JP5273148B2 - Luminescent panel - Google Patents

Description

The present invention relates to a light-emitting panel. More specifically, the present invention relates to a light-emitting panel in which a plurality of surface light-emitting elements are arranged on a substrate having an uneven structure on at least one surface.

  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 it is inferior in visibility.

  In the sealing helicopter part of each electroluminescent element (hereinafter also referred to as “EL element”) to be joined, the end of the EL layer is rounded outward and slanted from the sealing helicopter part to the joining part. An element structure that emits light in the direction has been reported (see, for example, Patent Document 1). Moreover, the structure which installs a color conversion filter in the light-projection surface side which bonded the side surfaces of several EL element has been reported (for example, refer 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 (see, for example, 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 (for example, see Patent Document 4).

  However, in all of these conventional techniques, the seam remains as a non-light-emitting portion, and particularly in the case of using an organic electroluminescence element (hereinafter also referred to as “organic EL element”) that has been developed in recent years. It is necessary to sufficiently seal each element, and 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 improves the visibility. There was a limit.

  Further, when a large size light emitting panel is configured by arranging a plurality of surface light emitting elements, a structure in which surface light emitting elements are juxtaposed in the same plane is usually used, but this configuration electrically connects the elements. It is necessary to secure a wiring area, and this wiring area has a drawback that it is easily recognized visually as a non-light emitting portion in the light emitting panel.

JP 2001-57288 A JP 2006-164618 A JP 2007-200267 A JP 2007-304584 A

The present invention has been made in view of the above problems and situations, and a solution to the problem is a large-sized light-emitting panel composed of a plurality of surface light-emitting elements, where the boundary between the surface light-emitting elements is visually It is to provide a light-emitting panel that is difficult to recognize. Further, a light-emitting panel of large size constituted by a plurality of surface light emitting element, Ru der to provide a light-emitting panel which can reduce the in-plane luminance unevenness of the light emitting panel.

  The above-mentioned problem according to the present invention is solved by the following means.

1. A light-emitting panel in which a plurality of surface light-emitting elements are disposed on a substrate having a concavo-convex structure on at least one surface, wherein the surface light-emitting elements are disposed in and on the concave portions of the concavo-convex structure, from a light emitting surface vertical direction A light emitting panel characterized in that, when the light emitting panel is viewed, the element on the bottom surface of the concave portion and the element on the convex portion are partially overlapped .

  2. 2. The light emitting panel according to 1 above, wherein the area of the concave portion and the convex portion is 1 to 3 times the light emitting area of the surface light emitting element disposed.

  3. 3. The light emitting panel as described in 1 or 2 above, wherein the surface light emitting element arranged in the recess is buried in the recess.

  4). The light-emitting panel according to any one of 1 to 3, wherein the surface light-emitting element is an organic electroluminescence element.

  5. Any one of 1 to 4 above, wherein the surface light emitting elements arranged in the concave portions and the surface light emitting elements arranged on the convex portions are alternately electrically connected in series. The light-emitting panel according to one item.

By the above means of the present invention, it is possible to provide a light-emitting panel that is a large-sized light-emitting panel composed of a plurality of surface light-emitting elements and in which the boundary between the surface light-emitting elements is not easily recognized visually. Further, a light-emitting panel of large size constituted by a plurality of surface light emitting element, Ru can provide a light emitting panel that can reduce the in-plane luminance unevenness of the light emitting panel.

  That is, according to the light emitting panel of the present invention, since the wiring region for electrically connecting the elements can be provided to be inclined in the light emitting surface vertical direction, when the light emitting panel is viewed from the light emitting surface vertical direction, The space between the elements can be reduced, and the boundary between the surface light emitting elements can be made difficult to be visually recognized. In addition, when the shape of the opening of the recess is narrowed, the elements on the recess and the elements on the protrusion should partially overlap when the light-emitting panel is viewed from the direction perpendicular to the light emission surface. The boundary between the surface light emitting elements can be further prevented from being visually recognized.

  Note that in a light-emitting panel composed of a plurality of surface light-emitting elements, when the elements are connected in parallel, when some of the elements are short-circuited, a current easily flows through this portion, and the light-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. In this regard, the light-emitting panel according to the present invention makes it difficult to visually recognize the boundary between the surface light-emitting elements by the surface light-emitting element disposed in the concave portion and the surface light-emitting element disposed in the convex portion. It is possible to easily adopt a configuration in which these surface light emitting elements are alternately electrically connected in series.

An example of a cross-sectional view of a substrate used in the light-emitting panel of the present invention An example of a cross-sectional view of a substrate used in the light-emitting panel of the present invention An example of a cross-sectional view of a substrate used in the light-emitting panel of the present invention An example of a cross-sectional view of a substrate used in the light-emitting panel of the present invention An example of a cross-sectional view of a substrate used in the light-emitting panel of the present invention An example of a cross-sectional view of a substrate used in the light-emitting panel of the present invention Example of sectional view of light emitting panel of the present invention Example of the figure which saw the light emission panel of this invention from the light emission surface perpendicular | vertical direction Sectional drawing of the A-A 'part of FIG. An example of a cross-sectional view of the light-emitting panel of the present invention; in the case where the edges of the concave and convex portions are rounded or missing An example of a conventional light emitting panel viewed from the direction perpendicular to the light exit surface Sectional drawing of the B-B 'part of the light emission panel shown in FIG. An example of a conventional light emitting panel viewed from the direction perpendicular to the light exit surface Sectional drawing of the C-C 'part of the light emission panel shown in FIG. In the light emitting panel shown in FIGS. 11 and 12, an example of a schematic diagram in which a plurality of surface light emitting elements constituting the panel are electrically connected. In the conventional light emitting panel shown in FIGS. 13 and 14, an example of a schematic view in which a plurality of surface light emitting elements constituting the panel are electrically connected. An example of a schematic diagram in which a plurality of surface light emitting elements constituting the light emitting panel of the present invention shown in FIG. 9 are electrically connected; in the case where the surface light emitting elements arranged in the recesses are not buried in the recesses FIG. 9 shows an example of a schematic diagram in which a plurality of surface light-emitting elements constituting the light-emitting panel according to the present invention shown in FIG. 9 are electrically connected; in the case where the surface light-emitting element disposed at the bottom of the recess is buried in the recess Example of enlarged view of FIG. Example of enlarged view of FIG.

  The light-emitting panel of the present invention is a light-emitting panel in which a plurality of surface light-emitting elements are disposed on a substrate having a concavo-convex structure on at least one surface, and the surface light-emitting elements are disposed in and on the concave portions of the concavo-convex structure. It is characterized by. This feature is a technical feature common to the inventions according to claims 1 to 6.

  As an embodiment of the present invention, from the viewpoint of manifesting the effects of the present invention, it is preferable that the area of the concave portion and the convex portion is 1 to 3 times the light emitting area of the surface light emitting element to be arranged. Moreover, it is preferable that the surface emitting element arrange | positioned in the said recessed part is embed | buried in the said recessed part.

  In this invention, it is preferable that the said surface emitting element is an organic electroluminescent element (organic EL element). Moreover, it is preferable that the surface light emitting element arrange | positioned in the said recessed part and the surface light emitting element arrange | positioned on the said convex part are the aspects electrically connected in series alternately.

  Accordingly, the light-emitting panel substrate used in the light-emitting panel of the present invention has a plurality of recesses for disposing a surface light-emitting element therein and a plurality of portions for disposing a surface light-emitting element above the surface. It is necessary to alternately have the convex portions.

  In addition, the “surface light emitting element” in the present application refers to an element (light source) that generates light having an optical distribution of a surface form. In addition, the “light emitting area” of the surface light emitting element refers to an area occupied by a region emitting light in a plane when the surface emitting element that has emitted light is viewed from the direction perpendicular to the light emitting surface.

  On the other hand, the “area of the concave and convex portions” of the substrate having a concavo-convex structure is the area occupied by each concave and convex portion in the plane when the substrate is viewed from the direction perpendicular to the light emitting surface. The “light emission area” and the “area of the concave and convex portions” can be measured using a method such as capturing an image with a scanner and using an image processing apparatus.

  Hereinafter, the present invention, its components, and the best mode and mode for carrying out the present invention will be described in detail.

(Structure of substrate and light-emitting panel)
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.
<Substrate structure>
FIG. 1 is an example of a cross-sectional view of a substrate used in the light-emitting panel of the present invention. Concave portions 1 and convex portions 2 are alternately formed on the surface light emitting element forming side of the substrate. The cross-sectional shape of the concave portion 1 and the convex portion 2 can take various shapes such as a quadrangle, a trapezoid, and a shape including a curve in a part thereof. 2 to 6 show examples of the shapes of the concave portion 1 and the convex portion 2.

As a method for forming a substrate having a concavo-convex structure on at least one surface according to the present invention, for example,
(1) A method of injecting molten resin into a mold having a shape obtained by inverting the shape of the concave portion and the convex portion provided on the substrate and molding by injection molding.
(2) In a state where the resin molded into a sheet shape is heated, pressing between the mold having a shape obtained by inverting the shape of the concave portion and the convex portion provided on the substrate and the metal plate, or a heated die A method of transferring the concavo-convex shape by using and pressing.
(3) Fill a resin into a sheet mold having a shape obtained by inverting the shape of the concave and convex portions provided on the substrate, affix the resin on the substrate, and then peel the sheet mold to provide an uneven portion on the surface of the substrate. Molding method,
(4) Using a roll having a shape obtained by inverting the shape of the concave and convex portions provided on the substrate on its peripheral surface, passing the molten sheet-shaped resin between the rolls and extruding it, thereby forming the concave and convex shape How to transfer.

  Etc. In addition, in the industry such as photolithography, laser processing, etc., various methods for forming and transferring a pattern on a surface of a sheet of resin, glass or the like or a substrate can be appropriately used. The methods (1) to (4) are preferred.

<Structure of light-emitting panel>
FIG. 7 shows an example of a cross-sectional view of the light-emitting panel of the present invention configured using the substrate shown in FIG. The surface light emitting elements 3 are alternately formed in the concave and convex portions of the concavo-convex structure. It is preferable that one surface light emitting element is disposed in each recess and each protrusion. In the concave and convex portions, the surface on which the surface light emitting element is disposed is preferably a flat surface.

  FIG. 8 is an example of a view of the light-emitting panel of the present invention as viewed from the direction perpendicular to the light exit surface. The surface light emitting elements 3 are alternately arranged inside the concave portion 1 and the convex portion 2 of the concavo-convex structure. In the present invention, the shape of the concave portion 1 and the convex portion 2 when the light emitting panel is viewed from the direction perpendicular to the light emitting surface may be other shapes such as a triangle and a pentagon.

  FIG. 9 is a cross-sectional view of the A-A ′ portion of FIG. 8. The substrate 7 is a common substrate constituting the surface light emitting element to be arranged, and the first electrode 4, the functional layer 5 including the light emitting layer, and the second electrode 6 are formed on the concave and convex portions of the substrate 7, respectively. A surface light emitting element is formed. Although not shown, usually a sealing film or a sealing layer is provided thereon.

  In this invention, it is preferable that the area of each recessed part 1 and each convex part 2 is 1-3 times the light emission area of the surface emitting element arrange | positioned, It is more preferable that it is 1-2 times, 1-1. .5 times is preferable.

  In the light emitting panel of the present invention, the closer the area of the concave portion 1 and the convex portion 2 is to the light emitting area of the surface light emitting element 3 to be arranged, the more the wiring region that electrically connects the elements is inclined in the direction perpendicular to the light emitting surface. When the light emitting panel is viewed from the direction perpendicular to the light emitting surface, the distance between the elements is reduced, and the boundary between the surface light emitting elements is hardly visually recognized. Further, it is more effective that the substrate 7 has a cross-sectional shape in which the opening is narrower than the bottom of the recess as shown in FIG.

  In this invention, it is preferable that the surface emitting element arrange | positioned in a recessed part is embed | buried in the said recessed part. In the present invention, the fact that the surface light emitting element disposed in the recess is buried in the recess means that the thickness of the surface light emitting element disposed in the recess is L and the depth of the recess is H. When L / H <1, it is preferable that 0.1 <L / H <0.8, considering the wiring resistance connecting the surface light emitting elements.

  In the present invention, L is the length from the lower end of the lower electrode to the upper end of the upper electrode, and in FIG. 9, is the length from the lower end of the first electrode to the upper end of the second electrode. In the light emitting panel of the present invention, when L / H <1, the insulating structure that reduces the risk of short circuit between the surface light emitting element disposed in the concave portion and the surface light emitting element disposed on the adjacent convex portion Easy to configure.

  In the case where the edge of the concave portion or convex portion is rounded or chipped, the H is arranged on the convex portion from the lower end of the lower electrode of the surface light emitting element arranged in the concave portion as shown in FIG. The height to the lower end of the lower electrode of the surface light emitting element.

  FIG. 11 shows an example of a diagram in which a conventional light emitting panel in which a plurality of surface light emitting elements 3 are arranged on the same surface of the substrate 7 is viewed from the direction perpendicular to the light emitting surface. 12 is a cross-sectional view of the B-B ′ portion of the light emitting panel shown in FIG. 11.

  FIG. 13 shows an example of a view of a conventional light emitting panel in which the surface light emitting elements 3 are formed between the barriers of the substrate 8 provided with the barrier structure, as viewed from the direction perpendicular to the light emitting surface. FIG. 14 is a cross-sectional view of the C-C ′ portion of the light emitting panel shown in FIG. 13. A partition wall 9 is provided on the substrate 8, and a first electrode 4, a functional layer 5 including a light emitting layer, and a second electrode 6 are formed therebetween, and the surface light emitting element 3 is disposed.

  FIG. 15 is a schematic view in which a plurality of surface light emitting elements constituting the panel are electrically connected in the conventional light emitting panel shown in FIGS. 11 and 12. A plurality of surface light emitting elements 3 are connected by wiring 10 using a conductive film, but it is necessary to secure an insulating region and a wiring region between the elements on the substrate between the surface light emitting elements in the in-plane direction. The spacing between the elements usually needs to be 2 to 5 mm or more, and this wiring area is easily visually recognized as a non-light emitting portion in the light emitting panel.

  FIG. 16 is a schematic view in which a plurality of surface light emitting elements constituting the panel are electrically connected in the conventional light emitting panel shown in FIGS. 13 and 14. The plurality of surface light emitting elements 3 are connected by wiring 10 using a conductive film. However, it is necessary to secure a wiring area in the in-plane direction on the partition between the surface light emitting elements, and this wiring area is a light emitting panel. It is easy to be visually recognized as a non-light emitting part.

  In a light emitting panel composed of a plurality of surface light emitting elements such as organic EL elements as in the present invention, when the elements are electrically connected in parallel, the light emitting panel itself emits light when some of the elements are short-circuited. There is a possibility that it will not. 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 electrically connect the elements to each other in series.

  17 and 18 are schematic views in which a plurality of surface light emitting elements constituting the light emitting panel of the present invention shown in FIG. 9 are electrically connected. A plurality of surface light emitting elements 3 are connected by wiring 10, but the wiring direction is substantially perpendicular to the in-plane direction of the substrate, so that the wiring area is visually recognized as a non-light emitting portion in the light emitting panel. Hateful. FIG. 17 shows a case where the surface light emitting device arranged in the recess is not buried in the recess, and FIG. 18 shows the surface light emitting device arranged in the bottom of the recess buried in the recess. Show the case.

  FIG. 19 is an example of an enlarged view of FIG. A plurality of surface light emitting elements 3 are arranged on the unevenness of the substrate 7. Each surface light emitting element 3 includes a first electrode 4, a functional layer 5 including a light emitting layer, and a second electrode 6 on a substrate 7. In the adjacent surface light emitting elements 3, the first electrodes 4 and the second electrodes 6 are alternately connected by wirings 10 using conductive films. An insulating portion 11 is provided to prevent a short circuit between the first electrode 4 and the second electrode 6. Although not shown, the plurality of surface light emitting elements 3 respectively arranged in the unevenness are covered with a sealing film on the second electrode 6. In the configuration of FIG. 18, the distance between adjacent surface light emitting elements is preferably 2 mm or less, more preferably 1 mm or less even when considering the thickness of the wiring 10 and the insulating portion 11 when viewed from the light emitting vertical direction.

  FIG. 20 is an example of an enlarged view of FIG. A plurality of surface light emitting elements 3 are arranged on the unevenness of the substrate 7. Each surface light emitting element 3 includes a first electrode 4, a functional layer 5 including a light emitting layer, and a second electrode 6 on a substrate 7. In the adjacent surface light emitting elements 3, the first electrodes 4 and the second electrodes 6 are alternately connected by wirings 10 using conductive curtains. An insulating portion 11 is provided to prevent a short circuit between the first electrode 4 and the second electrode 6. Although not shown, the plurality of surface light emitting elements 3 respectively arranged in the unevenness are covered with a sealing film on the second electrode 6. In the configuration of FIG. 20, since the thickness of the surface light emitting element disposed at the bottom of the concave portion is smaller than the depth of the concave portion, a part of the insulating portion 11 is omitted from the configuration shown in FIG. It is possible to further reduce the interval between the surface light emitting elements.

  In the light emitting panel shown in FIGS. 18 and 20, the first electrode 4, the functional layer 5 including the light emitting layer, and the second electrode 6 of the plurality of surface light emitting elements 3 are directly formed on the unevenness of the substrate 7, respectively. Although an example is shown, in the present invention, a plurality of surface light-emitting elements prepared by previously laminating functional layers including electrodes and light-emitting layers on a support substrate are used, and these surface light-emitting elements are formed on the uneven surface of the substrate 7. In addition, the light-emitting panel can be configured by arranging and sticking each using an adhesive or a pressure-sensitive adhesive.

  As can be seen from the above description, according to the light emitting panel of the present invention, since the wiring region for electrically connecting the elements can be provided inclining in the light emitting surface vertical direction, light is emitted from the light emitting surface vertical direction. When the panel is viewed, the distance between the elements can be reduced, and the boundary between the surface light emitting elements can be hardly visually recognized. In addition, when the opening of the concave portion is narrowed, the elements on the concave portion and the elements on the convex portion are partially overlapped when the light emitting panel is viewed from the direction perpendicular to the light emitting surface. It is possible to make it difficult to visually recognize the boundary between the surface light emitting elements.

  In a light-emitting panel composed of multiple surface light-emitting elements, when the elements are connected in parallel, when some of the elements are short-circuited, current can easily flow through this area, and the light-emitting panel itself can no longer emit light. There is sex. 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.

  The light emitting panel according to the present invention makes it difficult to visually recognize the boundary between the surface light emitting elements by using the surface light emitting elements disposed in the concave portions and the surface light emitting elements disposed in the convex portions. It is possible to easily adopt a configuration in which these are alternately electrically connected in series.

(Organic EL device)
Although there is no restriction | limiting in the surface emitting element used for the light emission panel of 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 of this invention by 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 as used in the field of this invention is a film thickness also including the said 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 the host compound contained in the light emitting layer of the organic EL device according to 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 according to 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, 2002-280180, 2001-247859, 2002-299060, 2001-313178, 2002-302671, 2001-345183, 2002. No. 324679, International Publication No. 02/15645, JP 2002-332291 A, 2002-50484, 2002-332292, 2002-83684, JP 2002-540572, JP 2 No. 02-117978, No. 2002-338588, No. 2002-170684, No. 2002-352960, Pamphlet of International Publication No. 01/93642, JP 2002-50483, No. 2002-1000047. No. 2002-173684, No. 2002-359082, No. 2002-17584, No. 2002-363552, No. 2002-184582, No. 2003-7469, No. 2002-525808. JP-A 2003-7471, JP-T 2002-525833, JP-A 2003-31366, JP-A 2002-226495, JP-A 2002-234894, JP-A 2002-2335076, JP-A 2002-24175 Gazette, 2001-319779, 2001-319780, 2002-62824, 2002-1000047, 2002-203679, 2002-343572, 2002-203678. A gazette etc. are mentioned.

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.

  In a broad sense, the hole blocking layer has a function of an electron transport layer and is composed of a hole blocking material having a function of transporting electrons and having a remarkably small ability to transport holes, while transporting electrons. By blocking holes, the recombination probability of electrons and holes can be improved. 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, in a broad sense, has a function of a hole transport layer, and is made of a material having a function of transporting holes while having a remarkably small ability to transport electrons, while transporting holes. By blocking electrons, the probability of recombination 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, and also 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] triphenylamine in which three triphenylamine units described in Japanese Patent No. 8 are linked in a starburst type ( MTDATA) and the like.

  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.
《Support substrate》
The support substrate (hereinafter also referred to as substrate, substrate, substrate, substrate, support, etc.) according to the organic EL device of the present invention is not particularly limited in the type of glass, plastic, etc., and is transparent. It may be opaque. When extracting light from the support substrate side, the support substrate is preferably transparent. Examples of the transparent support substrate preferably used include glass, quartz, and a transparent resin film. A particularly preferable support substrate 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. Furthermore, in order to improve the brittleness of the film, it is more preferable to have a laminated structure of these inorganic layers and organic material layers. 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.
<Method for forming barrier film>
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.

Examples of the opaque support substrate include metal plates / films such as aluminum and stainless steel, opaque resin substrates, ceramic substrates, and the like.
<Sealing>
Examples of the sealing means used for sealing the organic EL element according to 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. Furthermore, 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 order to transmit the emitted light, either the anode or the cathode of the organic EL element is configured to be light transmissive.
<< Method for producing organic EL element >>
As an example of the method for producing an organic EL device according to 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 surface light emitting device according to the present invention, but 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, A method of forming a diffraction grating between any layers of the transparent electrode layer 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 with 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.

  Further, 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 diminished when the thickness of the low refractive index medium becomes about the wavelength of light and the electromagnetic wave that has 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.

  When the light emitting panel is configured by arranging a plurality of the surface light emitting elements according to the present invention so that the light emitting areas of the surface light emitting elements as viewed from the light emitting surface vertical direction have a plurality of element laminated portions, the element laminated portion An adhesive and an adhesive can be used.

  The pressure-sensitive adhesive in the present invention is widely used in the industrial field, and is bonded by pressurization among agents or materials used in designations such as pressure-sensitive adhesives, adhesives, pressure-sensitive adhesives, adhesives, etc. It means something that is not accompanied.

  Although the kind of adhesive and adhesive is not specifically limited, It is preferable to use the adhesive and adhesive excellent in light transmittance. As 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 suitably 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.

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 emitting 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.

DESCRIPTION OF SYMBOLS 1 Concave part 2 Convex part 3 Surface light emitting element 4 1st electrode 5 Functional layer containing a light emitting layer 6 2nd electrode 7 Substrate 8 Substrate 9 Partition 10 Wiring using a conductive film 11 Insulation part

Claims (7)

  A light-emitting panel in which a plurality of surface light-emitting elements are disposed on a substrate having a concavo-convex structure on at least one surface, wherein the surface light-emitting elements are disposed in and on the concave portions of the concavo-convex structure, from a light emitting surface vertical direction When the light emitting panel is viewed, the element on the bottom surface of the concave portion and the element on the convex portion are partially overlapped and arranged.   The area of the said recessed part and the said convex part is 1-3 times the light emission area of the said surface emitting element arrange | positioned, The light emission panel of Claim 1 characterized by the above-mentioned.   The light emitting panel according to claim 1, wherein the surface light emitting element disposed in the concave portion is buried in the concave portion.   The said surface emitting element is an organic electroluminescent element, The light emission panel as described in any one of Claim 1- Claim 3 characterized by the above-mentioned.   5. The surface light emitting element disposed in the concave portion and the surface light emitting element disposed on the convex portion are alternately electrically connected in series. The light emission panel as described in any one.   The light emitting panel according to any one of claims 1 to 5, wherein the substrate has a cross-sectional shape in which an opening is narrower than a bottom surface of the recess.   The light emitting panel according to claim 1, wherein the concave portions and the convex portions are alternately arranged in a matrix direction on the substrate.