JP2016082101A - Light-emitting device - Google Patents

Abstract

Provided is a see-through type light emitting device in which photoluminescence is unlikely to occur in an organic layer located in a region other than a light emitting portion.
A light emitting unit is formed on a part of a first surface of a substrate, and includes a first electrode, a second electrode, and an organic layer. 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 the first electrode 110 to a portion located around the first electrode 110. The organic layer 120 includes a phosphorescent material. Specifically, the light emitting layer of the organic layer 120 is formed of a phosphorescent material instead of a fluorescent material.
[Selection] 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

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

  As an example of the problem to be solved by the present invention, in the case where the organic layer is formed in a region other than the light emitting portion, photoluminescence is less likely to occur in the organic layer located in the region other than the light emitting portion.

The invention according to claim 1 is a translucent substrate;
A first electrode, a second electrode, an organic layer positioned between the first electrode and the second electrode, and a light emitting part formed on the first surface of the substrate;
With
The organic layer is continuously formed over a region on the first electrode and a portion located around the first electrode, and a light-emitting device in which the peak of the light absorption region of the organic layer is not in the range of 480 nm to 580 nm It is.

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

The invention according to claim 8 is a transparent substrate,
A first electrode, a second electrode, an organic layer positioned between the first electrode and the second electrode, and a light emitting part formed on the first surface of the substrate;
With
The organic layer is formed only in a region between the first electrode and the second electrode, and the light emitter that constitutes the 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 transparent substrate,
A first electrode, a second electrode, an organic layer positioned between the first electrode and the second electrode, and a light emitting part formed on the first surface of the substrate;
With
The organic layer is a light emitting device formed only in a region between the first electrode and the second electrode, and a light emitter constituting the light emitting layer of the organic layer is a phosphorescent material.

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 of a light emitting device according to Example 2. 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 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. 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 peak of the light absorption region of the organic layer 120 is not between 480 nm and 600 nm. Specifically, the organic layer 120 includes a phosphorescent material. More specifically, a part or all of the phosphor constituting the light emitting layer of the organic layer 120 is excited by a recombination energy of holes and electrons, and is formed of a phosphorescent material mainly composed of phosphorescence. . Details will be described below.

The substrate 100 is a substrate that is transparent to visible light, such as a glass substrate or a resin substrate. When the substrate 100 is a glass substrate, the substrate 100 includes 80% by weight or more of sodium oxide, calcium oxide, and silicon oxide in total. If it does in this way, the light transmittance of the board | substrate 100 in 1st 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 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.

  A part or all of the light emitters constituting the light emitting layer of the organic layer 120 is formed using a phosphorescent material. By doing so, the peak of the light absorption region of the organic layer 120 becomes smaller than 480 nm to 580 nm. This peak is located at, for example, 400 nm or less. Further, the peak wavelength of the emission spectrum in 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. If it does in this way, in the organic layer 120, it will become difficult to produce photoluminescence resulting from external light.

  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.

  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.

  The edge of the first electrode 110 is covered with an insulating film 150. The insulating film 150 is made of, for example, a photosensitive resin material such as polyimide, and surrounds a portion of the first electrode 110 that becomes the light emitting portion 140. An edge in the width direction of the second electrode 130 is located on the insulating film 150. In other words, when viewed from 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 this drawing, the organic layer 120 is also formed on the top and side surfaces of the insulating film 150.

  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 region 102 and a second region 104. The first region 102 is a region that includes the organic layer 120 and does not include the insulating film 150 among 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 regions between the plurality of light emitting units 140. The area of the first region 102 is larger than the area 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 in this figure, the light-emitting device 10 has the 3rd area | region 106 further. The third region 106 is a region that includes the organic layer 120 and the insulating film 150 among regions between the plurality of light emitting units 140 and overlaps the second electrode 130.

  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 insulating film 150 is formed on the edge of the first electrode 110. For example, when the insulating film 150 is formed of a photosensitive resin, the insulating film 150 is formed in a predetermined pattern through an exposure and development process. 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 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 a light transmittance of a certain level or more.

  In this embodiment, the light emitting layer constituting the organic layer 120 includes a phosphorescent material and does not include 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 such as the substrate 100 is designed to have high translucency in the wavelength region of 480 nm to 580 nm. For this reason, it is difficult for photoluminescence to occur 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 photoluminescence emission spectrum 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 the light due to 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 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 that of 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 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 insulating film 150. For this reason, it can suppress that the electroconductive part 170 short-circuits with the insulating film 150. FIG.

  The timing for forming the conductive portion 170 is after the first electrode 110 is formed and before the insulating film 150 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, it is possible to suppress the light transmittance of the light emitting device 10 from being lowered as in the embodiment. 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.

(Example 2)
FIG. 3 is a cross-sectional view of the light emitting device 10 according to the second embodiment. 4 is a plan view of the light emitting device 10 shown in FIG. FIG. 3 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 Example 1 except that the light emitting device 10 includes a plurality of light emitting units 140.

  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 Substrate 102 1st area | region 104 2nd area | region 110 1st electrode 120 Organic layer 130 2nd electrode 140 Light-emitting part 150 Insulating film 170 Conductive part

Claims (9)

A translucent substrate;
A first electrode, a second electrode, an organic layer positioned between the first electrode and the second electrode, and a light emitting part formed on the first surface of the substrate;
With
The organic layer is continuously formed over a region on the first electrode and a portion located around the first electrode, and a light-emitting device in which the peak of the light absorption region of the organic layer is not in the range of 480 nm to 580 nm .   The light emitting device according to claim 1, wherein a peak wavelength of a photoluminescence emission spectrum of the organic layer is not in a range of 480 nm to 580 nm. A substrate having translucency and having a light transmittance of 20% or less of light of the first wavelength or less;
A first electrode, a second electrode, and an organic layer positioned between the first electrode and the second electrode, and a light emitting part formed on the first surface of the substrate;
With
The organic layer is continuously formed over a region on the first electrode and a portion located around the first electrode, and a peak wavelength of a light absorption region of the organic layer is equal to or less than the first wavelength. A light emitting device. The light emitting device according to claim 3.
The light emitting device wherein the first wavelength is 400 nm. In the light-emitting device as described in any one of Claims 1-4,
The light-emitting device which comprises the light emitting layer of the said organic layer contains a phosphorescent material at least. In the light-emitting device as described in any one of Claims 1-4,
The light-emitting device which comprises the light emitting layer of the said organic layer is a phosphorescent material. In the light-emitting device as described in any one of Claims 1-6,
The light emitting device, wherein the substrate includes a total of 80% by weight or more of sodium oxide, calcium oxide, and silicon oxide. A translucent substrate;
A first electrode, a second electrode, an organic layer positioned between the first electrode and the second electrode, and a light emitting part formed on the first surface of the substrate;
With
The organic layer is formed only in a region between the first electrode and the second electrode, and a light emitter constituting the light emitting layer of the organic layer includes at least a phosphorescent material. A translucent substrate;
A first electrode, a second electrode, an organic layer positioned between the first electrode and the second electrode, and a light emitting part formed on the first surface of the substrate;
With
The organic layer is formed only in a region between the first electrode and the second electrode, and a light emitter constituting the light emitting layer of the organic layer is a phosphorescent material.

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