JP2019117958A - Light-emitting device - Google Patents

Abstract

To make a photoluminescence less likely to occur in an organic layer located in a region other than a light emitting portion.SOLUTION: A light emitting unit 140 is formed on a part of a first surface of a substrate 100, and includes 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 organic layer 120 is continuously formed from a region overlapping with the first electrode 110 to a portion located around the first electrode 110. The organic layer 120 includes a phosphorescent material. Specifically, a light emitting layer of the organic layer 120 is formed of not a fluorescent material but a phosphorescent material .SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light emitting device.

  In recent years, development of a light emitting device using an organic EL is in progress. 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.

  There is a technology described in Patent Document 1 as one of light emitting devices using organic EL. In the technology of Patent Document 1, the second electrode is provided only in a part of the pixels in order to provide light transmission (see-through) to the display device using the organic EL. In such a structure, the region located between the plurality of second electrodes transmits light, and the display device can be light transmissive. In the technique described in Patent Document 1, a translucent insulating layer is formed between the plurality of second electrodes in order to define a pixel. In Patent Document 1, as a material of the insulating layer, an inorganic material such as silicon oxide and a resin material such as an acrylic resin are exemplified.

JP 2011-23336 A

  When the organic layer to be the light emitting layer is also formed in a region other than the light emitting portion, when the external light is incident on the organic layer located in this region, the external light is absorbed by the organic layer to generate photoluminescence is there. In this case, the light transmittance of the display device is reduced.

  As a problem to be solved by the present invention, when forming an organic layer also in a region other than the light emitting part, it is mentioned as an example that it is difficult for photoluminescence to occur in the organic layer located in the region other than the light emitting part.

The invention according to claim 1 is a light transmitting substrate,
A light emitting portion having a first electrode, a second electrode, an organic layer positioned between the first electrode and the second electrode, and formed on a first surface of the substrate;
Equipped with
The light emitting device wherein the organic layer is continuously formed over the region on the first electrode and the portion located around the first electrode, and the peak of the light absorption region of the organic layer is not 480 nm to 580 nm It is.

The invention according to claim 3 is a substrate having translucency and having a light transmittance of 20% or less of light of a first wavelength or less.
A light emitting portion formed on a first surface of the substrate, including a first electrode, a second electrode, and an organic layer positioned between the first electrode and the second electrode;
Equipped with
The organic layer is continuously formed over the region on the first electrode and the portion located around the first electrode, and the peak wavelength of the light absorption region of the organic layer is less than or equal to the first wavelength. It is a light emitting device.

The invention according to claim 8 is a light transmitting substrate,
A light emitting portion having a first electrode, a second electrode, an organic layer positioned between the first electrode and the second electrode, and formed on a first surface of the substrate;
Equipped with
The organic layer is formed only in a region between the first electrode and the second electrode, and a light emitter constituting a light emitting layer of the organic layer is a light emitting device including at least a phosphorescent material.

The invention according to claim 9 is a light transmitting substrate,
A light emitting portion having a first electrode, a second electrode, an organic layer positioned between the first electrode and the second electrode, and formed on a first surface of the substrate;
Equipped with
The organic layer is formed only in a region between the first electrode and the second electrode, and a light emitter constituting a light emitting layer of the organic layer is a light emitting device which is a phosphorescent material.

It is a sectional view showing the composition of the light emitting device concerning an embodiment. FIG. 1 is a cross-sectional view showing a configuration of a light emitting device according to a first embodiment. FIG. 7 is a cross-sectional view of a light emitting device according to a second embodiment. 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 components are denoted by the same reference numerals, and the description thereof will be appropriately omitted.

  FIG. 1 is a cross-sectional view showing the 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 the substrate 100 and the light emitting unit 140. The light emitting unit 140 is formed on a first surface of the substrate 100, and includes 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 organic layer 120 is continuously formed from a region overlapping with the first electrode 110 to a portion located around the first electrode 110. And the peak of the absorption region of the light of the organic layer 120 does not exist in 480 nm-600 nm. Specifically, the organic layer 120 contains a phosphorescent material. More specifically, the light-emitting body constituting the light-emitting layer of the organic layer 120 is partially or entirely formed of a phosphorescent material which is excited by the recombination energy of holes and electrons and is mainly made of phosphorescence. . The details will be described below.

The substrate 100 is a substrate having transparency to visible light, such as a glass substrate or a resin substrate. When the substrate 100 is a glass substrate, the substrate 100 contains 80 wt% or more in total of sodium oxide, calcium oxide, and silicon oxide. Thus, the light transmittance of the substrate 100 at the first wavelength or less (for example, 400 nm or less) can be made low (for example, 20% or less). The substrate 100 may have flexibility. In the case of having flexibility, the thickness of the substrate 100 is, for example, 10 μm or more and 1000 μm or less. 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 (polyether sulfone), 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 passing through the substrate 100. Is preferred.

  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 a lighting device, the plurality of light emitting units 140 extend in a line. On the other hand, when the light emitting device 10 is a display device, the plurality of light emitting units 140 are arranged to form a matrix, or to form a segment or display a predetermined shape (for example, to display an icon) It may be done. The plurality of light emitting units 140 are formed for each pixel.

  The first electrode 110 is a transparent electrode having light transparency. The material of the transparent electrode is a material containing a metal, for example, metal oxide such as ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), IWZO (Indium Tungsten Zinc Oxide), ZnO (Zinc Oxide) and the like. The thickness of the first electrode 110 is, for example, 10 nm or more and 500 nm or less. The first electrode 110 is formed by 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, for example, a configuration in which 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 vapor deposition. 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 an application 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. Also, all the layers of the organic layer 120 may be formed using a coating method.

  A part or all of the light emitters forming the light emitting layer of the organic layer 120 is formed using a phosphorescent material. In this way, the peak of the light absorption region of the organic layer 120 is smaller than 480 nm to 580 nm. This peak is located, for example, at 400 nm or less. In addition, the peak wavelength of the emission spectrum of the photoluminescence in the organic layer 120 is out of the wavelength range of 480 nm to 580 nm. Here, the substrate 100 is configured such that the first wavelength described in the description of the substrate 100 is larger than the peak wavelength of the light absorption region of the organic layer 120. In this way, in the organic layer 120, photoluminescence is less likely to occur due to external light.

  The organic layer 120 is continuously formed on the first electrode 110 and in at least a region of the substrate 100 located around the first electrode 110.

  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. Containing metal layers. In this case, the second electrode 130 has a light shielding property. The thickness of the second electrode 130 is, for example, 10 nm or more and 500 nm or less. 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. Therefore, when viewed in 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.

  The edge of the first electrode 110 is covered by the insulating film 150. The insulating film 150 is formed of, for example, a photosensitive resin material such as polyimide, and surrounds a portion to be the light emitting unit 140 in the first electrode 110. The widthwise edge of the second electrode 130 is located on the insulating film 150. In other words, when viewed in a direction perpendicular to the substrate 100, a part of the insulating film 150 protrudes from the second electrode 130. In the example shown in the figure, the organic layer 120 is also formed on the insulating film 150 and on the side surface.

  A plurality of light emitting units 140 are formed on the first surface of the substrate 100 so as to be separated from each other. The light emitting device 10 has a first area 102 and a second area 104. The first region 102 is a region that includes the organic layer 120 and does not include the insulating film 150 among the regions between the plurality of light emitting units 140. The second region 104 is a region including the organic layer 120 and the insulating film 150 among the regions between the plurality of light emitting units 140. The area of the first region 102 is larger than the area of 104. In the cross-sectional view, the width of the first region 102 is larger than the width of the second region 104.

  And in the example shown to this figure, the light-emitting device 10 has the 3rd area | region 106 further. The third region 106 is a region including the organic layer 120 and the insulating film 150 among the regions between the plurality of light emitting units 140 and overlapping the second electrode 130.

  Next, a method of manufacturing the light emitting device 10 will be described. First, the first electrode 110 is formed on the substrate 100 using, for example, a sputtering method. Then, the first electrode 110 is formed into a predetermined pattern using a photolithographic method. Next, the insulating film 150 is formed on the edge of the first electrode 110. For example, in the case where the insulating film 150 is formed of a photosensitive resin, the insulating film 150 is formed into a predetermined pattern through exposure and development steps. Then, the organic layer 120 and the second electrode 130 are formed in this order. When the organic layer 120 includes a layer formed by vapor deposition, this layer is formed in a predetermined pattern, for example, using a mask. The second electrode 130 is also formed in a predetermined pattern, for example, using 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 first region 102 is higher than the light transmittance of the second region 104. The area of the first region 102 is larger than the area of the second region 104. For this reason, the light emitting device 10 has light transmittance of a certain level or more.

  In the present embodiment, the light emitting layer constituting the organic layer 120 contains a phosphorescent material and does not contain a fluorescent material. In this way, the peak wavelength of the light absorption region in the organic layer 120 deviates from the wavelength range of 480 nm to 580 nm. On the other hand, the light emitting device 10 is a device that emits visible light, and the material of the substrate 100 and the like is designed to have high translucency in a wavelength range of 480 nm to 580 nm. For this reason, it becomes difficult to produce photoluminescence in the organic layer 120. Therefore, it can suppress that the light transmittance of the light-emitting device 10 falls. Furthermore, the peak wavelength of the emission spectrum of the photoluminescence in the organic layer 120 is located outside 480 nm to 580 nm. Therefore, even if photoluminescence occurs in the organic layer 120, it is difficult for a person to visually recognize light by photoluminescence. Therefore, it can further suppress that the light transmittance of the light-emitting device 10 falls.

Example 1
FIG. 2 is a cross-sectional view showing the configuration of the light emitting device 10 according to the first embodiment. The light emitting device 10 according to the present example has the same configuration as the light emitting device 10 according to the embodiment except that the conductive portion 170 is provided.

  The conductive portion 170 is, for example, an auxiliary electrode of the first electrode 110 and is in contact with the first electrode 110. The conductive portion 170 is formed of a material having a resistance value lower than that of the first electrode 110, and is formed of, for example, at least one metal layer. 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. There is. The second metal layer is the thickest of these three metal layers.

  The conductive portion 170 is covered by the insulating film 150. Therefore, a short circuit of the conductive portion 170 to the insulating film 150 can be suppressed.

  The timing for forming the conductive portion 170 is before forming the insulating film 150 after forming the first electrode 110. The conductive portion 170 is formed, for example, as follows. First, a conductive layer to be the conductive portion 170 is formed in this order using, for example, a film formation method such as a sputtering method. Next, a resist pattern (not shown) is formed on the conductive layer, and the conductive layer is etched (eg, wet etched) using the resist pattern as a mask. Thus, the conductive portion 170 is formed.

  Also in the present example, as in the embodiment, the decrease in the light transmittance of the light emitting device 10 can be suppressed. Further, since the conductive portion 170 is formed on the first electrode 110, the resistance value of the first electrode 110 can be reduced.

(Example 2)
FIG. 3 is a cross-sectional view of the light emitting device 10 according to the second embodiment. FIG. 4 is a plan view of the light emitting device 10 shown in FIG. FIG. 3 corresponds to the cross section AA in FIG. The light emitting device 10 according to the present embodiment has the same configuration as any of the light emitting devices 10 according to the embodiment or the example 1 except that the light emitting device 10 includes the plurality of light emitting units 140.

  In detail, 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 of the first surface of the substrate 100 located between the plurality of light emitting units 140. In other words, the organic layer 120 is continuously formed in the plurality of light emitting units 140 and the region between them.

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

  As mentioned above, although an embodiment and an example were described with reference to drawings, these are the illustrations of the present invention and can also adopt various composition except the above.

DESCRIPTION OF REFERENCE NUMERALS 10 light emitting device 100 substrate 102 first region 104 second region 110 first electrode 120 organic layer 130 second electrode 140 light emitting portion 150 insulating film 170 conductive portion

Claims (1)

A translucent substrate,
A light emitting portion having a first electrode, a second electrode, an organic layer positioned between the first electrode and the second electrode, and formed on a first surface of the substrate;
Equipped with
The light emitting device wherein the organic layer is continuously formed over the region on the first electrode and the portion located around the first electrode, and the peak of the light absorption region of the organic layer is not 480 nm to 580 nm .

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