JP2018032590A - Organic el element, illumination device including the same, planar light source, and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic EL element which is compatible with high light extraction efficiency and high emission uniformity.SOLUTION: An organic EL element includes: a light transmissive substrate; a light transmissive structure layer; a light transmissive first electrode; a functional layer including a light emitting layer; and a second electrode, in this order. The second electrode has a plurality of convex portions at least on the side of the light transmissive substrate and a distance between apexes of two adjacent convex portions is 5 μm or less.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an organic electroluminescence (EL) element with improved light extraction efficiency, and an illumination device, a planar light source, and a display device including the organic EL element.

  In recent years, light-emitting elements (organic EL elements) that utilize the organic EL phenomenon have attracted a great deal of attention as next-generation light-emitting devices used in lighting devices, display devices, and the like. The organic EL element is capable of surface emission, can be operated at a low temperature, can be reduced in cost, can be reduced in weight, and can be made into a flexible element. There are advantages such as low angular dependence, low power consumption, and the ability to fabricate extremely thin elements.

  An organic EL element generally includes an anode, a cathode, and an organic EL layer sandwiched between the anode and the cathode. Here, the organic EL layer includes a light emitting layer containing an organic light emitting material. If necessary, the organic EL layer may further include an electron transport layer, an electron injection layer, a hole transport layer, a hole injection layer and the like.

  An organic EL element includes a transparent substrate such as a glass substrate, an anode made of a transparent conductive material such as ITO (indium tin oxide), an organic EL layer, and a cathode made of metal in this order. You may have the bottom emission structure to take out. Alternatively, the organic EL element may have a top emission structure in which a cathode, an organic EL layer, and an anode made of a transparent conductive material are provided on the substrate in this order, and light is extracted from the side opposite to the substrate side. .

  Although the organic EL element has the above-mentioned advantages, there is a problem that the light extraction efficiency is low. The light extraction efficiency is the ratio of the total energy amount of light emitted into the atmosphere from the light extraction surface (for example, the substrate surface in the case of the bottom emission type) to the total energy amount of light generated in the light emitting layer. For example, since light generated in the light emitting layer is radiated in all directions, most of the light becomes a waveguide mode in which total reflection is repeated at the interface between two layers having different refractive indexes. For this reason, the light extraction efficiency in the target direction decreases due to the change to heat in the waveguide mode and the emission of light from the side surface of the element.

  In the organic EL element, since the distance between the light emitting layer and the metal cathode is short, a part of the light from the light emitting layer is converted to surface plasmon on the surface of the cathode and lost. This also reduces the light extraction efficiency. Since the light extraction efficiency affects the brightness of a display device, an illuminating device or the like provided with an organic EL element, various methods have been studied for improving the light extraction efficiency.

  As one of the methods for improving the light extraction efficiency, an organic EL element using a glass substrate provided with a condensing layer having a condensing property has been proposed. For example, Japanese Patent Laid-Open No. 2003-86353 discloses a light condensing layer composed of a light converging structure such as a microlens and a transparent resin covering the light converging structure (see Patent Document 1). . In this proposal, the transparent resin has a higher refractive index than the light collecting structure. By providing the condensing layer on the glass substrate, total reflection occurring on the surface of the glass substrate is suppressed, and the light extraction efficiency is improved.

  Further, as one method for improving the light extraction efficiency, a method using surface plasmon resonance has been proposed. For example, Japanese Patent No. 4762542 discloses a method of providing a one-dimensional or two-dimensional periodic microstructure on the surface of a metal layer (cathode) (see Patent Document 2). In this proposal, the periodic microstructure functions as a diffraction grating. Thereby, the energy converted into surface plasmon on the cathode surface is reconverted into light, and the light extraction efficiency is improved.

JP 2003-86353 A Japanese Patent No. 4762542

  However, even if the above-mentioned condensing layer is provided on the glass substrate, total reflection occurs at the interface between the condensing layer and the glass substrate, and thus it cannot be said that the light extraction efficiency from the organic EL element is sufficiently high. In addition, when the above-described periodic fine structure is provided in the metal layer, a leak electrode is generated due to the uneven structure of the metal layer, and uneven light emission is generated due to nonuniformity of each layer stacked on the metal phase. In addition, there are problems such as a decrease in stability over time. For this reason, even if a theoretically efficient periodic structure is provided on the metal layer, the organic EL element cannot always be stably manufactured. On the other hand, an organic EL element having further improved light extraction efficiency is demanded for power saving of the organic EL lighting device and / or manufacture of a flexible organic EL lighting device.

  An object of the present invention is to provide an organic EL device that achieves both high light extraction efficiency and high uniformity of light emission. Furthermore, an object of this invention is to provide the illuminating device, planar light source, and display apparatus containing this organic EL element.

The first embodiment of the present invention includes a light transmissive substrate, a light transmissive structure layer, a light transmissive first electrode, a functional layer including a light emitting layer, and a second electrode in this order. The second electrode relates to an organic EL element having a plurality of convex portions at least in the direction of the light-transmitting substrate and having a distance between vertices of two adjacent convex portions of 5 μm or less. Here, the height H _2a apparent each of the plurality of convex portions, the convex width W _2h at half height of the height H _2a apparent, and all Totsuhaba W _2w apparent at height H _2a Have
W _2h ≦ W _2w / 2 (Formula 2)
May be satisfied. Further, it is preferable that H _2a is 400nm from 50nm. Further, W _2w is preferably in the range of 400 nm to 3000 nm. Also, H _2a / W _2w is preferably in the range of 1/4 1/10 in.

  The organic EL element of the first embodiment may further include a barrier layer between the light transmissive substrate and the structural layer. Further, the organic EL element of the first embodiment may further include a light extraction lens layer on the surface opposite to the surface on which the structural layer of the light transmissive substrate is provided.

  The 2nd Embodiment of this invention is related with the illuminating device containing the organic EL element of 1st Embodiment. The third embodiment of the present invention relates to a planar light source including the organic EL element of the first embodiment. The fourth embodiment of the present invention relates to a display device including the organic EL element of the first embodiment.

  By adopting the above configuration, an organic EL element with high light extraction efficiency can be provided. Furthermore, by using this organic EL element, an illumination device, a planar light source, and a display device having excellent characteristics can be realized.

It is a schematic sectional drawing which shows the organic EL element which concerns on the 1st Embodiment of this invention. It is the elements on larger scale of the organic EL element of FIG. It is a schematic sectional drawing which shows another structural example of the organic EL element of this invention. It is a schematic sectional drawing which shows another structural example of the organic EL element of this invention. It is a figure for demonstrating the conditions of the recessed part contained in the structure layer of the organic EL element of this invention. It is a figure for demonstrating the conditions of the recessed part contained in the structure layer of the organic EL element of this invention. It is a figure for demonstrating the conditions of the recessed part contained in the structure layer of the organic EL element of this invention. It is a figure which shows an example of the shape of the structural layer of the organic EL element of this invention, (a) is a perspective view of a structural layer, (b) is a top view of a structural layer, (c) is cutting line VIIIc It is sectional drawing of the structural layer along -VIIIc. It is a figure which shows the example of the shape of the 2nd electrode of the organic EL element of this invention, (a) is a perspective view of a 2nd electrode, (b) is a top view of a 2nd electrode, (c) is It is sectional drawing of the 2nd electrode along cutting line IXc-IXc. It is a figure for demonstrating the conditions of the convex part contained in the 2nd electrode of the organic EL element of this invention. It is a schematic sectional drawing which shows an example of the illuminating device of the 2nd Embodiment of this invention, and the planar light source of 3rd Embodiment. It is a schematic sectional drawing which shows an example of the display apparatus of the 4th Embodiment of this invention.

  The present invention will be described with reference to the drawings. The present invention includes an organic EL element, a lighting device including the organic EL element, a planar light source, and a display device. Note that the present invention is not limited to the embodiments described below. Various changes or modifications can be made to the present invention based on the knowledge of those skilled in the art. Embodiments to which such changes or modifications are added are also included in the scope of the present invention.

(I) Organic EL Element First, the organic EL element according to the first embodiment of the present invention will be described.

  The organic EL element of the first embodiment of the present invention includes at least a substrate, a structural layer, a first electrode, a functional layer including a light emitting layer, and a second electrode. A configuration example of the organic EL element 100 of the present embodiment is shown in FIG. The organic EL element 100 according to the present embodiment includes a light transmissive substrate 102, a light transmissive structure layer 104, a light transmissive first electrode 106, a functional layer 108 including a light emitting layer, and a second electrode 110. It has a stacked structure. The organic EL element of the present invention has a bottom emission structure in which light is extracted from the light transmissive substrate 102 side.

  The organic EL element of the present invention has a structural layer 104. As shown in FIG. 2, the structural layer 104 has a plurality of recesses 202 on the surface on the first electrode 106 side in the direction of the first electrode. In addition, the structural layer 104 includes a crest portion (hereinafter referred to as “mountain portion”) 204 between adjacent recesses of the plurality of recesses 202. The shapes of the concave portion 202 and the mountain portion 204 are transferred to the first electrode 106, the functional layer 108, and the second electrode 110 stacked on the structural layer 104. The shape of the peaks and valleys transferred from the structural layer 104 to the second electrode 110 can be maintained on both the substrate-side surface and the opposite surface of the second electrode 110. As long as the shape of the structural layer 104 is maintained by the second electrode 110, the shape of the crests and valleys of the second electrode 110 is formed only on the surface of the second electrode 110 on the light transmitting substrate 102 side. May be. Here, the shape of the concave portion 202 of the structural layer is transferred to the convex portion (mountain portion) 206 on the surface of the second electrode 110 on the light transmitting substrate 102 side, and the shape of the peak portion 204 of the structural layer 104 is On the second electrode 110, it is transferred to the valley 208. As shown in FIG. 2, the second electrode 110 to which the shapes of the concave portion 202 and the peak portion 204 are transferred can efficiently extract the light 210 emitted from the functional layer 108 as the light 212 to the substrate side. to enable.

  The specific shape of the concave portion 202 and the condition of the concave shape of the structural layer 104 in the present invention, and the specific shape and the convex shape of the convex portion 206 of the second electrode 110 are described in the section of “Structural layer” described later. And in the section “Second Electrode”.

  The first electrode 106 is an electrode that has optical transparency and serves as an anode. The functional layer 108 includes a light emitting layer. The second electrode 110 is an electrode serving as a counter electrode of the first electrode 106 and serves as a cathode.

  In this specification, the light-transmitting property means a property (translucency) that is transparent to light. The light transmissive material used in the present invention is preferably transparent to light from the ultraviolet region to the infrared region. Specifically, the light transmissive material preferably has an average transmittance of 50% or more in a wavelength region from 350 nm to 800 nm. More preferably, the light transmissive material has an average transmittance of 80% or more in a wavelength region from 350 nm to 800 nm.

  As shown in FIG. 3, another configuration example of the organic EL element of the present invention is a light including a lens layer 302 and a light transmissive layer 304 on the surface opposite to the structural layer 104 of the light transmissive substrate 102. An extraction lens layer 310 may further be included.

  As shown in FIG. 4, still another configuration example of the organic EL element of the present invention includes a light transmissive substrate 102, a barrier layer 402, a structural layer 104, a first electrode 106, a functional layer 108, and a second electrode 110. Can be included. The barrier layer 402 is a layer for preventing intrusion of moisture or the like harmful to the structural layer 104, the first electrode 106, the functional layer 108, and the second electrode 110. Therefore, the barrier layer 402 is preferably provided between the light transmissive substrate 102 and the structural layer 104. In addition, this configuration example may further include a light extraction lens layer 310 as shown in FIG.

  In this specification, a portion including at least the light transmissive substrate 102, the structural layer 104, and the first electrode 106 is also referred to as a “light extraction substrate 120”. In addition, the light extraction lens layer 310 and the barrier layer 402, which are optional components, can be included in the light extraction substrate 120.

  Next, each part which comprises the organic EL element 100 is demonstrated in detail.

[Light transmissive substrate]
The light transmissive substrate 102 is a plate-like member that transmits predetermined light (preferably light in the visible region). The material is not particularly limited as long as it is conventionally used for organic EL elements such as glass and plastic. The light transmissive substrate 102 is preferably a glass plate, a substrate made of a polymer, a resin film, or the like.

  Examples of the glass plate include soda-lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, quartz glass and the like.

  The polymer constituting the light transmissive substrate 102 includes, for example, polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, polysulfone, and the like.

  Examples of the material of the resin film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN); polyolefins such as polyethylene, polypropylene, and polymethylpentene; cellophane, cellulose diacetate, cellulose triacetate (TAC), and cellulose acetate butyrate. Rate, cellulose acetate propionate (CAP), cellulose esters such as cellulose acetate phthalate, cellulose nitrate or derivatives thereof; polyvinylidene chloride; polyvinyl alcohol; polyethylene vinyl alcohol; syndiotactic polystyrene; polycarbonate; Polyimide; Polyethersulfone (PES); Polyphenylene sulfide; Polysulfur Containing cycloolefin resin and norbornene resin; down like; polyetherimides; polyetherketone imide, polyamides such as nylon; fluorine resin; polymethyl methacrylate, acrylic or polyarylates.

  In the organic EL element of the present invention, when a resin film is used as the light transmissive substrate 102, a resin film with a barrier layer in which a barrier layer described below is already provided on the surface of the resin film can also be used. .

[Barrier layer]
The barrier layer 402 is an optional component of the organic EL element of the present invention. The barrier layer may be a hybrid film including an inorganic or organic film, or both. The barrier layer has a water vapor permeability (25 ± 0.5 ° C., 90 ± 2% RH) measured by a method according to JIS K 7129-1992 of 0.01 g / (m ² · 24 h) or less. It is preferable to have. Furthermore, the barrier layer 402 has an oxygen permeability of 1.0 × 10 ⁻³ cm ³ / (m ² · 24 h · atm) or less and 1.0 × measured by a method according to JIS K 7126-1987. The water vapor permeability is preferably 10 ⁻³ g / (m ² · 24 h) or less. More preferably, the barrier layer 402 has a water vapor transmission rate of 1.0 × 10 ⁻⁵ g / (m ² · 24 h) or less.

  It is desirable that the material of the barrier layer 402 has a function of suppressing entry of moisture, oxygen, and the like that cause deterioration of the organic EL element 100. For example, the material of the barrier layer 402 may include silicon oxide, silicon dioxide, silicon nitride, and the like. Note that the barrier layer 402 made of an inorganic material may be fragile. In order to improve this vulnerability, it is more preferable that the barrier layer 402 has a laminated structure in which an inorganic layer made of the above-described inorganic material and an organic layer made of an organic material are laminated. There is no restriction | limiting in particular in the lamination | stacking order of an inorganic layer and an organic layer. The barrier layer 402 preferably has a stacked structure in which inorganic layers and organic layers are alternately stacked.

  The method for forming the barrier layer 402 is not particularly limited. The barrier layer 402 can be formed using means normally used in this technical field. For example, vacuum deposition method, sputtering method, reactive sputtering method, molecular beam epitaxy method, cluster ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma polymerization method, plasma CVD method, laser CVD method, thermal CVD method The barrier layer 402 can be formed using a coating method or the like.

[Structural layer]
The structural layer 104 has a plurality of recesses 202 on the surface on the first electrode 106 side in the direction of the first electrode 106 (see, for example, FIG. 2). In addition, there is a peak portion 204 between adjacent recesses of the plurality of recesses 202. The shapes of the recesses 202 and the peaks 204 are transferred to the first electrode 106, the functional layer 108, and the second electrode 110 stacked on the structural layer 104, and the shapes are maintained in the respective layers.

  The concave portion 202 provided in the structural layer 104 needs to satisfy a predetermined condition described below with reference to FIGS.

  In the structural layer 104, it is desirable that the distance between the bottom points of the adjacent recesses 202 is within a predetermined range.

  FIG. 5 shows the structural layer 104 in which a plurality of recesses 202 are formed. The distance between the bottom points of the adjacent recesses 202 is preferably 5 μm or less. More preferably, the distance between the bottom points of the adjacent recesses 202 is 3 μm or less. By setting the distance between the bottom points within the above-mentioned range, the convex portion transferred from the concave portion 202 of the structural layer 104 to the second electrode 110 efficiently emits the light emitted from the functional layer 108 side. The shape can be reflected. Specifically, the distance between the bottom point of the concave part represented by “A” in FIG. 5 and the bottom point of the concave part represented by “B”, “C”, “D”, “H” adjacent to each other is Within the above range, or the bottom of the concave portion represented by “A” in FIG. 5 and the bottom of the convex portion represented by adjacent “E”, “F”, “G”, “I” The distance from the point is preferably within the above range.

  Next, the relationship between the plurality of recesses 502 provided in the structural layer 104 will be described with reference to FIGS. 6 and 7.

  FIG. 6 shows a structural layer 104 having a recess 502 similar to FIG. Consider a plane 602 that passes through the bottom points 702, 704, 706, 708, and 709 of a plurality of recesses and is perpendicular to the structural layer 104. FIG. 7 shows a cross section indicated by a plane 602 with a recess 502a (having a bottom point 702) and two recesses 502b (having a bottom point 704) and 502c (having a bottom point 706) adjacent to the recess 502a. A cross-sectional shape is shown.

Here, attention is focused on one recess (in the following description, it is referred to as a recess 502a in FIG. 7). As shown in FIG. 7, the recess 502 a has a height H ₁₀ from the bottom side 104 a of the structural layer 104 to its bottom point 702. A crest 770 between the recess 502 a and the recess 502 b has a height H ₁₁ from the bottom 104 a of the structural layer 104 to its apex 710. Further, the peak portion 772 between the concave portion 502 a and the concave portion 502 c has a height H ₁₂ from the bottom side 104 a of the structural layer 104 to its apex 712.

Next, the height H ₁₁ of the two peak portions 770 and the height H _{12 of the} peak portion 772 are compared, and the smaller one is taken as the height H _1a of the _{peak portion} . The height H ₁₀ from the peak height H _1a to the bottom point 702 of the recess 502a is subtracted, and this value is taken as the apparent depth D _1a of the recess 502a. Next, a half position of the apparent depth D _1a of the recess 502a is set to a half-value height 764 of the recess 502a.

The width of the recess 502a at half position of the height 764 of the peak portion is defined as凹幅W _1h. Next, the position of the slope portion of the mountain portion 772 having the same height as the height H _1a of the mountain portion is defined as 780. The distance between the apex 710 of the peak portion 770 and the position 780 of the peak portion 772 is defined as the full recess width W _{1w of the} recess.

In the present invention, the concave width W _1h is preferably equal to or less than a value obtained by dividing the total concave width W _1w by two. That is, it is desirable to satisfy the following expression.

W _1h ≦ W _1w / 2 (Formula 1)

  The required value of the above equation is obtained by observing a desired region of the concave portion and peak portion of the structural layer in two dimensions using a scanning probe microscope (for example, AFM5400 manufactured by Hitachi High-Tech Science Co., Ltd.). be able to. In the present invention, after measuring images at 10 locations of the recesses and the ridges, an interval of 10 points or more is defined with a peak portion between an arbitrary recess in the image and a recess adjacent to the recess as one point. The average was obtained.

  As long as the region satisfies the above (Formula 1), the region may be periodically arranged in the structural layer 104 or may be randomly arranged. The region satisfying the above (Equation 1) is in the range of 50% to 100%, preferably 80% to 100% of the entire region of the structural layer. In the present invention, the structure layer 104 in which the concave portions are regularly arranged is more preferable, and the structure layer in which the regular concave portions are arranged in the entire structure layer 104 is most preferable.

  The structural layer 104 is light transmissive. The shape of the concave portion of the structural layer 104 is not particularly limited as long as the shape transferred to the second electrode 110 efficiently reflects the light emitted from the functional layer 108 toward the light transmissive substrate 102 side.

  Specifically, for example, the example of the concave portion includes a quadrangular pyramid-shaped concave portion 502 whose top side of the concave portion is a quadrangle as shown in FIGS. FIG. 8A is a perspective view showing an outline of the structural layer 104 having a quadrangular pyramid-shaped recess 502, FIG. 8B is a top view of the structural layer 104, and FIG. It is sectional drawing of the structural layer 104 along the cutting line VIIIc-VIIIc of FIG.8 (b).

  In the present invention, the recesses 502 preferably have a regular arrangement as shown in FIG. 8, but the arrangement transferred to the second electrode 110 efficiently transmits light emitted from the functional layer 108. There is no particular limitation as long as it reflects to the substrate 102 side. For example, a region having a regular arrangement, such as regions 810 and 812 surrounded by a dotted line in FIG. 8B, may be arranged so as to exist on a part of the entire surface of the structural layer.

  Although the shape of the concave portion of the structural layer 104 of the present invention has been described with reference to the drawings, the present invention is not limited to such a shape. The concave portion of the structural layer 104 may have a polygonal pyramid shape such as a triangular pyramid shape, a pentagonal pyramid shape, or a hexagonal pyramid shape instead of the quadrangular pyramid shape illustrated in FIG. 8. In the present invention, those having a bottom shape close to a circle are particularly preferable.

Further, the apparent depth D _1a (see FIG. 7) of the concave portion of the structural layer 104 is preferably 50 nm or more and 400 nm or less. When the apparent depth D _{1a of the} plurality of concave portions is lower than 50 nm, the apparent height H _2a of the convex portion of the second electrode 110 to which the shape of the structural layer 104 is transferred becomes low, so surface plasmon resonance The effect of can not be obtained. When the apparent depth D _{1a of the} plurality of recesses is higher than 400 nm, the apparent depth D _1a of the recess greatly exceeds the film thickness of a layer such as a light emitting layer included in the functional layer 108, and the layer uniformity Is significantly reduced. As a result, light emission failure due to uneven light emission, short circuit, etc. occurs.

The height difference between the apexes of two peaks adjacent to one recess of the structural layer 104 (for example, the difference between the height H ₁₁ of the peak 770 and the height H ₁₂ of the peak 772 (see FIG. 7)). Is preferably within 20% of the apparent depth D _1a of the recess. If the difference in height between two peaks adjacent to one recess exceeds 20% of the apparent height of the recess, the height uniformity of the peaks decreases, and the functional layer 108 and the second electrode 110 Uniformity decreases. As a result, light emission defects due to uneven light emission or short-circuiting occur.

Furthermore, the total recess width W _1w of the recesses of the structural layer 104 is preferably 400 nm or more and 3000 nm or less. When the total concave width W _1w is smaller than 400 nm, the total convex width W _2w of the convex portion of the second electrode 110 to which the shape of the structural layer 104 is transferred becomes smaller than the emission wavelength, and surface plasmon resonance is insufficient. There is no re-radiation. As a result, the effect of reducing surface plasmon absorption cannot be sufficiently obtained. When the total concave width W _1w is larger than 3000 nm, the total convex width W _2w of the convex portion of the second electrode 110 to which the shape of the structural layer 104 is transferred is too larger than the emission wavelength, so that it is absorbed without resonance. Light increases. As a result, the effect of reducing surface plasmon absorption cannot be sufficiently obtained.

In the present invention, the ratio of the apparent depth D _1a of the concave portion of the structural layer 104 to the total convex width W _{1w of the} concave portion, D _1a / W _1w, is in the range of 1/4 to 1/10. Is preferred. If D _1a / W _1w is larger than _¼ , the slope between the concave portion and the peak portion is not uniform during film formation. As a result, a light emission failure due to uneven light emission or short circuit occurs. If D _1a / W _1w is smaller than 1/10, the slope of the slope between the convex portion and the valley portion of the second electrode 110 to which the shape of the structural layer 104 is transferred becomes loose, and is regenerated by conversion of the surface plasmon. The traveling direction of the emitted light spreads in the lateral direction of the element, and the light extracted through the light-transmitting substrate 102 decreases. For this reason, the luminous efficiency cannot be improved.

  The material constituting the structural layer 104 is preferably a light transmissive resin. The resin may be, for example, low density or high density polyethylene, ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-hexene copolymer, ethylene-octene copolymer, ethylene-norbornene copolymer, ethylene- Polyolefin resins such as dimethanooctahydronaphthalene copolymer [ethylene-monone (DMON) copolymer], polypropylene, ethylene-vinyl acetate copolymer, ethylene-methyl methacrylate copolymer, ionomer resin; polyethylene terephthalate, poly Polyester resins such as butylene terephthalate and polyethylene naphthalate; nylon-6, nylon-6,6, metaxylenediamine-adipic acid condensation polymer; amide resins such as polymethylmethacrylamide; polymethyl methacrylate Any acrylic resin; polystyrene, styrene-acrylonitrile copolymer, styrene-acrylonitrile-butadiene copolymer, styrene-acrylonitrile resin such as polyacrylonitrile; hydrophobized cellulose resin such as cellulose triacetate and cellulose diacetate; polychlorinated Halogen-containing resins such as vinyl, polyvinylidene chloride, polyvinylidene fluoride, and polytetrafluoroethylene; hydrogen-bonding resins such as polyvinyl alcohol, ethylene-vinyl alcohol copolymer, and cellulose derivatives; polycarbonate resins, polysulfone resins, and polyethersulfone resins Engineering plastics such as polyether ether ketone resin, polyphenylene oxide resin, polymethylene oxide resin, polyarylate resin, liquid crystal resin Mention may be made of the butter, and the like.

  Fine particles may be added to the structural layer 104 to impart a refractive index adjustment effect and / or a light scattering effect. Such fine particles may be particles composed of inorganic fine particles, organic fine particles, or a combination thereof. For example, the organic fine particles are made of acrylic polymer, styrene polymer, styrene-acrylic polymer and its crosslinked product, melamine-formaldehyde condensate, polyurethane polymer, polyester polymer, silicone polymer, fluorine polymer, and copolymers thereof. Or a combination of these fine particles. In addition, the inorganic fine particles may be clay compound particles such as smectite, kaolinite, and talc, fine particles made of inorganic oxides such as silica, titanium oxide, alumina, silica alumina, zirconia, zinc oxide, barium oxide, strontium oxide, or carbonic acid. It includes fine particles made of inorganic compounds such as calcium, barium carbonate, barium chloride, barium sulfate, barium nitrate, barium hydroxide, aluminum hydroxide, strontium carbonate, strontium chloride, strontium sulfate, strontium nitrate, strontium hydroxide, and glass.

〔electrode〕
Hereinafter, the first electrode 106 and the second electrode 110 will be described. Here, description will be made assuming that the first electrode 106 is an anode and the second electrode 110 is a cathode. However, the present invention is not limited to these examples.

(First electrode: anode)
In the case where the first electrode 106 is used as an anode, for example, a metal, an alloy, a metal oxide, a conductive compound, or a mixture thereof is suitable as a material for forming the first electrode 106. The material of the anode is, for example, a conductive metal oxide such as antimony, tin oxide doped (added) tin oxide (ATO, FTO), tin oxide, zinc oxide, indium oxide, ITO, zinc indium oxide (IZO), Metals such as gold, silver, chromium and nickel, mixtures of these metals and conductive metal oxides, inorganic conductive materials such as copper iodide and copper sulfide, organic conductive materials such as polyaniline, polythiophene and polypyrrole Including. The anode may be a laminate. For example, the anode may be a laminate of layers made of the above materials. In the present invention, the anode is preferably formed using a conductive metal oxide. In view of productivity, high conductivity, transparency, etc., it is particularly preferable to form the anode using ITO.

  When light emitted from the anode side is taken out, it is desirable that the light transmittance of the anode be larger than 10%. The sheet resistance of the anode is preferably several hundred Ω / □ or less. Further, although depending on the material used, the anode usually has a film thickness in the range of 10 nm to 1000 nm, preferably in the range of 10 nm to 200 nm.

(Second electrode: cathode)
As described above, the shape of the structural layer 104 is transferred to the second electrode 110. The shapes of the convex portion 206 and the valley portion 208 of the second electrode 110 transferred from the concave portion 202 and the peak portion 204 of the structural layer 104 are formed on both the surface of the second electrode 110 on the light transmitting substrate 102 side and the opposite side surface. Can be formed. In addition, as long as the shape of the structural layer 104 is maintained by the second electrode 110, the shape of the convex portion 206 and the valley portion 208 of the second electrode 110 may be formed only on the surface of the second electrode 110 on the substrate side. .

  Here, the second electrode will be described in more detail with reference to FIGS. 9 and 10. FIG. 9A is a perspective view schematically showing the second electrode 110 having the convex portion 902, and FIG. 9B shows the second electrode 110 in the direction in which the convex portion 902 is formed (on the light transmitting substrate 102 side). ), And FIG. 9C is a cross-sectional view of the second electrode 110 taken along the cutting line IXc-IXc of FIG. 9B. FIG. 10 is an enlarged cross-sectional view of FIG. Note that the direction of the arrow 1050 in FIG. 10 indicates the light-transmitting substrate 102 side.

  As shown in FIG. 9, the shape of the concave portion 202 of the structural layer 104 is transferred to the convex portion 902 on the surface of the second electrode 110 on the substrate surface side, and the peak portion of the structural layer 104 is transferred to the second electrode 110. Above, it is transferred to the valley 904.

  In the second electrode 110, two adjacent convex portions 902 need to be provided within a predetermined distance range as described below. In the following description, it is assumed that the second electrode 110 has a convex portion 902 having a square bottom as shown in FIG. In the present invention, for example, the vertex of the convex portion represented by “A” in FIG. 9A and the vertex of the convex portion represented by adjacent “B”, “C”, “D”, “H”. Or the apex of the convex part represented by “A” in FIG. 9A and the convex part represented by “E”, “F”, “G”, “I” adjacent to The distance from the apex is preferably 5 μm or less. More preferably, the distance between two adjacent apexes of the convex portion 902 is 3 μm or less. When the distance is larger than such an interval, the shape of the convex portion 902 of the second electrode 110 cannot efficiently reflect the light emitted from the functional layer 108 toward the light transmissive substrate 102.

  As shown in FIG. 9B, a cross section in which the second electrode 110 is cut along a vertical plane including a cutting line IXc-IXc passing through the apexes of the plurality of convex portions 902 of the second electrode 110 is considered. FIG. 9C shows such a cross section, and FIG. 10 is an enlarged view of FIG. 9C. In FIG. 10, the cross-sectional shape of the convex part 902a and the two convex parts 902b and 902c adjacent to this is shown.

Here, attention is focused on one convex portion (in the following description, the convex portion 902a in FIG. 10). As shown in FIG. 10, the convex portion 902a is adjacent to the two valley portions 904a and 904b. A distance from the bottom point 1010 of the valley 904a to the vertex 1080 of the convex part 902a is defined as a height H ₂₁ . Similarly, the distance from the bottom point 1012 of 904b, to the apex 1080 of the convex portion 902a, and a height H _22. The smaller one of the height H ₂₁ and the height H ₂₂ is defined as an apparent height H _2a of the convex portion 902a. Next, a half position of the apparent height H _2a of the convex portion 902a is set to a half-value height 1068 of the convex portion 902a.

The width of the convex portion 902a at the half height height 1068 of the convex portion is defined as the convex width _W2h . Next, the position of the apparent height H _2a of the convex portion 902a (the height from the vertex 1080 is the height H on the slope of the convex portion 902a side of the valley portion 904b (the valley portion not used for the definition of the height 1060). 1070) (position equal to _2a ). The distance between the position 1070 and the bottom point 1010 of the valley 904a (the bottom point that defines H _2a ) is defined as the total convex width W _2w .

In the present invention, it is necessary to satisfy the relationship of the following (formula 2) between the convex width W _2h and the total convex width W _2w of the second electrode 110.

W _2h ≦ W _2w / 2 (Formula 2)

  The required value of the above equation is obtained by exposing a cross section in the radiation direction of light at an arbitrary position on the second electrode by, for example, a focused ion beam processing (FIB) processing method, and performing the second electrode by a scanning electron microscope analysis. It can be obtained by observing 110 convex portions 902 and trough portions 904. For FIB processing, for example, an apparatus such as NB-5000 manufactured by Hitachi High-Technologies Corporation can be used. For scanning electron microscope analysis, an apparatus such as S-5500 manufactured by Hitachi High-Technologies Corporation can be used. In the present invention, after measuring images at ten locations of the convex portion 902 and the valley portion 904, an arbitrary convex portion 902 in the image and two valley portions 904 adjacent to the convex portion 902 are set as 10 points. The average was calculated | required using the space | interval more than a point.

  If the region satisfies the above-described (Equation 2), the region may be periodically arranged with the second electrode 110 or may be randomly arranged. The region satisfying the above (Equation 2) is in the range of 50% to 100%, preferably 80% to 100% of the entire region of the second electrode 110. In the present invention, the second electrode 110 in which convex portions are regularly arranged is more preferable. Most preferably, regular protrusions are arranged on the entire second electrode 110.

  Specifically, for example, the convex portion of the second electrode 110 includes a quadrangular pyramid-shaped convex portion 902 shown in FIGS. FIG. 9A is a perspective view schematically showing the second electrode 110 having the convex portion 902, FIG. 9B is a bottom view overlooking the second electrode 110, and FIG. It is sectional drawing of the 2nd electrode 110 along the cutting line IXc-IXc of 9 (b).

  In the present invention, the convex portions 902 preferably have a regular arrangement as shown in FIG. 9, but may be any one that efficiently reflects the light emitted from the functional layer 108 toward the light transmissive substrate 102. There is no particular limitation. For example, a region having a regular arrangement, such as regions 918 and 920 surrounded by a dotted line in FIG. 9B, may be arranged so as to exist on a part of the entire surface of the structural layer.

  Although the shape of the convex part of the 2nd electrode 110 of this invention was demonstrated with reference to drawings, this invention is not limited to such a shape. The convex part of the 2nd electrode 110 like FIG. 9 mentioned above may have polygonal pyramid shapes, such as a triangular pyramid shape, a pentagonal pyramid shape, and a hexagonal pyramid shape instead of a quadrangular pyramid shape. In the present invention, those having a shape close to a circle are particularly preferable.

  In the present invention, the fine structure on the surface of the second electrode 110 is obtained by transferring the shape of the structural layer 104 described above. Therefore, the shape of the convex portion and the valley portion of the second electrode 110 is determined by the structural layer 104. Therefore, if the condition of (Expression 1) is satisfied, the condition of (Expression 2) is also satisfied.

  When (Equation 2) is not satisfied, the slope of the convex portion of the second electrode 110 swells toward the structure layer 104 side. In other words, the slope of the valley portion of the second electrode 110 becomes steeper toward the bottom point, so that the space near the bottom point of the valley portion is narrowed. Under this condition, a part of the light emitted from the light emitting layer in the functional layer 108 and traveling to the second electrode 110 side is confined by multiple reflection in the convex portion of the second electrode 110, so that Light reflection is reduced. As a result, the light extraction efficiency of the entire organic EL element is lowered. Therefore, when (Formula 2) is not satisfied, it is not preferable from the viewpoint of light extraction efficiency.

The apparent height H _2a of the convex part 902 of the second electrode 110 is preferably 50 nm or more and 400 nm or less. If the height H _2a of apparent protrusion 902 is less than 50nm, because the height H _2a apparent convex portion is low, not to obtain the effect of the surface plasmon resonance. When the apparent height H _2a of the convex portion is higher than 400 nm, the apparent depth D _1a of the concave portion of the structural layer 104 that is the shape transfer source is the film thickness of a layer such as a light emitting layer included in the functional layer. And the uniformity of the layer is significantly reduced. As a result, a light emission failure due to uneven light emission or short circuit occurs.

Furthermore, the total convex width W _2w of the second electrode 110 is preferably 400 nm or more and 3000 nm or less. If Zentotsuhaba W _2w is 400nm smaller than, Zentotsuhaba W _2w becomes smaller than the emission wavelength, resonance is not the re-radiated due to insufficient. As a result, the effect of reducing surface plasmon absorption cannot be sufficiently obtained. On the other hand, when the total convex width W _2w is larger than 3000 nm, the total convex width W _2w is too larger than the emission wavelength, so that the light absorbed without resonance increases. As a result, the effect of reducing surface plasmon absorption cannot be sufficiently obtained.

In the present invention, the ratio of the apparent height H _2a of the convex portion to the total convex width W _2w , H _2a / W _2w is preferably in the range of 1/4 to 1/10. If H _2a / W _2w is greater than ¼, the slope of the valley is not uniform during film formation. As a result, a light emission failure due to uneven light emission or short circuit occurs. When H _2a / W _2w is smaller than 1/10, the slope of the valley portion becomes sluggish, and the traveling direction of light re-radiated by the conversion of the surface plasmon spreads in the lateral direction of the device, and passes through the light-transmitting substrate 102. The extracted light is reduced. For this reason, the luminous efficiency cannot be improved.

  In the present invention, the fine shape of the lower surface of the second electrode 110 suppresses surface plasmon absorption. A part of the light emitted from the light emitting layer of the functional layer 108 is reflected by the second electrode 110 toward the light transmissive substrate 102 and can be effectively extracted. In this specification, “reflection” of light at the second electrode 110 means that the fine shape of the lower surface of the second electrode 110 converts surface plasmon and emits light toward the light transmissive substrate 102 side. And the meaning that both of the light emitted from the light emitting layer of the functional layer 108 is reflected by the second electrode 110 toward the light transmissive substrate 102 are included.

When the second electrode 110 is used as a cathode, examples of the material for forming the second electrode 110 include a metal having a low work function (referred to as an “electron-injecting metal”), an electrically conductive alloy compound, and these materials. Mixtures are preferred. The electron injecting metal desirably has a work function of 4 eV or less. Materials that can be used are, for example, sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ). Including mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like. Among these, from the viewpoint of electron injectability and durability against oxidation, a more suitable cathode material includes a mixture of an electron injectable metal and a second metal, which is a stable metal having a larger work function. Examples of such mixtures include, for example, magnesium / silver mixtures, magnesium / aluminum mixtures, magnesium / indium mixtures, and lithium / aluminum mixtures.

  Further, the sheet resistance of the second electrode 110 is preferably several hundred Ω / □ or less. The second electrode 110 usually has a film thickness in the range of 10 nm to 5 μm, preferably in the range of 50 nm to 200 nm.

[Functional layer]
The functional layer 108 is provided between the first electrode 106 and the second electrode 110 and includes a light emitting layer. The first electrode 106, the functional layer 108, and the second electrode 110 can have various stacked structures.

  Hereinafter, a laminated structure of the first electrode 106, the functional layer 108, and the second electrode 110 will be specifically described. As an example, the following layer configurations a) to p) are shown. Here, as described above, the first electrode 106 is an anode and the second electrode 110 is a cathode. That is, all layers between the anode and the cathode are the functional layer 108. The symbol “/” indicates that the layers sandwiching the symbol “/” are stacked adjacent to each other. The configuration of the functional layer 108 and the stacked structure of the first electrode 106, the functional layer 108, and the second electrode 110 are not limited to the following layer configurations a) to p).

a) Anode / light emitting layer / cathode b) Anode / hole injection layer / light emitting layer / cathode c) Anode / hole injection layer / light emitting layer / electron injection layer / cathode d) Anode / hole injection layer / light emitting layer / Electron transport layer / cathode e) Anode / hole injection layer / emission layer / electron transport layer / electron injection layer / cathode f) Anode / hole transport layer / emission layer / cathode g) Anode / hole transport layer / emission layer / Electron injection layer / cathode h) anode / hole transport layer / light emitting layer / electron transport layer / cathode i) anode / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode j) anode / hole Injection layer / hole transport layer / light emitting layer / cathode k) anode / hole injection layer / hole transport layer / light emitting layer / electron injection layer / cathode l) anode / hole injection layer / hole transport layer / light emitting layer / Electron transport layer / cathode m) anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode n) anode / light emitting layer / electron injection layer / cathode ) Anode / light emitting layer / electron transport layer / cathode p) anode / light emitting layer / electron transport layer / electron injection layer / cathode

  Hereinafter, each layer (light emitting layer, injection layer, transport layer) constituting the functional layer 108 will be described.

(Light emitting layer)
The light emitting layer is a layer that emits light by recombination of electrons and holes (holes) moving from the electrode, injection layer, or transport layer, and the light emitting portion may be in the layer of the light emitting layer. It may be the interface between the light emitting layer and the adjacent layer.

  The total thickness of the light emitting layer is not particularly limited. For example, the film thickness is preferably 2 nm to 5 μm, more preferably 2 nm to 200 nm, and particularly preferably 10 nm to 20 nm. A film thickness within the above range contributes to improving the uniformity of the film, preventing unnecessary application of a high voltage during light emission, and improving the stability of the emission color with respect to the drive current.

  The light emitting layer is at least one of a blue light emitting layer, a green light emitting layer, and a red light emitting layer. In the organic EL element, the blue light emitting layer is a monochromatic light emitting layer having a light emission maximum wavelength of 430 nm or more and 480 nm or less, the range, the green light emitting layer is a monochromatic light emitting layer having a light emission maximum wavelength of 510 nm or more and 550 nm or less, and a red light emitting layer Is preferably a monochromatic light emitting layer having a light emission maximum wavelength of 600 nm or more and 640 nm or less.

  The light emitting layer may be a layer formed by laminating these light emitting layers of at least three colors (blue light emitting layer, green light emitting layer, red light emitting layer) to form a white light emitting layer. Further, when a plurality of light emitting layers are stacked, a non-light emitting intermediate layer may be provided between the light emitting layers.

  The light emitting layer of the organic EL device of the present invention is preferably a white light emitting layer. That is, the organic EL device of the present invention is particularly effective when the light emitting layer of the organic EL device is a white light emitting layer. Moreover, it is preferable that the illuminating device, planar light source, and display apparatus of this invention contain a white light emitting layer. Therefore, it is preferable that the illuminating device, the planar light source, and the display device of the present invention have at least a part of an organic EL element whose light emitting layer is a white light emitting layer.

  The light emitting layer may contain a host compound and a light emitting dopant compound such as a phosphorescent dopant and a fluorescent dopant.

  Host compounds include, for example, carbazole derivatives, triarylamine derivatives, aromatic derivatives, nitrogen-containing heterocyclic compounds, thiophene derivatives, furan derivatives, oligoarylene compounds, etc., or carboline derivatives, diazacarbazole derivatives Etc.

  Luminescent dopant compounds include, for example, coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, pyrylium dyes, perylene dyes, Including stilbene dyes, polythiophene dyes, or rare earth complexes.

(Injection layer: hole injection layer, electron injection layer)
The injection layer is a layer provided between the electrode and the light emitting layer as necessary in order to lower the driving voltage, improve the light emission luminance, or the like. The injection layer includes a hole injection layer (anode buffer layer) and an electron injection layer (cathode buffer layer).

  As described above, the hole injection layer is provided between the anode and the light emitting layer (for example, the above-described layer structures b), c), d), e)), or the anode and the hole transport layer. (For example, between the above-described layer configurations j), k), l), m)).

  In addition, the electron injection layer is provided between the cathode and the light emitting layer (for example, layer configuration (c), g), k), n)) or between the cathode and the electron transport layer (for example, the layer). Provided in configurations e), i), m), and p)).

  Examples of the material for forming the hole injection layer include phthalocyanine typified by copper phthalocyanine, oxide typified by vanadium oxide, conductive carbon such as amorphous carbon, polyaniline (emeraldine), and polythiophene. .

  Materials for forming the electron injection layer include, for example, metals represented by strontium and aluminum, alkali metal compounds represented by lithium fluoride, alkaline earth metal compounds represented by magnesium fluoride, and aluminum oxide Oxides and the like.

  The hole injection layer and the electron injection layer are desirably very thin films. Although depending on the material used, the hole injection layer and the electron injection layer preferably have a film thickness in the range of 0.1 nm to 5 μm.

(Blocking layer: hole blocking layer, electron blocking layer)
The blocking layer is a layer provided as necessary in addition to the basic constituent layer of the organic compound thin film. The blocking layer includes a hole blocking layer and an electron blocking layer.

  The hole blocking layer has a function of an electron transport layer in a broad sense. The hole blocking layer is made of a hole blocking material having a function of transporting electrons and a very small ability to transport holes. The hole blocking layer can improve the probability of recombination of electrons and holes in the light emitting layer by blocking the transport of holes while transporting electrons. Moreover, the structure of the electron carrying layer mentioned later can be used as a hole-blocking layer as needed.

  The hole blocking layer preferably contains the carbazole derivative, the carboline derivative, the diazacarbazole derivative, or the like mentioned as the host compound.

  On the other hand, the electron blocking layer has a function of a hole transport layer in a broad sense. The electron blocking layer is made of a material having a function of transporting holes and a remarkably small ability to transport electrons. The electron blocking layer can improve the probability of recombination of electrons and holes in the light emitting layer by blocking the transport of electrons while transporting holes. Moreover, the structure of the positive hole transport layer mentioned later can be used as an electron blocking layer as needed.

  The hole blocking layer and the electron blocking layer preferably have a thickness of 3 nm to 100 nm, more preferably 5 nm to 30 nm.

(Transport layer: hole transport layer, electron transport layer)
The transport layer is a layer provided as necessary for transporting holes or electrons. The transport layer includes a hole transport layer and an electron transport layer.

(Hole transport layer)
The hole transport layer is made of a hole transport material having a function of transporting holes. The hole injection layer and the electron blocking layer described above are included in the hole transport layer in a broad sense. The hole transport layer may be a single layer or a multilayer structure of a plurality of layers.

  The hole transport material has any of the characteristics of hole injection or transport and electron barrier, and may be either organic or inorganic. Hole transport materials include, for example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, It includes conductive polymer oligomers such as fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline copolymers, and thiophene oligomers. The hole transport layer includes one or more of the above-described hole transport materials.

  The hole transport layer is formed as a thin film from the above-described hole transport material by a known method such as a vacuum deposition method or an LB method. There is no restriction | limiting in particular in the film thickness of a positive hole transport layer. The hole transport layer usually has a thickness of 5 nm to 5 μm, preferably 5 nm to 200 nm.

(Electron transport layer)
The electron transport layer is made of an electron transport material having a function of transporting electrons. The electron injection layer and hole blocking layer described above are included in the electron transport layer in a broad sense. The electron transport layer may be a single layer or a multilayer structure of a plurality of layers. The electron transport layer is provided adjacent to the cathode side of the light emitting layer.

  The electron transport material (also serving as a hole blocking material) may have a function of transmitting electrons injected from the cathode to the light emitting layer. Any conventionally known compound having such a function can be selected and used as an electron transport material. Electron transport materials include, for example, nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives, and the like. Furthermore, in the oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, or a quinoxaline derivative having a quinoxaline ring known as an electron-withdrawing group can also be used as an electron transport material. Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

  The electron transporting material is a metal complex of an 8-quinolinol derivative such as tris (8-quinolinol) aluminum (Alq), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo- 8-quinolinol) aluminum, tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq) and the like. The electron transport material also includes a metal complex in which the central metal of the metal complex is replaced with In, Mg, Cu, Ca, Sn, Ga, or Pb. In addition, a metal-free phthalocyanine, a metal phthalocyanine, or a material whose terminal is substituted with an alkyl group, a sulfonic acid group, or the like may be used as an electron transport material. Further, the distyrylpyrazine derivatives exemplified as the material for the light emitting layer can also be used as the electron transporting material. The electron transport layer includes one or more materials among the electron transport materials described above. Further, an electron transport layer having a high n property doped with impurities can also be used.

  The electron transport layer is formed of the above-described electron transport material by a known method such as a vacuum deposition method or an LB method. There is no restriction | limiting in particular about the film thickness of an electron carrying layer. The electron transport layer usually has a thickness in the range of 5 nm to 5 μm, preferably in the range of 5 nm to 200 nm.

[Light extraction lens layer]
Optionally, a light extraction lens layer 310 may be provided as a light scattering or condensing layer on the surface of the light transmissive substrate 102 opposite to the surface on which the structural layer 104 is provided (see FIGS. 3 and 4). ). The light extraction lens layer 310 includes a light transmissive layer 304 having light transmissive properties, and a lens layer 302 provided on the surface of the light transmissive layer 304. The lens layer 302 may be formed by molding the surface of the light transmissive layer 304 into a microlens array. Alternatively, a so-called condensing sheet may be used as the lens layer 302. By such a light extraction lens layer 310, the light can be condensed in a specific direction, for example, the light extraction direction of the organic EL element (direction 112 in FIG. 1), and the luminance in the specific direction can be increased.

  The resin material constituting the light extraction lens layer 310 is, for example: low density polyethylene, high density polyethylene, ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-hexene copolymer, ethylene-octene copolymer, Polyethylene resins such as ethylene-norbornene copolymer, ethylene-DMON copolymer, polypropylene, ethylene-vinyl acetate copolymer, ethylene-methyl methacrylate copolymer, ionomer resin; polyethylene terephthalate, polybutylene Polyester resins such as terephthalate and polyethylene naphthalate; Amide resins such as nylon-6, nylon-6,6, metaxylenediamine-adipic acid condensation polymer, polymethylmethacrylamide; Ryl resin; Polystyrene; Styrene-acrylonitrile resin such as styrene-acrylonitrile copolymer and styrene-acrylonitrile-butadiene copolymer; Polyacrylonitrile; Hydrophobized cellulose resin such as cellulose triacetate and cellulose diacetate; Polyvinyl chloride Halogen-containing resins such as polyvinylidene chloride, polyvinylidene fluoride, and polytetrafluoroethylene; hydrogen-bonding resins such as polyvinyl alcohol, ethylene-vinyl alcohol copolymer, and cellulose derivatives; polycarbonate resins, polysulfone resins, polyethersulfone resins, Engineering plastic resins such as polyetheretherketone resin, polyphenylene oxide resin, polymethylene oxide resin, polyarylate resin, and liquid crystal resin No.

  In the light extraction lens layer 310, the light scattering effect may be further improved by adding fine particles to the resin material described above. The fine particles contained in the light extraction lens layer 310 may be particles made of inorganic fine particles, organic fine particles, or a combination thereof.

  Organic fine particles to be added to the light extraction lens layer 310 include, for example, acrylic polymers, styrene polymers, styrene-acrylic polymers and cross-linked products thereof, melamine-formalin condensates, polyurethane polymers, polyester polymers, silicone polymers, Fluorine polymer, fine particles made of a copolymer thereof, or fine particles made of a combination thereof are included. The inorganic fine particles to be added to the light extraction lens layer 310 are: clay compound particles such as smectite, kaolinite, talc; silica, titanium oxide, alumina, silica alumina, zirconia, zinc oxide, barium oxide, strontium oxide, etc. Fine particles made of inorganic oxides; or calcium carbonate, barium carbonate, barium chloride, barium sulfate, barium nitrate, barium hydroxide, aluminum hydroxide, strontium carbonate, strontium chloride, strontium sulfate, strontium nitrate, strontium hydroxide, glass, etc. Fine particles made of the above inorganic compounds.

(Sealing member)
The display area of the organic EL element 100 is preferably covered with a sealing member. For example, the display region may be sealed by bonding the sealing member and the electrode and / or the supporting substrate with an adhesive.

  As long as the sealing member can cover the display area of the organic EL element 100, the sealing member may be concave or flat. Further, the sealing member is not particularly required to have transparency or electrical insulation.

  The sealing member includes, for example, a glass plate, a polymer plate or film, or a metal plate or film. Glass plates include in particular plates such as soda-lime glass, barium-strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, quartz glass and the like. Examples of the polymer plate include polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, and polysulfone. As the metal plate, one or more kinds of metal plates selected from the group consisting of stainless steel, iron, copper, aluminum, magnesium, nickel, zinc, chromium, titanium, molybdenum, silicon, germanium, and tantalum, or including these metals Includes alloy plates.

  The adhesive used for sealing is, for example: a photo-curing or thermosetting adhesive having a reactive vinyl group such as an acrylic acid-based oligomer or a methacrylic acid-based oligomer; a moisture-curing type such as 2-cyanoacrylate Adhesives: Epoxy-based thermosetting or chemical-curing (two-component mixed) adhesives; Hot-melt adhesives such as polyamide, polyester, polyolefin, etc .; Cationic curing UV-curing epoxy resin adhesives, etc. Including.

  The organic EL element 100 may be deteriorated by heat treatment. For this reason, it is preferable that the adhesive can be adhesively cured in a temperature range from room temperature to 80 ° C. Alternatively, an adhesive in which a desiccant is dispersed may be used. Application | coating of the adhesive agent to a sealing part may use a commercially available dispenser, and may perform it by printing like screen printing.

  It is preferable to inject a gas phase or liquid phase inactive substance into the gap between the sealing member and the display area of the organic EL element 100. Inert substances include, for example, inert gases such as nitrogen and argon, and inert liquids such as fluorinated hydrocarbons and silicone oils. In addition, the gap between the sealing member and the display area of the organic EL element 100 can be evacuated.

  Optionally, a hygroscopic member containing a hygroscopic compound may be disposed in the gap between the sealing member and the display region of the organic EL element 100. Examples of the hygroscopic compound include metal oxides (for example, sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide, etc.), sulfates (for example, sodium sulfate, calcium sulfate, magnesium sulfate, cobalt sulfate, etc.). ), Metal halides (eg, calcium chloride, magnesium chloride, cesium fluoride, tantalum fluoride, cerium bromide, magnesium bromide, barium iodide, magnesium iodide, etc.), perchloric acids (eg, barium perchlorate) , Magnesium perchlorate, etc.). Of these, anhydrous salts are preferably used for sulfates, metal halides, and perchloric acids.

<Method for producing organic EL element>
This invention includes the manufacturing method of the said organic EL element. This manufacturing method is
(A) preparing a light transmissive substrate 102;
(B) forming a structural layer 104 on the light transmissive substrate 102;
(C) forming the first electrode 106 on the structural layer 104;
(D) forming a functional layer 108 on the first electrode 106;
(E) A step of forming the second electrode 110 on the functional layer 108, and the second electrode 110 has a plurality of convex portions surrounded by valleys at least in the direction of the light transmissive substrate 102. And a step in which the distance between the vertices of the convex portions is 5 μm or less.

  The step (A) is a step of selecting an appropriate one from the light transmissive substrate 102 as described above, and performing cleaning and necessary pretreatment on the selected light transmissive substrate 102 as necessary. is there. Cleaning and necessary pretreatment are usually performed on the substrate of the organic EL element, and there is no particular limitation.

  Step (B) is a step of forming the structural layer 104 having a plurality of recesses. On the light-transmitting substrate 102 prepared in the step (A), a light-transmitting resin for constituting the structural layer 104 described above is uniformly applied, and the resin has a convex shape capable of forming a desired concave portion. The shape transfer substrate is pressed down, and a desired concave shape is transferred to the light transmissive resin. The obtained light-transmitting resin having a concave shape is light-cured or heat-cured to form the structural layer 104. The structural layer 104 can be formed by such a procedure. The shape transfer substrate has a shape that is transferred in advance so as to satisfy the above-described condition of the recess.

  Step (B) can be carried out using a conventional pattern forming method such as a photolithography method in addition to the transfer method as described above.

  Step (C) is a step of forming the first electrode 106 used as an anode. In the step (C), considering the suitability with the material constituting the first electrode 106, for example, (1) a physical method such as a vacuum deposition method, a sputtering method, an ion plating method, (2) CVD, plasma, etc. It can implement by the method selected suitably from well-known methods, such as chemical methods, such as CVD method. For example, when the first electrode 106 is formed using ITO, the step (C) can be performed by a direct current sputtering method, a high frequency sputtering method, a vacuum deposition method, an ion plating method, or the like.

  Note that, in the step (C), the first electrode 106 may be patterned by using chemical etching by a photolithography method or the like, or physical etching by a laser or the like for patterning when forming the first electrode 106. Good. Alternatively, the patterned first electrode 106 may be formed by a vacuum vapor deposition method through a mask or a sputtering method through a mask. Alternatively, the patterned first electrode 106 may be formed using a lift-off method, a printing method, or the like.

  Step (D) is a step of forming the functional layer 108 including the light emitting layer. The functional layer can be formed by a known method such as a vacuum evaporation method or an LB method using the necessary material for the functional layer 108 described above.

  Step (E) is a step of forming the second electrode 110 used as a cathode. The second electrode 110 can be formed by depositing the above-described material by a known method such as vacuum evaporation or sputtering. The second electrode 110 formed in this step has a pattern having a fine structure, for example, as shown in FIG. 9, to which the structure of the concave portion and the mountain portion formed by the structural layer is transferred.

  In the manufacturing method of this invention, the process of forming a barrier layer may be further included between the said process (A) and process (B). The barrier layer is made of the above-described barrier layer material by vacuum deposition, sputtering, reactive sputtering, molecular beam epitaxy, cluster ion beam, ion plating, plasma polymerization, atmospheric pressure plasma polymerization, plasma It can be obtained by forming a film by a known method such as a CVD method, a laser CVD method, a thermal CVD method, or a coating method.

  Moreover, the manufacturing method of the organic EL element of this invention may include the process of forming the light extraction lens layer 310 which has the condensing lens layer 302 and the light transmissive layer 304 following the said process (E). . The light extraction lens layer 310 can be formed by a method similar to the conventional method.

  In the method of the present invention, as described with reference to FIG. 2, the structural layer 104 is formed on the surface on the first electrode 106 side so as to have a plurality of recesses 202 in the direction of the first electrode 106. The In addition, there is a peak portion 204 between adjacent recesses of the plurality of recesses 202. As shown in FIG. 9, the shape of the concave portion 202 and the peak portion 204 is transferred to the second electrode 110. The shape of the second electrode efficiently reflects the light emitted from the functional layer and allows it to be extracted as light toward the substrate.

  The present invention includes an illumination device, a planar light source, and a display device including the organic EL element.

<Lighting device and planar light source>
The organic EL element of the present invention can be used as part of a lighting device and a planar light source. For example, in the case of a lighting device including a light-transmitting substrate, an anode, a functional layer, a cathode, a hygroscopic member, and a sealing member from the light emitting side, the organic EL element of the present invention is provided between the light-transmitting substrate and the cathode. Can be used. More specifically, for example, as shown in FIG. 11, the example of the lighting device of the present invention includes a light transmitting substrate 102, a structural layer 104, a first electrode (anode) 106, and a functional layer from the light emission side. 108, a second electrode (cathode) 110, a hygroscopic member (desiccant) 1202, and a sealing member 1204. The organic EL element 100 of the present invention corresponds to the configuration from the light transmissive substrate 102 to the second electrode 110. The planar light source can also have the same configuration as the lighting device. Manufacture of such an illuminating device and a planar light source can be performed according to manufacture of the said organic EL element.

<Display device>
The organic EL element of the present invention can be used for a part of a display device such as a color display. For example, from the display side of the device, a display device including a color filter glass substrate (including a glass substrate and a color filter layer), a protective layer, an anode, an organic layer including a white organic EL light emitting layer, and a cathode can be exemplified. In the display device of the present invention, the cathode portion may include a driving portion such as a silicon driving substrate.

  More specifically, as shown in FIG. 12, the display device of the present invention includes a light transmissive substrate 102, a color filter layer (for example, an RGB color filter layer) 1302, a barrier layer 402, a structure from the light extraction direction. An organic EL display including the layer 104, the first electrode (anode) 106, the functional layer 108, and the second electrode (cathode) 110 can be included. Such a display element can be manufactured by inserting a known appropriate film forming process (for example, a spin coat method or a vapor deposition method in the case of a color filter layer) in addition to the manufacture of the organic EL element.

  An example embodying the above-described embodiment will be described together with a comparative example as a comparison target. In the following example, the plurality of recesses 502 of the structural layer 104 have a quadrangular pyramid shape toward the light transmissive substrate 102 as shown in FIG. The plurality of concave portions 502 were periodically arranged so that the peak portions (that is, the top side portions of the concave portions) therebetween were in a lattice shape. The width and height between the recesses 502 were measured using a scanning probe microscope. Specifically, after obtaining images of ten concave portions 502, as shown in FIG. 7, a peak portion 770 between an arbitrary concave portion 502a in the image and the concave portions 502b and 502c adjacent to the concave portion 502a. , 772 as one point, the width and height of the interval between the recesses 502 were measured. And the interval of 10 or more points was measured, and the average value was defined as the width and height of the interval between the recesses in the structural layer.

  In the following example, description will be made based on the value of the fine structure on the structural layer 104. However, in this example, the fine structure on the structural layer 104 is inverted so that the light of the second electrode 110 is reflected. It was transferred to the surface on the side of the transparent substrate and satisfied the setting conditions of the fine structure on the second electrode 110 of the present invention.

<Example 1>
First, the light extraction substrate 120 in which the light transmissive substrate 102, the structural layer 104, and the light transmissive first electrode 106 were laminated in this order was manufactured. A light transmissive substrate 102 was prepared by washing an alkali-free glass plate having a size of 30 mm × 40 mm and a thickness of 0.7 mm.

Using a spin coater, a UV (ultraviolet) curable acrylic resin (Rioduras TYT manufactured by Toyo Ink Co., Ltd.) is applied on the light-transmitting substrate 102, and then heated in a hot air oven at 100 ° C. for 1 minute. A resin layer having a thickness of 1 μm was formed. Then, after pressing the film board which has a fine convex pattern on the surface of this resin layer, UV light (150 mJ / cm < ² >) was irradiated. Next, the film plate was peeled off to obtain a structural layer 104 having a concave pattern on the surface of the resin layer. On the surface of the structural layer 104, a plurality of recesses having an apparent depth D _1a of 150 nm, a total recess width W _1w of 750 nm, and a recess width W _1h of 375 nm were formed. . The shape of the surface of the structural layer 104 was confirmed with a scanning probe microscope.

  Next, an ITO film having a thickness of 100 nm was deposited on the surface of the structural layer 104 by sputtering, followed by patterning to form a first electrode 106 (anode) having optical transparency.

  A functional layer 108 was formed by depositing a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer on the surface of the first electrode 106 by an evaporation method.

  First, 4,4 ′, 4 ″ -tris (9-carbazole) triphenylamine was deposited to form a 35 nm-thick hole transport layer. Subsequently, a 15 nm thick layer of 4,4 ′, 4 ″ -tris (9-carbazole) triphenylamine doped with a tris (2-phenylpyridinato) iridium (III) complex, and tris [1- A layer of 1,3,5-tris (N-phenylbenzimidazol-2-yl) benzene doped with a phenylisoquinoline-C2, N] iridium (III) complex and a 15 nm-thick layer is deposited to emit light of a two-layer structure A layer was formed. Subsequently, 1,3,5-tris (N-phenylbenzimidazol-2-yl) benzene was deposited to form an electron transport layer having a thickness of 65 nm. Finally, lithium fluoride was deposited to form an electron injection layer with a thickness of 1.5 nm to obtain a functional layer 108 including a light emitting layer.

  Subsequently, aluminum was deposited on the surface of the functional layer 108 by vapor deposition to form a second electrode 110 having a thickness of 50 nm, and an organic EL element having a layer configuration i) was obtained.

  Subsequently, a condensing lens comprising a hemispherical microlens having a diameter of 5 μm and a cross prism structure having an apex angle of 89 degrees having a pitch of 5 μm on one surface of a PET film (light transmitting layer 304 made of a light transmitting sheet). The layer 302 was formed, and the light extraction lens layer 310 was obtained. Subsequently, the other surface of the light transmissive layer 304 was bonded to the light transmissive substrate 102 via an adhesive, and the organic EL element 100 having the light extraction lens layer 310 shown in FIG. 3 was obtained. At this time, the condensing lens layer 302 is the outermost surface on the light extraction side.

<Example 2>
Except for forming the structural layer 104 having a concave portion in which the apparent depth D _1a of the concave portion is 190 nm, the total concave width W _{1w of the} concave portion is 1000 nm, and the concave width W _1h is 500 nm. The procedure of Example 1 was repeated to obtain an organic EL device 100.

<Example 3>
Except for forming the structural layer 104 having a concave portion in which the apparent depth D _1a of the concave portion is 380 nm, the total concave width W _{1w of the} concave portion is 2000 nm, and the concave width W _1h is 1000 nm. The procedure of Example 1 was repeated to obtain an organic EL device 100.

<Example 4>
Except that the structural layer 104 having a concave portion in which the apparent depth D _1a of the concave portion is 50 nm, the total concave width W _{1w of the} concave portion is 400 nm, and the concave width W _1h is 150 nm is formed. The procedure of Example 1 was repeated to obtain an organic EL device 100.

<Example 5>
Except that the structure layer 104 having a recess having an apparent depth D _1a of the recess of 300 nm, a total recess width W _{1w of the} recess of 3000 nm, and a recess width W _1h of 1000 nm was formed. The procedure of Example 1 was repeated to obtain an organic EL device 100.

<Example 6>
Except that the structure layer 104 having a recess having an apparent depth D _1a of the recess of 100 nm, a total recess width W _{1w of the} recess of 400 nm, and a recess width W _1h of 180 nm was formed. The procedure of Example 1 was repeated to obtain an organic EL device 100.

<Example 7>
Except for forming the structural layer 104 having a concave portion in which the apparent depth D _1a of the convex portion is 400 nm, the total concave width W _{1w of the} concave portion is 2500 nm, and the concave width W _1h is 1200 nm, The procedure of Example 1 was repeated to obtain the organic EL element 100.

<Comparative Example 1>
A structural layer having a flat upper surface by irradiating the surface of the resin layer formed on the light-transmitting substrate 102 with UV light (150 mJ / cm ² ) without pressing a film plate having a fine convex pattern. Except that 104 was formed, the procedure of Example 1 was repeated to obtain the organic EL element 100.

<Comparative example 2>
Except that the structural layer 104 having a concave portion in which the apparent depth D _1a of the concave portion is 150 nm, the total concave width W _{1w of the} concave portion is 500 nm, and the concave width W _1h is 260 nm is formed. The procedure of Example 1 was repeated to obtain an organic EL device 100.

<Comparative Example 3>
Except for forming the structural layer 104 having a recess having an apparent depth D _1a of the recess of 90 nm, a total recess width W _{1w of the} recess of 350 nm, and a recess width W _1h of 100 nm. The procedure of Example 1 was repeated to obtain an organic EL device 100.

<Comparative Example 4>
Except that the structural layer 104 having a concave portion in which the apparent depth D _1a of the concave portion is 30 nm, the total concave width W _{1w of the} concave portion is 500 nm, and the concave width W _1h is 260 nm is formed. The procedure of Example 1 was repeated to obtain an organic EL device 100.

<Comparative Example 5>
Except for forming the structural layer 104 having a recess having an apparent depth D _1a of the recess of 500 nm, a total recess width W _{1w of the} recess of 1000 nm, and a recess width W _1h of 400 nm. The procedure of Example 1 was repeated to obtain an organic EL device 100.

<Comparative Example 6>
Except for forming the structural layer 104 having a concave portion in which the apparent depth D _1a of the concave portion is 300 nm, the total concave width W _{1w of the} concave portion is 4000 nm, and the concave width W _1h is 2200 nm. The procedure of Example 1 was repeated to obtain an organic EL device 100.

<Evaluation>
About the organic EL element of Examples 1-7 and Comparative Examples 1-6, the extraction efficiency of light was measured. Table 1 shows the details of the structure of the structural layer 104 in the organic EL elements of Examples 1 to 7 and Comparative Examples 1 to 6, and the results of evaluating the light extraction efficiency ratio and the presence or absence of short circuits.

A constant current with a current density of 20 mA / cm ² was passed through the organic EL element from a direct current (DC) power source, and the total emitted light was measured with an integrating sphere, and the light extraction efficiency ratio was determined based on the measurement result. The light extraction efficiency ratio is a ratio of the amount of total emitted light of Examples 1 to 7 and Comparative Examples 2 to 6 to the amount of total emitted light of Comparative Example 1 having no recess in the structural layer. The case where the light extraction efficiency ratio was 1.6 or more was determined as “◎”, and the case where the light extraction efficiency ratio was 1.5 or more and less than 1.6 was determined as “◯”. Further, the case where the light extraction efficiency ratio was 1.1 or more and less than 1.5 was determined as “x”. Furthermore, when the light extraction efficiency ratio was less than 1.1, it was determined as “XX”.

  As shown in Table 1, it was confirmed that the organic EL elements of Examples 1 to 7 had a high light extraction efficiency ratio of 1.55 to 1.85. Thereby, in the organic EL element of Example 1 to Example 7, it turned out that the light extraction efficiency is improving compared with the organic EL element of the comparative example 1. This is because the convex structure transferred from the concave portion of the structural layer 104 on the surface of the second electrode 110 on the functional layer 108 side suppresses surface plasmon absorption and increases the reflectance of light on the second electrode. It is presumed that it was improved.

On the other hand, the organic EL device of Comparative Example 2 had a light extraction efficiency ratio of 1.45 of 1.45, and did not show a sufficient effect.
this is:
(A) Since the concave width W _1h is larger than the total concave width W _1w of the structural layer 104, the inclined surface of the concave portion has a shape swelled toward the light transmissive substrate 102; and (b) the structural layer 104 It is estimated that the apparent depth D _1a of the concave portion is larger than the total concave width W _1w of the concave portion. The factor (a) is such that the convex portion of the second electrode 110 swells toward the light-transmitting substrate 102 side. As a result, the slope of the valley adjacent to the convex portion of the second electrode 110 becomes steeper toward the bottom of the valley, and the space in the valley, particularly in the vicinity of the bottom, becomes narrow, and the surface of the second electrode 110 is reduced. It is estimated that the reflectance of light has decreased. The factor (b) excessively increases the apparent height H _2a of the convex portion with respect to the total convex width W _2w of the second electrode 110. As a result, it is presumed that the reflectance of the light traveling from the functional layer 108 toward the second electrode 110 side and traveling near the bottom of the valley of the second electrode 110 is greatly reduced.

Although the organic EL element of Comparative Example 3 had a light extraction efficiency ratio of 1.23, which was slightly higher than the organic EL element of Comparative Example 1, it did not show sufficient effects. This is because the total concave width W _1w of the structural layer 104 is small and the total convex width W _2w of the second electrode 110 is small. (C) Re-emission of light due to re-conversion of surface plasmons on the surface of the second electrode 110. Is not sufficient; and (d) it is presumed that (d) a decrease in reflectance on the surface of the second electrode 110 occurred.

The organic EL element of Comparative Example 4 had a light extraction efficiency ratio equivalent to that of the organic EL element of Comparative Example 1, and did not exhibit sufficient effects. This is because: (a) because the concave width W _1h is larger than the total concave width W _1w of the structural layer 104, the inclined surface of the concave portion has a shape swelled toward the light-transmitting substrate 102; and (e) It is presumed that the apparent depth D _1a of the concave portion of the structural layer 104 is small. The factor (e) is presumed that the apparent height H _2a of the second electrode 110 is lowered, and the light re-emission due to the re-conversion of the surface plasmon on the surface of the second electrode 110 is insufficient.

The organic EL device of Comparative Example 5 had a lower light extraction efficiency ratio than the organic EL device of Comparative Example 1, and did not show sufficient effects. This is: (f) The apparent depth D _1a of the concave portion is larger than the total concave width W _1w of the surface of the structural layer 104, and the apparent depth D _1a of the concave portion of the structural layer 104 is the functional layer. It is estimated that the film thickness is significantly larger than 108. The factor (f) is the light that travels from the functional layer 108 toward the second electrode 110 as a result of excessive increase in the apparent height H _2a of the convex portion with respect to the total convex width W _2w of the second electrode 110. It is presumed that the reflectance of light traveling near the bottom of the valley of the second electrode 110 is greatly reduced. Further, it is estimated that the uniformity of the film thickness of the functional layer 108 formed on the first electrode 106 was adversely affected. More specifically, since the apparent height H _2a of the convex portion with respect to the total convex width W _2w of the second electrode 110 is excessive, the peak portion of the structural layer 104 has a steep shape, and the functional layer 108 It is estimated that the film thickness has decreased relatively. The film thickness of the functional layer 108 on the first electrode 106 is reduced above a part of the peak, and carriers (holes and electrons) move between the first electrode 106 and the second electrode 110. It is presumed that the carriers that locally dominate the peripheral portion and increase the number of carriers that pass through the functional layer 108 (specifically, the light emitting layer) without contributing to light emission. Due to the influence of the factors (b) and (f), the light extraction efficiency ratio of the organic EL element of Comparative Example 5 is estimated to be lower than that of the organic EL element of Comparative Example 1 having the second electrode 110 having no uneven structure. The

The organic EL device of Comparative Example 6 had a light extraction efficiency ratio equivalent to that of the organic EL device of Comparative Example 1, and did not exhibit sufficient effects. This is presumably because (g) the total concave width W _1w of the structural layer 104 is very large with respect to the apparent depth of the concave portion of the structural layer 104. Factor (g) causes the convex portion of the second electrode 110 to which the shape of the concave portion of the structural layer 104 is transferred to be gentle, and makes the surface of the second electrode 110 closer to the light transmissive substrate 102 close to a plane. As a result, it is estimated that the effect of light re-emission by surface plasmon conversion was not obtained.

  As described above, the organic EL element according to the present invention includes a light-transmitting structural layer 104, a light-transmitting first electrode 106, a functional layer 108 including a light-emitting layer, and a light-transmitting substrate 102. The second electrode 110 is laminated in this order. Further, the structural layer 104 is provided with a recess having a relationship of (Equation 1). Thereby, it was found that an organic EL element having improved light extraction efficiency can be obtained.

  Further, although the present invention has been described with reference to the embodiments, the present invention is not limited to the above embodiments, and can be appropriately changed or modified within the scope described in the claims.

DESCRIPTION OF SYMBOLS 100 Organic EL element 102 Light transmissive substrate 104 Structural layer 104a Bottom of structural layer 106 First electrode 108 Functional layer 110 Second electrode 202 Concave portion of structural layer 204 Convex portion of structural layer 206 Convex portion of second electrode 208 Second electrode Trough portion 302 condensing lens layer 304 light transmitting layer 310 light extraction lens layer 402 barrier layer 502, 502a, 502b, 502c concave portion of structural layer 710, 712 vertex of peak portion 770, 772 peak portion 810, 812 regular 902, 902a, 902b, 902c Second electrode convex portion 904, 904a, 904b Second electrode valley portion 918, 920 Region having regular arrangement 1010, 1012 Bottom point 1068 Half value height of convex portion 902a 1080 Top of convex part of second electrode 1202 Hygroscopic member 1204 Sealing member 1302 Color filter layer

Claims (10)

  An organic EL element including a light transmissive substrate, a light transmissive structure layer, a light transmissive first electrode, a functional layer including a light emitting layer, and a second electrode in this order, wherein the second electrode includes at least the An organic EL element having a plurality of convex portions on the light transmissive substrate side and having a distance between vertices of two adjacent convex portions of 5 μm or less. Wherein the plurality of respective convex portions, the height H _2a apparent, projection width W _2h at half height of the height H _2a on the apparent total Totsuhaba W _2w at the height H _2a on the apparent W _2w and W _2h are W _2h ≦ W _2w / 2 (Formula 2)
The organic EL element according to claim 1, satisfying the relationship: The organic EL element according to claim 2, wherein H _2a is in a range from 50 nm to 400 nm. The organic EL element according to claim 2 or 3, wherein W _2w is in a range of 400 nm to 3000 nm. _5. The organic EL device according to claim 2, wherein H _2a / W _2w is in a range from ¼ to 1/10.   The organic EL device according to claim 1, further comprising a barrier layer between the light transmissive substrate and the structural layer.   The organic EL element according to claim 1, further comprising a light extraction lens layer on a surface opposite to the surface on which the structural layer of the light transmissive substrate is provided.   The illuminating device containing the organic EL element of any one of Claim 1 to 7.   The planar light source containing the organic EL element of any one of Claim 1 to 7.   The display apparatus containing the organic EL element of any one of Claim 1 to 7.

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