JP2018098134A - Light transmission type organic electroluminescent panel and organic electroluminescence light-source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a light transmission type organic electroluminescent panel superior in light permeability; and an organic electroluminescence light-source device arranged by lamination of the panels.SOLUTION: Disclosed are a light transmission type organic electroluminescent panel, and an organic electroluminescence light-source device arranged by laminating two or more such light transmission type organic electroluminescent panels. The light transmission type organic electroluminescent panel comprises an optically transparent substrate, a positive electrode, a luminescent layer, a negative electrode and a sealant. As to the light transmission type organic electroluminescent panel, the light emission spectrum has at least one peak in a visible light region of 400-800 nm in wavelength; the average light transmittance during non-emission is 60% or more in a wavelength range of the half value width of the peak; and if the number of peaks of the at least one peak is more than one, the difference in average light transmittance during non-emission in a wavelength range of the half value width of any two peaks selected among them is within 25%.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a light transmissive organic electroluminescence panel and an organic electroluminescence light source device formed by stacking the panels.

  Organic electroluminescence panels (hereinafter referred to as “organic EL panels”) are thin films, self-luminous, and can be made flexible, so they can be used in a variety of applications such as lighting panels and display display backlights. Various product developments are underway. The organic EL panel is usually composed of a laminate in which an anode, a light emitting layer, a cathode, and a sealing material are sequentially laminated on a substrate.

  In recent years, development of a light transmissive organic EL panel has been promoted by making a substrate, an anode, a light emitting layer, a cathode, and a sealing material light transmissive. An organic EL light source device in which a plurality of light-transmitting organic EL panels are stacked not only increases the amount of light emission, but also realizes a three-dimensional light emission expression with depth, enabling a unique light emission design that has never existed before. I understand. Therefore, in the light transmissive organic EL panel, it is the most important characteristic that the panel itself is excellent in light transmittance, and it is required to increase the transmittance of visible light as much as possible.

  However, since the transparent electrode or the like is slightly inferior in light transmittance, the light transmittance of the light transmissive organic EL panel is still insufficient. In particular, when the light transmissive organic EL panels are stacked and used as described above, the light transmittance is significantly reduced, and thus the number of stacked layers is limited.

  Patent Document 1 discloses an organic EL light source device in which a plurality of organic EL light sources in which organic EL elements are formed on a light-transmitting substrate are stacked.

JP 2006-155940 A

  In the organic EL light source device disclosed in Patent Document 1, for example, blue, green, and red organic EL light sources are stacked. For this reason, light of various wavelengths is absorbed by each light source layer, and it is estimated that the amount of emitted light is greatly reduced.

  The present invention has been made in view of such a situation. The subject of this invention is providing the organic electroluminescent light source device formed by laminating | stacking the light transmissive organic electroluminescent panel excellent in the light transmittance, and the said panel.

  In order to solve the above problems, the inventors do not improve the transmittance in the entire visible light region having a wavelength of 400 to 800 nm, but depending on the spectrum of light emitted by the organic EL panel, the specific wavelength of the spectrum. We studied to make it possible to efficiently transmit only the light. As a result, the light transmittance of the organic EL panel was substantially improved by adjusting the configuration of the organic EL panel. The present invention has been created as a result of such studies. The present invention has the following configuration.

  (1) A light transmissive organic EL panel including a light transmissive substrate, an anode, a light emitting layer, a cathode, and a sealing material, and the emission spectrum has at least one peak in a visible light region having a wavelength of 400 to 800 nm. And, in the wavelength range of the half width of the peak, the average light transmittance at the time of non-light emission is 60% or more, and when there are a plurality of the peaks, the wavelength of the half width of any two peaks selected from them A light transmissive organic EL panel, wherein a difference in average light transmittance when no light is emitted in a range is within 25%.

  (2) The light transmissive organic EL panel as described in (1) above, which has an optical adjustment layer for adjusting the optical path length.

  (3) The light-transmitting organic EL panel according to (2), wherein the optical adjustment layer is formed of a low refractive index material containing fluorine.

  (4) The light transmissive organic EL panel according to any one of (1) to (3), wherein an antireflection layer is provided on the surface of the light emitting surface.

  (5) An organic EL light source device obtained by laminating two or more light transmissive organic EL panels according to any one of (1) to (4).

  (6) The organic EL light source device according to (5), wherein a specular reflection type organic EL panel is laminated on a surface opposite to the light emitting surface.

  The light transmissive organic EL panel of the present invention is excellent in light transmittance. And the organic electroluminescent light source device formed by laminating | stacking the said panel can be utilized as a light source device with a large light quantity.

(A) It is typical sectional drawing of the organic electroluminescent panel of this embodiment. (B) It is typical sectional drawing of the modification of the organic electroluminescent panel of this embodiment. (A) It is typical sectional drawing of the organic electroluminescent panel of this embodiment. (B) It is typical sectional drawing of the modification of the organic electroluminescent panel of this embodiment. (C) It is typical sectional drawing of the modification of the organic electroluminescent panel of this embodiment. (D) It is typical sectional drawing of the modification of the organic electroluminescent panel of this embodiment. (A) It is typical sectional drawing of the organic electroluminescent light source device which laminated | stacked two organic electroluminescent panels of this embodiment. (B) It is a typical sectional view of an organic EL light source device which laminated three organic EL panels of this embodiment. (C) It is a typical sectional view of an organic EL light source device which laminated four organic EL panels of this embodiment. It is a chart of the emission spectrum and transmission spectrum of an organic EL panel having two peaks whose emission spectra are separated. It is a chart of the emission spectrum of the organic EL panel having two peaks in which the emission spectrum is close. (A) It is a light emission color coordinate of the organic EL panel of a structure difference which has two peaks from which the emission spectrum separated. (B-1)-(b-7) It is an emission spectrum of the organic EL panel of a different structure which has two peaks from which the emission spectrum separated. (A) It is the light emission color coordinate of the organic EL panel of a different structure which has two peaks in which the emission spectrum is close. (B-1) to (b-7) are emission spectra of organic EL panels having different structures having two peaks close to each other.

  Hereinafter, embodiments of the present invention will be described. However, the present invention is not limited to the embodiments described below, and the embodiments can be arbitrarily changed and implemented without departing from the gist of the present invention. it can.

<Light transmissive organic EL panel>
The light transmissive organic EL panel can be used as a light transmissive organic EL panel by making each component such as a substrate, an anode, a light emitting layer, a cathode, and a sealing material light transmissive. In addition, light generated in the light emitting layer can be extracted from either the front side or the back side.

  An organic EL light source device in which a plurality of organic EL panels having the same emission spectrum are stacked is useful as a light-transmissive organic EL panel because it can increase the amount of emitted light. Furthermore, in an organic EL light source device in which a plurality of organic EL panels having the same emission spectrum are stacked, the spectrum of light emitted from each panel changes subtly as it passes through the other panels, and thereby the depth. It has been found that a three-dimensional light emission expression can be realized. By utilizing such a phenomenon, it is expected that an unprecedented unique light emitting design can be realized, which leads to a new usage of the organic EL panel. Here, the emission spectrum is a spectrum of light emitted from the organic EL panel.

  However, since the emission spectrum emitted from the organic EL panel is generally different from the spectrum absorbed by the organic EL panel, when a plurality of organic EL panels are stacked, the light emitted from one organic EL panel is different from the other. Absorbed by the panel. Therefore, the light emission amount of the organic EL light source device in which a plurality of organic EL panels are stacked does not increase as expected. Even if only the light transmittance is examined, for example, even if the average light transmittance of one organic EL panel is 80%, when the three organic EL panels are stacked, the average light transmittance is about 51%. It will decline.

  In order to increase the light transmittance of the organic EL panel, it is most preferable that the organic EL panel does not have an absorption peak in a visible light region having a wavelength of 400 to 800 nm. However, there are many difficulties in making the entire organic EL panel composed of various materials transparent over the entire visible light region. Therefore, the present inventors have examined increasing transparency with respect to the emission spectrum on the premise that an organic EL light source device is configured by stacking a plurality of organic EL panels having the same specific emission spectrum. did. Here, the transparency is the transparency when the organic EL panel is not emitting light.

  As a basic method, it is necessary to select the material and manufacturing method of each constituent element that constitutes the organic EL panel, and to increase the transparency of each constituent element with respect to visible light. Furthermore, in order to improve the transparency with respect to the emission spectrum, it was studied to increase the transparency at the peak wavelength in the emission spectrum.

  In order to increase the light transmittance with respect to the peak of a specific wavelength in the emission spectrum, it is necessary to optimize the material and thickness of each layer constituting the organic EL panel. By the way, when the organic EL panel emits light, the light is reflected at the interface between the organic EL panel and the outside world, returned to the inside, and then emitted. There is a phenomenon. In order to cope with this phenomenon, attention was paid to the optical path length in the thickness direction of the organic EL panel. If the phase of the light is reversed between the light emitted after passing through the panel only once and the light emitted after passing through the panel multiple times, the amount of light emitted by the interference is reduced. It will attenuate greatly. In order to prevent such attenuation due to interference, the thickness of the organic EL panel is appropriately adjusted in accordance with the specific wavelength of the peak.

  In order to adjust the thickness of the organic EL panel corresponding to the specific wavelength of the peak, the thickness of each layer may be adjusted as appropriate. For example, it can be adjusted by changing the thickness of the sealing layer. However, in order to further adjust the thickness in the organic EL panel, it is preferable to provide an optical adjustment layer as one of the layers constituting the organic EL panel. The optical adjustment layer is used to set the thickness of the organic EL panel so that the light interference is minimized. When the emission spectrum has a plurality of peaks, the thickness of the organic EL panel is adjusted so that light interference is minimized. A description of the optical adjustment layer will be given later.

  The emission spectrum of the organic EL panel usually has at least one peak in the visible light region having a wavelength of 400 to 800 nm. When the number of peaks is one, it is necessary to increase the transmittance at the wavelength of the peak. At this time, in order to prevent the hue of the emission spectrum from changing when the panels are stacked, the average light transmittance of the organic EL panel at the time of non-emission (hereinafter, “ It may be described only as “average light transmittance”.) Is required to be 60% or more. If the average light transmittance is 60% or more in the wavelength range of the half width of the peak, light having a wavelength in the vicinity of the peak that determines the hue can be sufficiently transmitted, so that a change in hue can be reduced. It is more preferable that the average light transmittance when not emitting light in the wavelength range of the half width of the peak is 70% or more.

  Here, the average light transmittance can be measured as an average light transmittance in a specific wavelength range based on JIS K-7361-1: 1997.

  On the other hand, when the emission spectrum has two peaks in the visible light region having a wavelength of 400 to 800 nm, in the same manner as described above, in the wavelength range of the half width of the peak, the peak is not emitted. The average light transmittance of the organic EL panel needs to be 60% or more, and more preferably 70% or more.

  Furthermore, if the transmittance values at the two peak positions are significantly different, the spectrum of the light after transmission changes, the relative size of the two peaks changes, and the hue changes. It will be. Therefore, when the emission spectrum has two peaks, it is necessary that the difference in average light transmittance during non-emission in the wavelength range of the half width of the two peaks is within 25%. The difference in average light transmittance when no light is emitted in the wavelength range of the half width of the two peaks is more preferably within 10%.

  The same can be considered when the emission spectrum has three or more peaks in the visible light region having a wavelength of 400 to 800 nm. That is, for each peak, in the wavelength range of the half width of the peak, the average light transmittance of the organic EL panel when not emitting light is required to be 60% or more, and more preferably 70% or more. In addition, the difference in average light transmittance at the time of non-light emission in the wavelength range of the half width of any two peaks selected from a plurality of peaks needs to be within 25%, and is within 10%. It is more preferable.

  If it is an organic EL panel having such light transmission performance, even if an organic EL light source device is formed by laminating two or more organic EL panels, the hue of light emission does not change greatly, and the organic EL panel does not change. The light source device can be used effectively by increasing the amount of light.

  As a method of controlling the average light transmittance in the specific wavelength range as described above, there is a method of appropriately adjusting the thickness of the organic EL panel as described above. The optical adjustment layer is used to adjust the thickness of the organic EL panel to a predetermined thickness. The method of properly adjusting the thickness of the organic EL panel is to calculate the optical path length based on the theory of wave optics based on the refractive index (n value) and extinction coefficient (k value) in each layer. This is a method for determining the thickness of the layer. For calculating the thickness of the organic EL panel, set the emission intensity, emission color, and film thickness range that can be formed for each layer, and use a genetic algorithm based on wave optics to maximize the arbitrary average transmittance. This is done by performing optimization calculation. Specific calculation methods are described in, for example, Japanese Patent Application Laid-Open No. 2014-86345 and International Publication No. WO2013 / 187118. The material of each layer constituting the organic EL panel will be described later.

  In the present embodiment, it is necessary to adjust the thickness and material of the organic EL panel corresponding to the peak of the specific wavelength in the emission spectrum, and therefore it is preferable that the number of peaks in the emission spectrum is smaller. One or two is preferred.

  FIG. 4 is a chart of an emission spectrum and a transmission spectrum of an organic EL panel having an emission spectrum having two peaks. The full width at half maximum was obtained for each of the two peaks (peak 1 and peak 2) of the emission spectrum and shown in the figure as two wavelength ranges. In the wavelength range of the half width of peak 1, the average light transmittance of the organic EL panel needs to be 60% or more. Further, in the wavelength range of the half width at peak 2, the average light transmittance of the organic EL panel needs to be 60% or more. For this reason, the organic EL panel preferably has a transmission spectrum in which the light transmittance is particularly high in the wavelength range of the half width of peak 1 and peak 2. Further, the difference in average light transmittance in the wavelength range of the half width of the two peaks needs to be within 25%.

  FIG. 5 is a chart of an emission spectrum of an organic EL panel having an emission spectrum having two peaks, as in FIG. In the emission spectrum of FIG. 5, since the two peaks are relatively close to each other, when the wavelength range of the half width of the two peaks was obtained, they overlap each other, and the half widths of the two peaks are combined. There is only one wavelength range. In this case as well, the average light transmittance of the organic EL panel needs to be 60% or more in the wavelength range of the half width of the two peaks. Also in this case, the difference in average light transmittance in the wavelength range of the half width of the two peaks needs to be within 25%.

<Configuration of organic EL panel>
The organic EL panel of this embodiment includes a substrate and an anode, a light emitting layer, a cathode, and a sealing material formed on the substrate. The organic EL element can be configured to emit light by the three basic structural units of the anode, the light emitting layer, and the cathode. FIG. 1 is a cross-sectional view for explaining the mutual positional relationship between a substrate, an anode, a light emitting layer, a cathode and a sealing material, which are basic structural units constituting an organic EL panel.

  FIG. 1A is a schematic cross-sectional view of the organic EL panel 10. The organic EL panel 10 includes an optical adjustment layer 16, a first electrode (anode) 13, a light emitting layer 14, a second electrode (cathode) 15, an optical adjustment layer 16, and a nitrogen layer in order on a glass plate 12 that is a substrate. (Void) 18 and glass plate 12 are formed.

  FIG. 1B is a schematic cross-sectional view of a modified example of the organic EL panel. The organic EL panel 11 includes an optical adjustment layer 16, a first electrode (anode) 13, a light emitting layer 14, a second electrode (cathode) 15, an optical adjustment layer 16, and a barrier on a barrier substrate 19 that is a substrate. A layer 17, an adhesive layer 20, and a barrier substrate 19 are formed.

  Since the organic EL element formed on the substrate is easily affected by the external environment, it is sealed in order to block it from the outside. Specifically, a material having excellent barrier properties is used for the substrate, and the upper surface and the peripheral portion of the organic EL element formed on the substrate are sealed with a sealing material. In addition, on the substrate, in order to send an electric signal to the anode and the cathode of the organic EL element, a take-out electrode drawn out from the sealing material is provided.

  FIG. 2 is a cross-sectional view for explaining the configuration of an organic EL panel including a sealing material and the like around the periphery of the organic EL element. FIG. 2A is a schematic cross-sectional view of the organic EL panel 30. The organic EL panel 30 includes, on a flexible substrate 34 having a barrier layer 35, in order, a first electrode (anode) 36, a light emitting layer 37, a second electrode (cathode) 38, a sealing layer 39, and a transparent hygroscopic agent layer 40. A sealing substrate 42 having a sealing layer 41 and a barrier layer 35 is formed. The sealing layer 39 seals the peripheral portion of the organic EL element including the first electrode 36, the light emitting layer 37, and the second electrode 38. The sealing layer 41 further seals the peripheral portion of the sealing layer 39.

  FIG. 2B is a schematic cross-sectional view of a modified example of the organic EL panel. The organic EL panel 31 includes a first electrode (anode) 36, a light emitting layer 37, a second electrode (cathode) 38, an optical adjustment layer 43, a sealing layer 39, in order, on a flexible substrate 34 having a barrier layer 35. A sealing substrate 42 having a transparent hygroscopic agent layer 40, a sealing layer 41, and a barrier layer 35 is formed. The sealing layer 39 seals the peripheral portion of the organic EL element, and the sealing layer 41 further seals the peripheral portion of the sealing layer 39.

  FIG. 2C is a schematic cross-sectional view of a modified example of the organic EL panel. In the organic EL panel 32, the configuration of the organic EL panel 31 shown in FIG. 2B is directly installed on the substrate 45 having the barrier layer 35, and the substrate 45 having the sealing layer 44 and the barrier layer 35 is further formed. ing. The sealing layer 39 seals the peripheral portion of the organic EL element, the sealing layer 41 further seals the peripheral portion of the sealing layer 39, and the sealing layer 44 closes the peripheral portion of the sealing layer 41. Further sealing is performed.

  FIG. 2D is a schematic cross-sectional view of a modified example of the organic EL panel. The organic EL panel 33 is the same as the configuration of the organic EL panel 32 except for the position of the transparent moisture absorbent layer 40 in the configuration of the organic EL panel 32 of FIG.

  FIG. 3 is a cross-sectional view for explaining the configuration of the organic EL light source device of the present embodiment. The organic EL light source device is formed by stacking two or more organic EL panels. In FIG. 3, the detailed structure of the organic EL panel shown in FIG. 1 is shown in a simplified manner. That is, each layer such as the optical adjustment layer, the barrier layer, the adhesive layer, and the nitrogen (void) is not shown, and only the configuration in which the first electrode 54, the light emitting layer 55, and the second electrode 56 are stacked is an organic EL. The configuration including various modifications of the panel is shown.

  FIG. 3A is a schematic cross-sectional view of an organic EL light source device 51 in which two organic EL panels are stacked. On the substrate 57, a first organic EL panel, an adhesive layer 58 for joining the organic EL panels, a second organic EL panel, and the substrate 57 are laminated.

  FIG. 3B is a schematic cross-sectional view of an organic EL light source device 52 in which three organic EL panels are stacked. On the substrate 57, the first organic EL panel, the adhesive layer 58, the second organic EL panel, the adhesive layer 58, the third organic EL panel, and the substrate 57 are laminated.

  FIG. 3C is a schematic cross-sectional view of an organic EL light source device 53 in which four organic EL panels are stacked. On the substrate 57, the first organic EL panel, the adhesive layer 58, the second organic EL panel, the adhesive layer 58, the third organic EL panel, the adhesive layer 58, the fourth organic EL panel, A substrate 57 is laminated.

  Hereinafter, each structural unit which comprises said organic EL panel and organic EL light source device is demonstrated.

(substrate)
The substrate is indicated by reference numerals 12 and 19 in FIG. 1, 34 and 45 in FIG. 2, and 57 in FIG. The substrate is not particularly limited as long as it is made of a transparent material, and an inorganic glass plate, an organic resin film, or the like can be used. Examples of the glass plate include soda lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz. A preferred substrate is a resin film capable of giving flexibility to the organic EL panel. Examples of the resin of the resin film include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polyetherimide, polyetheretherketone, polyphenylene sulfide, polyarylate, polyimide, polycarbonate (PC ), Cellulose triacetate (TAC), cellulose acetate propionate (CAP), and the like. Among these, polyethylene terephthalate (PET), polyethylene naphthalate (PEN) and the like are preferable.

The substrate preferably has a barrier layer formed on at least one surface thereof. The barrier layer is indicated by 17 in FIG. 1 and 35 in FIG. Regarding the barrier performance of the barrier layer, specifically, the water vapor permeability (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) measured by a method according to JIS K 7129-1992 is 0. A barrier layer of 0.01 g / (m ² · 24 h · atm) or less is preferable. Further, the oxygen permeability measured by a method according to JIS K 7126-1987 is 1 × 10 ⁻³ ml / (m ² · 24 h · atm) or less, and the water vapor permeability (25 ± 0.5 ° C., A barrier layer having a relative humidity (90 ± 2)% RH) of 1 × 10 ⁻⁵ g / (m ² · 24 h · atm) or less is preferable.

The material for forming the barrier layer may be any material that has a function of suppressing intrusion of moisture, oxygen, or the like that degrades the organic EL element, and includes an inorganic substance, an organic substance, or a hybrid of these. As a material for forming the barrier layer, for example, inorganic materials such as SiO ₂ , Si ₃ N ₄ , Al ₂ O ₃ , TiO ₂ , SiOxCy, and SiOxNy are used. Furthermore, in order to improve the fragility of the barrier layer, the barrier layer preferably has a laminated structure. The laminated structure can be formed, for example, by alternately laminating inorganic layers and organic layers a plurality of times. As a method for forming the barrier layer, 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, coating method and the like.

Examples of the flexible substrate having a barrier layer include a high barrier base material in which a barrier layer such as SiO ₂ is formed on a polyethylene terephthalate (PET) film.

  The surface of the substrate may be subjected to a surface treatment such as imparting easy adhesion to ensure wettability and adhesion of the coating solution. Examples of the surface treatment include surface activation treatment such as corona discharge treatment, flame treatment, ultraviolet treatment, high frequency treatment, glow discharge treatment, active plasma treatment, and laser treatment. In addition, an easy-adhesive layer is formed by applying polyester, polyamide, polyurethane, vinyl copolymer, butadiene copolymer, acrylic copolymer, vinylidene copolymer, epoxy copolymer, etc. Also good.

  Although the thickness of a board | substrate is not specifically limited, 10-200 micrometers is preferable. When the thickness of the substrate is within this range, the substrate is excellent in mechanical strength and flexible. A more preferable upper limit of the thickness of the substrate is 150 μm, and a more preferable lower limit is 20 μm.

(Encapsulant)
The sealing material has a barrier property and is used to isolate and seal the organic EL element on the substrate from the outside. Some sealing materials are used as flat sealing members, and others are used as soft sealing agents having adhesiveness and curability. Since the flat sealing member is made of the same material as that of the substrate, the sealing member and the substrate can be used for any purpose without being distinguished from each other. In addition, since the soft sealant having adhesiveness and curability is composed of the same material as the adhesive, the sealant and the adhesive can be used for any purpose without being distinguished from each other. it can.

  In FIG. 1, the uppermost glass plate 12 and the barrier substrate 19 are used both as a substrate and as a sealing material. In FIG. 2, the uppermost sealing substrate 42 and substrate 45 are used as a substrate and a sealing member, and the sealing layer 39, the sealing layer 41, and the sealing layer 44 have adhesiveness and curability. It is used as a soft sealant. In FIG. 3, the uppermost substrate 57 is used as both a substrate and a sealing material.

  The sealing member constituting the sealing material is not particularly limited as long as it is made of a transparent material, and an inorganic glass plate, an organic resin film, or the like can be used. Since the explanation about the glass plate and the resin film is the same as that for the substrate, the explanation is omitted.

  In the resin film having barrier properties, a barrier layer is formed on the resin film. The material constituting the barrier layer may be a metal, an inorganic material, an organic material, or a hybrid thereof. The barrier layer may be composed of a single material, or may be a mixture or laminate composed of a plurality of materials. The barrier performance of the barrier layer is required to be equivalent to that of the barrier layer formed on the substrate. Since the specific content of the barrier performance is the same as that of the barrier layer formed on the substrate, the description thereof is omitted.

  When the barrier layer is a metal, the metal layer can be relatively easily formed on the resin film by a method such as vapor deposition or sputtering. However, when the metal layer is formed thick, the transparency is greatly reduced. Therefore, it is necessary to control the barrier property and transparency to an appropriate thickness that satisfies both. Examples of the metal used for forming the metal layer include metals such as aluminum, copper, and nickel, and alloys such as stainless steel and aluminum alloy.

  On the other hand, when the barrier layer is an inorganic material, an organic material, or a hybrid thereof, any material may be used as long as it has a function of suppressing entry of moisture, oxygen, and the like that degrade the organic EL element. Since the specific example of the inorganic substance of the barrier layer and the method of forming the barrier layer are the same as those of the barrier layer formed on the substrate, the description thereof is omitted.

  The soft sealing material having adhesiveness and curability can be used as both a sealing material and an adhesive. Examples of the material used for the soft sealing material include photo-curing or thermosetting adhesives such as acrylic resins having a reactive vinyl group such as acrylic acid oligomers and methacrylic acid oligomers, 2-cyano. Moisture curable adhesives such as acrylic esters, thermosetting or chemical curable (two-component mixed) adhesives such as epoxy resins, hot melt polyamide, polyester and polyolefin adhesives, cationic curing Examples include ultraviolet curable epoxy resin adhesives and silicone resin adhesives. The material used for the sealing material or the adhesive may be a material to which a filler is added as long as there is no significant problem with transparency. Examples of the filler include soda glass, alkali-free glass, silica, metal oxides such as titanium dioxide, antimony oxide, titania, alumina, zirconia, and tungsten oxide. The material used for the sealing material or the adhesive can be applied by a coating method such as roll coating, spin coating, screen printing, spray coating, or the like.

(Adhesive layer)
As a layer for bonding various layers, there is an adhesive layer. The adhesive layer is indicated by the symbol 20 in FIG. As a material constituting the adhesive layer, any of a thermosetting resin, a photocurable resin, and a thermoplastic resin can be used. As the thermosetting resin, for example, epoxy resin, acrylic resin, silicone resin, urea resin, melamine resin, phenol resin, resorcinol resin, unsaturated polyester resin, polyurethane resin, etc. Resin. Examples of the photocurable resin include radical curable resins such as ester acrylates, urethane acrylates, epoxy acrylates, melamine acrylates, acrylic resin acrylates, etc., or radical photocurable resins using resins such as urethane polyesters, epoxies, vinyl ethers, and the like. Examples thereof include a cationic photocurable resin using a resin. Examples of the thermoplastic resin include polyethylene, polypropylene, polyamide, polyethylene terephthalate (PET), polyvinyl alcohol (PVA), ethylene-vinyl acetate copolymer (EVA), ethylene-propylene copolymer, ethylene-acrylic acid copolymer. Polymers, ethylene-methacrylic acid copolymers, polyvinylidene chloride (PVDC), ionomers and the like can be used.

(Light emitting layer)
In the light-emitting layer, holes injected directly from the anode or from the anode through the hole transport layer and the like are recombined with electrons injected directly from the cathode or from the cathode through the electron transport layer and the like. This is a layer that emits light. The light emitting layer is indicated by 14 in FIG. 1, 37 in FIG. 2, and 55 in FIG. Note that the portion that emits light may be inside the light emitting layer, or may be an interface between the light emitting layer and a layer adjacent thereto.

  The light emitting layer is preferably formed of an organic light emitting material including a host compound (host material) and a light emitting material (light emitting dopant compound). When the light emitting layer is configured in this manner, an arbitrary emission color can be obtained by appropriately adjusting the type of the light emitting material to be contained. As the light-emitting material contained in the light-emitting layer, for example, a phosphorescent light-emitting material (phosphorescent compound or phosphorescent compound), a fluorescent light-emitting material, or the like can be used. Note that the light emitting layer may contain one type of light emitting material or a plurality of types of light emitting materials having different light emission maximum wavelengths. About a specific luminescent material, it can select from a well-known material suitably and can be used. As a method for forming the light emitting layer, a vapor deposition method is generally used.

  In addition to the light emitting layer, layers such as an electron transport layer, a hole transport layer, a hole blocking layer, an electron blocking layer, an electron injection layer (cathode buffer layer), and a hole injection layer (anode buffer layer) as necessary Can be formed as appropriate. The specific contents of each layer can be appropriately selected from known knowledge and applied. As a method for forming each of these layers, a vapor deposition method is generally used.

(anode)
The anode is an electrode that supplies (injects) holes to the light emitting layer. The anode is indicated by the symbol 13 in FIG. 1, 36 in FIG. 2, and 54 in FIG. Although the material which comprises an anode is not restrict | limited in particular, Usually, a material with a large work function (4 eV or more) is preferable. As a material used for an anode, it is possible to form with electrode materials, such as a metal, those alloys, an electroconductive compound, and these mixtures, for example. As an anode material having excellent light transmittance, metals such as silver and aluminum and alloys thereof, indium oxide / tin (ITO), indium / zinc oxide (IZO), ZnO ₂ , TiN, ZrN, HfN, TiOx, VOx , CuI, InN, GaN, CuAlO ₂ , CuGaO ₂ , SrCu ₂ O ₂ , LaB ₆ , RuO _{2 and the} like. Among these, metallic silver is preferable in terms of conductivity and transparency. However, since the transparency decreases as the silver thickness increases, it is necessary to adjust the thickness in the range of 1 to 20 nm, for example.

  As a method for forming the anode, there are a dry film forming method and a wet film forming method. Dry (vacuum) film forming methods include vapor deposition and sputtering. As a method for forming a pattern by a dry film formation method, a method such as pattern film formation using a metal mask, wet etching using a photoresist or printing, lift-off, or the like can be used. On the other hand, examples of the wet film forming method include a coating method and an ink jet method. In these methods, it is possible to form a pattern directly.

(cathode)
The cathode is an electrode that supplies (injects) electrons to the light emitting layer. The cathode is indicated by the symbol 15 in FIG. 1, 38 in FIG. 2, and 56 in FIG. The material constituting the cathode is not particularly limited, but usually a material having a small work function (4 eV or less) is preferable. The material used for the cathode can be formed of an electrode material such as a metal (electron-injecting metal), an alloy, an electrically conductive compound, and a mixture thereof. As a method for forming the cathode, a vapor deposition method is generally used. Examples of the cathode material excellent in light transmittance include the same materials as those mentioned as the anode material excellent in light transmittance. In particular, the cathode material having excellent light transmittance includes metals such as silver and aluminum, metal oxides such as indium tin oxide (ITO), alloys such as silver magnesium, silver copper, silver palladium, silver indium, and indium zinc oxide. There is. Among these, metallic silver or a silver alloy is preferable in terms of conductivity and transparency. However, since the transparency decreases as the silver thickness increases, it is necessary to adjust the thickness in the range of 1 to 20 nm, for example. Moreover, in order to further improve electroconductivity and transparency, you may dope metals, such as magnesium, to silver.

(Optical adjustment layer)
The optical adjustment layer is a layer used for adjusting the optical path length, and is denoted by reference numeral 16 in FIG. 1 and 43 in FIG. The optical adjustment layer is adjusted to a thickness that can reduce the interference of light as much as possible according to the specific wavelength of the peak of the emission spectrum. One layer of the optical adjustment layer may be provided in the organic EL panel, or a plurality of layers may be provided at different locations. It is preferable to provide a plurality of optical adjustment layers because it is easy to adjust the optical path length. The optical adjustment layer is preferably installed at a position that does not directly affect light emission. The material constituting the optical adjustment layer is preferably a material that is excellent in transparency and does not change the phase or hue of light, and examples thereof include magnesium fluoride, Nb ₂ O ₃ , and TiO ₂ .

(Antireflection layer)
The antireflection layer is provided on the surface of the light emitting surface of the organic EL panel. The antireflection layer is installed in order to suppress reflection and increase the transmittance. In some cases, the light emitted from the organic EL panel to the outside is not reflected inward at the interface. When used in an organic EL light source device to be described later, the antireflection layer is installed on the surface of the outermost light emitting surface. Although the material which comprises an antireflection layer is not specifically limited, For example, the moth-eye sheet | seat using the continuous change of the refractive index by nanosized unevenness | corrugation, AR sheet | seat using interference, etc. can be mentioned.

(Transparent moisture absorbent layer)
The transparent hygroscopic layer is installed in the organic EL panel sealed with a sealing material to absorb moisture discharged from each layer constituting the organic EL panel and remove the moisture in the organic EL panel. Is the layer to be played. The transparent moisture-absorbing layer is indicated by a symbol 40 in FIG.

  The transparent hygroscopic agent layer is required to have hygroscopicity and excellent transparency. Examples of the hygroscopic agent that can be used in the transparent hygroscopic agent layer include metal oxides (eg, sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide), sulfates (eg, 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 (For example, barium perchlorate, magnesium perchlorate, etc.). Of these, sulfates, metal halides, and anhydrous salts of perchloric acids are preferred.

<Organic EL light source device>
The organic EL light source device is configured by stacking two or more organic EL panels. The number of stacked layers is not particularly limited, but 2 to 10 is preferable. When organic EL panels having the same emission spectrum, that is, the same hue, are stacked and used, the light amount is amplified and can be used as a light source device with a large light amount. In addition, even if one of the plurality of organic EL panels fails to emit light, it can be used as a spare light source that is unlikely to fail because light emission is maintained by another panel. . In addition, when the emission spectra from a plurality of panels are slightly shifted, a three-dimensional light emission expression having a depth can be realized. Furthermore, various infinite lighting designs can be expressed by changing the emission spectra from each organic EL panel.

  In FIG. 3, when the organic EL panels are stacked, the adhesive layer 58 is used as a layer for bonding the organic EL panels. However, as a method for stacking the organic EL panels, the method using the adhesive layer 58 is used. It is not limited to. Other fixing methods can be appropriately used as long as they can be fixed so that the mutual positional relationship of the organic EL panels can be maintained. Other fixing methods include, for example, a method of using an adhesive sealing material instead of an adhesive layer, and a method of fixing the peripheral portions of the organic EL panels to each other after simply overlapping the organic EL panels. .

(Specular reflection type organic EL panel)
Since the organic EL light source device is transparent, it can basically emit light from either the front surface or the back surface. However, when emitting light only from the front surface, the specular reflection type organic EL panel can be installed on the surface opposite to the light emitting surface so that the light emitted from the back surface is emitted from the front surface side. The specular reflection type organic EL panel is a panel provided with a mirror surface on the surface so as to emit light only from one surface and totally reflect inward so that light does not leak from the other surface. By installing the specular reflection type organic EL panel on the surface opposite to the light emitting surface of the organic EL light source device, an organic EL light source device having a larger light amount can be obtained.

(Organic EL panel, manufacturing method of organic EL light source device)
About the manufacturing method and manufacturing conditions of an organic EL panel and an organic EL light source device, a known manufacturing method and manufacturing conditions applied to a general organic EL panel may be used unless otherwise specified.

  Examples in which the effects of the present invention have been confirmed will be described below. The present invention is not limited to this embodiment.

[Experimental Example 1]
<Production of organic EL panel>
By the method shown below, the organic EL panel No. 1-24 were produced.

(Layer structure)
As the layer structure of the organic EL panel, the layer structure shown in FIGS. 1A and 1B was prepared.
Organic EL panel No. 1 to 12 have the layer structure of FIG. Reference numerals 13 to 24 denote the layer configuration of FIG.

(Preparation of substrate)
As a substrate, a 700 μm thick soda-lime glass plate (manufactured by Eagle, product number XG) and a polyethylene terephthalate (PET) film with a barrier layer described below were used.

<Preparation of PET film with barrier layer>
A PET film having a thickness of 50 μm (manufactured by Teijin DuPont Films, Ltd., ultra-high transparency PET Type K) was prepared. On the PET film, the following polysilazane-containing liquid is applied with a wireless bar so that the average thickness after drying is 300 nm, and heat-treated for 1 minute in an atmosphere of temperature 85 ° C. and humidity 55% RH. And dried. Subsequently, it hold | maintained for 10 minutes in the atmosphere of temperature 25 degreeC and humidity 10% RH (dew point temperature -8 degreeC), the dehumidification process was performed, and the polysilazane content layer was formed on PET film.

  Next, the PET film on which the polysilazane-containing layer is formed is fixed on the operation stage of an excimer irradiation apparatus MECL-M-1-200 (manufactured by M.D. Com) and modified under the following modification treatment conditions. The polysilazane modified layer which consists of 300 nm was formed, and the PET film with a barrier layer was obtained.

<Polysilazane-containing liquid>
As the polysilazane-containing liquid, a 10% by mass dibutyl ether solution of perhydropolysilazane (Aquamica NN120-10, non-catalytic type, manufactured by AZ Electronic Materials Co., Ltd.) was prepared.

<Reforming treatment conditions>
Irradiation wavelength: 172 nm
Lamp filled gas: Xe
Excimer lamp light intensity: 130 mW / cm ² (172 nm)
Distance between sample and light source: 1mm
Stage heating temperature: 70 ° C
Oxygen concentration in the irradiation device: 0.5%
Excimer lamp irradiation time: 5 seconds

(Formation of optical adjustment layer)
An optical adjustment layer made of magnesium fluoride was formed on the substrate in order to increase the average light transmittance in the wavelength range of the half-width of the peak corresponding to the peaks of the emission spectra of three types of incident light described later. The optical adjustment layer made of magnesium fluoride was formed by a vacuum deposition method. The thickness of the optical adjustment layer was adjusted by a tooling factor for converting the fluctuation of a crystal resonator used in general vapor deposition into an actual film thickness.

(Formation of anode)
On the substrate on which the optical adjustment layer was formed, an anode made of an IZO film having a thickness of 150 nm was formed by sputtering.

(Formation of light emitting layer)
In the vacuum layer of the vacuum evaporation system, the organic functional layers including the light emitting layer (hole transport / injection layer, light emitting layer, hole blocking layer, electron transport / injection layer) are sequentially placed on the anode as follows. Formed.

<Hole transport / injection layer>
A hole transport / injection layer that serves both as a hole injection layer and a hole transport layer made of α-NPD, heated by energizing a heating boat containing α-NPD represented by the following structural formula as a hole transport injection material Was formed on the anode. At this time, the deposition rate was 0.1 nm / second to 0.2 nm / second, and the film thickness was 20 nm.

<Light emitting layer>
Next, the heating boat containing the host material H4 represented by the following structural formula and the heating boat containing the phosphorescent compound Ir-4 represented by the following structural formula were respectively energized independently, so that the host material H4 and the phosphorescent light emission were emitted. The light emitting layer made of the active compound Ir-4 was formed on the hole transport / injection layer. At this time, the energization of the heating boat was adjusted so that the deposition rate was the host material H4: phosphorescent compound Ir-4 = 100: 6. The thickness was 30 nm.

<Hole blocking layer>
Next, a heating boat containing BAlq represented by the following structural formula as a hole blocking material was energized and heated to form a hole blocking layer made of BAlq on the light emitting layer. At this time, the deposition rate was 0.1 nm / second to 0.2 nm / second, and the thickness was 10 nm.

<Electron transport / injection layer>
Thereafter, as an electron transport material, a heating boat containing the following compound 10 and a heating boat containing potassium fluoride were energized independently, and an electron injection layer and an electron transport layer made of the compound 10 and potassium fluoride were respectively supplied. An electron transport / injection layer that also serves as the above was formed on the hole blocking layer. At this time, the energization of the heating boat was adjusted so that the deposition rate was compound 10: potassium fluoride = 75: 25. The thickness was 30 nm.

(Formation of cathode)
Next, the substrate on which the organic functional layer is formed in another vacuum layer is transferred, fixed to a substrate holder of a commercially available vacuum deposition apparatus, and silver (Ag) and a small amount of magnesium (Mg) are placed on a tungsten resistance heating boat. Was installed in a vacuum chamber of a vacuum deposition apparatus.

Next, after depressurizing the vacuum tank to 4 × 10 ⁻⁴ Pa, the heating boat containing silver was energized and heated. Thus, a cathode made of Ag doped with Mg having a thickness of 10 nm was formed at a deposition rate of 0.1 to 0.2 nm / second. The mixing ratio of Mg to Ag in the formed cathode was 7 atm%.

(Formation of optical adjustment layer)
In the same manner as the optical adjustment layer described above, an optical adjustment layer was formed again on the cathode.

(Formation of barrier layer>
As the barrier layer, a SiN layer was formed by a deposition CVD plasma CVD apparatus under the following conditions. The film thickness of the SiN layer was 300 nm.
The SiN layer includes an electrode provided to face the buffer layer, a high-frequency power source that supplies plasma excitation power to the electrode, a bias power source that supplies bias power to a holding member that holds the substrate, and an electrode And a gas supply means for supplying a carrier gas and a source gas toward the plasma CVD film forming apparatus.
Silane gas (SiH ₄ ), ammonia gas (NH ₃ ), nitrogen gas (N ₂ ), and hydrogen gas (H ₂ ) were used as the film forming gas. The supply amounts of these gases were 100 sccm for silane gas, 200 sccm for ammonia gas, 500 sccm for nitrogen gas, and 500 sccm for hydrogen gas. The film forming pressure was 50 Pa.
The electrode was supplied with 3000 W plasma excitation power at a frequency of 13.5 MHz from a high frequency power source. Further, 500 W bias power was supplied to the holding member from a bias power source.

(Nitrogen layer formation)
A glass plate having a square recess formed in a portion including the central light emitting region was prepared so that the light emitting region of the organic EL element and the glass surface were not in direct contact. A desiccant sheet (moisture removal sheet, manufactured by Dynic) was attached to a portion of the glass plate that was not the light emitting region. Thereafter, an ultraviolet curable epoxy resin (XNR5516Z manufactured by Nagase Sangyo Co., Ltd.) was applied to a portion of the outer periphery of the glass plate that was not a recess using a dispenser. The glass plate and the organic EL element were bonded together in a glove box substituted with nitrogen, and then irradiated with ultraviolet rays in the form of a mask on the light emitting portion to cure the ultraviolet curable epoxy resin in the outer peripheral portion. The obtained laminated body was an organic EL panel having a layer structure shown in FIG. 1A in which a nitrogen layer was formed between the glass plate and the organic EL element.

(Formation of adhesive layer and adhesion to substrate)
Formation of the adhesive layer and adhesion to the upper substrate were performed using an epoxy thermosetting adhesive (Elephan CS manufactured by Yodogawa Paper Co., Ltd.) as an adhesive. After applying an epoxy thermosetting adhesive on the barrier layer, it was adhered to the upper substrate (glass plate or PET film with a barrier layer). Then, in a glove box with an oxygen concentration of 10 ppm or less and a water concentration of 10 ppm or less, vacuum is applied under the conditions of 80 ° C., 0.04 MPa load, reduced pressure (1 × 10 ⁻³ MPa or less) suction for 20 seconds, and press for 20 seconds. Pressed. Then, in the glove box, it heated for 30 minutes on a 110 degreeC hotplate, the adhesive layer was thermosetted, and the organic electroluminescent panel which has the layer structure as described in FIG.1 (b) was obtained.

(Thickness adjustment)
The film thickness of the organic EL panel was adjusted in order to increase the average light transmittance in the wavelength range of the half width of the peak corresponding to the peaks of the emission spectra of three types of incident light described later.
As described above, the method for adjusting the film thickness of the organic EL panel is an optimization calculation based on the theory of wave optics based on the refractive index (n value) and extinction coefficient (k value) in each layer. To obtain the thickness of the layer. For calculating the film thickness of the organic EL panel, set the emission intensity, emission color, and film thickness range for each layer, and use a genetic algorithm based on wave optics to maximize the arbitrary average transmittance. The optimization calculation was performed.

<Production of organic EL light source device>
An organic EL light source device was produced using the produced organic EL panel.
Four organic EL panels were prepared, and an adhesive layer was formed between the organic EL panels in the same manner as in the method for forming the adhesive layer, and was pressed and bonded by heat curing.

<Evaluation of organic EL panel>
Three types of light, red, blue and white, were used as incident light on the organic EL panel. Among these, red and blue light had one emission spectrum peak. Moreover, the peak of the emission spectrum of white light was two. The half-widths of the two peaks of white light overlap each other, and the half-width of the peak is only one wavelength range.

(Average light transmittance for all wavelengths)
The average light transmittance (%) at the time of non-light emission in the whole wavelength region of wavelength 400 to 800 nm was measured. As a measuring device, a spectrophotometer U3310 manufactured by Hitachi High-Technologies Corporation was used.

(Average light transmittance of the peak of incident light)
The average light transmittance (%) at the time of non-emission in the wavelength range of the half width of the peak of incident light was measured. As a measuring device, a spectrophotometer U3310 manufactured by Hitachi High-Technologies Corporation was used.
Red peak: 600 nm, half-width range: 560-640 nm
Blue peak: 460 nm, full width at half maximum: 440 to 480 nm
White peak: 460 nm and 550 nm, full width at half maximum: 440 to 570 nm

(Luminescence intensity of 4 laminated products)
The light emission intensity of an organic EL light source device in which four organic EL panels were stacked was measured. The light emission intensity of the four-layered product here means that one organic EL panel farthest from the light emitting surface on the opposite side of the light emitting surface emits light, and the remaining three organic EL panels are not emitting light. The light emission intensity on the light emitting surface side is measured. A numerical value was determined as relative light emission intensity, assuming that the light emission intensity of only one organic EL panel was 100. The emission intensity was measured using a spectral radiance meter CS-2000 (manufactured by Konica Minolta).

The produced organic EL panel No. The production conditions and evaluation results of 1 to 24 are shown in Table 1. In Table 1, the sealing method of the organic EL panel having the configuration of FIG. 1A is described as “can sealing”, and the sealing method of the organic EL panel having the configuration of FIG. , Described as “lamination sealing”. Moreover, the sealing material of the organic EL panel having the configuration of FIG. 1A is described as “N ₂ / glass” (nitrogen gas / glass plate), and the organic EL panel having the configuration of FIG. The sealing material was described as “adhesive layer / barrier film” (adhesive layer / PET film with barrier layer).

  As can be seen from Table 1, in the wavelength range of the full width at half maximum of the incident light peak, the thickness of the organic EL panel is adjusted so that the average light transmittance is adjusted to 60% or more. The emission intensity was as high as 10% or more, and was excellent in light transmittance with respect to incident light (invention product). In addition, the organic EL panel in which the optical adjustment layer is provided and the average light transmittance of the peak of incident light is further increased, the emission intensity of the four-layer product is higher than that of the organic EL panel in which the optical adjustment layer is not provided. It was even more expensive.

  In addition, the organic EL panel using red and blue incident light having one emission spectrum peak has a film thickness as compared with the organic EL panel using a plurality of white incident lights having emission peaks. Since the adjustment is easy, the average light transmittance of the peak of incident light is high, and the light emission intensity of the four-layered product is high. In addition, the difference of the average light transmittance of the two peaks of the organic EL panel using white incident light was both within 25% (organic EL panels No. 9 to 12, 21 to 24).

  When a PET film is used as the substrate, the barrier layer on the PET film is colored yellow, and therefore absorbs part of the blue incident light. Therefore, the average light transmittance of the peak of the incident light and the emission intensity of the four-layered product tend to be slightly inferior in the case of the blue incident light compared to the case of the red incident light.

[Experiment 2]
In accordance with Experimental Example 1, organic EL panel No. 31-37 and 41-47 were produced. The layer structure of the organic EL panel of Experimental Example 2 is shown in FIG. Other manufacturing methods were carried out in the same manner as in Experimental Example 1.

Two types of light, BR and GR, were used as incident light on the organic EL panel. Among these, BR light was a mixture of blue and red light, and had two emission spectrum peaks. Since both peaks are separated, the half width of the peak is in two wavelength ranges.
On the other hand, the GR light was a mixture of green and red light, and the emission spectrum had two peaks. Since both peaks are close to each other, the half width of the peak is one wavelength range.

  The thickness and thickness of the optical adjustment layer were adjusted in order to change the average light transmittance in the wavelength range of the half width of the peak corresponding to the peaks of the emission spectra of the two types of incident light. Then, corresponding to the two types of incident light, when the light transmittance of peak 1 is 100%, seven types of organic EL panels are used so that the light transmittance of peak 2 becomes a relatively different value. Was made.

  For each organic EL panel, the difference in light transmittance and the chromaticity x, y of the emission spectrum in the wavelength range of the half width of the two peaks were determined. The evaluation conditions for each characteristic are as follows.

(Average light transmittance of the peak of incident light)
The average light transmittance (%) at the time of non-emission in the wavelength range of the half width of the peak of incident light was measured. As a measuring device, a spectrophotometer U3310 manufactured by Hitachi High-Technologies Corporation was used.

(Chromaticity x, y)
The chromaticity was measured using a spectral radiance meter CS-2000 manufactured by Konica Minolta.

  The evaluation results of the produced organic EL panel are shown in Tables 2 and 3. Table 2 shows characteristics of various organic EL panels when incident light is BR, and Table 3 shows characteristics of various organic EL panels when incident light is GR.

  FIG. 6 corresponds to Table 2. FIG. 6A illustrates color coordinates of light emission of seven types of organic EL panels when BR light is used as incident light. 6 (b-1) to (b-7) respectively show seven types of organic EL panel No. The emission spectrum of 31-37 was shown.

  FIG. 7 corresponds to Table 3. FIG. 7A illustrates color coordinates of light emission of seven types of organic EL panels when GR light is used as incident light. 7 (b-1) to 7 (b-7) each show seven types of organic EL panel Nos. The emission spectrum of 41-47 was shown.

In Table 2, organic EL panel No. Since the difference of the average light transmittance in the wavelength range of the half width of the two peaks is 0, 34 was used as a reference for evaluation. When the difference in the average light transmittance in the wavelength range of the half width of the two peaks is within 25% (organic EL panel No. 32-36), the x value No. in the chromaticity coordinates of light emission. The difference from 34 is 0.040 or less, and the y value No. The difference from 34 was 0.020 or less, and it was found that there was little difference in the hue of the emission spectrum.
6 (b-2) to 6 (b-6). Also in the emission spectra of 32 to 36, the fluctuation of the two peaks shows the organic EL panel No. Compared to the emission spectra of Nos. 31 and 37 (FIGS. 6B-1 and 6B-7), the emission spectra were relatively small.

  In Table 3, the organic EL panel No. Since the difference of the average light transmittance in the wavelength range of the half width of the two peaks is 0, 41 was used as the evaluation reference. When the incident light is GR light and the two peaks of the emission spectrum are close to each other, even if the difference in average light transmittance in the wavelength range of the half width of the two peaks is varied, the difference in hue of the emission spectrum Was relatively small.

  In each organic EL panel, the average light transmittance in the wavelength range of the half width of the two peaks of incident light was 60% or more (organic EL panels No. 31 to 37, 41 to 47). .

10, 11, 30, 31, 32, 33 Organic EL panel 51, 52, 53 Organic EL light source device

Claims (6)

A light transmissive organic electroluminescence panel comprising a light transmissive substrate, an anode, a light emitting layer, a cathode and a sealing material,
The emission spectrum has at least one peak in the visible light region having a wavelength of 400 to 800 nm,
In the wavelength range of the half width of the peak, the average light transmittance at the time of non-light emission is 60% or more
When there are a plurality of peaks, a difference in average light transmittance during non-light emission in a wavelength range of half width of any two peaks selected from the peaks is within 25%. Electroluminescence panel.   The light transmission type organic electroluminescence panel according to claim 1, further comprising an optical adjustment layer for adjusting an optical path length.   The light transmission type organic electroluminescence panel according to claim 2, wherein the optical adjustment layer is made of a low refractive index material containing fluorine.   The light-transmitting organic electroluminescence panel according to claim 1, further comprising an antireflection layer on a surface of the light emitting surface.   The organic electroluminescent light source device formed by laminating | stacking two or more light transmission type organic electroluminescent panels of any one of Claims 1-4.   6. The organic electroluminescence light source device according to claim 5, wherein a specular reflection type organic electroluminescence panel is laminated on a surface opposite to the light emitting surface.

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