TECHNICAL FIELD

The present disclosure relates to a method for manufacturing a light-emitting device such as an organic EL (Electro Luminescence) device, and in particular to the improvement of a sealing technology for preventing the degradation of a light-emitting device caused by moisture and oxygen.

DESCRIPTION OF THE RELATED ART

In recent years, development has been carried out on a technology for applying organic EL devices to displays and lighting apparatuses. An organic EL device includes a substrate and a multilayered light-emitting structure. The multilayered light-emitting structure includes an anode, a light-emitting layer, and a cathode which are layered over the substrate. When voltage is applied between the anode and the cathode, electric current flows through the light-emitting layer to emit light. In general, such a multilayered light-emitting structure includes a layer formed with a material that is easily degraded by moisture and oxygen. Accordingly, in the organic EL device, it is common to use a sealing film to cover the multilayered light-emitting structure formed on the substrate in order to prevent intrusion of moisture and oxygen from external environment.

According to Patent Literature 1, a substrate protection film made of alumina is formed on a resin substrate. Then, an organic EL structure is formed on the substrate protection film, and a device protection film made of alumina is formed on the organic EL structure (paragraphs 0044-0059). Patent Literature 1 recites that formation of these protection films can prevent degradation of the organic EL structure (paragraphs 0064-0067).

According to Patent Literature 2, a plastic film is formed into a bag, and a sealing film having gas barrier properties is formed inside the bag-shaped plastic film. Then, an organic EL panel is inserted in the bag-shaped plastic film. In this state, the bag-shaped plastic film is vacuum-compressed (paragraphs 0025-0032). Patent Literature 2 recites that the above structure can prevent degradation of the organic EL panel (paragraph 0038).

CITATION LIST

Patent Literature

Patent Literature 1

Japanese Patent Application Publication No. 2003-332042

Patent Literature 2

Japanese Patent No. 3761843

SUMMARY

Conventionally, a multiple production method is often employed in manufacturing an organic EL device or any other device including a substrate on which a multi-layered element is formed. According to the multiple production method, after a plurality of elements are simultaneously formed on a large substrate, the substrate is cut so as to separate the plurality of elements from one another. Suppose that the multiple production method is employed to manufacture an organic EL device. In this case, a plurality of multilayered light-emitting structures are formed on a large substrate. Then, a sealing film is formed to entirely cover the multilayered light-emitting structures. The substrate over which the sealing film is formed is then cut so as to separate the multilayered light-emitting structures from one another. With the multiple production method, the multilayered light-emitting structures are formed with use of the large substrate which is easily handled during the manufacturing of the organic EL device. This improves the productivity of organic EL devices.

On the other hand, if the substrate is cut without any measures being taken, the interface between the substrate and the sealing film will be exposed at a cut surface of the substrate. As a result, moisture and oxygen can easily infiltrate from the interface. In particular, during cutting of the substrate, stress is applied to the substrate and the sealing film. As a result, the sealing film is likely to peel off at the interface between the substrate and the sealing film, creating an infiltration path of moisture and oxygen. On the other hand, it is possible to form the sealing film after cutting the substrate into multiple substrates. In this way, the cutting surface of each separate substrate obtained as a result of the cutting is covered with the sealing film. However, this method causes the lowering of productivity since the substrates obtained as a result of the cutting are individually handled during the forming of the sealing film.

In view of the above problem, one non-limiting and exemplary embodiment provides a technology for manufacturing a light-emitting device resistant to the infiltration of moisture and oxygen, without causing the lowering of productivity.

In one general aspect, the techniques disclosed here feature a method for manufacturing a light-emitting device, comprising: forming, over a substrate, a plurality of multilayered light-emitting structures each including a first electrode, a light-emitting layer, and a second electrode; forming, in the substrate, a plurality of grooves that surround the multilayered light-emitting structures individually; forming, over the substrate, a sealing film that covers the multilayered light-emitting structures and the grooves; and separating the multilayered light-emitting structures from one another after forming the sealing film, by cutting the substrate such that, in each groove, part of the sealing film covering a given inner side surface of the groove remains, the given inner side surface being adjacent to any of the multilayered light-emitting structures.

The given inner side surface of each groove serves as part of the outer side surface of each separate substrate obtained as a result of the cutting. In the above method for manufacturing a light-emitting device, the substrate is cut into multiple substrates such that, in each groove, part of the sealing film covering the given inner side surface of the groove remains. As a result, part of the outer side surface of each separate substrate is covered by the sealing film. This prevents the exposure of the interface between the sealing film and the top surface of each separate substrate obtained as a result of the cutting, allowing for the manufacture of a light-emitting device resistant to the infiltration of moisture and oxygen. Also, according to the above method for manufacturing a light-emitting device, the sealing film is formed before the substrate is cut. Therefore, productivity is not lowered during forming of the sealing film. This allows for manufacturing of a light-emitting device resistant to the infiltration of moisture and oxygen, without causing the lowering of productivity.

These general and specific aspects may be implemented using a device.

Additional benefits and advantages of the disclosed embodiments will be apparent from the specification and figures. The benefits and/or advantages may be individually provided by the various embodiments and features of the specification and drawings disclosed, and need not all be provided in order to obtain one or more of the same.

