JP2016149316A - Light-emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a sealing film hard to function as a capacitive element having resistivity.SOLUTION: A first terminal 112 and a second terminal 132 are formed on a substrate 100. A first lead-out wiring 114 is formed on the substrate 100, and electrically connects the first terminal 112 and a first electrode 110. A second lead-out wiring 134 is formed on the substrate 100, and electrically connects the second terminal 132 and a second electrode 130. A sealing film 160 is formed on the substrate 100, and seals a light-emitting unit 140. The sealing film 160 is a lamination film laminated with a plurality of inorganic layers. A region (first portion 102) of the substrate 100 located between the first lead-out wiring 114 and the second lead-out wiring 134 includes a region in which the sealing film 160 is not formed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light emitting device.

  In recent years, development of light-emitting devices having organic EL (Organic Electroluminescence) elements as light-emitting elements has been progressing. The organic EL element has a configuration in which an organic layer is sandwiched between a first electrode and a second electrode. Since the organic layer is vulnerable to moisture and oxygen, the organic EL element needs to be sealed. One method for sealing the organic EL element is to use a sealing film. For example, Patent Documents 1 and 2 describe using a laminated film in which a plurality of sealing layers are laminated as a sealing film.

  For example, Patent Document 1 discloses that the lower sealing layer is made of calcium oxide, alumina, silica, titania, indium oxide, tin oxide, silicon oxide, silicon nitride, or aluminum nitride, and the upper sealing layer is made of a material. It describes that an organic layer is used for the stop layer.

Patent Document 2 describes that the sealing film has a four-layer structure. Then, SiN, SiON, or SiO is used for the material of the lowermost sealing layer, amorphous silicon, SiO ₂ , or SiO is used for the upper sealing layer, and an organic material is used for the upper sealing layer. The use of SiN, SiON, or SiO for the upper sealing layer is described.

JP 2012-238611 A JP 2014-179278 A

  When the organic EL element is sealed using the sealing film, the sealing film is in contact with both the first electrode and the second electrode. As a result of studies by the present inventors, it has been found that when the sealing film has a structure in which a plurality of thin sealing layers are stacked, the sealing film functions as a capacitive element having resistance. If such a capacitive element exists, the light emission quality of the light emitting device and the inspection of the light emitting device are affected. Here, when a voltage is applied between the first electrode and the second electrode in order to operate the organic EL element, the timing at which the organic EL element emits light is delayed due to accumulation of charge in the sealing film. When no voltage is applied between the first electrode and the second electrode to stop the organic EL element, the charge accumulated in the sealing film flows toward the organic EL element, and the light emission of the organic EL element stops. Will be delayed.

  An example of a problem to be solved by the present invention is that the sealing film is difficult to function as a capacitive element having resistance.

The invention according to claim 1 is a substrate;
A light emitting unit formed on the substrate and including a first electrode, a second electrode, and an organic layer positioned between the first electrode and the second electrode;
A first terminal formed on the substrate;
A second terminal formed on the substrate;
A first lead wiring formed on the substrate and electrically connecting the first terminal to the first electrode;
A second lead wiring formed on the substrate and electrically connecting the second terminal to the second electrode;
A sealing film formed on the substrate and sealing the light emitting unit;
With
The sealing film is a laminated film in which a plurality of inorganic layers are laminated,
The first portion located between the first lead wiring and the second lead wiring in the substrate is a light emitting device having a region where the sealing film is not formed.

It is a top view of the light-emitting device concerning an embodiment. It is the figure which removed the partition, the 2nd electrode, the organic layer, and the insulating layer from FIG. It is AA sectional drawing of FIG. It is BB sectional drawing of FIG. It is CC sectional drawing of FIG. It is the figure which expanded the area | region enclosed with the dotted line (alpha) of FIG. It is an equivalent circuit diagram of a light-emitting device. It is a figure which shows the modification of FIG. It is a figure which shows the modification of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

  FIG. 1 is a plan view of a light emitting device 10 according to the embodiment. FIG. 2 is a view in which the partition 170, the second electrode 130, the organic layer 120, and the insulating layer 150 are removed from FIG. 3 is a cross-sectional view taken along line AA of FIG. 1, FIG. 4 is a cross-sectional view taken along line BB of FIG. 1, and FIG. 5 is a cross-sectional view taken along line CC of FIG. 1 and 2, the sealing film 160 is indicated by a dotted line for explanation.

  The light emitting device 10 according to the embodiment includes a substrate 100, a light emitting unit 140, a first terminal 112, a second terminal 132, a first extraction wiring 114, a second extraction wiring 134, and a sealing film 160. The light emitting unit 140 is formed on the substrate 100 and includes a first electrode 110, an organic layer 120, and a second electrode 130. The organic layer 120 is located between the first electrode 110 and the second electrode 130. The first terminal 112 and the second terminal 132 are formed on the substrate 100. The first lead wiring 114 is formed on the substrate 100 and electrically connects the first terminal 112 and the first electrode 110. The second lead wiring 134 is formed on the substrate 100 and electrically connects the second terminal 132 and the second electrode 130. The sealing film 160 is formed on the substrate 100 and seals the light emitting unit 140. As will be described later, the sealing film 160 is a laminated film in which a plurality of inorganic layers are laminated. A region (first portion 102) located between the first lead wiring 114 and the second lead wiring 134 in the substrate 100 has a region where the sealing film 160 is not formed. This region may be an opening provided in the sealing film 160. Details will be described below.

  In the example shown in this figure, the light emitting device 10 is a display device, and includes a substrate 100, a first electrode 110, a plurality of first terminals 112, a plurality of second terminals 132, a light emitting portion 140, an insulating layer 150, and a plurality of openings 152. A plurality of openings 154, a plurality of first extraction wirings 114, an organic layer 120, a second electrode 130, a plurality of second extraction wirings 134, and a plurality of partition walls 170. However, the light emitting device 10 may be a lighting device. In this case, the light emitting device 10 may have the first terminal 112, the first lead wiring 114, the second terminal 132, and the second lead wiring 134 one by one.

When the light emitting device 10 is a bottom emission type, the substrate 100 is formed of a light transmissive material such as glass or a light transmissive resin. However, when the light emitting device 10 is a top emission type, the substrate 100 may be formed of a material that does not have translucency. The substrate 100 is, for example, a polygon such as a rectangle. The substrate 100 may have flexibility. In the case where the substrate 100 has flexibility, the thickness of the substrate 100 is, for example, not less than 10 μm and not more than 1000 μm. In particular, when the substrate 100 is glass, the thickness of the substrate 100 is, for example, 200 μm or less. When the substrate 100 is a resin, the substrate 100 is formed using, for example, PEN (polyethylene naphthalate), PES (polyethersulfone), PET (polyethylene terephthalate), or polyimide. When the substrate 100 is a resin, an inorganic barrier film such as SiN _x or SiON is formed on at least one surface (preferably both surfaces) of the substrate 100 in order to suppress moisture from permeating the substrate 100. .

  The light emitting unit 140 has an organic EL element. This organic EL element has a configuration in which a first electrode 110, an organic layer 120, and a second electrode 130 are laminated in this order. The light emitting unit 140 is provided for each pixel of the display device.

  The first electrode 110 is a transparent electrode having optical transparency. The transparent conductive material constituting the transparent electrode is a metal-containing material, for example, a metal oxide such as ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), IWZO (Indium Tungsten Zinc Oxide), or ZnO (Zinc Oxide). is there. The thickness of the first electrode 110 is, for example, not less than 10 nm and not more than 500 nm. The first electrode 110 is formed using, for example, a sputtering method or a vapor deposition method. The first electrode 110 may be a carbon nanotube or a conductive organic material such as PEDOT / PSS.

  The organic layer 120 has a light emitting layer. The organic layer 120 has a configuration in which, for example, a hole injection layer, a light emitting layer, and an electron injection layer are stacked. A hole transport layer may be formed between the hole injection layer and the light emitting layer. In addition, an electron transport layer may be formed between the light emitting layer and the electron injection layer. The organic layer 120 may be formed by a vapor deposition method. In addition, at least one layer of the organic layer 120, for example, a layer in contact with the first electrode 110, may be formed by a coating method such as an inkjet method, a printing method, or a spray method. In this case, the remaining layers of the organic layer 120 are formed by vapor deposition. Moreover, all the layers of the organic layer 120 may be formed using the apply | coating method.

  The second electrode 130 is made of, for example, a metal selected from the first group consisting of Al, Au, Ag, Pt, Mg, Sn, Zn, and In, or an alloy of a metal selected from the first group. Contains a metal layer. In this case, the second electrode 130 has a light shielding property. The thickness of the second electrode 130 is, for example, not less than 10 nm and not more than 500 nm. However, the second electrode 130 may be formed using the material exemplified as the material of the first electrode 110. The second electrode 130 is formed using, for example, a sputtering method or a vapor deposition method.

  Note that the materials of the first electrode 110 and the second electrode 130 described above are for the case where the light emitting device 10 is a bottom emission type. When the light emitting device 10 is a top emission type, the material of the first electrode 110 and the material of the second electrode 130 are reversed. That is, the material of the second electrode 130 is used as the material of the first electrode 110, and the material of the first electrode 110 is used as the material of the second electrode 130.

  The first electrode 110 extends in a line shape in the first direction (Y direction in FIG. 1). The end portion of the first electrode 110 is connected to the first lead wiring 114. The first lead wiring 114 has a conductive layer made of the same material as the first electrode 110. This conductive layer is integrated with the first electrode 110. In the example shown in this drawing, the end of the first lead-out wiring 114 is the first terminal 112. Further, since a plurality of first terminals 112 are provided, a plurality of first lead wires 114 are also provided.

  A conductor layer 180 may be formed on the first lead wiring 114. The conductor layer 180 is made of a material having a lower resistance than that of the first lead wiring 114, for example, a metal. The conductor layer 180 may have a multilayer structure. In this case, the conductor layer 180 includes, for example, a first conductive layer that is a metal layer such as Mo or Mo alloy, a second conductive layer that is a metal layer such as Al or Al alloy, and a metal layer such as Mo or Mo alloy. The third conductive layer is stacked in this order. The thickness of the second conductive layer is, for example, not less than 50 nm and not more than 1000 nm. Preferably it is 100 nm or less. The first conductive layer and the third conductive layer are thinner than the second conductive layer, for example, 30 nm or less, preferably 25 nm or less. Note that the conductor layer 180 may or may not cover the first terminal 112.

  As shown in FIGS. 1 and 3 to 5, the insulating layer 150 is formed on the plurality of first electrodes 110 and in a region therebetween. A plurality of openings 152 and a plurality of openings 154 are formed in the insulating layer 150. The plurality of second electrodes 130 extend in parallel to each other in a direction intersecting the first electrode 110 (for example, a direction orthogonal to the X direction in FIG. 1). A partition wall 170, which will be described in detail later, extends between the plurality of second electrodes 130. The opening 152 is located at the intersection of the first electrode 110 and the second electrode 130 in plan view. Specifically, the plurality of openings 152 are arranged in the direction in which the first electrode 110 extends (the Y direction in FIG. 1). The plurality of openings 152 are also arranged in the extending direction of the second electrode 130 (X direction in FIG. 1). For this reason, the plurality of openings 152 are arranged to form a matrix.

  The opening 154 is located in a region overlapping with one end side of each of the plurality of second electrodes 130 in plan view. The openings 154 are arranged along one side of the matrix formed by the openings 152. When viewed in a direction along this one side (for example, the Y direction in FIG. 1, ie, the direction along the first electrode 110), the openings 154 are arranged at a predetermined interval. A part of the second lead wiring 134 is exposed from the opening 154. The second lead wiring 134 is connected to the second electrode 130 through the opening 154.

  The second lead wire 134 is a wire that connects the second electrode 130 to the second terminal 132, and has a conductive layer made of the same material as the first electrode 110. This conductive layer is separated from the first electrode 110. One end side of the second lead wire 134 is located below the opening 154, and the other end side of the second lead wire 134 is drawn to the outside of the insulating layer 150. In the example shown in the figure, the other end side of the second lead wiring 134 is a second terminal 132. A conductor layer 180 may be formed on the second lead wiring 134. The conductor layer 180 may or may not cover the second terminal 132. In the example shown in this figure, a plurality of second terminals 132 are provided. For this reason, a plurality of second lead wires 134 are also provided.

  In the region overlapping with the opening 152, the organic layer 120 is formed. The hole injection layer of the organic layer 120 is in contact with the first electrode 110, and the electron injection layer of the organic layer 120 is in contact with the second electrode 130. For this reason, the light emitting part 140 is located in each of the regions overlapping with the opening 152.

  In the example shown in FIGS. 3 and 4, the layers constituting the organic layer 120 are shown to protrude to the outside of the opening 152. As shown in FIG. 1, the organic layer 120 may be formed continuously between adjacent openings 152 in the direction in which the partition 170 extends, or may not be formed continuously. Good. However, as shown in FIG. 5, the organic layer 120 is not formed in the opening 154.

  As shown in FIGS. 1 to 4, the second electrode 130 extends in a second direction (X direction in FIG. 1) that intersects the first direction. A partition wall 170 is formed between the adjacent second electrodes 130. The partition wall 170 extends in parallel to the second electrode 130, that is, in the second direction. The base of the partition 170 is, for example, the insulating layer 150. The partition 170 is, for example, a photosensitive resin such as a polyimide resin, and is formed in a desired pattern by being exposed and developed. The partition wall 170 may be made of a resin other than a polyimide resin, for example, an inorganic material such as an epoxy resin, an acrylic resin, or silicon dioxide.

  The partition wall 170 has a trapezoidal cross-sectional shape (reverse trapezoidal shape). That is, the width of the upper surface of the partition wall 170 is larger than the width of the lower surface of the partition wall 170. Therefore, if the partition wall 170 is formed before the second electrode 130, the second electrode 130 is formed on one surface side of the substrate 100 by using an evaporation method or a sputtering method. Can be formed collectively. The partition wall 170 also has a function of dividing the organic layer 120.

  In addition, a conductive member such as an FPC (Flexible Printed Circuit) is connected to the first terminal 112 and the second terminal 132. In the example shown in this drawing, the first terminal 112 and the second terminal 132 are arranged along the same side (first side) of the substrate 100. For this reason, when FPC is used as the conductive member, the first terminal 112 and the second terminal 132 can be connected to one FPC.

  The light emitting device 10 further has a sealing film 160. The sealing film 160 is provided to seal the light emitting unit 140. The sealing film 160 is formed on the surface of the substrate 100 where the light emitting unit 140 is formed, and covers the light emitting unit 140. The sealing film 160 is made of, for example, an insulating material, more specifically, an inorganic material. The thickness of the sealing film 160 is preferably 300 nm or less. Moreover, the thickness of the sealing film 160 is, for example, 50 nm or more. The sealing film 160 is formed using an ALD (Atomic Layer Deposition) method. By using the ALD method, the step coverage of the sealing film 160 is increased.

  The sealing film 160 is removed in at least a part of a region (first portion 102) located between the first extraction wiring 114 and the second extraction wiring 134 in the substrate 100. On the other hand, the first lead wiring 114 and the second lead wiring 134 are covered with a sealing film 160. Therefore, the portion of the edge of the sealing film 160 located at the first portion 102 emits light more than the portion of the edge of the sealing film 160 that overlaps with the first extraction wiring 114 and the portion that overlaps with the second extraction wiring 134. It is located near the portion 140 and the insulating layer 150.

  In the example shown in this figure, a plurality of first lead wires 114 are provided, and a plurality of second lead wires 134 are also provided. The first portion 102 of the substrate 100 is located between the first lead wire 114 located closest to the second lead wire 134 and the second lead wire 134 located closest to the first lead wire 114. Yes.

  Further, the substrate 100 may be exposed at a portion of the first portion 102 where the sealing film 160 is removed. However, a resin layer for protecting the light emitting device 10 may be formed on this portion and the sealing film 160.

  FIG. 6 is an enlarged view of a region surrounded by a dotted line α in FIG. As shown in this figure, the sealing film 160 has a laminated structure in which a plurality of films are laminated. By doing in this way, the film | membrane stress which arises in the sealing film 160 can be made small compared with the case where the sealing film 160 is formed with one film. Note that any film constituting the sealing film 160 is formed of an inorganic film. These inorganic films are formed using, for example, an ALD method.

  The sealing film 160 has a configuration in which at least three films are stacked. The thickness of these films is, for example, 3 nm or more and 10 nm or less. In the example shown in FIG. 6, the number of sealing layers constituting the sealing film 160 is four. However, the number of sealing layers constituting the sealing film 160 may be more than this (for example, 10 or more layers).

  In the example shown in this figure, the sealing film 160 has a configuration in which a first sealing film 162 made of a first material and a second sealing film 164 made of a second material are repeatedly laminated in this order. ing. The first material is an insulating material. The second material is also preferably an insulating material. The first insulating material is, for example, aluminum oxide, and the second insulating material is, for example, titanium nitride. By forming the sealing layer in contact with the light emitting portion 140 with aluminum oxide, the moisture resistance of the sealing film 160 at room temperature can be improved. Further, by forming the second sealing film 164 covering the first sealing film 162 with titanium nitride, the moisture resistance of the sealing film 160 at high temperature can be improved.

  Next, a method for manufacturing the light emitting device 10 in this embodiment will be described. First, the first electrode 110, the first terminal 112, the second terminal 132, the first lead wire 114, and the second lead wire 134 are formed on the substrate 100.

  Next, a conductive film to be the conductor layer 180 is formed in a region including the first lead wiring 114 and the second lead wiring 134. Next, the conductive film is formed into a predetermined pattern using, for example, a photolithography method. Thereby, the conductor layer 180 is formed.

  Next, the insulating layer 150 is formed over the first electrode 110, and the partition wall 170 is formed over the insulating layer 150. The method for forming the partition 170 is similar to the method for forming the insulating layer 150. However, it is not necessary to irradiate the partition wall 170 with light after performing exposure and development and before performing heat treatment. Next, the organic layer 120 and the second electrode 130 are formed.

  Next, the first sealing film 162 and the second sealing film 164 are repeatedly formed in this order by using, for example, an ALD method. Thereby, the sealing film 160 is formed. Thereafter, at least a part of a portion located on the first terminal 112, a portion located on the second terminal 132, and a portion located on the first portion 102 are removed from the sealing film 160. The removal of the sealing film 160 is performed using, for example, a lift-off method. In this case, before the sealing film 160 is formed, a lift-off layer is formed in a region where the sealing film 160 is to be removed.

  FIG. 7 is an equivalent circuit diagram of the light emitting device 10. When the light emitting unit 140 of the light emitting device 10 is caused to emit light, a voltage is applied between the first lead wire 114 and the second lead wire 134. Further, the sealing film 160 is in contact with the first extraction wiring 114 and the second extraction wiring 134. Further, the sealing film 160 is formed of an insulating film, but has a structure in which a large number of thin sealing layers are stacked. Therefore, when viewed in an equivalent circuit, the sealing film 160 has a configuration in which a capacitor and a resistor are connected in series between the first lead-out wiring 114 and the second lead-out wiring 134. For this reason, a certain amount of current flows through the sealing film 160, and as a result, charges are accumulated in the sealing film 160 when the light emitting unit 140 emits light. This electric charge flows into the light emitting unit 140 when a voltage is no longer applied between the first extraction wiring 114 and the second extraction wiring 134. As a result, the response speed when turning off the light emitting unit 140 decreases. Further, when the light emitting unit 140 is turned on, part of the current flows through the sealing film 160. For this reason, the response speed when the light emitting unit 140 is turned on also decreases.

  On the other hand, according to the present embodiment, at least a part of the sealing film 160 is removed between the first extraction wiring 114 and the second extraction wiring 134. For this reason, the magnitude of the resistance in the equivalent circuit diagram of FIG. 7 increases. Therefore, it is difficult for current to flow through the sealing film 160, and as a result, the response speed of the light emitting unit 140 is unlikely to decrease.

  As shown in the plan view of FIG. 8, the portion of the first portion 102 where the sealing film 160 is removed may overlap the insulating layer 150. In other words, the edge of the insulating layer 150 is not covered with the sealing film 160 in the region located between the first lead wiring 114 and the second lead wiring 134. Even if it does in this way, it becomes difficult to flow an electric current through the sealing film 160, As a result, the response speed of the light emission part 140 becomes difficult to fall.

  Furthermore, as shown in the plan view of FIG. 9, not only the portion of the sealing film 160 positioned at the first portion 102 but also the portion positioned above the first lead wiring 114 and the second lead wiring 134. The located part may also be removed. In this case, the sealing film 160 may or may not cover the portion of the edge of the insulating layer 150 that overlaps the first lead wiring 114 and the second lead wiring 134.

  As mentioned above, although embodiment and the Example were described with reference to drawings, these are illustrations of this invention and can also employ | adopt various structures other than the above.

DESCRIPTION OF SYMBOLS 10 Light-emitting device 100 Board | substrate 102 1st part 110 1st electrode 112 1st terminal 114 1st extraction wiring 120 Organic layer 130 2nd electrode 132 2nd terminal 134 2nd extraction wiring 140 Light-emitting part 150 Insulating layer 160 Sealing film 162 1st 1 sealing film 164 2nd sealing film

Claims (5)

A substrate,
A light emitting unit formed on the substrate and including a first electrode, a second electrode, and an organic layer positioned between the first electrode and the second electrode;
A first terminal formed on the substrate;
A second terminal formed on the substrate;
A first lead wiring formed on the substrate and electrically connecting the first terminal to the first electrode;
A second lead wiring formed on the substrate and electrically connecting the second terminal to the second electrode;
A sealing film formed on the substrate and sealing the light emitting unit;
With
The sealing film is a laminated film in which a plurality of inorganic layers are laminated,
The light emitting device in which a first portion of the substrate located between the first lead wiring and the second lead wiring has a region where the sealing film is not formed. The light-emitting device according to claim 1.
Comprising an insulating layer defining the light emitting portion;
The edge of the sealing film located in the first part is a light emitting device located closer to the insulating layer than the part of the edge of the sealing film that overlaps the first lead wiring. The light-emitting device according to claim 1 or 2,
A plurality of the light emitting units,
The first terminal, the second terminal, the first lead wire, and the second lead wire are provided for each of the plurality of light emitting units,
The light emitting device, wherein the first portion is located between the first lead wire closest to the plurality of second lead wires and the second lead wire closest to the plurality of first lead wires. The light emitting device according to claim 3.
The substrate is rectangular;
The light emitting device, wherein the plurality of first terminals and the plurality of second terminals are arranged along a first side of the rectangle. In the light-emitting device as described in any one of Claims 1-4,
The light emitting device in which the substrate is exposed in at least a part of the first portion.

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