JP5217844B2 - Surface emitting panel for lighting - Google Patents

Description

The present invention relates to a surface emitting panel for illumination .

  In recent years, there has been an increasing demand for large-sized light-emitting panels for lighting or displays. The development of large-sized light-emitting elements has had difficult problems, such as an increase in manufacturing and device costs and difficulty in suppressing in-plane luminance unevenness in a large area.

  On the other hand, studies have been made to construct a large light emitting panel by joining small light emitting panels together. However, since a joint between small-sized light emitting panels exists as a non-light emitting portion, it has been conventionally studied to make the joint inconspicuous because the visibility is poor.

  There is an element structure in which the sealing helicopter part of each EL element to be joined has a roundness toward the outside at the end of the EL layer, and light is emitted in an oblique direction from the sealing helicopter part to the joining part. Has been reported (for example, see Patent Document 1). In addition, a configuration in which a color conversion filter is installed on the light emission surface side in which the side surfaces of a plurality of EL elements are bonded together has been reported (see, for example, Patent Document 2). Furthermore, a configuration has been reported in which a plurality of light-emitting panels using thin-film bonding plates for side sealing are joined to reduce the distance between the individual light-emitting panels (for example, see Patent Document 3). There has also been reported a display configuration in which a plurality of panels in the vicinity of the joint are connected as small-sized and high-luminance light emission (see, for example, Patent Document 4).

However, in these conventional technologies, the seam remains as a non-light-emitting portion. In particular, when using an organic EL element that has been developed in recent years, each element must be sufficiently sealed. It is necessary to secure the interval between the light emitting surfaces of adjacent elements, and the method of arranging the elements in the in-plane lateral direction still has a limit in improving the visibility.
JP 2001-57288 A JP 2006-164618 A JP 2007-200267 A JP 2007-304584 A

An object of the present invention, there is provided a large size illumination light emitting panel which is composed of a plurality of surface light emitting element, the boundary between the surface light-emitting element is to provide a visually recognized hardly illumination light emitting panel. Further, a light-emitting panel of large size constituted by a plurality of surface-emitting devices, to provide a reduced illumination light emitting panel plane luminance unevenness of the light emitting panel.

  The above object of the present invention can be achieved by the following configuration.

1. A surface emitting panel having a top emission type surface light emitting element and a bottom emission type surface light emitting element and emitting light in one direction, wherein the top emission type surface light emitting element and the bottom emission type surface light emitting element The light emitting direction is arranged to be the light emitting direction of the surface light emitting panel, the surface light emitting elements are connected in series , and the surface light emitting panel has a light transmissive element support substrate, A top emission type surface light emitting element is disposed on one surface of the element supporting substrate, and a bottom emission type surface light emitting element is disposed on the other surface of the light transmitting element supporting substrate. Surface emitting panel for lighting.

2. 2. The surface emitting panel for illumination according to 1 above, wherein the light-transmitting element supporting substrate is a common element substrate constituting each of a top emission type surface emitting element and a bottom emission type surface emitting element.

3. When the surface emitting panel is viewed from the vertical direction of the light emitting surface, a top emission type surface light emitting element and a bottom emission type surface light emitting element are alternately arranged, and a light emitting region of the top emission type surface light emitting element and a bottom emission type 3. The surface emitting panel for illumination according to 1 or 2, wherein the light emitting region of the surface light emitting element is joined or overlapped.

4). 4. The lighting surface emitting panel according to any one of claims 1 to 3 , wherein at least one selected from the top emission type surface emitting element and the bottom emission type surface emitting element is an organic EL element.

The present invention provides a light-emitting panel of large size constituted by a plurality of surface light emitting element, the boundary between the surface-emitting element, provide a visually recognized hardly illumination light emitting panel, composed of a plurality of surface emitting element Thus, it is possible to provide an illumination light-emitting panel that has reduced in-plane luminance unevenness of the light-emitting panel.

  The present invention will be described in more detail. The present invention relates to a large-sized surface light-emitting panel configured by arranging a plurality of surface light-emitting elements and emitting light in one direction, and more specifically, a top emission type surface light-emitting element, a bottom emission type surface light-emitting element, A surface light emitting panel having a surface emitting panel, wherein the light emission direction of the top emission type surface light emitting element and the bottom emission type surface light emitting element is arranged to be the light emission direction of the surface light emitting panel. .

  When the surface emitting panel is viewed from the vertical direction of the light emitting surface, the top emission type surface light emitting device and the bottom emission type surface light emitting device are alternately arranged, and the light emitting region of the top emission type surface emitting device and the bottom emission type surface The non-light emitting area in the surface light emitting panel surface is reduced or eliminated by arranging the light emitting elements so that they are joined or overlapped with each other. This panel structure reduces the boundary between the surface light emitting elements during light emission. Can be made difficult to be visually recognized.

  In a surface-emitting panel composed of a plurality of surface-emitting elements, when the elements are connected in parallel, when some of the elements are short-circuited, a current easily flows through this area, and the surface-emitting panel itself emits light. There is a possibility of disappearing. In order to limit only a part of the part of the short-circuiting element to the non-light-emitting portion and minimize the influence on the light-emitting panel, it is preferable to connect the elements in series. According to the configuration of the present invention, since the cathodes and the anodes are alternately arranged between the adjacent surface light emitting elements, the series connection is facilitated and the non-light emitting region between the surface light emitting elements is reduced or eliminated. Panels can be configured.

  Further, the surface light emitting panel has a light transmissive element support substrate, a top emission type surface light emitting element is disposed on one surface of the light transmissive element support substrate, and the other of the light transmissive element support substrates is arranged. According to the configuration in which the bottom emission type surface emitting element is arranged on the surface of the element, the light emitting area of the element can be joined or overlapped with each other when the surface emitting panel is viewed from the light emitting surface vertical direction, A light emitting panel in which the non-light emitting area between the surface light emitting elements is reduced or eliminated can be easily configured.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, embodiment of this invention is not limited to these.

  FIG. 1 is a plan view showing an example of a surface light emitting panel according to an embodiment of the present invention as seen from the light emitting surface side. A top emission type surface light emitting device and a bottom emission type surface light emitting device are alternately arranged. FIG. 2 is a plan view showing an example in which a surface light-emitting panel is configured using a surface light-emitting element having a rectangular light-emitting surface. 1 and 2, T represents a top emission type surface light emitting device, and B represents a bottom emission type surface light emitting device.

  3-6 is a side view explaining the XX 'part of the surface emitting panel shown in FIG.1 and FIG.2.

  FIG. 3 shows an example in which top emission type surface light emitting devices 1 and bottom emission type surface light emitting devices 2 are alternately arranged in the same plane. Reference numeral 3 denotes a substrate of the surface light emitting element. 4 and 5 are examples in which the position of the light emitting surface of the top emission type surface light emitting element and the position of the light emitting surface of the bottom emission type surface light emitting element as viewed from the direction of the light emitting surface are shifted.

  FIG. 6A shows a surface emitting panel viewed from the direction perpendicular to the light emitting surface, where the light emitting region of the top emission type surface light emitting device and the light emitting region of the bottom emission type surface light emitting device are joined or overlapped. This is an example of arrangement.

  FIG. 6B shows a bonding of the light emitting region of the top emission type surface light emitting device and the light emitting region of the bottom emission type surface light emitting device when the surface emitting panel in FIG. It is an enlarged view of the junction part at the time of arrange | positioning. In the present invention, the fact that the light emitting region of the top emission type surface light emitting element and the light emitting region of the bottom emission type surface light emitting device are joined and arranged means that the surface emitting panel is viewed from the direction perpendicular to the light emitting surface. The light emission region of the top emission type surface light emitting device and the light emission region of the bottom emission type surface light emitting device are not observed overlapping each other, and no gap is observed at the boundary between the light emission regions. It does not mean that they are joined together.

  FIG. 6C shows the overlap of the light emission region of the top emission type surface light emitting device and the light emission region of the bottom emission type surface light emitting device when the surface light emitting panel in FIG. It is an enlarged view of the overlap part at the time of arrange | positioning. In the present invention, the light emitting region of the top emission type surface light emitting device and the light emitting region of the bottom emission type surface light emitting device are arranged so as to overlap each other. The light emitting region of the top emission type surface light emitting device and the light emitting region of the bottom emission type surface light emitting device are observed to overlap each other, and does not necessarily mean that the light emitting regions are physically overlapped and joined.

  The functional layer 5 including the light emitting layer has a first electrode 4 and a second electrode 6. Sealing is not shown.

  FIG. 7 shows a surface emitting panel according to the present invention, in which the surface emitting panel has a light-transmitting element supporting substrate 7, and a top emission type surface emitting element is provided on one surface of the light transmitting element supporting substrate 7. 1 is disposed on the other surface of the light-transmitting element support substrate 7, and the bottom emission type surface light emitting element 2 and the bottom emission type surface light emitting element 1 are seen from the light emitting surface direction of the surface emitting panel. It is a side view explaining the example of the surface emitting panel arrange | positioned so that the emission type surface emitting element 2 may become alternate.

  FIG. 8A shows a light emitting region of a top emission type surface light emitting device and a light emitting region of a bottom emission type surface light emitting device in the surface light emitting panel related to FIG. This is an example in which these are joined together or overlapped.

  FIG. 8B shows a bonding of the light emitting region of the top emission type surface light emitting device and the light emitting region of the bottom emission type surface light emitting device when the surface emitting panel in FIG. It is an enlarged view of the junction part at the time of arrange | positioning.

  FIG. 8 (c) shows that the light emitting region of the top emission type surface light emitting device overlaps the light emitting region of the bottom emission type surface light emitting device when the surface emitting panel in FIG. It is an enlarged view of the overlapping part at the time of arrange | positioning. Sealing is not shown.

  The support substrate used in the light-transmitting element support substrate in the present invention and the surface light-emitting element constituting the surface light-emitting panel of the present invention is not particularly limited in the type of glass, plastic, etc. Examples thereof include glass, quartz, and a transparent resin film. Particularly preferred is a resin film capable of giving flexibility to the organic EL element.

  Examples of the resin film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, cellulose acetate propionate (CAP), Cellulose esters such as cellulose acetate phthalate and cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide, polyether Sulfone (PES), polyphenylene sulfide, polysulfones, polyether Examples include cycloolefin resins such as luimide, polyetherketoneimide, polyamide, fluororesin, nylon, polymethylmethacrylate, acrylic or polyarylate, Arton (trade name, manufactured by JSR) or Apel (trade name, manufactured by Mitsui Chemicals). It is done.

On the surface of the resin film, an inorganic film, an organic film, or a hybrid film of both may be formed. Water vapor permeability measured by a method in accordance with JIS K 7129-1992 (40 ° C., 90% RH) Is preferably a barrier film of 0.01 g / m ² · day · atm or less, and further has an oxygen permeability (20 ° C., 100% RH) of 10 measured by a method according to JIS K 7126-1992. ⁻³ g / m ² / day or less and a water vapor transmission rate of 10 ⁻³ g / m ² / day or less are preferable, and both the water vapor transmission rate and the oxygen transmission rate are 10 ^−5. More preferably, it is g / m ² / day or less.

  As a material for forming the barrier film, any material may be used as long as it has a function of suppressing entry of elements that cause deterioration of elements such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like can be used. Further, in order to improve the brittleness of the film, it is more preferable to have a laminated structure of these inorganic layers and layers made of organic materials. Although there is no restriction | limiting in particular about the lamination | stacking order of an inorganic layer and an organic layer, It is preferable to laminate | stack both alternately several times.

  The method for forming the barrier film is not particularly limited. For example, the 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 weight A combination method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, and the like can be used, but an atmospheric pressure plasma polymerization method as described in JP-A-2004-68143 is particularly preferable.

  In the present invention, a pressure-sensitive adhesive and an adhesive can be used to dispose the surface light emitting element on the light transmissive element supporting substrate. The types of the pressure-sensitive adhesive and the adhesive are not particularly limited, and in the adhesive, a curable adhesive that forms a high molecular weight body or a crosslinked structure by various chemical reactions after being applied and bonded is preferably used. Specific examples of pressure-sensitive adhesives and adhesives that can be used in the present invention include, for example, urethane-based, epoxy-based, aqueous polymer-isocyanate-based, acrylic-based curable adhesives and pressure-sensitive adhesives, and moisture-cured urethane adhesives. And anaerobic pressure-sensitive adhesives such as polyether methacrylate type, ester type methacrylate type and oxidized type polyether methacrylate, cyanoacrylate type instantaneous adhesive, acrylate and peroxide type two-pack type instantaneous adhesive, and the like. Moreover, you may mix an antistatic agent and various fillers in an adhesive using a well-known method.

  The method for applying the pressure-sensitive adhesive and the adhesive is not particularly limited, and examples thereof include general methods such as gravure coater, micro gravure coater, comma coater, bar coater, spray coating, and ink jet method.

  FIG. 9 shows a surface light emitting panel according to the present invention, in which the surface light emitting panel has a light transmissive element support substrate, and a top emission type surface light emitting element is provided on one surface of the light transmissive element support substrate. In which a bottom emission type surface light emitting element is disposed on the other surface of the light transmissive element support substrate, the light transmissive element support substrate is a top emission type surface light emitting element, and a bottom surface. It is a side view explaining the example which is the common element substrate 7 which comprises each of an emission type surface light emitting element. The top emission type surface light emitting element 1 is disposed on one surface of the common element substrate 7, and the bottom emission type surface light emitting element 2 is disposed on the other surface of the common element substrate 7. , The top emission type surface light emitting device 1 and the bottom emission type surface light emitting device 2 are formed alternately.

  FIG. 10A shows a light emitting region of the top emission type surface light emitting device and a light emitting region of the bottom emission type surface light emitting device when the surface light emitting panel is viewed from the direction perpendicular to the light emitting surface. Are formed by joining or overlapping each other.

  FIG. 10B shows a bonding of the light emitting region of the top emission type surface light emitting device and the light emitting region of the bottom emission type surface light emitting device when the surface emitting panel in FIG. 10A is viewed from the direction perpendicular to the light emitting surface. It is an enlarged view of the junction part at the time of arrange | positioning.

  FIG. 10C shows the light emitting region of the top emission type surface light emitting element overlapped with the light emitting region of the bottom emission type surface light emitting device when the surface emitting panel in FIG. It is an enlarged view of the overlapping part at the time of arrange | positioning. Sealing is not shown.

  A conventional general surface light emitting panel configured by using a plurality of surface light emitting elements with respect to the surface light emitting panel according to the present invention is shown in FIGS.

  FIG. 11 illustrates an aspect from the side surface direction. The surface light emitting panel 8 is generally configured by arranging the surface light emitting elements 9 in the same plane. Means such as connecting the side surfaces of the surface light emitting elements 9 via a connecting portion or arranging them on a common support substrate is used.

  FIG. 12 is an enlarged view of adjacent surface light emitting elements viewed from the light emitting surface direction, and FIG. 13 is an enlarged view of a joint portion of the surface light emitting elements viewed from the side surface direction. The light emitting area is indicated by 11. The joint portion 10 at the boundary of the surface light emitting element 9 constituting the surface light emitting panel 8 is formed of a curable resin or the like, but usually has a width of about 2 to 5 mm, so that it is easily visually recognized as a non-light emitting region.

  In addition, in a surface light-emitting panel composed of a plurality of surface light-emitting elements such as organic EL elements, when the elements are connected in parallel, the surface light-emitting panel itself may not emit light when some of the elements are short-circuited. There is. In order to limit only a part of the part of the short-circuit elements to the non-light-emitting portion and minimize the influence on the entire light-emitting panel, it is preferable to connect the elements in series.

  In the conventional surface light emitting devices shown in FIGS. 11 to 13, in order to alternately connect the cathodes and anodes between adjacent surface light emitting devices, for example, the electrodes on the emission surface side of the surface light emitting device are adjacent surface emitting devices. Since it is necessary to connect to the electrode on the side opposite to the emission surface side of the element, this wiring becomes complicated and it is necessary to secure a sufficient area for the wiring.

  FIG. 14 shows an example of an enlarged view of adjacent surface light emitting elements when the surface light emitting panel according to the present invention shown in FIGS. 3 to 5, 7, and 9 is viewed from the light emitting surface direction.

  Since the surface emitting panel 8 according to the present invention can be easily formed in series by arranging the cathode and the anode alternately between adjacent surface emitting elements, the conventional surface emitting panel shown in FIGS. Compared to a general surface light emitting panel, the distance between the joints 10 between the surface light emitting elements can be reduced, and a light emitting panel with a reduced non-light emitting region can be formed.

  FIG. 15 is an enlarged view of adjacent surface light emitting elements when the surface light emitting panel according to the present invention shown in FIGS. 6A, 8A, and 10A is viewed from the light emitting surface direction. Indicated. In the surface light emitting panel 8 shown in FIG. 15, since the light emitting regions of the surface light emitting elements are joined or overlapped when viewed from the direction perpendicular to the light emitting surface, no light is emitted at the joint between the surface light emitting elements. A light-emitting panel in which the area is further reduced or eliminated can be formed.

  7 and 9, the surface light-emitting panel includes a light-transmitting element supporting substrate, and a top emission type surface emitting light is provided on one surface of the light-transmitting element supporting substrate. According to the configuration in which the elements are disposed and the bottom emission type surface light emitting elements are disposed on the other surface of the light transmissive element supporting substrate, the surface light emitting elements on each surface are connected in series, and the surface When the light emitting panel is viewed from the direction perpendicular to the light emitting surface, the light emitting areas of the elements can be joined or overlapped to form a light emitting panel in which the non-light emitting areas between the surface light emitting elements are eliminated.

  In the surface light emitting panel according to the present invention, gaps between a plurality of surface light emitting elements may be filled with an inorganic material such as glass or silica, a resin, an adhesive, an adhesive, or the like. Transparent resins such as PET (polyethylene terephthalate), TAC (triacetyl cellulose), PC (polycarbonate), or PMMA (polymethyl methacrylate), and adhesives such as urethane, epoxy, aqueous polymer-isocyanate, and acrylic Agents, anaerobic pressure-sensitive adhesives such as polyether methacrylate type, ester type methacrylate type, oxidized type polyether methacrylate and the like, and urethane type, epoxy type, aqueous polymer-isocyanate type, acrylic type curable adhesives, etc. Furthermore, various UV curable resins, thermosetting resins, and the like can be used. Further, a light scattering material and a light reflecting material can be filled.

  Furthermore, although omitted in the drawing, sealing, a protective film, an auxiliary electrode, and the like may be provided as necessary, and electrodes other than the first electrode 4 and the second electrode 6 may be laminated. The arrangement of the first electrode 4 and the second electrode 6 may be reversed.

  In addition to the light emitting layer, the functional layer 5 including the light emitting layer includes a charge injection layer, a charge transport layer, an insulating layer, a carrier block layer, an intermediate layer, a light adjustment layer, a protective film, a barrier layer, and a mixed layer thereof. It can be arbitrarily provided.

  Although there is no restriction | limiting in the surface emitting element used for the light emission panel in connection with this invention, It is preferable that it is an EL element and it is more preferable that it is an organic EL element.

  Hereinafter, although the preferable aspect in the case of comprising the light emission panel in connection with this invention with an organic EL element is demonstrated, this invention is not limited to this.

Preferred specific examples of the layer structure of the organic EL element are shown below.
(I) Anode / light emitting layer / electron transport layer / cathode (ii) Anode / hole transport layer / light emitting layer / electron transport layer / cathode (iii) Anode / hole transport layer / light emitting layer / hole blocking layer / electron Transport layer / cathode (iv) anode / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer / cathode (v) anode / anode buffer layer / hole transport layer / light emitting layer / hole Blocking layer / electron transport layer / cathode buffer layer / cathode Here, the light emitting layer preferably contains at least two kinds of light emitting materials having different emission colors, and a single layer or a light emitting layer comprising a plurality of light emitting layers A unit may be formed. The hole transport layer also includes a hole injection layer and an electron blocking layer.
<Light emitting layer>
The light emitting layer according to the present invention is a layer that emits light by recombination of electrons and holes injected from the electrode, the electron transport layer, or the hole transport layer, and the light emitting portion is in the layer of the light emitting layer. May be the interface between the light emitting layer and the adjacent layer.

  The light emitting layer according to the present invention is not particularly limited in its configuration as long as the contained light emitting material satisfies the above requirements.

  Moreover, there may be a plurality of layers having the same emission spectrum and emission maximum wavelength.

  It is preferable to have a non-light emitting intermediate layer between each light emitting layer.

  The total thickness of the light emitting layers in the present invention is preferably in the range of 1 to 100 nm, and more preferably 30 nm or less because a lower driving voltage can be obtained. In addition, the sum total of the film thickness of the light emitting layer said by this invention is a film thickness also including this intermediate | middle layer, when a nonluminous intermediate | middle layer exists between light emitting layers.

  The thickness of each light emitting layer is preferably adjusted to a range of 1 to 50 nm, more preferably adjusted to a range of 1 to 20 nm. There is no particular limitation on the relationship between the film thicknesses of the blue, green and red light emitting layers.

  For the production of the light emitting layer, a light emitting material or a host compound, which will be described later, is formed by forming a film by a known thinning method such as a vacuum deposition method, a spin coating method, a casting method, an LB method, an ink jet method, or the like. it can.

  In the present invention, a plurality of light emitting materials may be mixed in each light emitting layer, and a phosphorescent light emitting material and a fluorescent light emitting material may be mixed and used in the same light emitting layer.

  In the present invention, the structure of the light-emitting layer preferably contains a host compound and a light-emitting material (also referred to as a light-emitting dopant compound) and emits light from the light-emitting material.

  As a host compound contained in the light emitting layer of the organic EL device of the present invention, a compound having a phosphorescence quantum yield of phosphorescence emission at room temperature (25 ° C.) of less than 0.1 is preferable. More preferably, the phosphorescence quantum yield is less than 0.01. Moreover, it is preferable that the volume ratio in the layer is 50% or more among the compounds contained in a light emitting layer.

  As the host compound, known host compounds may be used alone or in combination of two or more. By using a plurality of types of host compounds, it is possible to adjust the movement of charges, and the organic EL element can be made highly efficient. Moreover, it becomes possible to mix different light emission by using multiple types of luminescent material mentioned later, and can thereby obtain arbitrary luminescent colors.

  The host compound used in the present invention may be a conventionally known low molecular compound or a high molecular compound having a repeating unit, and a low molecular compound having a polymerizable group such as a vinyl group or an epoxy group (evaporation polymerizable light emitting host). )But it is good.

  As the known host compound, a compound that has a hole transporting ability and an electron transporting ability, prevents the emission of light from being increased in wavelength, and has a high Tg (glass transition temperature) is preferable. Here, the glass transition point (Tg) is a value obtained by a method based on JIS-K-7121 using DSC (Differential Scanning Colorimetry).

  Specific examples of known host compounds include compounds described in the following documents. For example, Japanese Patent Application Laid-Open Nos. 2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357777, 2002-334786, 2002-8860 Gazette, 2002-334787 gazette, 2002-15871 gazette, 2002-334788 gazette, 2002-43056 gazette, 2002-334789 gazette, 2002-75645 gazette, 2002-338579 gazette. No. 2002-105445, No. 2002-343568, No. 2002-141173, No. 2002-352957, No. 2002-203683, No. 2002-363227, No. 2002-231453. No. 2003-3165, No. 2002-234888, No. 2003-27048, No. 2002-255934, No. 2002-286061, No. 2002-280183, No. 2002-299060. 2002-302516, 2002-305083, 2002-305084, 2002-308837, and the like.

  Next, the light emitting material will be described.

  As the light-emitting material according to the present invention, a fluorescent compound or a phosphorescent material (also referred to as a phosphorescent compound or a phosphorescent compound) is used.

  In the present invention, a phosphorescent material is a compound in which light emission from an excited triplet is observed. Specifically, it is a compound that emits phosphorescence at room temperature (25 ° C.), and the phosphorescence quantum yield is 0 at 25 ° C. A preferred phosphorescence quantum yield is 0.1 or more, although it is defined as 0.01 or more compounds.

  The phosphorescent quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen) of Experimental Chemistry Course 4 of the 4th edition. The phosphorescence quantum yield in a solution can be measured using various solvents. However, when a phosphorescent material is used in the present invention, the phosphorescence quantum yield (0.01 or more) is achieved in any solvent. Just do it.

  There are two types of light emission of the phosphorescent material. In principle, the carrier recombination occurs on the host compound to which the carrier is transported to generate an excited state of the host compound, and this energy is transferred to the phosphorescent material. Energy transfer type to obtain light emission from the phosphorescent light emitting material, and another one is that the phosphorescent light emitting material becomes a carrier trap, and recombination of carriers occurs on the phosphorescent light emitting material, and light emission from the phosphorescent light emitting material is obtained. Although it is a trap type, in any case, the excited state energy of the phosphorescent material is required to be lower than the excited state energy of the host compound.

  The phosphorescent light-emitting material can be appropriately selected from known materials used for the light-emitting layer of the organic EL element, and is preferably a complex compound containing a group 8-10 metal in the periodic table of elements. More preferably, an iridium compound, an osmium compound, or a platinum compound (platinum complex compound), or a rare earth complex, and most preferably an iridium compound.

  Specific examples of the compound used as the phosphorescent material are shown below, but the present invention is not limited to these. These compounds are described, for example, in Inorg. Chem. 40, 1704-1711, and the like.

  A fluorescent substance can also be used for the organic electroluminescent element of the present invention. Representative examples of fluorescent emitters (fluorescent dopants) include coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, pyrylium dyes. Examples thereof include dyes, perylene dyes, stilbene dyes, polythiophene dyes, and rare earth complex phosphors.

  Conventionally known dopants can also be used in the present invention. For example, International Publication No. 00/70655 pamphlet, JP-A Nos. 2002-280178, 2001-181616, 2002-280179, 2001 181617, 2001-345183, 2002-324679, WO 02/15645, JP-A 2002-332291, 2002-50484, 2002-332292, 2002-83684, JP-T 2002-540572, JP-A 2002-117978, 2002-338588, 2002-170684, 2002-352960, International Publication No. 01/93642 No. Pamphlet G, JP 2002-50483 A, 2002-100476, 2002-173684, 2002-359082, 2002-17584, 2002-363552, 2002-184582. JP, 2003-7469, JP 2002-525808, JP 2003-7471, JP 2002-525833, JP 2003-31366, 2002-226495, 2002 No. 234894, No. 2002-235076, No. 2002-241771, No. 2001-31979, No. 2001-319780, No. 2002-62824, No. 2002-1000047, No. 2002. 203679 Publication, the 2002-343572 and JP Laid Nos. 2002-203678 and the like.

In the present invention, at least one light emitting layer may contain two or more kinds of light emitting materials, and the concentration ratio of the light emitting materials in the light emitting layer may vary in the thickness direction of the light emitting layer.
《Middle layer》
In the present invention, a case where a non-light emitting intermediate layer (also referred to as an undoped region) is provided between the light emitting layers will be described.

  The non-light emitting intermediate layer is a layer provided between the light emitting layers in the case of having a plurality of light emitting layers.

  The film thickness of the non-light emitting intermediate layer is preferably in the range of 1 to 20 nm, and further in the range of 3 to 10 nm suppresses interaction such as energy transfer between adjacent light emitting layers, and the current of the device This is preferable because a large load is not applied to the voltage characteristics.

  The material used for the non-light emitting intermediate layer may be the same as or different from the host compound of the light emitting layer, but may be the same as the host material of at least one of the adjacent light emitting layers. preferable.

  The non-light-emitting intermediate layer may contain a non-light-emitting layer, a compound common to each light-emitting layer (for example, a host compound), and each common host material (where a common host material is used) In the case where the physicochemical characteristics such as phosphorescence emission energy and glass transition point are the same, or the molecular structure of the host compound is the same, etc.) The barrier is reduced, and the effect of easily maintaining the injection balance of holes and electrons even when the voltage (current) is changed can be obtained. Furthermore, by using a host material having the same physical characteristics or the same molecular structure as the host compound contained in each light-emitting layer in the undoped light-emitting layer, device fabrication, which is a major problem in conventional organic EL device fabrication, is achieved. Complexity can also be eliminated.

  When the organic EL device is used in the present invention, since the host material is responsible for carrier transport, a material having carrier transport capability is preferable. Carrier mobility is used as a physical property representing carrier transport ability, but the carrier mobility of an organic material generally depends on the electric field strength. Since a material having a high electric field strength dependency easily breaks the balance between injection and transport of holes and electrons, it is preferable to use a material having a low electric field strength dependency of mobility for the intermediate layer material and the host material.

  On the other hand, in order to optimally adjust the injection balance of holes and electrons, it is also preferable that the non-light emitting intermediate layer functions as a blocking layer described later, that is, a hole blocking layer and an electron blocking layer. It is done.

<< Injection layer: electron injection layer, hole injection layer >>
The injection layer is provided as necessary, and there are an electron injection layer and a hole injection layer, and as described above, it exists between the anode and the light emitting layer or the hole transport layer and between the cathode and the light emitting layer or the electron transport layer. May be.

  An injection layer is a layer provided between an electrode and an organic layer in order to reduce drive voltage and improve light emission luminance. “Organic EL element and its forefront of industrialization (issued by NTT Corporation on November 30, 1998) 2), Chapter 2, “Electrode Materials” (pages 123 to 166) in detail, and includes a hole injection layer (anode buffer layer) and an electron injection layer (cathode buffer layer).

  The details of the anode buffer layer (hole injection layer) are described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069 and the like. As a specific example, copper phthalocyanine is used. Examples thereof include a phthalocyanine buffer layer represented by an oxide, an oxide buffer layer represented by vanadium oxide, an amorphous carbon buffer layer, and a polymer buffer layer using a conductive polymer such as polyaniline (emeraldine) or polythiophene.

  The details of the cathode buffer layer (electron injection layer) are described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like. Specifically, strontium, aluminum, etc. Metal buffer layer typified by lithium, alkali metal compound buffer layer typified by lithium fluoride, alkaline earth metal compound buffer layer typified by magnesium fluoride, oxide buffer layer typified by aluminum oxide, etc. . The buffer layer (injection layer) is preferably a very thin film, and the film thickness is preferably in the range of 0.1 nm to 5 μm although it depends on the material.

<Blocking layer: hole blocking layer, electron blocking layer>
The blocking layer is provided as necessary in addition to the basic constituent layer of the organic compound thin film as described above. For example, it is described in JP-A Nos. 11-204258, 11-204359, and “Organic EL elements and their forefront of industrialization” (issued by NTT, Inc. on November 30, 1998). There is a hole blocking (hole blocking) layer.

  The hole blocking layer has a function of an electron transport layer in a broad sense, and is made of a hole blocking material that has a function of transporting electrons and has a remarkably small ability to transport holes. The probability of recombination of electrons and holes can be improved by blocking. Moreover, the structure of the electron carrying layer mentioned later can be used as a hole-blocking layer concerning this invention as needed. The hole blocking layer is preferably provided adjacent to the light emitting layer.

  On the other hand, the electron blocking layer has a function of a hole transport layer in a broad sense, and is made of a material having a function of transporting holes while having a very small ability to transport electrons, and transporting electrons while transporting holes. By blocking, the recombination probability of electrons and holes can be improved. Moreover, the structure of the positive hole transport layer mentioned later can be used as an electron blocking layer as needed. The film thickness of the hole blocking layer and the electron transport layer according to the present invention is preferably 3 to 100 nm, and more preferably 5 to 30 nm.

《Hole transport layer》
The hole transport layer is made of a hole transport material having a function of transporting holes, and in a broad sense, a hole injection layer and an electron blocking layer are also included in the hole transport layer. The hole transport layer can be provided as a single layer or a plurality of layers.

  The hole transport material has any one of hole injection or transport and electron barrier properties, and may be either organic or inorganic. For example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, Examples thereof include stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers, particularly thiophene oligomers.

  The above-mentioned materials can be used as the hole transport material, but it is preferable to use a porphyrin compound, an aromatic tertiary amine compound and a styrylamine compound, particularly an aromatic tertiary amine compound.

  Representative examples of aromatic tertiary amine compounds and styrylamine compounds include N, N, N ′, N′-tetraphenyl-4,4′-diaminophenyl; N, N′-diphenyl-N, N′— Bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine (TPD); 2,2-bis (4-di-p-tolylaminophenyl) propane; 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane; N, N, N ′, N′-tetra-p-tolyl-4,4′-diaminobiphenyl; 1,1-bis (4-di-p-tolyl) Aminophenyl) -4-phenylcyclohexane; bis (4-dimethylamino-2-methylphenyl) phenylmethane; bis (4-di-p-tolylaminophenyl) phenylmethane; N, N′-diphenyl-N, N ′ − (4-methoxyphenyl) -4,4′-diaminobiphenyl; N, N, N ′, N′-tetraphenyl-4,4′-diaminodiphenyl ether; 4,4′-bis (diphenylamino) quadriphenyl; N, N, N-tri (p-tolyl) amine; 4- (di-p-tolylamino) -4 ′-[4- (di-p-tolylamino) styryl] stilbene; 4-N, N-diphenylamino- (2-diphenylvinyl) benzene; 3-methoxy-4′-N, N-diphenylaminostilbenzene; N-phenylcarbazole, as well as two of those described in US Pat. No. 5,061,569 Having a condensed aromatic ring in the molecule, for example, 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), JP-A-4-3086 4,4 ′, 4 ′ ″-tris [N- (3-methylphenyl) -N-phenylamino] triphenyl in which three triphenylamine units described in No. 8 are linked in a starburst type An amine (MTDATA) etc. are mentioned.

  Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used. In addition, inorganic compounds such as p-type-Si and p-type-SiC can also be used as the hole injection material and the hole transport material.

  JP-A-11-251067, J. Org. Huang et. al. A so-called p-type hole transport material described in a book (Applied Physics Letters 80 (2002), p. 139) can also be used. In the present invention, it is preferable to use these materials because a light-emitting element with higher efficiency can be obtained.

  The hole transport layer can be formed by thinning the hole transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method. it can. Although there is no restriction | limiting in particular about the film thickness of a positive hole transport layer, Usually, 5 nm-about 5 micrometers, Preferably it is 5-200 nm. The hole transport layer may have a single layer structure composed of one or more of the above materials.

  Alternatively, a hole transport layer having a high p property doped with impurities can be used. Examples thereof include JP-A-4-297076, JP-A-2000-196140, 2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like.

  In the present invention, it is preferable to use a hole transport layer having such a high p property because a device with lower power consumption can be produced.

《Electron transport layer》
The electron transport layer is made of a material having a function of transporting electrons, and in a broad sense, an electron injection layer and a hole blocking layer are also included in the electron transport layer. The electron transport layer can be provided as a single layer or a plurality of layers.

  Conventionally, in the case of a single electron transport layer and a plurality of layers, an electron transport material (also serving as a hole blocking material) used for an electron transport layer adjacent to the light emitting layer on the cathode side is injected from the cathode. As long as it has a function of transferring electrons to the light-emitting layer, any material can be selected and used from among conventionally known compounds. For example, nitro-substituted fluorene derivatives, diphenylquinone derivatives Thiopyrandioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives and the like. Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron withdrawing group can also be used as an electron transport material. Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

In addition, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq ₃ ), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) Aluminum, tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), etc., and the central metals of these metal complexes are In, Mg Metal complexes replaced with Cu, Ca, Sn, Ga, or Pb can also be used as electron transport materials. In addition, metal-free or metal phthalocyanine, or those having terminal ends substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron transporting material. Further, the distyrylpyrazine derivatives exemplified as the material of the light emitting layer can also be used as the electron transport material, and inorganic semiconductors such as n-type-Si and n-type-SiC can be used as well as the hole injection layer and the hole transport layer. It can be used as an electron transport material.

  The electron transport layer can be formed by thinning the electron transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method. Although there is no restriction | limiting in particular about the film thickness of an electron carrying layer, Usually, 5 nm-about 5 micrometers, Preferably it is 5-200 nm. The electron transport layer may have a single layer structure composed of one or more of the above materials.

  Further, an electron transport layer having a high n property doped with impurities can also be used. Examples thereof include JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, 2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like.

  In the present invention, it is preferable to use an electron transport layer having such a high n property because an element with lower power consumption can be manufactured.

<Sealing>
Examples of the sealing means used for sealing the organic EL element of the present invention include a method of bonding a sealing member, an electrode, and a support substrate with an adhesive.

  The sealing member may be disposed so as to cover the display area of the organic EL element, and may be concave or flat. Moreover, transparency and electrical insulation are not particularly limited.

  Specifically, a glass plate, a polymer plate, a film, a metal plate, a film, etc. are mentioned. Examples of the glass plate include soda-lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz. Examples of the polymer plate include polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, and polysulfone. Examples of the metal plate include those made of one or more metals or alloys selected from the group consisting of stainless steel, iron, copper, aluminum, magnesium, nickel, zinc, chromium, titanium, molybdenum, silicon, germanium, and tantalum.

In the present invention, a polymer film and a metal film can be preferably used because the element can be thinned. Furthermore, the polymer film preferably has an oxygen permeability of 10 ⁻³ g / m ² / day or less and a water vapor permeability of 10 ⁻³ g / m ² / day or less. The water vapor permeability and oxygen permeability are more preferably 10 ⁻⁵ g / m ² / day or less.

  For processing the sealing member into a concave shape, sandblasting, chemical etching, or the like is used. Specific examples of the adhesive include photocuring and thermosetting adhesives having reactive vinyl groups such as acrylic acid oligomers and methacrylic acid oligomers, and moisture curing adhesives such as 2-cyanoacrylates. be able to. Moreover, heat | fever and chemical curing types (two-component mixing), such as an epoxy type, can be mentioned. Moreover, hot-melt type polyamide, polyester, and polyolefin can be mentioned. Moreover, a cationic curing type ultraviolet curing epoxy resin adhesive can be mentioned.

  In addition, since an organic EL element may deteriorate by heat processing, what can be adhesive-hardened from room temperature to 80 degreeC is preferable. A desiccant may be dispersed in the adhesive. Application | coating of the adhesive agent to a sealing part may use commercially available dispenser, and may print it like screen printing.

  In addition, it is also preferable to coat the electrode and the organic layer on the outside of the electrode facing the support substrate with the organic layer interposed therebetween, and form an inorganic or organic layer in contact with the support substrate to form a sealing film. it can. In this case, the material for forming the film may be any material that has a function of suppressing intrusion of elements that cause deterioration of elements such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like may be used. it can. Further, in order to improve the brittleness of the film, it is preferable to have a laminated structure of these inorganic layers and layers made of organic materials. The method for forming these films is not particularly limited. For example, vacuum deposition, sputtering, reactive sputtering, molecular beam epitaxy, cluster ion beam method, ion plating method, plasma polymerization method, atmospheric pressure A plasma polymerization method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used.

  In the gap between the sealing member and the display area of the organic EL element, it is preferable to inject an inert gas such as nitrogen or argon, or an inert liquid such as fluorinated hydrocarbon or silicon oil in the gas phase and the liquid phase. . A vacuum can also be used. Moreover, a hygroscopic compound can also be enclosed inside.

  Examples of the hygroscopic compound include metal oxides (for example, sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide) and sulfates (for example, sodium sulfate, calcium sulfate, magnesium sulfate, cobalt sulfate). Etc.), metal halides (eg calcium chloride, magnesium chloride, cesium fluoride, tantalum fluoride, cerium bromide, magnesium bromide, barium iodide, magnesium iodide etc.), perchloric acids (eg perchloric acid) Barium, magnesium perchlorate, and the like), and anhydrous salts are preferably used in sulfates, metal halides, and perchloric acids.

《Protective film, protective plate》
In order to increase the mechanical strength of the element, a protective film or a protective plate may be provided on the outer side of the sealing film on the side facing the support substrate with the organic layer interposed therebetween or on the sealing film. In particular, when the sealing is performed by the sealing film, the mechanical strength is not necessarily high, and thus it is preferable to provide such a protective film and a protective plate. As a material that can be used for this, the same glass plate, polymer plate / film, metal plate / film, and the like used for the sealing can be used, but the polymer film is light and thin. Is preferably used.

"electrode"
The surface light emitting device according to the present invention has at least a first electrode and a second electrode. When an organic EL element is used, one is usually composed of an anode and the other is a cathode. The preferred anode and cathode configurations are described below.

"anode"
As the anode in the organic EL element, an electrode material made of a metal, an alloy, an electrically conductive compound, or a mixture thereof having a high work function (4 eV or more) is preferably used. Specific examples of such an electrode material include metals such as Au, and conductive light transmissive materials such as CuI, indium tin oxide (ITO), SnO ₂ , and ZnO. Alternatively, a material such as IDIXO (In ₂ O ₃ —ZnO) that can form an amorphous light-transmitting conductive film may be used. For the anode, these electrode materials may be formed into a thin film by a method such as vapor deposition or sputtering, and a pattern having a desired shape may be formed by a photolithography method. ), A pattern may be formed through a mask having a desired shape when the electrode material is deposited or sputtered. Or when using the substance which can be apply | coated like an organic electroconductivity compound, wet film forming methods, such as a printing system and a coating system, can also be used. The sheet resistance as the anode is preferably several hundred Ω / □ or less. Further, although the film thickness depends on the material, it is usually selected in the range of 10 to 1000 nm, preferably 10 to 200 nm.

"cathode"
On the other hand, as the cathode, a material having a low work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof as an electrode material is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like.

Among these, from the point of durability against electron injection and oxidation, etc., a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function than this, for example, a magnesium / silver mixture, Magnesium / aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al ₂ O ₃ ) mixtures, lithium / aluminum mixtures, aluminum and the like are preferred. The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. The sheet resistance as the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 to 200 nm.

In addition, in order to transmit the emitted light, either the anode or the cathode of the organic EL element can be configured by appropriately using the electrode material so as to be light transmissive. When making the anode side light-reflective, for example, aluminum and aluminum alloy, silver and silver compounds can be used to make light-reflective, and the light-reflective layer using these materials, the ITO, A light-transmitting anode such as SnO ₂ or ZnO can also be used in combination. When the cathode side is made light-transmitting, for example, a conductive material such as aluminum and an aluminum alloy, silver and a silver compound is made thin with a thickness of about 1 to 20 nm, and then mentioned in the description of the anode. By providing a film of a conductive light-transmitting material, a light-transmitting cathode can be obtained.

<< Method for producing organic EL element >>
As an example of the method for producing the organic EL device of the present invention, a method for producing an organic EL device comprising an anode / hole injection layer / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode will be described.

  First, a thin film made of a desired electrode material, for example, a material for an anode is formed on a suitable support substrate by a method such as vapor deposition or sputtering so as to have a film thickness of 1 μm or less, preferably 10 to 200 nm to produce an anode. . Next, an organic compound thin film of a hole injection layer, a hole transport layer, a light emitting layer, a hole blocking layer, and an electron transport layer, which are organic EL element materials, is formed thereon.

As a method for thinning the organic compound thin film, there are a vapor deposition method and a wet process (spin coating method, casting method, ink jet method, printing method) as described above, but it is easy to obtain a uniform film and a pinhole. From the point of being difficult to form, a vacuum deposition method, a spin coating method, an ink jet method, and a printing method are particularly preferable. Further, different film forming methods may be applied for each layer. When employing a vapor deposition method for film formation, the vapor deposition conditions vary depending on the type of compound used, but generally a boat heating temperature of 50 to 450 ° C., a degree of vacuum of 10 ⁻⁶ to 10 ⁻² Pa, and a vapor deposition rate of 0.01 to It is desirable to select appropriately within the range of 50 nm / second, substrate temperature −50 to 300 ° C., film thickness 0.1 nm to 5 μm, preferably 5 to 200 nm.

  After these layers are formed, a thin film made of a cathode material is formed thereon by a method such as vapor deposition or sputtering so as to have a thickness of 1 μm or less, preferably in the range of 50 to 200 nm, and a cathode is provided. Thus, a desired organic EL element can be obtained. The organic EL element is preferably produced from the hole injection layer to the cathode consistently by a single evacuation, but may be taken out halfway and subjected to different film forming methods. At that time, it is necessary to consider that the work is performed in a dry inert gas atmosphere.

  In addition, it is also possible to reverse the production order and produce the cathode, the electron injection layer, the electron transport layer, the light emitting layer, the hole transport layer, the hole injection layer, and the anode in this order. When a DC voltage is applied to the multicolor liquid crystal display device thus obtained, light emission can be observed by applying a voltage of about 2 to 40 V with the positive polarity of the anode and the negative polarity of the cathode. An alternating voltage may be applied. The alternating current waveform to be applied may be arbitrary.

  An organic EL element generally emits light within a layer having a refractive index higher than that of air (refractive index of about 1.6 to 2.1) and can extract only about 15 to 20% of light generated in the light emitting layer. It has been said. This is because light incident on the interface (interface between the transparent substrate and air) at an angle θ greater than the critical angle causes total reflection and cannot be extracted outside the device, or between the transparent electrode or light emitting layer and the transparent substrate. This is because the light is totally reflected between the light and the light is guided through the transparent electrode or the light emitting layer, and as a result, the light escapes in the direction of the element side surface.

  As a method for improving the light extraction efficiency, for example, a method of forming irregularities on the surface of the transparent substrate to prevent total reflection at the interface between the transparent substrate and the air (for example, US Pat. No. 4,774,435). ), A method of improving the efficiency by giving the substrate a light condensing property (for example, JP-A-63-314795), a method of forming a reflective surface on the side surface of the element (for example, JP-A-1-220394) Gazette), a method of forming an antireflection film by introducing a flat layer having an intermediate refractive index between the substrate and the light emitter (for example, Japanese Patent Application Laid-Open No. 62-172691), and a substrate between the substrate and the light emitter. A method of introducing a flat layer having a lower refractive index than that (for example, Japanese Patent Application Laid-Open No. 2001-202827), a diffraction grating between any one of the substrate, the transparent electrode layer and the light emitting layer (including between the substrate and the outside). Method of forming There is 1-283751 JP), and the like.

  In the present invention, these methods can be used in combination with the element according to the present invention. However, a method of introducing a flat layer having a lower refractive index than the substrate between the substrate and the light emitter, or a substrate and a transparent electrode A method of forming a diffraction grating between any of the layers and the light emitting layer (including between the substrate and the outside) can be suitably used. In the present invention, by combining these means, it is possible to obtain an element having higher luminance or durability.

  When a medium having a low refractive index is formed between the transparent electrode and the transparent substrate with a thickness longer than the wavelength of light, the light extracted from the transparent electrode has a higher extraction efficiency to the outside as the refractive index of the medium is lower.

  Examples of the low refractive index layer include aerogel, porous silica, magnesium fluoride, and a fluorine-based polymer. Since the refractive index of the transparent substrate is generally about 1.5 to 1.7, the low refractive index layer preferably has a refractive index of about 1.5 or less. Furthermore, it is preferable that it is 1.35 or less.

  The thickness of the low refractive index medium is preferably at least twice the wavelength in the medium. This is because the effect of the low-refractive index layer is reduced when the thickness of the low-refractive index medium is about the wavelength of light and the electromagnetic wave exuded by evanescent enters the substrate.

  The method of introducing a diffraction grating into an interface or any medium that causes total reflection is characterized by a high effect of improving light extraction efficiency. This method uses the property that the diffraction grating can change the direction of light to a specific direction different from refraction by so-called Bragg diffraction, such as first-order diffraction and second-order diffraction. Among them, light that cannot be emitted due to total reflection between layers, etc. is diffracted by introducing a diffraction grating into any layer or medium (in a transparent substrate or transparent electrode), and the light is emitted outside. I want to take it out.

  It is desirable that the diffraction grating to be introduced has a two-dimensional periodic refractive index. This is because light emitted from the light-emitting layer is randomly generated in all directions, so in a general one-dimensional diffraction grating having a periodic refractive index distribution only in a certain direction, only light traveling in a specific direction is diffracted. The light extraction efficiency does not increase so much. However, by making the refractive index distribution a two-dimensional distribution, light traveling in all directions is diffracted, and light extraction efficiency is increased.

  The position where the diffraction grating is introduced may be in any one of the layers or in the medium (in the transparent substrate or the transparent electrode) as described above, but is preferably in the vicinity of the organic light emitting layer where light is generated.

  At this time, the period of the diffraction grating is preferably about 1/2 to 3 times the wavelength of light in the medium. The arrangement of the diffraction grating is preferably two-dimensionally repeated, such as a square lattice, a triangular lattice, or a honeycomb lattice.

  The surface light emitting device according to the present invention is processed on the light extraction side of the support substrate, for example, so as to provide a structure on the microlens array, or in combination with a so-called condensing sheet, in a specific direction, for example, the device light emitting surface On the other hand, the brightness | luminance in a specific direction can be raised by condensing in a front direction.

  As an example of the microlens array, quadrangular pyramids having a side of 30 μm and an apex angle of 90 degrees are two-dimensionally arranged on the light extraction side of the substrate. One side is preferably 10 to 100 μm. If it becomes smaller than this, the effect of diffraction will generate | occur | produce and color, and if too large, thickness will become thick and is not preferable.

  As the condensing sheet, for example, a sheet that is put into practical use in an LED backlight of a liquid crystal display device can be used. As such a sheet, for example, a brightness enhancement film (BEF) manufactured by Sumitomo 3M Limited can be used. As the shape of the prism sheet, for example, the base material may be formed by forming a △ -shaped stripe having a vertex angle of 90 degrees and a pitch of 50 μm, or the vertex angle is rounded and the pitch is changed randomly. Other shapes may be used.

  Moreover, in order to control the light emission angle from a light emitting element, you may use together a light diffusing plate and a film with a condensing sheet. For example, a diffusion film (light-up) manufactured by Kimoto Co., Ltd. can be used.

  The method for forming the pressure-sensitive adhesive layer and the adhesive layer on the element laminate is not particularly limited, and a general method such as a gravure coater, a micro gravure coater, a comma coater, a bar coater, a spray coating, an ink jet method, or the like. Is mentioned.

<Application>
The surface light emitter and the light emitting panel according to the present invention can be used as a display device, a display, and various light emission sources. Examples of light sources include home lighting, interior lighting, clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources for optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processors, and light sources for optical sensors. Although it is not limited to this, it can be effectively used for a backlight of a liquid crystal display device combined with a color filter and a light source for illumination.

  When used as a backlight of a display in combination with a color filter, it is preferably used in combination with a light collecting sheet in order to further increase the luminance.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

<< Fabrication of surface light emitting element >>
[Fabrication of Surface Light Emitting Element-201]
After patterning a support substrate in which ITO (indium tin oxide) was formed to a thickness of 120 nm on a glass substrate of 22 mm × 22 mm and a thickness of 0.7 mm as a first electrode (anode), this ITO transparent electrode The transparent support substrate attached with is ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and after UV ozone cleaning for 5 minutes, this transparent support substrate is connected to a commercially available vacuum deposition apparatus in a plasma processing chamber. Fixed to the substrate holder. In addition, each of the vapor deposition crucibles in the vacuum vapor deposition apparatus was filled with an optimum amount of the constituent material of each layer for device fabrication. The evaporation crucible used was made of a resistance heating material made of molybdenum or tungsten.

After performing plasma treatment for 2 minutes at an oxygen pressure of 1 Pa and an electric power of 100 W (electrode area of about 450 cm ² ), the substrate was transferred to an organic layer deposition chamber without being exposed to the atmosphere, and an organic layer was formed.

First, after reducing the vacuum to 1 × 10 ⁻⁴ Pa, the deposition crucible containing m-MTDATA was energized and heated, and deposited on a transparent support substrate at a deposition rate of 0.1 nm / second. A hole injection layer was provided. Next, α-NPD was vapor-deposited in the same manner to provide a 30 nm hole transport layer.

  Next, each light emitting layer was sequentially provided in the following procedure.

  Compounds D-3 and H-1 were co-evaporated at a deposition rate of 0.1 nm / second so that D-3 would have a concentration of 9% by mass, and a blue phosphorescence emission having an emission maximum wavelength of 470 nm and a thickness of 20 nm. A layer was formed. Next, compounds D-1 and CBP were co-evaporated at a deposition rate of 0.1 nm / second so that D-1 would have a concentration of 5% by mass, and a green phosphorescent light emitting layer having an emission maximum wavelength of 518 nm and a thickness of 5 nm. Formed. Next, compounds D-2 and CBP were co-evaporated at a deposition rate of 0.1 nm / second so that D-2 had a concentration of 8% by mass, and a red phosphorescent emitting layer having an emission maximum wavelength of 622 nm and a thickness of 5 nm. Formed. Thereafter, Compound M-1 is vapor-deposited to a thickness of 10 nm to form a hole blocking layer, and CsF is co-deposited with Compound M-1 so that the film thickness ratio is 10%. A layer was formed. Furthermore, aluminum 110nm was vapor-deposited and the 2nd electrode (cathode) was formed, and the white bottom emission type organic EL element was obtained. The light emitting area viewed from the direction perpendicular to the light emitting surface was a 20 mm × 20 mm square, and the center of the glass substrate coincided with the center of the light emitting area. Next, the non-light-emitting surface of the organic EL element was covered with a glass case to obtain a surface light-emitting element 201.

  FIG. 16 is a cross-sectional view of the surface light emitting device 201, and the organic EL device is covered with a glass cover 103. The sealing operation with the glass cover was performed in a glove box (in an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more) in a nitrogen atmosphere without bringing the organic EL element into contact with the atmosphere. In FIG. 16, 104 is a glass substrate, 105 is a second electrode (light reflective), 106 is a functional layer including an organic EL light emitting layer, and 107 is a first electrode (light transmissive). The glass cover 103 is filled with nitrogen gas 108. The glass cover 103 is bonded to the glass substrate 104 using a UV curable resin 110. Although not shown in the drawing, wiring connection portions of the first electrode (anode) and the second electrode (cathode) for connecting a plurality of surface light emitting elements are provided in the UV curable resin 110 portion.

[Production of Light-Emitting Panel 1: Comparative Example]
As shown in FIGS. 18A and 18B, five surface light-emitting elements-201 are prepared and pasted on a common glass substrate 113 with a light-transmitting UV curable resin. Produced. FIG. 17 is a simplified side view of the individual surface light emitting elements 201 constituting the light emitting panel 1, and the surface light emitting elements are formed on the substrate 104. FIG. 17 shows only the glass cover 103, the second electrode 105, the functional layer 106 including the organic EL light emitting layer, and the first electrode 107. FIG. 18A is a diagram showing the light emitting panel 1 as viewed from the direction perpendicular to the light emitting surface, and the light emitting region is indicated by 111. FIG. 18B is a side view of the light-emitting panel 1. In addition, although not shown in figure, each surface light emitting element was electrically connected in series and the space | interval of each surface light emitting element needed 5 mm in order to ensure the wiring between surface light emitting elements.

[Fabrication of Surface Light Emitting Element-202]
In the fabrication of the surface light emitting device-201, first, aluminum is deposited as a light reflecting film on a glass substrate with a thickness of 110 nm, and then SiO ₂ is deposited as an insulating film with a thickness of 20 nm, and then an ITO film is formed and an electron transport layer is formed. After that, a top emission type organic EL device was manufactured in the same manner except that a light transmissive second electrode (cathode) was formed by depositing a silver paste of 10 nm and then depositing ITO of 100 nm.

  Next, similarly to the surface light-emitting device-201, the non-light-emitting surface of the organic EL device was covered with a glass case to obtain a surface light-emitting device-202.

  FIG. 19 is a cross-sectional view of a surface light emitting device-202, 104 is a glass substrate, 105 is a second electrode (light transmissive), 106 is a functional layer including an organic EL light emitting layer, and 107 is a first electrode (light reflective). ), An insulating film 109, and a light reflecting film 112. The glass cover 103 is filled with nitrogen gas 108. The glass cover 103 is bonded to the glass substrate 104 using a UV curable resin 110. Although not shown in the drawing, wiring connection portions of the first electrode (anode) and the second electrode (cathode) for connecting a plurality of surface light emitting elements are provided in the UV curable resin 110 portion.

[Production of Light-Emitting Panel 2: Present Invention]
Three surface light-emitting elements-201 and two surface light-emitting elements-202 are manufactured, and these are formed on a common glass substrate 113 as shown in FIGS. 21 (a) and 21 (b). The light emitting panel 2 was produced by alternately pasting with a cured resin. FIG. 20 is a simplified side view of individual surface light emitting elements 202 constituting the light emitting panel 2 together with the surface light emitting elements 201, and the surface light emitting elements are formed on the substrate 104. FIG. 20 shows a functional layer 106 including a glass cover 103, a second electrode 105, and an organic EL light emitting layer. The first electrode 107, the insulating film 109, and the light reflecting film 112 are collectively light reflective. The first electrode layer 114 is illustrated. 21A is a diagram showing the light emitting panel 2 viewed from the direction perpendicular to the light emitting surface, and FIG. 21B is a side view of the light emitting panel 2. FIG. In the surface light emitting element-201, the substrate 104 and the common glass substrate 113 are attached, and in the surface light emitting element-202, the glass cover 103 and the common glass substrate 103 are attached. The light emitting surface of the light emitting panel 2 is the surface on the side where the surface light emitting elements -201 and 202 are not attached to the common glass substrate 113. The adjacent surface light emitting elements are electrically connected in series. However, since the anode and the cathode are adjacent to each other, the connection is easy, and the distance between the surface light emitting elements is about 1 mm. The space between the surface light emitting element and the common glass substrate 113 is filled with a light transmissive UV curable resin, and the surface light emitting elements are electrically connected in series.

[Production of Light-Emitting Panel 3: Present Invention]
Three surface light-emitting elements-201 and two surface light-emitting elements-202 are manufactured, and as shown in FIGS. 22 (a) and 22 (b), the light emission surface side of the common glass substrate 113 is used. The surface light emitting element -202 is disposed on the surface of the glass substrate 113, and the surface light emitting element -201 is disposed on the surface opposite to the light emitting surface of the glass substrate 113 so as to be alternately arranged. The substrate 104 of the surface light emitting element and the common glass substrate 113 were pasted with a light transmissive UV curable resin, and the light emitting panel 3 was produced. FIG. 22A is a view showing the light emitting panel 3 viewed from the direction perpendicular to the light emitting surface, and FIG. 22B is a side view of the light emitting panel 3. When viewed from the direction perpendicular to the light emitting surface of the glass substrate 113, the light emitting region 111 of the adjacent surface light emitting element-201 and the light emitting region 111 of the surface light emitting element-202 are disposed to be joined without a gap. The surface light emitting elements -202 arranged on the light emitting surface side surface of the glass substrate 113 are electrically connected in series, and the surface light emission arranged on the surface of the glass substrate 113 opposite to the light emitting surface. The elements -201 are electrically connected in series.

[Production of Light-Emitting Panel 4: Present Invention]
Using the manufacturing method of the surface light emitting elements-201 and 202, a glass substrate of 20 mm × 100 mm was used, and the light emitting area as viewed from the direction perpendicular to the light emitting surface was 20 mm × 20 mm, similar to the surface light emitting element-201 on one surface. Two bottom emission type surface light emitting elements which are squares of the same are the same as those of the surface light emitting element-202 on the other surface of the glass substrate, and the light emitting area viewed from the direction perpendicular to the light emitting surface is a square having a square of 20 mm × 20 mm. A panel 4 was formed in which three emission type surface light emitting elements were alternately formed so that the light emitting regions overlapped when viewed from the light emitting surface direction. FIG. 23A is a view showing the light emitting panel 4 viewed from the direction perpendicular to the light emitting surface, and FIG. 23B is a side view of the light emitting panel 4. A top emission type surface light emitting device -202 is formed on the light emitting surface side surface of the glass substrate 113, and a bottom emission type surface light emitting device -201 is formed on the surface opposite to the light emitting surface of the glass substrate 113. The glass substrate 113 is a common element substrate constituting the surface light emitting element-201 and the surface light emitting element-202. The light emitting regions 111 of the surface light emitting elements 201 and the light emitting regions 111 of the surface light emitting elements 202 that are alternately arranged are formed so as to overlap each other when viewed from the direction perpendicular to the light emitting surface of the glass substrate 113. In FIG. 23 (b), 115a indicates the edge of the light emitting region of the top emission type surface light emitting device formed on the light emitting surface side surface of the glass substrate 113, and 115b indicates the light emitting surface of the glass substrate 113. Indicates the edge of the light emitting region of the bottom emission surface emitting device formed on the opposite surface. The overlap width w of the light emitting regions was 1 mm. The surface light emitting elements -202 arranged on the light emitting surface side surface of the glass substrate 113 are electrically connected in series, and the surface light emission arranged on the surface of the glass substrate 113 opposite to the light emitting surface. The elements -201 are electrically connected in series.

[Evaluation of light emitting panels 1 to 4]
The light emitting panels 1 to 4 were arranged side by side to emit light and compared visually.

  The light-emitting panel 1 is clearly inferior in visibility because the non-light-emitting area exists as a wide area between adjacent light-emitting areas. On the other hand, in the light-emitting panel 2, the luminance reduction at the element connection portion is considerably improved. The light emission panel 3 and the light emission panel 4 were most excellent in visibility, with almost no luminance reduction observed at the element connection portion.

[Production of light-emitting panel 5: comparison]
Twenty-five surface light-emitting elements-201 are manufactured, and these are shown in FIGS. 24A and 24B. As shown in FIGS. 24A and 24B, five 5 × 5 matrix forms in the vertical direction and five horizontal directions in the surface. In addition, the light-emitting panel 5 was manufactured by pasting on a common glass substrate 113 with a light transmissive UV curable resin. FIG. 24A is a diagram showing the light emitting panel 5 viewed from the direction perpendicular to the light emitting surface, and the light emitting area is indicated by 111. FIG. 24B is a side view of the light emitting panel 5. Although not shown, five surface light emitting elements are electrically connected in series in the row direction, and then 25 surface light emitting elements are connected by sequentially connecting them in the column direction. Connected in series. In order to secure wiring between the surface light emitting elements, the interval between the surface light emitting elements required 5 mm.

[Production of Light-Emitting Panel 6: Present Invention]
Twelve surface light-emitting elements-201 and 13 surface light-emitting elements-202 are manufactured, and these are the surfaces on the light emission surface side of the common glass substrate 113 as shown in FIGS. 25 (a) to 25 (c). Further, five surface light emitting elements-202 are alternately arranged on the surface opposite to the light emitting surface of the glass substrate 113, and five surface light emitting elements-201 are alternately arranged in the vertical direction in the surface when viewed from the light emitting surface side of the glass substrate. Then, the substrate 104 of each surface light emitting element and the common glass substrate 113 are pasted with a light transmissive UV curable resin so as to be arranged in a 5 × 5 matrix in the row direction, and the light emitting panel 6 is attached. Produced.

  FIG. 25A is a view showing the light-emitting panel 6 viewed from the direction perpendicular to the emission surface, and FIG. 25B is an AA ′ portion, a CC ′ portion, and an EE ′ portion of the light-emitting panel 6. FIG. 25C is a cross-sectional view of the portion, the FF ′ portion, the HH ′ portion, and the JJ ′ portion, and FIG. 25C shows the BB ′ portion, DD ′ portion, G- It is sectional drawing of a G 'part and an II' part. The surface light emitting elements -202 arranged on the light emitting surface side surface of the glass substrate 113 are electrically connected in series, and the surface light emission arranged on the surface of the glass substrate 113 opposite to the light emitting surface. The elements -201 are electrically connected in series. In FIG. 25A, the surface of the surface light emitting element-202 disposed on the light emitting surface side surface of the glass substrate 113 and the surface disposed on the surface opposite to the light emitting surface side of the glass substrate 113. The element substrate 117 of the light emitting element-201 is arranged without a gap when viewed from the direction perpendicular to the light emitting surface.

[Evaluation of the light-emitting panels 5 and 6]
The light emitting panels 5 and 6 were arranged side by side to emit light and compared visually.

  The light emitting panel 5 has a large non-light emitting area between adjacent light emitting areas in a band shape, and thus clearly has poor visibility. On the other hand, the light emitting panel 6 had a small reduction in luminance at the element connection portion and was excellent in visibility.

It is a top view which shows an example which showed the surface emitting panel in connection with embodiment of this invention from the light-projection surface side. It is a top view which shows the example which comprised the surface emitting panel using the surface emitting element whose light emission surface is a rectangle. It is a side view explaining the XX 'part of the surface emitting panel shown in FIG.1 and FIG.2. It is a side view of another form explaining the XX 'part of the surface emitting panel shown in FIG.1 and FIG.2. It is a side view of another form explaining the XX 'part of the surface emitting panel shown in FIG.1 and FIG.2. It is the side view (a) of another form explaining the XX 'part of the surface emitting panel shown in FIG.1 and FIG.2, and the enlarged view of the junction part (b) and the overlap part (c). FIG. 3 is a side view of a surface light emitting panel according to the present invention in which top emission type surface light emitting elements and bottom emission type surface light emitting elements are alternately arranged. It is the side view (a) of the surface emitting panel arrange | positioned so that a top emission type surface emitting element and a bottom emission type surface emitting element may become alternate, and the enlarged view of the junction part (b) and the overlapping part (c). . It is a side view of the surface emitting panel which is a common element substrate in which the light-transmitting element supporting substrate constitutes each of the top emission type surface emitting element and the bottom emission type surface emitting element. A side view (a) of a surface emitting panel, which is a common element substrate in which a light-transmitting element supporting substrate constitutes each of a top emission type surface emitting element and a bottom emission type surface emitting element, and a joint portion (b) thereof, It is an enlarged view of an overlap part (c). It is a side view of the conventional general surface emitting panel comprised using a some surface emitting element. It is the enlarged view seen from the light-projection surface direction of the conventional common surface emitting panel comprised using a some surface emitting element. It is the enlarged view seen from the side surface direction of the conventional common surface emitting panel comprised using a some surface emitting element. It is the enlarged view which looked at the surface emitting panel in connection with this invention from the light-projection surface direction. It is the enlarged view of another form which looked at the surface emitting panel concerning this invention from the light-projection surface direction. It is a side view of the surface light emitting element concerning this invention. It is a side view of the surface light emitting element concerning this invention. It is the figure which showed the comparative light emission panel. It is a side view of the surface light emitting element concerning this invention. It is a side view of the surface light emitting element concerning this invention. It is the figure which showed the light emission panel in connection with this invention. It is the figure which showed another light emission panel in connection with this invention. It is the figure which showed another light emission panel in connection with this invention. It is the figure which showed the comparative light emission panel. It is the figure which showed another light emission panel in connection with this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Top emission type surface light emitting element 2 Bottom emission type surface light emitting element 3 Substrate of surface light emitting element 4 1st electrode 5 Functional layer containing a light emitting layer 6 2nd electrode 7 Light-transmitting element support substrate 8 Surface emitting panel 9 Surface light emission Element 10 Junction 11 Light-emitting area 103 Glass cover 104 Glass substrate 105 Second electrode (light reflectivity)
106 Functional layer including EL display layer 107 First electrode (light transmissive)
108 Nitrogen gas 109 Insulating film 110 UV curable resin 111 Light emitting region 112 Light reflecting film 113 Common glass substrate 114 Light reflective first electrode layer 115 Edge of light emitting region 116 Element substrate of surface light emitting element -202 117 Surface light emitting element- 201 element substrate 201 surface light-emitting element-201 of the present invention
202 surface light emitting device-202 of the present invention
T Top emission type surface light emitting element B Tom emission type surface light emitting element

Claims (4)

A surface emitting panel having a top emission type surface light emitting element and a bottom emission type surface light emitting element and emitting light in one direction, wherein the top emission type surface light emitting element and the bottom emission type surface light emitting element The light emitting direction is arranged to be the light emitting direction of the surface emitting panel, and the surface emitting elements are connected in series,
The surface-emitting panel has a light-transmitting element support substrate, a top emission type surface light-emitting element is disposed on one surface of the light-transmitting element support substrate, and the other of the light-transmitting element support substrates A surface emission panel for illumination , wherein a bottom emission type surface light emitting element is disposed on the surface of the surface. 2. The surface emitting panel for illumination according to claim 1 , wherein the light transmissive element supporting substrate is a common element substrate constituting each of a top emission type surface emitting element and a bottom emission type surface emitting element. . When the surface emitting panel is viewed from the vertical direction of the light emitting surface, a top emission type surface light emitting element and a bottom emission type surface light emitting element are alternately arranged, and a light emitting region of the top emission type surface light emitting element and a bottom emission type The surface emitting panel for illumination according to claim 1 or 2, wherein the light emitting region of the surface light emitting element is joined or overlapped. The surface emitting panel for illumination according to any one of claims 1 to 3 , wherein at least one selected from the top emission type surface light emitting element and the bottom emission type surface light emitting element is an organic EL element. .

Images