Display device and manufacturing method thereof

A display device includes a first substrate, a sealing layer located along an edge of the first substrate, a second substrate coupled with the first substrate via the sealing layer, a display part located on the second main surface and within a sealed space, and a filler filling the sealed space and including a particle solid drying agent dispersed therein. The display part includes an organic EL element located on the second substrate, the organic EL element including a first electrode, an organic EL layer, and a second electrode stacked in order from the second substrate. Additionally, the display part includes an organic sacrifice layer located on and in contact with the second electrode, and a first inorganic protective layer located on and in contact with the organic sacrifice layer. The filler is located between the first inorganic protective layer and the first substrate.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority of Japanese Patent Application No. 2017-124058, filed Jun. 26, 2017, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

An aspect of the present disclosure relates to a display device and a manufacturing method thereof.

BACKGROUND

In recent years, an organic EL display device has been in the focus of attention as a display device which uses an organic EL material (EL: Electro-Luminescence) as a light-emitting material. An organic EL element which is configured to have the organic EL material interposed between a pair of electrodes is likely to be affected by moisture. For example, water in contact with the organic EL element may cause the electrode to be degraded, that is, oxidized or peeled off and so on. Accordingly, a measure is taken for the organic EL display device against water intruding into an area where the organic EL element is provided.

For example, Japanese Unexamined Patent Publication No. 2014-201574 discloses the organic EL display device having a so-called filled sealing structure. In Japanese Unexamined Patent Publication No. 2014-201574, a filler containing a complex compound drying agent is filled in a space sealed by an element substrate and sealing substrate (sealed space). Japanese Unexamined Utility Model Publication No. H3-121700 discloses an inorganic EL display device in which a powdery water-absorbing substance (solid drying agent) is contained in a silicon resin layer.

SUMMARY

If the complex compound drying agent as disclosed in Japanese Unexamined Patent Publication No. 2014-201574 is compared with the powdery (particulate) solid drying agent as disclosed in Japanese Unexamined Utility Model Publication No. H3-121700, the latter tends to exhibit a higher water-capturing property. Accordingly, in view of achieving a prolonged lifetime of the organic EL display device, the organic EL display device may have a filled sealing structure using the filler containing the solid drying agent. However, when such a filler is filled into the sealed space or the like, breakage of the organic EL element may occur due to the solid drying agent. Therefore, if the solid drying agent is used, a yield of the organic EL display device may decrease.

An organic EL display device according to an aspect of the present disclosure comprises a first substrate having a first main surface, a frame-shaped sealing layer provided on the first main surface and along an edge of the first substrate, a second substrate formed into one body with the first substrate via the sealing layer, and having a second main surface facing the first main surface, a display part provided on the second main surface and within a sealed space surrounded and sealed by the first substrate, the sealing layer, and the second substrate, and a filler filling the sealed space and having a particle solid drying agent dispersed therein. The display part may comprise an organic EL element provided on the second main surface and having a first electrode, an organic EL layer, and a second electrode stacked in order from the second main surface, an organic sacrifice layer located on and in contact with the second electrode, and a first inorganic protective layer located on and in contact with the organic sacrifice layer. The filler layered on the organic EL element in a thickness direction of the first substrate is located between the first inorganic protective layer and the first substrate.

By preventing the solid drying agent dispersed in the filler from directly contacting the organic EL element, it is possible to reduce or prevent the solid drying agent damaging the surface of the second electrode. The organic sacrifice layer and the first inorganic protective layer are stacked in order in the thickness direction between the organic EL element and the filler. Therefore, when the solid drying agent presses the first inorganic protective layer, the solid drying agent compresses and deforms the organic sacrifice layer via the first inorganic protective layer. This allows the stress due to the solid drying agent to be relaxed by the organic sacrifice layer, and the organic EL layer is unlikely to be compressed and deformed. In addition, when the solid drying agent moving in the direction crossing or transverse to the thickness direction scratches the first inorganic protective layer, the first inorganic protective layer may be dragged by the solid drying agent and slide on the organic sacrifice layer. This may cause the organic sacrifice layer to become indented or otherwise deformed. In this case also, the second electrode is unlikely to move together with the solid drying agent owing to the deformation of the organic sacrifice layer. Accordingly, since the second electrode in the organic EL element is unlikely to slide, it is possible to prevent the organic EL layer from becoming deformed. Therefore, even in the case that the particle solid drying agent is dispersed in the filler, it is possible to prevent the organic EL element from being damaged by the solid drying agent, and the organic EL display device can be manufactured with a good yield.

The organic sacrifice layer may include at least one of the organic materials included in the organic EL layer. In this case, the organic sacrifice layer can be formed at a low cost.

The first inorganic protective layer may include a conductive layer constituted by the conductive materials included in the second electrode. In this case, the first inorganic protective layer can be formed at a low cost.

The first inorganic protective layer may include at least one of a silicon oxide layer, a silicon nitride oxide layer, a silicon nitride layer, a titanium oxide layer, and an aluminum oxide layer. In this case, a fine insulating layer can be included in the first inorganic protective layer. The insulating layer may be configured to prevent the solid drying agent from penetrating through the first inorganic protective layer and the organic sacrifice layer, so that the solid drying agent does not migrate to the organic EL element.

The solid drying agent may include at least one of alkali earth metal oxide and alkali earth metal chloride. The solid drying agent may exhibit a water-capturing property.

In some example embodiments, the organic EL display device may further comprise a second inorganic protective layer covering the display part, wherein the filler layered on the organic EL element in a thickness direction of the first substrate may be located between the second inorganic protective layer and the first substrate. In this case, the second inorganic protective layer may be configured to prevent any moisture included in the filler from being transferred to the organic EL element.

A thickness of the organic sacrifice layer may be not less than 10 nm and not more than 200 nm. In this case, the stress due to the solid drying agent applying to the organic EL element can be relaxed by the organic sacrifice layer.

A thickness of the first inorganic protective layer may be not less than 50 nm and not more than 300 nm. In this case, it is possible to prevent the solid drying agent penetrating through the first inorganic protective layer. Moreover, adverse effects on an electro-optic property and lifetime of the organic EL element caused by the first inorganic protective layer can be prevented.

DETAILED DESCRIPTION

Hereinafter, a description is given of embodiments according to the present disclosure referring to the attached drawings. In the following description, the same components or components having the same function are designated by the same reference sign, and a duplicated description is omitted. Whereas some of the materials or layers of the display device are described below as being “located on” or “layered on” each other, for example a first layer located on a second layer, this is not intended to necessarily require contact between the two layers. Rather, in some example embodiments an intervening layer(s) or material(s) may be located between the first layer and the second layer.

A description is given of a configuration of an organic EL display device with reference toFIG. 1toFIG. 3.FIG. 1is a schematic plan view of the organic EL display device.FIG. 2is a schematic sectional view taken along a line A-A inFIG. 1.FIG. 3is an enlarged partial view ofFIG. 2.

As illustrated inFIG. 1toFIG. 3, an organic EL display device1may comprise a passive matrix display device. The organic EL display device1includes a first substrate2and a second substrate3which are stacked to each other, a display part4, a wiring part5, a frame-shaped sealing layer6, a filler7, an integrated circuit8, an FPC9(flexible printed circuit board), and a protective resin10. Hereinafter, a description is given with the direction in which the first substrate2and the second substrate3are stacked to each other being referred to merely as a “stacked direction”. The stacked direction corresponds to a thickness direction of the first substrate2and the second substrate3.

The first substrate2serves as a sealing substrate and is provided to face the second substrate3. The first substrate2comprises, for example, a glass substrate, a ceramics substrate, a metal substrate, a plastic substrate, or any combination thereof. The first substrate may have flexibility. A main surface2a(first main surface) of the first substrate2facing the second substrate3has a substantially rectangular shape. An edge of the main surface2ais in contact with the sealing layer6.

The second substrate3may be formed into one body with the first substrate2via the sealing layer6. Additionally, the display part4and the wiring part5may be located on the second substrate3. The second substrate3may comprise, for example, a glass substrate or a flexible substrate (e.g., plastic substrate, etc.) having translucency. A main surface3a(second main surface) of the second substrate3has a substantially rectangular shape similar to the main surface2a, and faces the main surface2a. Short sides of the main surface3aare substantially the same in length as short sides of the main surface2a, and long sides of the main surface3aare longer than long sides of the main surface2a. Accordingly, if the short sides on one side of the main surfaces2aand3aare aligned, a part of the main surface3ais exposed from the first substrate2. A distance between the main surfaces2aand3ain the stacked direction is 10 μm to 30 μm, for example. Note that the phrase “substantially the same as” in the embodiments represents a concept not only expressing being fully identical but also encompassing a slight difference (e.g., up to around several %).

The display part4is configured to emit a light by being supplied with a current, and is located on the main surface3aof the second substrate3. The display part4is provided within a sealed space S which is surrounded and sealed by the first substrate2, the second substrate3, and the sealing layer6. The display part4includes a plurality of organic EL elements11arranged in a matrix, an organic sacrifice layer12located on and in contact with each organic EL element11, a first inorganic protective layer13located on and in contact with the organic sacrifice layer12, an insulating film14provided to surround the organic EL element11seen in the stacked direction, and an element separator15located on the insulating film14.

Each organic EL element11is configured to emit a light by being supplied with a current, and is located on the main surface3aof the second substrate3. The organic EL element11has a first electrode21, an organic EL layer22, and a second electrode23stacked in order from the main surface3a.

The first electrode21may comprise a transparent conductive layer serving as an anode, that extends along a long side direction (e.g. length or longitudinal direction) of the main surface3a. Examples of materials constituting the first electrode21include a conductive material having translucency such as ITO (indium tin oxide) and IZO (indium zinc oxide). The first electrode21may be formed by patterning a transparent conductive film formed on the main surface3a. In some example embodiments, the first electrode21is formed by, for example, a PVD method (physical vapor deposition) such as a vacuum deposition method and a sputtering method.

The organic EL layer22includes at least an organic light emitting layer including a light emitting material. The organic EL layer22may have, in addition to the organic light emitting layer, an electron injection layer, an electron transport layer, a hole transport layer, a hole injection layer, and the like. The light emitting material may be a low-molecular organic compound or a high-molecular organic compound. A fluorescent material or a phosphorescence material may be used as the light emitting material. The electron injection layer, the electron transport layer, the hole transport layer, and the hole injection layer each contain an organic material. For example, the hole transport layer contains α-NPD that is a low-molecular organic compound showing a hole transport property, and the electron transport layer contains Alq3that is a low-molecular organic compound showing an electron transport property. A thickness of the organic EL layer22is not less than 100 nm and not more than 300 nm, for example. The organic EL layer22is formed by the PVD method, for example.

The second electrode23is a conductive layer serving as a cathode, and extends along a direction of the short side (e.g. width or lateral direction) of the main surface3a. Example of materials (conductive materials) constituting the second electrode23include metal such as aluminum, and silver. Example of the conductive materials may include alkali earth metal (magnesium, calcium, etc.) or may include a material having translucency such as IZO (indium zinc oxide) and ITO (indium tin oxide). A plurality of conductive materials may be included in the conductive material. A thickness of the second electrode23is not less than 50 nm and not more than 300 nm, for example. The second electrode23is formed by the PVD method, for example.

The organic sacrifice layer12is an organic layer for protecting the organic EL element11from being damaged from the second electrode23side. A shape of the organic sacrifice layer12seen in the stacked direction is substantially the same as a shape of the second electrode23. The organic sacrifice layer12includes at least one of the organic materials included in the organic EL layer22, for example. In this case, the organic sacrifice layer12can be formed by a manufacturing apparatus for the organic EL element11. In order to inexpensively and easily form the organic sacrifice layer12, the organic sacrifice layer12may be constituted by the organic materials which are often contained in the organic EL element11in a large amount (e.g., α-NPD, Alq3, etc.). A thickness of the organic sacrifice layer12is not less than 10 nm and not more than 200 nm, for example. In this case, the organic EL element11can be protected without providing an excessive amount of the organic sacrifice layer12. The organic sacrifice layer12is formed by the PVD method similar to the organic EL layer22.

The first inorganic protective layer13may be configured to prevent damage of the organic EL element11from the second electrode23side similar to the organic sacrifice layer12. A shape of the first inorganic protective layer13seen in the stacked direction is substantially the same as the shape of the second electrode23. The first inorganic protective layer13has at least one of an inorganic conductive layer and an inorganic insulating layer. In a case that the first inorganic protective layer13has an inorganic conductive layer, the inorganic conductive layer may be a conductive layer constituted by the conductive materials contained in the second electrode23. In this case, the first inorganic protective layer13can be formed by the manufacturing apparatus, for the organic EL element11. In a case that the first inorganic protective layer13has an inorganic insulating layer, the inorganic insulating layer may have at least one of a silicon oxide layer, a silicon nitride oxide layer, a silicon nitride layer, a titanium oxide layer, and an aluminum oxide layer. A thickness of the first inorganic protective layer13is not less than 50 nm and not more than 300 nm, for example. In this case, the organic EL element11can be protected without affecting an optical property and the like of the organic EL element11. The first inorganic protective layer13is formed by the PVD method similar to the second electrode23.

The insulating film14may be configured to provide a non-light-emitting part in the display part4, or to prevent undesirable (unintended) short-circuiting between the first electrode21and the second electrode23. The insulating film14may be an inorganic insulating film such as a silicon oxide film and a silicon nitride film, or an organic insulating film such as a polyimide film, a cycloolefin resin film, and an acrylic resin film, for example. A thickness of the insulating film14is not less than 50 nm and not more than 3000 nm (3 μm), for example. The insulating film14is provided after the first electrode21is formed and before the organic EL layer22is formed.

The element separator15may comprise an insulating material configured to separate the second electrodes23from each other in the display part4. The element separator15extends along the direction of the short side of the main surface3a, and has an inverse tapered shape in cross-section. The element separator15is provided after the insulating film14is formed and before the organic EL layer22is formed. Accordingly, the organic EL layer22and the second electrode23may have a desired shape owing to the element separator15by forming the organic EL layer22and the second electrode23through the PVD method after forming the element separator15. Similarly, the organic sacrifice layer12and the first inorganic protective layer13each have a shape similar to the organic EL layer22and the second electrode23, seen in the stacked direction. The element separator15includes a negative type photosensitive resin, for example.

In the sealed space S, a second inorganic protective layer16is provided to cover the display part4. The second inorganic protective layer16is provided in order to protect the organic EL element11, the organic sacrifice layer12, and the first inorganic protective layer13, and to prevent moisture intrusion into the organic EL element11. The second inorganic protective layer16is an inorganic insulating layer. The second inorganic protective layer16may have at least one of a silicon oxide layer, a silicon nitride oxide layer, a silicon nitride layer, a titanium oxide layer, and an aluminum oxide layer. A thickness of the second inorganic protective layer16is not less than 10 nm and not more than 300 nm, for example. In this case, the second inorganic protective layer16may protect the organic EL element11and the like as well as the second inorganic protective layer16can prevent the moisture from intruding into the organic EL element11. The second inorganic protective layer16is formed by the PVD method, for example.

The wiring part5includes a plurality of routing wirings, and has a first area5aand a second area5b. The first area5ais provided with a routing wiring W which connects the display part4with the integrated circuit8. The routing wiring W includes a molybdenum alloy layer, an aluminum alloy layer, and a molybdenum alloy layer stacked in order, for example. The routing wiring W may be formed at the same time as the first electrode21or second electrode23of the organic EL element11. The second area5bis provided with a routing wiring (not illustrated) that connects the integrated circuit8with the FPC9, and that is formed at the same time as the routing wiring W. The wiring part5may be provided with a barrier film for protecting the above routing wirings. The barrier film is an insulating film such as a silicon oxide film and a silicon nitride film, for example. This barrier film may be formed at the same time as the insulating film14.

The sealing layer6serves as an attaching material for coupling the first substrate2with the second substrate3, and serves as a lateral wall for defining the sealed space S. The sealing layer6is provided along an edge on the main surface2aof the first substrate2, and is in contact with the edge thereon and the main surface3aof the second substrate3. The sealing layer6is also in contact with the routing wirings constituting the wiring part5(e.g., the routing wiring W provided to the first area5a). The sealing layer6has a rectangular frame shape along the edge of the main surface2aseen in the stacked direction. The sealing layer6includes an ultraviolet curable resin having adhesiveness, for example. The sealing layer6may include a spacer or the like such as glass fibers, silica particles, resin balls and the like.

The filler7is housed within the sealed space S to fill a space in the sealed space S. The filler7may fill the sealed space S with no void. The filler7layered on the organic EL element11in the stacked direction is located between the second inorganic protective layer16and the first substrate2. The filler7contains a base material7aand a particulate solid drying agent7bdispersed in the base material7a. In order to control the level of viscosity, the base material7amay comprise one or more curable resins, for example. Examples of the base material7ainclude a silicone resin, and an acrylic resin. The solid drying agent7bincludes at least one of alkali earth metal oxide and alkali earth metal chloride, for example. Examples of alkali earth metal oxide include magnesium oxide (MgO), calcium oxide (CaO), and strontium oxide (SrO). Examples of alkali earth metal chloride include calcium chloride, and magnesium chloride. The solid drying agent7bmay be constituted by a plurality of particles. For example, the solid drying agent7bmay be a combination of alkali earth metal oxide particles and alkali earth metal chloride particles, and may contain a plurality of kinds of alkali earth metal oxide particles. A ratio of the solid drying agent7bto the filler7is not less than 30 mass % and not more than 60 mass %. In this case, it is possible to prevent moisture intrusion into the organic EL element11and to prevent damage to the organic EL element11due to the solid drying agent7b. In addition, the probability of aggregation of the solid drying agent7bin the base material7acan be reduced. An average particle diameter of the solid drying agent7bis not less than 0.1 μm and not more than 2 for example. A liquid drying agent including metal alkoxide as a water-capturing component may be included in the filler7.

The integrated circuit8is a driver circuit controlling light-emitting or light-non-emitting of each organic EL element11. The integrated circuit8is mounted on an area exposed from the first substrate2on the main surface3aof the second substrate3, and is connected with the wiring part5. The integrated circuit8is an IC chip or the like, for example. The number of integrated circuits8mounted on the main surface3amay be one or more.

The FPC9is connected with the routing wiring of the second area5bin the wiring part5, and is a wiring for connecting the organic EL display device1with an external device. The FPC9is formed using a flexible plastic substrate, for example. The external device connected with the FPC9is a power source, a current control circuit and the like, for example.

The protective resin10is configured to protect the wiring part5and integrated circuit8which are outside the sealed space S. The protective resin10is deposited on an area on the main surface3awhich is not covered by the first substrate2. The protective resin10may comprise one or more curable resins, for example.

Next, a description is given of a method of filling the filler7through an ODF (One Drop Filling) method with reference toFIG. 4AtoFIG. 4C.FIG. 4AtoFIG. 4Care each a schematic view for illustrating a method of filling a filler. Note that, in the description of this filling method, the display part4, the wiring part5, the integrated circuit8, and the FPC9are omitted for purposes of simplifying the description.

First, as illustrated inFIG. 4A, the first substrate2provided with an adhesive31is prepared. In some example embodiments, the adhesive31becomes the sealing layer6in a later step of the method. The adhesive31is provided to have a rectangular frame shape on the main surface2aof the first substrate2. Next, the filler7is dropped on the main surface2aof the first substrate2. The filler7is dropped in an area surrounded by the adhesive31on the main surface2a. The number of places where the filler7is dropped on the main surface2amay be one or more.

Then, as illustrated inFIG. 4B, the second substrate3is layered or located on the first substrate2prior to being sealed in a low pressure state or vacuum state. A pressure is applied to each of the first substrate2and the second substrate3to decrease a distance between the first substrate2and the second substrate3in the stacked direction. As a result, the filler7spreads toward an adhesive31side while filling the voids in the sealed space S. Accordingly, as illustrated inFIG. 4C, the filler7fills the sealed space S with no void. After attaching the second substrate3to the first substrate2, the adhesive31is irradiated by an ultraviolet light in an atmospheric pressure state and the adhesive31is heated to form the sealing layer6. At this time, the filler7may be cured.

Next, referring toFIG. 5toFIG. 7B, a description is given of an action and effect exerted by the organic EL display device1according to one or more embodiments, as compared with a comparison example.FIG. 5is a schematic sectional view of an organic EL display device according to a comparison example.FIG. 6Ais an enlarged partial view ofFIG. 5, andFIG. 6Bis a further enlarged view of a portion ofFIG. 6Asurrounded by a broken line.FIG. 7Ais a partial enlarged sectional view of the organic EL display device according to the embodiments, andFIG. 7Bis a further enlarged view of a portion ofFIG. 7Asurrounded by a broken line.

As illustrated inFIG. 5, an organic EL display device100according to the comparison example has the same configuration as the example organic EL display device1except that an organic sacrifice layer and a first inorganic insulating layer are not provided in the display part104, and a second inorganic insulating layer covering the display part104is not provided. Accordingly, in the comparison example, the filler7containing the solid drying agent7bis provided in the sealed space S.

The solid drying agent7bdispersed in the base material7ain the filler7may aggregate. For example, as illustrated inFIG. 6A, an aggregate C of the solid drying agent7bhaving a sufficient size to make contact with both the organic EL element11in the display part104and the main surface2aof the first substrate2may be contained in the filler7. The aggregate C may be in contact with a surface of the organic EL element11(that is, a surface of the second electrode23) when filling the filler7, and then the surface thereof may be damaged due to the aggregate C. When the first substrate2and the second substrate3are coupled via the sealing layer6, the aggregate C in contact with the first substrate2may press against the organic EL element11. The aggregate C in contact with the first substrate2may move in a direction crossing or transverse to the stacked direction to scratch the second electrode23.

In addition, the thermal expansion coefficients of some or all of the members constituting the organic EL display device1may be different from a thermal expansion coefficient of the solid drying agent7b. Accordingly, when cooling the material after a heating process has been performed in order to form the sealing layer6, for example, a stress caused by the above difference in the thermal expansion coefficients may be generated on an interface of the solid drying agent7b. When the solid drying agent7bis in contact with the organic EL element11, the stress is generated between the solid drying agent7band the organic EL element11. Owing to this stress, the solid drying agent7bmay press against the organic EL element11, or the solid drying agent7bmay scratch the second electrode23. Further, when the organic EL display device1is used, the organic EL element11generates heat. Accordingly, the solid drying agent7bmay press against the organic EL element11, or the solid drying agent7bmay scratch the second electrode23, not only when manufacturing the organic EL display device1, but also when using the organic EL display device1.

As described above, the second electrode23and the organic EL layer22may be compressed by the solid drying agent7b(or the aggregate C) that is pressing against the organic EL element11as illustrated inFIG. 6B. Here, the organic compound included in the organic EL layer22is accumulated by the van der Waals' force, whereas the metal contained in the second electrode23is generally accumulated by metal bonding indicating a bonding force stronger than the van der Waals' force. Accordingly, since a density and strength of the organic EL layer22is likely to be smaller than the second electrode23that is an inorganic conductive layer, the organic EL layer22is more likely to be compressed and deformed than the second electrode23. Moreover, a bonding force between the organic EL layer22and the second electrode23is weak. Accordingly, when the solid drying agent7b(or the aggregate C) moves to scratch the second electrode23, the second electrode23may be dragged by the solid drying agent7band slide on the organic EL layer22. At this time, a stress may concentrate on a part of the second electrode23that slides, causing the organic EL layer22to deform. If the organic EL layer22in the organic EL element11is damaged due to the scratching or deformation, the first electrode21and the second electrode23may contact each other. This may increase a leakage current due to the organic EL element11, or generate short-circuiting between the first electrode21and the second electrode23, or the like. In this case, a so-called pinhole may be formed in the display part4.

In the comparison example, in order to prevent the damage of the organic EL element11, a protective film which is harder than the solid drying agent7bmay be provided on the organic EL element11, or a protective film having a thickness of several micrometers may be provided on the organic EL element11, for example. However, in the former case, the harder protective film may cause a stress to be applied to the organic EL element11. This may result in an adverse effect on an electro-optic property and lifetime of the organic EL element11. In the latter case, since additional time is taken in order to form the protective film with a sufficient thickness, productivity of the organic EL display device1decreases and a manufacturing cost of the organic EL display device1significantly increases.

In contrast, the organic EL display device1according to one or more embodiments includes the organic sacrifice layer12located on and contact with the second electrode23, and the first inorganic protective layer13located on and contact with the organic sacrifice layer12, as illustrated inFIGS. 7A and 7B. The filler7layered on the organic EL element11in the stacked direction is located between the first inorganic protective layer13and the first substrate2. Accordingly, since the solid drying agent7bdispersed in the filler7is prevented from directly contacting the organic EL element11, it is possible to prevent the solid drying agent7bfrom damaging the surface of the second electrode23. The organic sacrifice layer12and the first inorganic protective layer13are stacked in order (e.g., sequentially) in the stacked direction between the organic EL element11and the filler7. Therefore, when the solid drying agent7bpresses against the first inorganic protective layer13, the solid drying agent7bcompresses and deforms the organic sacrifice layer12via the first inorganic protective layer13. This allows the stress due to the solid drying agent7bto be relaxed by the organic sacrifice layer12. Therefore, the organic EL layer22is unlikely to be compressed and deformed. In addition, in case the solid drying agent7bmoves in a direction crossing or transverse to the stacked direction to scratch the first inorganic protective layer13, the first inorganic protective layer13slides on the organic sacrifice layer12and deforms the organic sacrifice layer12. In this case, the second electrode23is unlikely to move together with the solid drying agent7bowing to the deformation of the organic sacrifice layer12. Accordingly, since the second electrode23in the organic EL element11is unlikely to slide, it is possible to prevent the organic EL layer22from becoming deformed. Therefore, even in the case that the particle solid drying agent7bis dispersed in the filler7, it is possible to prevent the organic EL element11from being damaged by the solid drying agent7b, and the organic EL display device1can be manufactured with a good yield. Even when a solid foreign matter is contained in the filler7, damage to the organic EL element11may be prevented by including the organic sacrifice layer12and the first inorganic protective layer13, and the organic EL display device1can be manufactured with a good yield.

The organic sacrifice layer12may include at least one of the organic materials contained in the organic EL layer22in order to lower the manufacturing cost of the organic sacrifice layer12. As a specific example, after manufacturing the organic EL element11, the manufacturing apparatus for the organic EL element11is used to form the organic sacrifice layer12on the organic EL element11while maintaining the vacuum state, and thereby, the organic sacrifice layer12can be formed at a low cost.

The first inorganic protective layer13may include a conductive layer constituted by the conductive materials contained in the second electrode23in order to lower the manufacturing cost of the first inorganic protective layer13. As a specific example, after manufacturing the organic EL element11, the manufacturing apparatus for the organic EL element11is used to form the first inorganic protective layer13on the organic sacrifice layer12while maintaining the vacuum state, and thereby, the first inorganic protective layer13can be formed at a low cost.

The first inorganic protective layer13may include at least one of a silicon oxide layer, a silicon nitride oxide layer, a silicon nitride layer, a titanium oxide layer, and an aluminum oxide layer. A fine insulating layer can be contained in the first inorganic protective layer13. The insulating layer may be configured to prevent the penetration or migration of the solid drying agent7bthrough the first inorganic protective layer13and the organic sacrifice layer12to arrive at the organic EL element11.

The solid drying agent7bmay include at least one of alkali earth metal oxide and alkali earth metal chloride. The solid drying agent7bmay exhibit a water-capturing, water-retention or water-absorption property.

The organic EL display device1includes the second inorganic protective layer16covering the display part4, and the filler7layered on the organic EL element11in the stacked direction is located between the second inorganic protective layer16and the first substrate2. Accordingly, the moisture included in the filler7can be reduced or prevented from arriving at the organic EL element11by the second inorganic protective layer16.

In some example embodiments, the thickness of the organic sacrifice layer12is not less than 10 nm and not more than 200 nm. Accordingly, the stress due to the solid drying agent7bapplying to the organic EL element11can be relaxed by the organic sacrifice layer12. In addition, the manufacturing cost for the organic EL display device1can be decreased.

In some example embodiments, the thickness of the first inorganic protective layer13is not less than 50 nm and not more than 300 nm. Accordingly, the solid drying agent7bmay be prevented from passing through the first inorganic protective layer13. Moreover, adverse effects on the electro-optic property and lifetime of the organic EL element11caused by the first inorganic protective layer13can be prevented. In addition, the manufacturing cost for the organic EL display device1can be decreased.

The organic EL display device according to the disclosure is not limited to the above described embodiments, and other various modifications may be adopted.FIG. 8is a schematic sectional view of an organic EL display device according to an example modification. An organic EL display device1A illustrated inFIG. 8includes, in addition to the configuration of the organic EL display device1according to the above embodiments, a reinforcing film41in contact with the main surface2aof the first substrate2, and a reinforcing film42in contact with the main surface3aof the second substrate3. In view of preventing moisture permeability, each of the reinforcing films41and42may include at least one of a silicon oxide film, a silicon nitride film, a silicon nitride oxide film, and an aluminum oxide film, for example. In the example modification, the first substrate2and the second substrate3each have flexibility. Therefore, the reinforcing film41is provided in order to reinforce the first substrate2, and the reinforcing film42is provided in order to reinforce the second substrate3. Additionally, in such an example modification, an action and effect similar to the above described embodiments are exerted. Additionally, even in a case that the organic EL display device1A comprises a flexible display, breakage of the first substrate2and second substrate3can be prevented.

In the above embodiments and the above example modification, the second inorganic protective layer16may not be provided in the sealed space S. In this case, the filler7layered on the organic EL element11in the stacked direction is located between the first inorganic protective layer13and the first substrate2.

In the above embodiments and the above example modification, the organic EL display device is not limited to a passive matrix display device. For example, the organic EL display device may be an active matrix display device. In this case, transistors and the like corresponding to the respective organic EL elements are provided.

In the above embodiments and the above example modification, both the first substrate and the second substrate are not limited to a substantially rectangular shape seen in the stacked direction. For example, both the first substrate and the second substrate may have a polygonal shape, or a substantially circular shape seen in the stacked direction. Similarly, the sealing layer provided to the first substrate may have a polygonal frame shape, or a substantially annular shape seen in the stacked direction. Therefore, the sealing layer may have at least one corner or no corner.

It is to be understood that not all aspects, advantages and features described herein may necessarily be achieved by, or included in, any one particular example embodiment. Indeed, having described and illustrated various examples herein, it should be apparent that other examples may be modified in arrangement and detail. We claim all modifications and variations coming within the spirit and scope of the subject matter claimed herein.