JP2013258045A - Organic el light-emitting body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic EL light-emitting body which can enhance the value when used in the interior lighting, or the like, while ensuring high design properties.SOLUTION: The organic EL light-emitting body includes, at least on one side of a translucent substrate, a lamination of a transparent conductive layer, an organic light-emitting layer, and a metal conductive layer, and has wiring to be connected with the transparent conductive layer on the periphery of the lamination, and further includes, on the other side of the translucent substrate, a concealing diffusion layer of thickness Dv to which diffusion particles for concealing the wiring are added. The reflectance Rm between the wiring and the translucent substrate satisfies a relation 0.9<Tp/(1-Rp×Rm), where Tp is the total light transmittance, and Rp is the total light reflectance. The mean free path Lp of the light incident to the concealing diffusion layer determined by Lp=1/(ρ×Sp/Vp)) satisfies a relation 10Lp<Dv<30Lp, where Sp is the scattering cross-section of diffusion particles in the concealing diffusion layer, Vp is grain volume and ρ is volume density.

Description

  The present invention relates to an organic EL light-emitting body used for, for example, an illumination light source, a guide light, electrical decoration, a display, a liquid crystal backlight, and the like, and more particularly to improvement in design by disposing a layer that conceals wiring and the like.

  An organic EL (electroluminescence) illuminant is thin and can be formed into a free shape such as a disk shape or an oval shape, and thus has been expected to be used as interior lighting with high designability.

  However, the organic EL light emitter is generally formed by forming a transparent electrode on a glass substrate, and further laminating a hole transport layer, a light emitting layer, and a back metal electrode, and ITO is particularly used as a transparent electrode. Although it is often held, its conductivity is not sufficiently high, and a metal electrode is disposed around the ITO to compensate for its low conductivity.

  FIG. 10 shows an example of a conventional organic EL light emitter. In this organic EL light-emitting body 10, a transparent anode (transparent conductive layer) 122 is formed on one surface of a translucent substrate 102, and a hole transport layer 126, a light emitting layer 128, a cathode (metal) are further formed thereon. A conductive layer is sequentially stacked, and an anode wiring 112 connected to the anode 122 and a cathode wiring 114 connected to the cathode 124 are provided around the stacked portion.

  In such a configuration, the light 12 emitted from the light emitting layer 128 passes through the translucent substrate 102 and is diffused to the outside. In FIG. 10, E1 indicates a non-light emitting portion, and E2 indicates a light emitting portion.

  However, as described above, the conventional organic EL light emitter compensates for the low conductivity by arranging a metal electrode for increasing the conduction of a transparent conductive layer such as ITO as the anode 122. Yes.

  For this reason, the conventional organic EL light emitter has a poor design because the wiring pattern and the like are arranged around the light emitting portion E2. In addition, a non-light-emitting portion E1 is formed around the light-emitting portion E2, and even when a plurality of organic EL light-emitting bodies are arranged side by side, a gap that does not emit light is formed between adjacent light-emitting bodies. It has become.

  In addition, an organic EL light emitting device including a transparent electrode on the front surface side of the organic light emitting layer and a metal electrode on the back surface side of the organic light emitting layer is formed. Is formed on the back surface side of the transparent substrate and a light diffusing plate is provided on the front surface side of the transparent substrate, so that the organic EL light emitter does not emit light (when not emitting light), A part of the light irradiated from the outside is diffusely reflected on or inside the diffusion plate, the remaining light is transmitted through the diffusion plate, and the light transmitted through the diffusion plate is reflected by the metal electrode and diffuses again. It is known that the mirror surface of the metal electrode is not visually recognized from the outside as a result of being incident and diffused on the plate (see, for example, Patent Document 1).

International Publication No. 96/34514 Pamphlet

  The problem to be solved by the present invention is to dispose a concealable diffusion layer that conceals a wiring pattern or the like on the forefront of the organic EL light emitter, thereby concealing the wiring disposed around the light emitting portion, etc. It is to provide an organic EL light-emitting body capable of obtaining high design properties and improving the value when used for interior lighting or the like.

  The organic EL light emitter of the present invention has a laminated portion in which at least a transparent conductive layer, an organic light emitting layer, and a metal conductive layer are laminated on one surface of a translucent substrate, and the transparent conductive layer is formed around the laminated portion. And having a concealing diffusion layer having a thickness Dv formed by adding diffusion particles for concealing the wiring to the other surface of the translucent substrate, When the total light transmittance of the concealable diffusion layer is Tp and the total light reflectance is Rp, 0.9 <Tp / (1−Rp · Rm), and the concealable diffusion layer determined by Lp = 1 / (ρ · Sp / Vp)) from the scattering cross section Sp of the diffusing particles of the concealable diffusion layer, the particle volume Vp, and the volume density ρ. Characterized in that the mean free path Lp of the light incident on the surface satisfies 10 · Lp <Dv <30 · Lp To do.

  According to the organic EL light emitter of the present invention, a concealing diffusion layer that conceals a wiring pattern or the like is disposed on the forefront of the organic EL light emitter, thereby concealing the wiring disposed around the light emitting portion and the like. Therefore, it is possible to provide an organic EL light-emitting body that can obtain high designability and can improve the value when used in interior lighting or the like.

Sectional drawing which shows typically the structure of the organic electroluminescent light emitting body concerning embodiment of this invention. Sectional drawing which shows typically the other structure of the organic electroluminescent light emitting body which concerns on embodiment of this invention. Sectional drawing which shows typically the other structure of the organic electroluminescent light-emitting body which concerns on embodiment of this invention. Explanatory drawing which shows typically the example which tiled the organic electroluminescent light-emitting body which concerns on embodiment of this invention. Explanatory drawing which shows typically the other example which tiled the organic electroluminescent light-emitting body which concerns on embodiment of this invention. Explanatory drawing which shows typically an example of the utilization form of the organic electroluminescent light emitting body which concerns on embodiment of this invention. Sectional drawing which shows typically the example of the organic electroluminescent light emitting body which has a metal plate in the back side which concerns on embodiment of this invention. Explanatory drawing which shows typically the other example of the organic electroluminescent light-emitting body which has a metal plate in the back side which concerns on embodiment of this invention. Explanatory drawing which shows typically an example of the utilization form of the organic electroluminescent light-emitting body which has a metal plate in the back side which concerns on embodiment of this invention. Sectional drawing which shows the structure of the conventional organic electroluminescent light-emitting body typically.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 schematically shows a configuration of an organic EL light emitter according to an embodiment of the present invention. Note that the same parts as those of the conventional organic EL light emitting body shown in FIG. 10 are denoted by the same reference numerals and description thereof is omitted, and different parts will be described.

  In FIG. 1, the organic EL light emitter 10 according to the present embodiment has a thickness Dv concealment formed by adding diffusion particles for concealing the anode wiring 112 and the like on the other surface side of the translucent substrate 102. A diffusion layer 92 is provided. The concealing diffusion layer 92 is formed on the resin base 96, and the surface of the resin base 96 opposite to the concealing diffusion layer 92 is disposed on the translucent group via the translucent diffusion adhesive layer 94. It is bonded on the other surface of the material 102.

  In the organic EL light emitter 10 configured as described above, the light 12 emitted from the light emitting layer 128 is diffused by the concealable diffusion layer 92 containing the diffusing particles to become the diffused light 14.

  Conventionally, as described above, a metal electrode is disposed to increase the conduction of a transparent electrode such as ITO serving as an anode, thereby compensating for the low conductivity. For this reason, a non-light emitting portion is formed around the panel. On the other hand, not all of the light emitted from the light emitting layer 128 goes outside, but the light that is totally reflected at the outermost surface is guided through the glass substrate. In addition, in order to reduce the light that emits the guided light to the outside, a diffusive film can be disposed on the outermost surface of the panel. Also in this case, not all light comes out, but there is light that is reflected and guided.

  Even if an organic EL diffusion hiding layer is arranged, the light that is reflected from the panel out of the light emitted from the panel and directly incident on the diffusion hiding layer is larger than the light that goes out to the outside. End up. The light reflected from the outermost surface to the inside is reflected again by the reflection surface of the panel, and part of the light is again emitted to the outside. Therefore, the utilization factor of light can be increased by increasing the reflectance as much as possible.

  At this time, if the transmittance of the film is high, it is possible to blur the edge by providing sufficient diffusibility. However, if the edges are blurred, the transmittance of the diffusion film generally decreases, and the light extraction efficiency decreases.

  Therefore, the present invention has a reflective layer around the light emitting portion. If the ratio between the width of the extended portion and the thickness of the glass is narrow, the gap can be sufficiently filled. However, since the outer edge portion also exhibits the effect of extracting light, it needs a certain extent. This width has an effect that light oozes out because light is diffused in the diffusion layer. This width is preferably about 1 to 2 times the thickness of the glass. If it is narrower than this width, the light that oozes out from the edge will not be sufficiently reused and will enter the panel again, so that sufficient efficiency cannot be obtained. If the width is larger than twice, sufficient light cannot be extracted at the edge portion, and the edge portion is dark and visually recognized as a seam.

  Therefore, since the emitted light 12 from the light emitting part E2 is emitted from the non-light emitting part E1 by the diffused light 14, the non-light emitting part E1 is concealed from the user side.

  For this reason, conventionally, the organic EL light emitting element has a poor design because the wiring pattern or the like is disposed around the light emitting portion E2, and the like, but according to the present invention, such a portion is hidden. High designability can be obtained.

  Such a concealable diffusion layer 92 can be formed on the resin substrate 96 by adding particles made of a transparent layer and silicone or the like by coextrusion to form a cloudy resin into a sheet shape. . At this time, the transparent layer can be prepared by using an acrylic resin or a polycarbonate resin and kneading a silicone resin or the like with the same kind of resin.

  In addition, as another method for producing such a concealing sheet, silicone particles are similarly kneaded with an ultraviolet curable acrylate resin or the like and coated on a base material made of polyethylene terephthalate or the like. be able to.

  At this time, if the concealing diffusion layer 92 is too thick, the transmittance is lowered. Therefore, a thickness thinner than 90 μm is preferable. The total light transmittance at this time is preferably 60% or more.

  However, the non-light-emitting portion E1 outside the light-emitting portion E2 has the anode wiring 112, which becomes a mirror-like reflection surface S1 on the translucent substrate 102 side, and reflects the light 16 reflected by the concealable diffusion layer 92. The light is reflected again, and light is incident again on the concealable diffusion layer 92. The light emitted to the outside in the non-light emitting portion E1 including the re-incident portion is given by the following expression when the light amount of the original light emitting portion E2 is “1”.

DL = Tp / (1- (1-Tp) · Rm)
Here, Tp is the transmittance of the concealable diffusion layer 92, and Rm is the reflectance of the reflecting surface S1. Tables 1, 2 and 3 below show the results of experiments conducted on various panels based on this formula. In Table 1, Table 2, and Table 3, “hiding layer” is an abbreviation for hiding diffusion layer 92.

  As can be seen from the evaluations in Tables 1, 2 and 3, when DL given by the above formula is higher than 0.9, the non-light emitting portion E1 can obtain the same luminance as the light emitting portion E2, and the wiring Loss of light at the part can be suppressed. If it is 0.9 or less, light loss occurs, and sufficient efficiency cannot be obtained.

  Further, by making the mean free path Lp of the diffusion particles added to the concealable diffusion layer 92 sufficiently short with respect to the layer thickness, the boundary line between the non-light emitting portion E1 and the light emitting portion E2 can also be concealed. . Therefore, when the mean free path Lp is smaller than 10 times the thickness Dv of the concealable diffusion layer 92, the diffusibility of the concealable diffusion layer 92 is not sufficient, so that the boundary line can be seen. On the other hand, if it is larger than 30 times, sufficient concealment can be obtained, but the reflection due to backscattering becomes high and the efficiency is lowered.

  The concealable diffusion layer 92 is made of a resin such as an acrylic resin, a polystyrene resin, an epoxy resin, or a copolymer thereof, such as silicone particles, acrylic / polystyrene particles, melamine particles, or aluminum oxide, titanium oxide, etc. of these hollow particles. It can be formed by dispersing metal oxide particles or the like, whereby a refractive index difference of 0.05 to 0.6 can be obtained, so that light can be sufficiently diffused.

  These particle diameters are preferably 0.1 to 8 μm, more preferably 0.5 to 4 μm.

  As the resin substrate 96, polycarbonate resin, acrylic resin, polyethylene naphthalate resin, polyolefin resin, or the like can be used. A resin substrate 96 having a thickness of 75 μm or more can be used. If it is less than 75 micrometers, the resin base material 96 will be damaged also in a normal use environment. In addition, if the thickness of the resin base material 96 exceeds 1000 μm, it is not preferable because the bonding becomes difficult.

  In addition, if the light-transmitting substrate 102 has a glossy shape that does not scatter light, it is desirable that the light is further guided to the end.

  In addition, as shown in FIG. 2, a reflective layer (such as a film that reflects light) 111 made of metal oxide and / or metal may be attached between the translucent substrate 102 and the anode wiring 112.

  Further, as shown in FIG. 3, an insulating layer 116 may be formed on the portion of the anode wiring 112 on the translucent substrate 102 so as to surround the anode wiring 112. The insulating layer 116 is, for example, partially coated with a transparent resin, and preferably has a high heat resistance such as polyimide.

  The transmittance of the insulating layer 116 is preferably 5% or more and 30% or less at a wavelength of 550 nm. If the absorption is higher than 30%, light loss occurs. In addition, a thing with less heat absorption than 5% cannot obtain a thing with high heat resistance.

  In addition, it is more desirable that the light reaches the end of the organic EL light emitter because the joint is not noticeable when the organic EL light emitters are arranged. Moreover, a pseudo curved surface can be created by connecting the organic EL light emitters as described above.

  FIG. 4 shows a specific example of tiling the organic EL light emitter 10 configured as described above. FIG. 4A is a plan view seen from the back side (cathode 124 side) of the organic EL light emitter 10. FIG. 4B is a plan view seen from the surface side (the concealable diffusion layer 92 side) of the organic EL light-emitting body 10. In this example, for example, three rectangular organic EL light emitters 10 are tiled.

  FIG. 5 shows another specific example in which the organic EL light emitter 10 configured as described above is tiled. FIG. 5A is a plan view seen from the back side (cathode 124 side) of the organic EL light emitter 10. The figure shows a plan view as seen from the surface side (the concealable diffusion layer 92 side) of the organic EL light-emitting body 10. In this example, for example, three elongate rectangular organic EL light emitters 10 are tiled.

  FIG. 6 shows an example of how the organic EL light emitter 10 shown in FIG. 5 is used. This example shows a case where it is used as a guide light by being installed on the stairs 51.

FIG. 7 shows another embodiment of the organic EL light emitter 10. In this example, a plurality of (in this example, two) organic EL light emitters are bonded to the back side of the organic EL light emitter 10 by pasting a metal plate 106 press-molded in advance through a sealing layer / adhesive layer 104. It is set as the illuminating body in which 10 continues.
In the example of FIG. 7, the concealable diffusion layer 92, the resin base material 96, and the translucent diffusion adhesive layer 94 are provided in common for the two organic EL light emitters 10.

  Such an illuminator can be formed into a pseudo-arbitrary shape by laying a plurality of organic EL light emitters 10 like tiles, and a planar organic EL light emitter is attached to a curved metal plate. By combining them, it is possible to obtain a lighting device that is pseudo but curved. Also in this case, the anode wiring 112 and the non-light-emitting portion E1 can be concealed by the concealable diffusion layer 92, so that a pseudo light-emitting layer can be obtained. it can.

  Since the metal plate 106 has a feature that it can be freely processed, it is possible to obtain an illuminating device having a free pseudo-curved surface by integrating the organic EL light emitters along the shape thereof. As a material of the metal plate 106, a commonly used aluminum plate, aluminum alloy plate, brass plate, or stainless steel plate can be used. In particular, it is preferable to use an aluminum alloy plate from the viewpoint of weight. The thickness of the concealable diffusion layer 92 is preferably 0.5 to 1.5 mm. If it is thinner than 0.5 mmt, it will be easily damaged even in a normal use environment, and if it is thicker than 1.5 mmt, the workability will deteriorate.

  At this time, since it is assumed that the surface of the metal plate 106 is touched with bare hands, the surface temperature is preferably 43 degrees or less because there is a possibility of low temperature burns when the surface temperature is 44 degrees or more.

  For this reason, you may install the layer which suppresses heat conductivity in the exterior of the metal plate 106 to such an extent that heat dissipation is not impaired. Such a material may be a methacrylic resin, and only a lot of heat rays may escape.

  Moreover, since the concealable diffusion layer 92 is thick, it may be cracked when bent. The thick concealable diffusion layer 92 was formed. For example, an acrylic resin styrene filler was added to the concealable diffusion layer 92. The concealable diffusion layer 92 needs to have a thickness of 60 μm or more, and the amount of filler added is also 20%. However, such a sheet will crack when bent. Therefore, the thickness is set to about 40 μm, and the amount of added particles is set to about 40%. At that time, no cracking occurred, but the adhesiveness between the concealing diffusion layer 92 and the translucent substrate 102 was lowered under high temperature and high humidity, and the concealing diffusion layer 92 became transparent. The phenomenon of floating from.

  Therefore, the use of rubber-like particles as diffusion particles was examined. It has been found that such cracking can be prevented by adding rubber particles used in general flooring. However, the transmittance is low and the luminance is greatly reduced.

  For this reason, an experiment was conducted using silicone rubber. At this time, a silicone rubber having a size of about 10 μm was used. Thereby, the thing of the transmittance | permeability about 82% was obtained, and the fall of the brightness was hardly seen. However, some black spots are visible. Therefore, an experiment was performed using a silicone rubber having a particle diameter of 3 μm. As a result, the sunspots were sufficiently hidden.

  Further, in the case of 10 μm, there were some portions where the adhesion was low, but when the particle size was 3 μm, sufficient adhesion was obtained. In addition, with respect to the amount of particles added, 10 parts by weight does not provide sufficient flexibility.

  In addition, in order to disperse the particles in the binder and obtain a sufficient hiding property, it is desirable that the mean free path calculated from the scattering cross-sectional area of the particles and the addition amount thereof is 1/10 or less of the film thickness. . The addition amount of silicone rubber particles is preferably 10 to 45 parts by weight.

  FIG. 8 shows another specific example in which the organic EL light emitter 10 having the metal plate 106 on the back side is tiled. FIG. 8A is a plan view seen from the back side (cathode 124 side) of the organic EL light emitter 10. The figure shows a plan view as seen from the surface side (the concealable diffusion layer 92 side) of the organic EL light-emitting body 10. In this example, for example, three elongate rectangular organic EL light emitters 10 are tiled.

  In the example of FIG. 8, the concealable diffusion layer 92, the resin base material 96, and the translucent diffusion adhesive layer 94 are provided in common for the three organic EL light emitters 10.

  FIG. 9 shows an example of a usage form of the organic EL light emitter 10 having the metal plate 106 on the back side shown in FIG. This example shows a case where it is used as a guide light by being installed on the staircase 52.

  DESCRIPTION OF SYMBOLS 10 ... Organic EL light-emitting body, 91 ... Diffusing particle, 92 ... Concealment diffusion layer, 94 ... Adhesive layer, 96 ... Resin base material, 102 ... Translucent base material, 104 ... Sealing layer / adhesion layer, 106 ... Metal Plate ... 122 ... Anode, 124 ... Cathode, 126 ... Hole transport layer, 128 ... Light emitting layer, 111 ... Reflective layer, 112 ... Anode wiring, 114 ... Cathode wiring, 116 ... Insulating layer, E1 ... Non-light emitting part, E2 ... Light emitting part.

Claims (4)

While having a laminated portion in which at least a transparent conductive layer, an organic light emitting layer, and a metal conductive layer are laminated on one surface of the translucent substrate, and having a wiring connected to the transparent conductive layer around the laminated portion, And it has a concealing diffusion layer having a thickness Dv formed by adding diffusion particles for concealing the wiring on the other surface of the translucent substrate,
When the reflectance Rm between the wiring and the translucent substrate is Tp, the total light transmittance of the concealing diffusion layer is Rp,
0.9 <Tp / (1-Rp · Rm)
And the scattering cross section Sp of the diffusing particles of the concealable diffusion layer, the particle volume Vp, and the volume density ρ Lp = 1 / (ρ · Sp / Vp))
The mean free path Lp of the light incident on the concealable diffusion layer calculated in
10 ・ Lp <Dv <30 ・ Lp
An organic EL light emitter characterized by satisfying the above.   The organic EL light-emitting body according to claim 1, wherein the concealable diffusion layer is disposed on the other surface of the translucent substrate via a translucent diffusion adhesive layer.   The concealable diffusion layer is formed on a resin substrate, and the surface of the resin substrate opposite to the concealable diffusion layer is bonded to the light transmissive substrate via an adhesive layer. The organic EL light-emitting body according to claim 1 or 2.   4. The organic EL light-emitting body according to claim 2, wherein a reflective layer made of metal oxide and / or metal is disposed between the wiring and the translucent substrate.

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