of the organic light emitting display device100is reduced.

The second thin film112may comprise an organic material, for example, acrylic resin. The second thin films112aand112bplanarize the surfaces of the first thin films111aand111bdisposed under the second thin films112aand112b.

A condition of the surface on which the second thin film112is formed is important when the second thin film112comprises an organic material. When the second thin film112comprising an organic material covers the first thin film111, a portion of the second thin film112is disposed on the substrate101and other portion of the second thin film112is disposed on the first thin film111. Since the second thin film112disposed on the substrate101and the second thin film112disposed on the first thin film111are supported on different surfaces, a minute gap may exist between the second thin film112and the substrate101, and/or between the second thin film112and the first thin film111through which external moisture or oxygen may penetrate into the organic light emitting unit102, thereby damaging the organic light emitting unit102. However, according to one embodiment, the second thin film112is surrounded by the first thin film111, and thus, the entire second thin film112may have a uniform foundation.

FIG. 3is a cross-sectional diagram schematically illustrating a another embodiment of n organic light emitting display device200; andFIG. 4is a perspective plan view schematically illustrating the organic light emitting display device200ofFIG. 3.

The organic light emitting display device200illustrated inFIGS. 3 and 4differs from the organic light emitting display device100illustrated inFIGS. 1 and 2, further including a getter layer213. In other words, the substrate101, the organic light emitting unit102, the first thin film111, and the second thin film112included in the organic light emitting display device200ofFIGS. 3 and 4are the same or similar to those of the organic light emitting display device100described above. Accordingly, the detailed description thereof is omitted here and the getter layer213is described below.

The getter layer213, which includes separate layers213aand213b, is interposed between the first thin film111and the second thin film112, and is not disposed over the upper portion of the organic light emitting unit102. After the second thin film112ais formed on the first thin film111a, the getter layer213ais formed on a region d4over which the second thin film112ais not formed on the first thin film111a. The first thin film111bcovers the second thin film112aand the getter layer213a. The second thin film112band the getter layer213bare disposed on the first thin film111b. The first thin film111cis formed to cover the second thin film112band the getter layer213b. In other words, the getter layers213aand213bare interposed between the first thin films111a,111b, and111c. Since the getter layer213is not disposed on the second thin films112aand112b, the thickness of the sealing unit110may be reduced thereby providing a thin organic light emitting display device100.

The getter layer213may be generally comprise getter materials that react with moisture and oxygen, thereby preventing or reducing moisture and oxygen penetration into the organic light emitting unit102. The getter layer213may comprise metals such as Ba, Ca, Ti, Sr, and Ce, and/or metal oxides such as BaO and CaO.

The getter layers213aand213bare interposed between the first thin films111a,111b, and111cand react with any oxygen or moisture that penetrates past the first thin films111a,111b, and111c, protecting the organic light emitting unit102from oxygen or moisture, thereby increasing the life of the organic light emitting display device200.

The getter layers213aand213bmay be formed by any suitable method for forming a thin film, for example, sputtering, CVD, PECVD, PECVD, metal organic chemical vapor deposition (MOCVD), evaporation, atomic layer deposition (ALD), and/or thermal chemical vapor deposition polymer film (TCVDPF).

When the getter layers213aand213bare formed using the above method, the getter layers213aand213bmay be formed by using one shadow mask. In other words, one patterned shadow mask is used to form the plurality of the getter layers213aand213bon the first thin films111aand111b, instead of forming on a region corresponding to the upper portion of the second thin film112.

As described above, since the plurality of the first thin films111a,111b, and111c, the plurality of the second thin films112aand112b, and the plurality of the getter layers213aand213bare respectively formed by using one shadow mask, the sealing unit110comprising the plurality of the thin films may be formed using a total of three shadow masks and thus a manufacturing cost of the organic light emitting display device200may be reduced.

Embodiments of the organic light emitting display device prevent or reduce infiltration of external moisture or oxygen therein.