JP2016072283A - Light emission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light emission device in which a first electrode and a second electrode are not short-circuited with each other even when no insulation layer is provided.SOLUTION: A light emission device 10 is, for example, an illumination device or a display device, and has a substrate 100 and a light emission unit 140. The light emission unit 140 is formed at a part of a first surface of the substrate 100, and has a first electrode 110, a second electrode 130 and an organic layer 120. The second electrode 130 covers the first electrode 110. The organic layer 120 is located between the first electrode 110 and the second electrode 130. The edge and side surface of the first electrode 110 is in contact with the organic layer 120. The organic layer 120 is formed continuously over a region extending from an area overlapped with the first electrode 110 to a portion located around the first electrode 110. The organic layer 120 is thicker than the first electrode 110.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light emitting device.

  In recent years, development of light-emitting devices using organic EL has progressed. This light-emitting device is used as a lighting device or a display device, and has a configuration in which an organic layer is sandwiched between a first electrode and a second electrode. In general, a transparent material is used for the first electrode, and a metal material is used for the second electrode.

  One of the light emitting devices using organic EL is a technique described in Patent Document 1. In the technique of Patent Document 1, the second electrode is provided only in a part of the pixel so that the display device using the organic EL has light transmittance (see-through). In such a structure, since the region positioned between the plurality of second electrodes transmits light, the display device can have light transmittance. In the technique described in Patent Document 1, a light-transmitting insulating layer is formed between the plurality of second electrodes in order to define pixels. Patent Document 1 exemplifies inorganic materials such as silicon oxide and resin materials such as acrylic resin as the material of the insulating layer.

JP 2011-23336 A

  There is a light transmittance as an index for evaluating light transmittance. This light transmittance indicates the ratio of light that has entered a certain object. In general, even a light-transmitting material does not have a light transmittance of 100%. On the other hand, in a light-emitting device using an organic layer, an edge of the first electrode may be covered with an insulating layer in order to suppress a short circuit between the first electrode and the second electrode. In such a case, part of the light is absorbed when passing through the insulating layer. In this case, the light transmittance of the light emitting device is lowered.

  As an example of the problem to be solved by the present invention, in the light emitting device, the first electrode and the second electrode are prevented from being short-circuited, for example, at the edge and side surface of the first electrode without providing an insulating layer. Can be mentioned.

The invention according to claim 1 is a translucent substrate;
A light emitting part formed on the substrate;
With
The light emitting unit includes a first electrode, a second electrode, and an organic layer positioned between the first electrode and the second electrode,
With
The edges and side surfaces of the first electrode are in contact with the organic layer,
The organic layer is a light emitting device that is continuously formed from a region overlapping with the first electrode 110 to a portion positioned around the first electrode and is thicker than the first electrode.

It is sectional drawing which shows the structure of the light-emitting device which concerns on embodiment. 1 is a cross-sectional view illustrating a configuration of a light emitting device according to Example 1. FIG. 6 is a cross-sectional view illustrating a configuration of a light emitting device according to Example 2. FIG. 6 is a cross-sectional view of a light emitting device according to Example 3. FIG. It is a top view of the light-emitting device shown in 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 cross-sectional view illustrating a configuration of a light emitting device 10 according to the embodiment. The light emitting device 10 according to the embodiment is, for example, a lighting device or a display device, and includes a substrate 100 and a light emitting unit 140. The light emitting unit 140 is formed on a part of the first surface of the substrate 100 and includes the first electrode 110, the second electrode 130, and the organic layer 120. The second electrode 130 covers the first electrode 110. The organic layer 120 is located between the first electrode 110 and the second electrode 130. Further, the edge and the side surface of the first electrode 110 are in contact with the organic layer 120. The organic layer 120 is continuously formed from a region overlapping the first electrode 110 to a portion located around the first electrode 110. The organic layer 120 is thicker than the first electrode 110. Details will be described below.

The substrate 100 is a light-transmitting substrate such as a glass substrate or a resin substrate. The substrate 100 may have flexibility. In the case of flexibility, the thickness of the substrate 100 is, for example, not less than 10 μm and not more than 1000 μm. The substrate 100 is, for example, a polygon such as a rectangle or a circle. When the substrate 100 is a resin substrate, 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 substrate, 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 prevent moisture from permeating the substrate 100. It is preferable.

  A light emitting unit 140 is formed on one surface of the substrate 100. The light emitting unit 140 has a configuration in which the first electrode 110, the organic layer 120, and the second electrode 130 are stacked in this order. When the light emitting device 10 is an illumination device, the plurality of light emitting units 140 extend in a line shape. On the other hand, when the light emitting device 10 is a display device, the plurality of light emitting units 140 are arranged so as to form a matrix, or form a segment or display a predetermined shape (for example, display an icon). It may be. The plurality of light emitting units 140 are formed for each pixel.

  The first electrode 110 is a transparent electrode having optical transparency. The material of the transparent electrode is a material containing a metal, for example, a metal oxide such as ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), IWZO (Indium Tungsten Zinc Oxide), or ZnO (Zinc Oxide). 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 in this order. 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 organic layer 120 is continuously formed on the first electrode 110 and in each of the regions of the substrate 100 located at least around the first electrode 110. For this reason, the edge and side surface of the first electrode 110 are surely covered with the organic layer 120.

  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. In the example shown in the figure, the light emitting device 10 is wider than the first electrode 110. For this reason, when viewed from the direction perpendicular to the substrate 100, the entire first electrode 110 is overlapped and covered by the second electrode 130 in the width direction.

  An insulating layer is not formed between the first electrode 110 and the organic layer 120. For this reason, the edge of the first electrode 110 is not covered with the insulating layer, and the edge and the side surface of the first electrode 110 are in contact with the organic layer 120. In order to prevent the first electrode 110 and the second electrode 130 from being short-circuited, the organic layer 120 is thicker than the first electrode 110. For example, the thickness of the organic layer 120 when the light emitting unit 140 is observed in a cross section cut perpendicularly to the substrate 100 is larger than the thickness of the first electrode 110. By forming the organic layer 120 in this manner, the thickness of the organic layer 120 in contact with the edge and side surface of the first electrode 110 is short-circuited between the first electrode 110 and the second electrode 130 at the edge and side surface of the first electrode 110. Thickness that does not. The thickness of the organic layer 120 is, for example, not less than 2 times and not more than 5 times the thickness of the first electrode 110. Moreover, the thickness of the organic layer 120 is 60 nm or more and 400 nm or less, for example. The thickness of the first electrode 110 is, for example, not less than 30 nm and not more than 200 nm.

  Further, when viewed from a direction perpendicular to the substrate 100, the light emitting device 10 includes a first region 102 and a second region 104. The first region 102 is a region overlapping with the second electrode 130. When the second electrode 130 has a light shielding property, the first region 102 is a region that does not transmit light. The second region 104 is a region that does not overlap with the second electrode 130. Since the light transmittance of the second electrode 130 is lower than the light transmittance of the first electrode 110, the light transmittance of the second region 104 is higher than the light transmittance of the first region 102. The area of the first region 102 is smaller than the area 104. Further, the area of the substrate 100 where the light emitting part 140 is formed (in other words, the area of the light emitting part) is the area of the substrate 100 where the light emitting part 140 is not formed (in other words, the area of the non-light emitting part). Smaller than).

  Next, a method for manufacturing the light emitting device 10 will be described. First, the first electrode 110 is formed on the substrate 100 by using, for example, a sputtering method. Next, the first electrode 110 is formed into a predetermined pattern using a photolithography method. Next, the organic layer 120 and the second electrode 130 are formed in this order. When the organic layer 120 includes a layer formed by an evaporation method, this layer is formed in a predetermined pattern using, for example, a mask. The second electrode 130 is also formed in a predetermined pattern using, for example, a mask. Thereafter, the light emitting unit 140 is sealed using a sealing member (not shown).

  In the present embodiment, the light transmittance of the second region 104 is higher than the light transmittance of the first region 102. The area of the second region 104 is larger than the area of the first region 102. For this reason, the light emitting device 10 has a light transmittance of a certain level or more.

  In this embodiment, the edge of the first electrode 110 is not covered with an insulating layer. For this reason, the light transmittance of the light emitting device 10 is higher than when the edge of the first electrode 110 is covered with an insulating layer. Furthermore, in this embodiment, the organic layer 120 is thicker than the first electrode 110. For this reason, it can suppress that the organic layer 120 becomes thin in the part which overlaps with the edge of the 1st electrode 110, As a result, it can suppress that the 1st electrode 110 and the 2nd electrode 130 are short-circuited. If the thickness of the organic layer 120 is twice or more the thickness of the first electrode 110, the first electrode 110 and the second electrode 130 are particularly difficult to short-circuit.

Example 1
FIG. 2 is a cross-sectional view illustrating a configuration of the light emitting device 10 according to the first embodiment. The light emitting device 10 according to this example has the same configuration as the light emitting device 10 according to the embodiment except that the width of the second electrode 130 is narrower than the width of the first electrode 110. Specifically, at least in a certain cross section, the two edges of the second electrode 130 are both positioned closer to the center of the first electrode 110 than the edge of the first electrode 110. In this case, the width of the light emitting unit 140 is equal to the width of the first region 102.

  Also according to the present example, as in the embodiment, the first electrode 110 and the second electrode 130 can be prevented from being short-circuited. In addition, since the width of the second electrode 130 is narrower than the width of the first electrode 110, the second electrode 130 does not overlap with a region located on the edge of the first electrode 110 in the organic layer 120. Therefore, it is possible to further suppress a short circuit between the first electrode 110 and the second electrode 130. In addition, light emission that is generated between adjacent electrodes (for example, the first electrode 110 and the first electrode 110 or the second electrode 130 of the adjacent light-emitting portion 140), that is, so-called crosstalk light emission can be prevented.

(Example 2)
FIG. 3 is a cross-sectional view illustrating a configuration of the light emitting device 10 according to the second embodiment. The light emitting device 10 according to this example has the same configuration as that of the light emitting device 10 according to the embodiment, except that the conductive portion 170 is provided. Although the resistance is expected to increase as the organic layer 120 becomes thicker, the increase in resistance can be compensated for by providing the conductive portion 170.

  The conductive portion 170 is, for example, an auxiliary electrode for the first electrode 110 and is in contact with the first electrode 110. The conductive portion 170 is formed of a material having a lower resistance value than that of the first electrode 110, and is formed using, for example, at least one metal layer. The conductive portion 170 has a configuration in which, for example, a first metal layer such as Mo or Mo alloy, a second metal layer such as Al or Al alloy, and a third metal layer such as Mo or Mo alloy are stacked in this order. Yes. Of these three metal layers, the second metal layer is the thickest.

  The conductive portion 170 is covered with the organic layer 120. For this reason, the conductive part 170 is not directly connected to the second electrode 130. Note that the thickness of the conductive portion 170 is not less than 0.2 times and not more than 0.5 times the thickness of the organic layer 120, for example, not less than 30 nm and not more than 400 nm.

  The timing for forming the conductive portion 170 is after the first electrode 110 is formed and before the organic layer 120 is formed. The conductive portion 170 is formed as follows, for example. First, a conductive layer to be the conductive portion 170 is formed in this order by using a film forming method such as a sputtering method. Next, a resist pattern (not shown) is formed on the conductive layer, and the conductive layer is etched (for example, wet etching) using the resist pattern as a mask. Thereby, the conductive part 170 is formed.

  Also according to the present example, as in the embodiment, the first electrode 110 and the second electrode 130 can be prevented from being short-circuited. In addition, since the conductive portion 170 is formed on the first electrode 110, the resistance value of the first electrode 110 can be reduced. In addition, the conductive portion 170 is covered with the organic layer 120. For this reason, it can suppress that the electroconductive part 170 and the 2nd electrode 130 are short-circuited. In addition, it is desirable that the conductive portion 170 is inside the end portion of the second electrode 130, that is, in the first region 102.

(Example 3)
FIG. 4 is a cross-sectional view of the light emitting device 10 according to the third embodiment. FIG. 5 is a plan view of the light emitting device 10 shown in FIG. 4 corresponds to the AA cross section of FIG. The light emitting device 10 according to this example has the same configuration as that of the light emitting device 10 according to the embodiment or Examples 1 and 2 except that a plurality of light emitting units 140 are provided.

  Specifically, the light emitting device 10 is a lighting device, and includes a plurality of linear light emitting units 140. The plurality of light emitting units 140 are disposed apart from each other on the first surface of the substrate 100. Specifically, the plurality of light emitting units 140 are linear and extend in the same direction. The organic layer 120 is also formed in a region located between the plurality of light emitting units 140 on the first surface of the substrate 100. In other words, the organic layer 120 is continuously formed in the plurality of light emitting units 140 and a region between them.

  Also according to the present example, as in the embodiment, the first electrode 110 and the second electrode 130 can be prevented from being short-circuited. In addition, since the organic layer 120 is continuously formed in the plurality of light emitting portions 140 and a region between them, it is not necessary to use a mask having a fine pattern when forming the organic layer 120. Therefore, the cost for manufacturing the light emitting device 10 can be reduced.

  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 area | region 104 2nd area | region 110 1st electrode 120 Organic layer 130 2nd electrode 140 Light-emitting part 170 Conductive part

Claims (7)

A translucent substrate;
A light emitting part formed on the substrate;
With
The light emitting unit includes a first electrode, a second electrode, and an organic layer positioned between the first electrode and the second electrode,
With
The edges and side surfaces of the first electrode are in contact with the organic layer,
The organic layer is formed continuously from a region overlapping with the first electrode to a portion located around the first electrode, and is thicker than the first electrode. The light-emitting device according to claim 1.
The area of the substrate where the light emitting part is not formed is larger than that of the area where the light emitting part is formed. The light-emitting device according to claim 1 or 2,
The light transmittance of the second electrode is lower than the light transmittance of the first electrode,
When viewed from a direction perpendicular to the substrate, the area covered with the second electrode has a smaller area than the area not covered with the second electrode. In the light-emitting device as described in any one of Claims 1-3,
The light emitting device wherein the thickness of the organic layer is twice or more the thickness of the first electrode. In the light-emitting device as described in any one of Claims 1-4,
The light emitting device having a thickness of the organic layer of 60 nm to 400 nm. In the light-emitting device as described in any one of Claims 1-5,
A light-emitting device in which a plurality of the light-emitting portions are formed apart from each other on the substrate. In the light-emitting device as described in any one of Claims 1-6,
The width of the second electrode is a light emitting device narrower than the width of the first electrode.

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