WO2005112513A1

WO2005112513A1 - Electroluminescent device, illuminator and display

Info

Publication number: WO2005112513A1
Application number: PCT/JP2005/008878
Authority: WO
Inventors: Yasumi Yamada; Motofumi Kashiwagi
Original assignee: Zeon Corporation
Priority date: 2004-05-17
Filing date: 2005-05-16
Publication date: 2005-11-24

Abstract

Increase in emission intensity and reduction in power consumption of an electroluminescent device are demanded intensely and various efforts have been made to effectively take out light emitted from the light-emitting layer, but further enhancement of light taking-out efficiency is still required. A novel or high performance illuminator or display can be obtained by developing such a device. Disclosed is an electroluminescent device comprising a medium refractive index layer, a first electrode layer, a light-emitting layer and a second electrode layer formed sequentially in this order on a transparent substrate. This electroluminescent device satisfies the relation: nS < nM < nE where nS is the refractive index of the transparent substrate, nM is the refractive index of the medium refractive index layer, and nE is the refractive index of the first electrode layer. Also disclosed are a high performance illuminator and display employing such an electroluminescent device.

Description

Elect port luminescence element, lighting device, and display device

Technical field

The present invention relates to an electorifice luminescence element, a lighting device, and a display device, and more particularly, to an electoral port luminescence element, a lighting device, and a display device that have high luminance and consume less power.

Background art

As shown in FIG. 12, for example, a general electore luminescent element is provided on a flat transparent substrate 1 and a lower portion of the transparent substrate 1 in the drawing, and is also called an anode or a transparent electrode. One electrode layer 2, a light emitting layer 3 provided on the lower side of the first electrode layer 2 in the figure, and a second electrode layer 4 provided on the lower side of the light emitting layer 3 in the figure and also referred to as a cathode or a metal electrode. It is configured with. The light generated in the light emitting layer 3 is emitted upward through the first electrode layer 2 and is emitted from the transparent substrate 1 to the outside of the electroluminescent device (usually in the air). At this time, the efficiency with which light generated in the light emitting layer 3 can be emitted from the transparent substrate 1 to the outside of the electorescence luminescent element, that is, the light extraction efficiency is usually 20% or less. Improving extraction efficiency is a major issue. As a means for solving such a problem, reduction of reflection loss at the interface between the transparent substrate 1 and the outside of the electroluminescent device or the interface between the first electrode layer 2 and the transparent substrate 1 can be considered. For example, Patent Literatures 1 and 2 disclose a method for reducing reflection loss at an interface between a transparent substrate 1 and the outside of an electroluminescent device. In this reflection loss reduction method, when light is emitted from the transparent substrate 1 to the outside, light that is totally reflected at the interface due to the difference in the refractive index between the transparent substrate 1 and the outside of the electora luminescent element is removed. The interface shape in 1 is devised for transmission.

[0003] Patent Document 2 discloses that as shown in FIG. 13, light extraction efficiency can be increased by forming a minute unevenness group, that is, a minute lens array 11, on the surface of the transparent substrate 1 which is in contact with the outside. I have. According to such a configuration, the radiated light emitted from the light emitting layer 3 in various directions has its incident angle changed by the microlens array 11 formed on the surface of the transparent substrate 1. As a result, the reflection loss due to the total reflection of the emitted light at the interface is suppressed, so that the light extraction efficiency is improved as compared with the case where the surface of the transparent substrate 1 is flat. However, while such a method can reduce the reflection loss at the interface between the transparent substrate 1 and the outside of the electroluminescent device to some extent, sufficient light emission luminance is still obtained.

[0004] Patent Document 3 discloses a method for reducing reflection loss at the interface between the first electrode layer 2 and the transparent substrate 1. In this document, a transparent material layer having a lower refractive index than the transparent substrate 1 is formed at the interface between the first electrode layer 2 and the transparent substrate 1 so that the light emitting layer 3 at the interface between the transparent material layer and the transparent substrate 1 is formed. Total reflection of light emitted from In this case, at the interface between the first electrode layer 2 and the transparent material layer, a refractive index difference larger than the refractive index difference between the first electrode layer 2 and the transparent substrate 1 occurs. There is a problem that the reflection loss of the light from the light emitting layer 3 due to the total reflection at the portion increases.

Patent Document 1: JP-A-973983

Patent Document 2: Japanese Patent Application Laid-Open No. 2003-59641

Patent Document 3: JP 2003-142262 A (US2003116719 (A1), EP1309017 (A3))

Disclosure of the invention

Problems to be solved by the invention

[0006] There is a great demand for an increase in the emission intensity and a reduction in power consumption of the electoran luminescence element, and various devices have been devised for effectively extracting the light emitted from the light emitting layer as described above. However, a sufficient reflection loss reduction technology has not yet achieved satisfactory light extraction efficiency. It is desired that the light reflection loss at the interface between the first electrode layer and the transparent substrate, the reflection loss in the transparent substrate, and the like be improved to further improve the light extraction efficiency of the entire electroluminescent device. Development of new or high-performance lighting devices and display devices has been awaited due to the development of such devices.

Means for solving the problem

[0007] In order to solve the above-mentioned problems, a first invention provides an elector luminescence having an intermediate refractive index layer, a first electrode layer, a light emitting layer, and a second electrode layer in this order on a transparent substrate. An element, wherein the refractive index of the transparent substrate is n, the refractive index of the intermediate refractive index layer is n, Where n is the refractive index of the electrode layer, n <n <n.

E S M E

It is a sense element. Generally, when scattered light is transmitted from a medium to a medium with a large refractive index !, the reflection loss of light at the interface greatly depends on the difference in refractive index between the two media. Therefore, by inserting a medium having an index of refraction intermediate between these media, the reflection loss of light as a whole is reduced. The present invention is an invention utilizing such effects.

[0008] In a second aspect based on the first aspect, the difference in the refractive index between the first electrode layer and the intermediate refractive index layer, and the difference in the refractive index between the intermediate refractive index layer and the transparent substrate. Are electorific luminescence elements each having a value of 0.5 or less.

[0009] In a third aspect based on the first aspect, the intermediate refractive index layer is composed of two or more layers, and the refractive index of each layer constituting the intermediate refractive index layer is close to that of the first electrode layer. Η, η, ··· η in order from the layer, and electroluminescence with η> η> η>

Ml M2 Mk E Ml M2 Mk S

Sense element. The principle of this invention is the same as that of the first invention, but the difference in the refractive index at the interface between the first electrode layer, the adjacent intermediate refractive index layers, and the transparent substrate is reduced to gradually increase the refractive index. By changing it, the reflection loss of light is further reduced.

[0010] A fourth invention is the electroluminescent device according to the third invention, wherein a difference in refractive index between adjacent layers constituting the intermediate refractive index layer is 0.3 or less.

[0011] In a fifth aspect based on the first aspect, the elect structure wherein at least one surface of the transparent substrate, that is, at least one of the upper surface and the lower surface of the transparent substrate, is provided with a plurality of uneven structures. It is an oral luminescence element. As described above, when light of various directional forces is transmitted from a high-refractive index medium to a low-refractive index medium, the boundary of the concavo-convex structure is such that the angle of incidence of the light changes more than the flat boundary surface. When the reflection loss of light is smaller on the surface, the reflection loss of light is further reduced by utilizing the principle.

[0012] A sixth invention is the electorific luminescence device according to the first invention, wherein a reflection structure is provided on a side surface of the transparent substrate. Light from the light-emitting layer of the electoran luminescence element is radiated in all directions without directivity. Only the light directly directed to the upper surface of the transparent substrate is used. Light directed in other directions is reflected or refracted Unless it is directed to the upper surface of the transparent substrate in some way, it cannot be used. From this point of view, the invention is to increase the light extraction efficiency by providing a scattered light reflection structure on the side surface of the transparent substrate. Here, the side surface is an end surface other than the front surface (upper surface or lower surface of the transparent substrate), that is, an end surface along the thickness direction of the transparent substrate.

[0013] A seventh invention is the electroluminescent device according to the sixth invention, wherein the reflection structure portion has an uneven structure. According to the present invention, the uneven structure on the side surface increases the incident angle of scattered light entering the side surface from the light emitting layer side to facilitate total reflection, thereby directing light emitted to the outside to the transparent substrate side, As a result, the side surface functions as a reflection structure. In particular, a specific concave-convex structure described later fulfills a suitable light reflection function on the side surface.

[0014] An eighth invention is the electroluminescent device according to the sixth invention, wherein the reflection structure is a mirror surface. By making the side surface a mirror surface, almost all of the scattered light that also tends to emit a side force can be reflected to the transparent substrate side, and the light extraction efficiency can be further improved.

[0015] A ninth invention is the electroluminescence device according to the first invention, further comprising a gas noria layer having a water vapor transmission rate of 0.1 lg / m ² day or less between the transparent substrate and the first electrode layer. Element. In general, the electorophore luminescent element often uses an organic substance which is susceptible to gas such as water vapor and oxygen as a luminescent layer material, and an invention for preventing these gases from entering the luminescent layer. It is.

[0016] A tenth invention is the electroluminescent device according to the first invention, wherein the transparent substrate has a water absorption of 0.1% or less and a linear thermal expansion coefficient of 0 to 80 ppm / K. The present invention suppresses the influence of water vapor and the like on the light emitting layer of the electroluminescent device, thereby preventing the electroluminescent device from being deformed or destroyed in a use environment.

[0017] An eleventh invention is the electroluminescent device according to the first invention, wherein the transparent substrate is made of a resin having an alicyclic structure. It utilizes that the resin having an alicyclic structure effectively exhibits the function of the tenth invention.

[0018] A twelfth invention is a lighting device provided with the elect-opening luminescence element according to any one of the first inventions. [0019] A thirteenth invention is a display device provided with the electorifice luminescence element according to any one of the first inventions. The above-mentioned electoran luminescence element is excellent in light extraction efficiency and the like, and the twelfth and thirteenth inventions provide a suitable lighting device, display device or backlight device for the display device using the same. ! / Puru.

The invention's effect

[0020] The electoran luminescence element of the present invention suppresses light transmission loss at the interface between the transparent substrate and the first electrode layer, and has extremely excellent light extraction efficiency. Further, according to the ninth to eleventh inventions, it is possible to provide an electroluminescent device having excellent light extraction efficiency, stable performance, and a long lifetime. Further, in the twelfth and thirteenth inventions, it is possible to provide a high-performance lighting device and display device using such a high-performance elector emission luminescence element.

Brief Description of Drawings

FIG. 1 is a configuration diagram showing an electorifice luminescence device according to a first embodiment of the present invention.

FIG. 2 is an example showing a configuration diagram of an electorifice luminescence element of the present invention.

FIG. 3 is a configuration diagram showing an electorifice luminescence device of Example 2 of the present invention. The lower part shows an enlarged plan view of the microlens array.

FIG. 4 is a conceptual diagram showing another embodiment of the electorophore luminescent device of the present invention.

FIG. 5 is a conceptual diagram showing another embodiment of the electorophore luminescent device of the present invention. The lower part shows an enlarged plan view of the microlens array.

FIG. 6 is an explanatory diagram of the behavior of light rays in the transparent substrate of the electoran luminescence element shown in FIG.

FIG. 7 is a conceptual diagram of an electorifice luminescence element of Example 4. The lower part shows an enlarged plan view of the micro lens array.

[FIG. 8] FIG. 8 is an explanatory diagram of the behavior of light rays in the transparent substrate of the electoran luminescence element of FIG.

FIG. 9 is a configuration diagram illustrating an electorescence luminescent element with a mirror surface according to a fifth embodiment.

FIG. 10 is a configuration diagram showing an electorifice luminescence element according to Example 3 of the present invention. The The lower part shows an enlarged plan view of the microlens array.

FIG. 11 is a configuration diagram showing an electorifice luminescence element of Comparative Example 3. The lower part shows an enlarged plan view of the microlens array.

FIG. 12 is a configuration diagram showing an electorifice luminescence element of Comparative Example 1.

FIG. 13 is a configuration diagram showing an electorifice luminescence element of Comparative Example 2.

Explanation of symbols

[0022] 1 transparent substrate

la, lb Light rays totally reflected on the side of the transparent substrate and emitted from the transparent substrate surface

2 First electrode layer

3 Light-emitting layer

4 Second electrode layer

5, 5 'Intermediate refractive index layer

5 (5Ml-5Mk) Intermediate refractive index layer

6 Gas barrier layer

7 Microlens array pitch of microlens array

8 Mirror surface, for example, aluminum foil

9 One light source in the light emitting layer

10, 20, 30, 40, 50 Elect-opening luminescence element

11 Micro lens array

30A uneven structure

X reflective structure

BEST MODE FOR CARRYING OUT THE INVENTION

A preferred embodiment of the present invention will be described in detail with reference to FIGS. The embodiments described below are preferred specific examples of the present invention, and various technically preferred limits are applied. The scope of the present invention particularly limits the present invention in the following description. Are not limited to these embodiments unless otherwise described.

[0024] <First aspect>

FIG. 1 shows a configuration of a first embodiment of an electorifice luminescence element according to the present invention. Yes. In FIG. 1, the electroluminescent element 10 includes a transparent substrate 1, an intermediate refractive index layer 5 provided on the lower surface side of the transparent substrate 1 in the drawing, and a first electrode provided on the lower surface side of the intermediate refractive index layer 5. The light emitting device includes a layer 2, a light emitting layer 3 provided on the lower surface side of the first electrode layer 2, and a second electrode layer 4 provided on the lower surface side of the light emitting layer 3. The electoran luminescent element 10 emits light by an electoran luminescence effect by applying a predetermined driving voltage from a driving power supply (not shown) between the first electrode layer 2 and the second electrode layer 4. Then, the light passes through the transparent first electrode layer 2, the intermediate refractive index layer 5, and the transparent substrate 1, and is emitted to the outside (usually in the atmosphere) above the transparent substrate 1. Various illumination devices and display devices can be provided using the emitted light.

The transparent substrate 1 is usually configured as a square or rectangular light-transmitting flat plate. The intermediate refractive index layer 5 is a layer formed in close contact with the lower surface of the transparent substrate 1. The intermediate refractive index layer 5 is made of a material having a refractive index between the refractive index of the transparent substrate 1 and the refractive index of the first electrode layer 2. Assuming that a medium layer with a large refractive index has a refractive index of Nl and a medium layer with a small refractive index has a refractive index of N2, generally, incident light from various directions is transmitted from a medium layer having a refractive index of N1 to a medium layer having a refractive index of N2. In this case, the reflection loss of the incident light on the planar interface is expressed by the equation (N1−N2) ² / (N1 + N2) ² (JD Rancourt, Sciety of Photo Optical (UK, 1996/07/07) / 31), "Optical Thin Films; Users H andbookj," (translated by Shigetaro Ogura, Nikkan Kogyo Shimbun, 1996, "Optical Thin Film Users'Book")).

That is, if the layer structure is made so as to reduce the refractive index difference between the two medium layers, the reflection loss can be reduced. In addition, when a medium layer having a refractive index intermediate between the two medium layers (referred to as a refractive index N3) is inserted between these medium layers, the reflection loss of the light as a whole is determined by the reflection at each interface. By taking the sum of the losses, it can be expressed by the formula {(N1-N3) V (N1 + N3) ² } + {(N3-N2) 2Z (N3 + N2) ² }. For example, the transparent substrate 1 is made of glass having a refractive index Nl = l.5, and the first electrode layer 2 is made of indium tin oxide having an N2 = 2.0 (hereinafter, appropriately referred to as “ITO”). If a layer of N3 = l.6 is formed as the intermediate refractive index layer 5, the reflection loss at the glass-boundary surface is about 2%, but the interface between the ΙΤΟ-intermediate refractive index layer and the intermediate refractive index layer Refractive index power at the interface The sum of the calculated reflection losses is about 1%, which is reduced to about half. It is understood that it is. As can be seen from the comparison between the two equations, the reflection loss of light passing between the two medium layers can be reduced by introducing a medium layer having an intermediate refractive index between the two medium layers, that is, an intermediate refractive index layer. Will decrease. The present invention utilizes this effect.

[0027] The intermediate refractive index layer 5 may be an inorganic material or an organic material as long as it is transparent or translucent. Generally, a transparent conductive film such as ITO, IZO, or ZnO having a refractive index of about 2.0 is used as the first electrode layer 2, and the transparent substrate 1 has a refractive index of about 1.5. Since a glass or transparent resin of a certain degree is used, as the intermediate refractive index layer 5, a material having an intermediate refractive index between these refractive indexes, that is, about 1.5 to 2.0 may be selected. . The difference in the refractive index between the first electrode layer 2 and the intermediate refractive index layer 5 and the difference in the refractive index between the intermediate refractive index layer 5 and the transparent substrate 1 are each preferably 0.5 or less. Preferably, each is 0.3 or less. Specific examples of the transparent inorganic material can be represented by chemical formulas, for example, n = l.7 Si 0, n = l.6 Al O, n = l.9 YO, n = l.9 Nb O, n = l. 9 Ta O, composition

2 3 2 3 2 5 2 5

[AIO from n = l. 6 to 1.8; Ito] [Single layer of inorganic film such as SiON from n = l. 5 to 1.9. Examples of the transparent resin include polymers such as acrylic resin with n = l.7 and unsaturated polyester resin with n = l.6. Here, n indicates a refractive index (the same applies hereinafter). Other examples include linear polyolefin resins such as polyethylene and polypropylene; polyether sulfide; triacetyl cellulose; polycarbonate resins; polystyrene resins; resins having an alicyclic structure; Further, an inorganic film or an organic film in which pores are formed to control the refractive index may be used. Although there is no particular limitation on these production methods, an evaporation method, a sputtering method, and a CVD method are generally used.

[0028] <Second embodiment>

As shown in FIG. 2, the electorescence luminescent element 20 of the second embodiment corresponding to the third invention is different from the first embodiment in that the intermediate refractive index layer 5 includes a plurality of layers 5M1 to 5Mk. The difference is in the configuration. The following description focuses on this difference. Let n be the refractive index of the first electrode layer 2 and n be the refractive index of the transparent substrate 1, and sequentially from the first electrode layer 2 to the transparent substrate 1.

E S

The refractive indices of the layers 5Ml to 5Mk constituting the laminated intermediate refractive index layer 5 are denoted by n, n,... Η in order from the one closer to the first electrode layer 2. Here, the refractive index of each layer 5Ml to 5Mk is n

Ml M2 Mk

>n>n> · ·>η> n. Such multiple layers 5Ml ~ 5Mk By inserting, a larger reflection loss reduction effect can be obtained as compared with the case where the intermediate refractive index layer 5 is not composed of a plurality of layers 5Ml to 5Mk. The difference between the refractive indices of the adjacent layers 5 Ml to 5 Mk is preferably 0.3 or less, more preferably 0.2 or less. In addition, if the plurality of layers 5Ml to 5Mk are in an extreme state where they are infinitely increased, the change in the refractive index can be made closer to a continuous change, so that the reflection loss can be further suppressed. In other words, such an extreme state means that the refractive index of the intermediate refractive index layer 5 is directed from the first electrode layer 2 to the transparent substrate 1 to the refractive index of the first electrode layer 2 to the refractive index of the transparent substrate 1. It corresponds to the case where it continuously changes. The present invention includes such a case. Further, the intermediate refractive index layer 5 may also have a part of the function of another layer, for example, the first electrode layer 2 or the transparent substrate 1, or may have a function of a gas nolia layer or the like. Each of the layers 5Ml to 5Mk may be used by appropriately combining the above-mentioned inorganic materials and organic materials. Each layer 5Ml to 5Mk is, for example, a film made of Al O of n = l.6, SiO of n = l.7, and YΟ of n = l.

2 3 2 3

It can be used by being laminated on a board. Also, a mixture of these materials does not work. Alternatively, lamination is performed while changing the composition of an inorganic film such as AIO in which η = 1.6 to 1.8 depending on the composition or SiON in which η = 1.5 to 1.9 depending on the composition, and the refractive index of the film. May be a film in which is changed continuously or intermittently.

As shown in FIG. 3, the elector luminescent device 30 of the third embodiment corresponding to the fifth invention is different from the first embodiment in that a plurality of uneven structures are provided on at least one surface of the transparent substrate 1. Is different. That is, in the electorum luminescence element 30, a plurality of uneven structures 30A are formed on the upper surface of the transparent substrate 1 in the drawing. In this embodiment, the same effect of improving the light extraction efficiency as in the first embodiment and the effect of improving the light extraction efficiency at the interface of the concavo-convex structure described in Patent Document 2 are utilized. That is, by providing the uneven structure 30A, when the light from the light emitting layer 3 passes through the first electrode layer 2 and the transparent substrate 1 and is emitted to the outside of the transparent substrate 1, the incident angle is changed. The loss due to total reflection is suppressed. The shape of the concavo-convex structure 30A may be, for example, a hexagonal pyramid, a quadrangular pyramid, a triangular pyramid, a circular cone, a triangular prism, a lens dome, or a concave-convex lens shape. It is formed as a cone and is formed integrally with the transparent substrate 1. Yes. The quadrangular pyramid-shaped uneven structure 30A is arranged along the long side direction and the short side direction of the transparent substrate 1 at a predetermined arrangement pitch 7, for example, 0.01 to Lmm. It is preferable that the height difference of the concavo-convex structure 30A is selected in the range of 0.01 m to 100 m in that the light extraction efficiency can be improved. When the concavo-convex structure is formed in a conical shape, a conical convex portion protruding upward is formed instead of the quadrangular pyramid. In this case, it is preferable that the bottom surface of the conical convex portion is formed so as to be a rectangular circumscribed circle of the bottom surface of the quadrangular pyramid. The portions protruding in the long side direction and the short side direction from the rectangular shape near the bottom surface of the conical convex portion are cut off, so that mutually adjacent cones do not interfere with each other. Further, these conical projections are arranged along the long side and the short side of the transparent substrate 1 at a predetermined arrangement pitch, for example, 0.01 to Lmm, and have a height of 0.01 to LOO. Preferably, it is selected within the range of / zm.

When the uneven structure is present at the interface between the high-refractive index layer and the relatively low-refractive index layer, it enters the low-refractive index layer from the high-refractive index layer from various directions and transmits while partially reflecting. The scattered light can be emitted to the low-refractive-index layer side while suppressing the reflection loss of the light and increasing the transmission efficiency. From such a point of view, the effect can be exerted as long as there is a difference in the refractive index of the layer interface between the upper and lower surfaces of the transparent substrate 1 and the upper and lower surfaces. In addition, although the uneven structure of the same shape may be arranged on the surface of the transparent substrate 1 without any gap, the uneven structure is not particularly required. It does not matter if different shapes, for example pyramids and cones, or even differently sized pyramids, cones, etc., are densely or sparsely arranged. For manufacturing, for example, a concavo-convex structure in which quadrangular pyramids of the same shape are continuously arranged vertically and horizontally without gaps is convenient.

Next, the function of the concavo-convex structure will be described. When light passes through the interface between both layers from a medium layer with a high refractive index to a medium layer with a relatively low refractive index, the transmission efficiency of light rays from all directions on the medium layer side with a high refractive index is flat. It is known that it is improved by having an uneven structure such as a quadrangular pyramid at the interface compared to the interface. Furthermore, it is known that these concavo-convex structures have the effect of providing directivity of light from all directions, that is, scattered light (Patent Documents 1 and 2). Looking at each of the uneven structures 30A on the surface of the transparent substrate 1, the light emitted from the light emitting layer 3 is uniformly concave from all directions below through the first electrode layer 2 and the intermediate refractive index layer 5. The light enters the convex structure 30A. Since the uneven structure 30A is formed, for example, in the shape of a quadrangular pyramid having an apex on the top, reflection, particularly loss of light downward due to total reflection is reduced, and most of the light from all directions is assured. It can be guided upward. That is, the reflection loss of the light emitted from the light emitting layer 3 is reduced, and the light extraction efficiency is improved. Generally, the refractive index decreases in the order of the intermediate refractive index layer 5, the transparent substrate 1, and the atmosphere (upper side of the transparent substrate 1). Therefore, the effect of improving light extraction efficiency by the uneven structure 30A can be exerted between the intermediate refractive index layer 5 and the transparent substrate 1 or between the transparent substrate 1 and the atmosphere.

Here, another function of improving light extraction efficiency when an uneven structure is provided at the interface between the intermediate refractive index layer 5 and the transparent substrate 1 will be described. As described above, the interface having the concavo-convex structure has a suitable light directivity providing effect when light is transmitted from the high refractive index medium to the low refractive index medium. On the other hand, in order to efficiently transmit light from the high-refractive-index transparent substrate 1 to the relatively low-refractive-index atmosphere, it is necessary to suppress reflection loss due to reflection at the interface of the transparent substrate 1, especially loss due to total reflection. No. For this purpose, light incident on the upper (atmospheric side) surface of the transparent substrate 1 from the lower side of the transparent substrate may be changed to light in a direction in which the incident angle with respect to this surface decreases. In other words, the light of various directions emitted from the light emitting layer 3 is incident on the upper surface of the transparent substrate 1 at the interface between the intermediate refractive index layer 5 and the transparent substrate 1 at a small incident angle, that is, near vertical. To change the direction. This can be realized by forming an uneven structure at the interface between the intermediate refractive index layer 5 and the transparent substrate 1. When an uneven structure is provided at the interface between the intermediate refractive index layer 5 and the transparent substrate 1 as described above, a further improvement in light extraction efficiency can be expected.

The uneven structure in the present invention has a height of 0.01 to: LOO / zm, more preferably 1-1 to 100 / zm, and a pitch of 10 111 to 1111111 in the vertical and horizontal directions of the transparent substrate 1, more preferably It is desirable that a plurality of concave / convex structures, that is, a plurality of microlens elements are arranged in the range of 10 / ζπι to 0.1 mm. The concavo-convex structure may be arranged on a part of the electorifice luminescent element, but is preferably arranged on at least the entirety of one surface of the transparent substrate in order to exhibit the function of the electorate luminescent element as a whole. Regardless of the method of manufacturing the uneven structure, any structure may be used as long as the uneven structure exhibits the above-described function. Normal manufacturing methods include melt molding, injection molding, casting, embossing, and electron beam microscopy. A fine working method, a roll forming method, an inflation method, or the like may be used.

Sixth force Elect-port luminescent element 40 of a fourth embodiment corresponding to the eighth invention is different from the first embodiment in that reflective structure portion X is provided on the side surface of transparent substrate 1 as shown in FIG. It is different in that it is. Hereinafter, the difference will be mainly described. As shown in FIG. 4, the electroluminescent element 40 is configured by laminating a transparent substrate 1, an intermediate refractive index layer 5, a first electrode layer 2, a light emitting layer 3, and a second electrode layer 4 in order from the top. I have. The electroluminescent element 40 is configured such that the light emitting layer 3 emits light by an electroluminescent effect by applying a predetermined driving voltage to a driving power source (not shown) between the first electrode layer 2 and the second electrode layer 4. Then, the light passes through the transparent first electrode layer 2, the intermediate refractive index layer 5, and the transparent substrate 1, and is emitted outside the electroluminescent element 40 above the transparent substrate 1. Various lighting devices and display devices can be provided by using such an electorifice luminescence element 40.

In the present invention, the reflection structure portion has a function of, for example, reflecting light emitted directly from the side surface of the transparent substrate 1 to the outside of the electroluminescent element 40 and emitting the light toward the inside of the transparent substrate 1. It is the structural part that has. In this embodiment, as shown in FIG. 4, the reflective structure portion X is formed on the side surface of the transparent substrate 1 in such a shape that the downward force is also directed upward and spread. In this case, of the light directed to the side surface of the transparent substrate 1, more light changes its direction to the inside of the transparent substrate 1 due to total reflection at the side surface. Therefore, if the side structure as shown in FIG. 4 is used, the light emitted from one point of the light-emitting layer 3, for example, the light source 9 becomes large on the side surface of the transparent substrate 1 and totally reflected, and Come back inside. Then, the light is emitted upward to the surface force of the transparent substrate 1 and is effectively used. In general, light has a relatively high refractive index. 屈折 Low refractive index from a medium! ヽ When passing through a medium, all light incident above the critical angle has the property of being totally reflected. That is, assuming that the medium with a high refractive index, that is, the refractive index of the transparent substrate is n, and the medium with a low refractive index, that is, the refractive index of the atmosphere is n, the critical angle is 0 c.

H, then,

0 c is represented by the equation sin ^_1 (n / n).

L H

[0036] In this embodiment, such a property of the light beam is used. In FIG. 4, the light beam from the light source 9 is totally reflected and is emitted upward as a light beam la. The reflective structure portion X on the side surface of the transparent substrate 1 is transparent without transmitting the light from the light emitting layer 3 below the transparent substrate 1 without transmitting the side force of the transparent substrate 1. What is necessary is just to have a function of emitting light to the upper surface of the substrate 1.

In addition, the reflective structure of the present invention may have a substantially trapezoidal shape in which the cross-sectional structure of the side surface of the transparent substrate 1 spreads upward as shown in FIG. 5 and FIG. In FIGS. 5 and 6, the upper surface of the transparent substrate 1 is emphasized with irregularities, but the irregularities are very small, and the actual appearance of the upper surface looks almost flat. In this case, only one side surface may be extended upward, but preferably a trapezoidal shape in which both side surfaces are extended upward so as to increase the angle of incidence. Further, it is preferable that all four sides have such a structure. For example, as shown in FIGS. 7 and 8, the cross-sectional structure of the side surface of the transparent substrate 1 is such that a plurality of thin transparent substrates having the above-described cross-sectional structure of an upwardly convex curve are overlapped. There is a structure of the state. Of course, a structure in which a plurality of the trapezoidal transparent substrates are stacked may be used. Thereby, although the effect of preventing transmission loss from the side surface is the same, the size of the upper surface and the lower surface of the transparent substrate 1 is made substantially the same, thereby facilitating manufacturing and handling. In FIG. 8, the rightmost ray from the light source 9 is totally internally reflected at the side and changes its direction upward. This light ray goes out of the transparent substrate 1 once, but it is directed to the upper direction due to the change of direction, so it is immediately incident on the upper transparent substrate 1 part and finally the upper surface force of the transparent substrate 1 Be used effectively. In order to form such a structure, for example, the present invention can be easily implemented by forming a groove having the above shape on a side surface of a transparent substrate in parallel with a plane.

[0038] The reflection structure of the present invention can also be implemented by forming an uneven structure on the side surface of the transparent substrate. The above-described side surface structure is also a kind of uneven structure. For example, it is only necessary to form unevenness in a shape such as a quadrangular pyramid, a triangular pyramid, a hexagonal pyramid, a cone, and a dome. In the case of a pyramid such as a quadrangular pyramid, the apex force is also directed to the bottom surface. It is preferable that the vertical axis is inclined such that the apex side (outside of the substrate) is higher than the bottom side (inside of the substrate). . This is because incident light from the light emitting layer to the side surface is easily reflected, and the structure is obtained.

[0039] Further, as a structure exhibiting the function of the reflection structure, there is a mode in which the side surface is a mirror surface as shown in Fig. 9. If a glossy substance 8 such as a metal is added to the side surface of the transparent substrate 1 and the side surface is made a mirror surface, the light incident on the side surface from the light emitting layer 3 is almost completely reflected and returns to the inside of the transparent substrate 1. It is used effectively. For example, a metal thin film is formed on the side surface, and the side surface is surrounded by a plate having a mirror surface. Such a reflective structure is located on the side of the transparent substrate 1. Even if it is formed partially, it is effective to form the entire four side surfaces from the viewpoint of improving the light extraction efficiency of the electroluminescent device. As a further preferred embodiment of the present invention, a mirror surface is provided on the lower surface of the electorescence luminescent element, that is, the lower surface of the second electrode layer 4, or the lower surface of the second electrode layer 4 itself has a mirror surface function, and Output efficiency can be improved. For example, this can be realized by forming the second electrode layer 4 with a glossy metal such as aluminum.

[0040] <Fifth aspect>

A fifth embodiment corresponding to the ninth invention will be described with reference to FIG. In the electoral luminescence device 50 of the embodiment of the invention shown in FIG. 10, a gas noria layer 5 having a water vapor transmission rate of 0.1 lg'm ² Z days or less is provided between the transparent substrate 1 and the first electrode layer 2. It has been done. The transparent substrate 1 is usually made of a transparent inorganic material such as glass having strength and gas-nolia force. However, in order to obtain an electroluminescent device having a thin and excellent flexibility, it is suitable to use a thin and flexible resin as a transparent substrate. When a resinous material is used as the transparent substrate 1, it is preferable to have a gas nolia layer 5 '. The gas barrier layer 5 'is provided between the transparent substrate 1 and the first electrode layer 2, and is preferably made of a material having a water vapor transmission rate of 0.1 lg'm ² Z days or less. The measurement of the water vapor transmission rate was carried out at 40 ° C using a commercially available water vapor transmission rate measuring instrument such as “PERMATRAN-W” manufactured by MOCON, based on the infrared sensor method of IS K7129 B method. This is performed in an atmosphere with a humidity of 90% RH. The positional relationship with the intermediate refractive index layer 5 does not need to be particularly limited. In FIG. 4, the intermediate refractive index layer 5 is located on the upper side. However, it is preferable that the refractive index of the gas barrier layer 5 'is set to an intermediate value between the refractive indices of the layers on both sides sandwiching this layer. In this way, the gas barrier layer 5 'is a force that also functions as an intermediate refractive index layer.

[0041] The function of the gas nolia layer 5 'is to prevent the light emitting layer 3 or the electrode layer from deteriorating. If the light emitting layer 3 is an organic material or the electrode layer is a metal material, these may be deteriorated by water vapor in the air atmosphere. In the case where the water vapor permeability of the transparent substrate 1 is low, it is effective to insert a gas nolia layer having a high gas noria property between the transparent substrate 1 and the first electrode layer 2. In this case, the oxygen permeability is generally low. Gas Noria layer the water vapor permeability 0. lg'm ² Zday less, preferably 0. 08g'm ² Z date than Must be below. The material of the gas barrier layer 5 'is, for example, SiOx, AlO, AIO, Si

2 3 x

ON and SiNx. The refractive index of the gas nolia layer 5 is preferably the refractive index between the transparent substrate 1 and the first electrode layer 2. As a manufacturing method of the gas barrier layer 5 ', a vapor deposition method, a sputtering method, and a CVD method are generally used. Note that the gas noria layer 5 ′ can also serve as the intermediate refractive index layer 5 as described above. The thickness of the gas nolia layer 5 is usually 0.02 to 1 / ζπι, preferably 0.05 to 0.

[0042] In the present invention, the water absorption of the transparent substrate is preferably 0.1% or less, and the linear thermal expansion coefficient is preferably from ^ to 80 pp mZK. More preferably, the water absorption is 0.05% or less, and the thermal expansion coefficient is Power is ~ 70ppmZK. As a result, there is almost no performance degradation due to deformation of the electoran luminescence element under normal use environment. It is also expected that the lower the water absorption, the lower the water vapor permeability of the substrate. The transparent substrate 1 is usually made of a transparent inorganic material such as glass having strength and gas-nolia force. However, in order to obtain an electorescence luminescent element which is thin and has excellent flexibility, it is suitable to use a thin and flexible resin as a transparent substrate. Examples of the transparent substrate include polymers such as acrylic resin with n = l.7 and unsaturated polyester resin with n = 1.6. Other examples include linear polyolefin resins such as polyethylene and polypropylene; polyether sulfide; polycarbonate resins; polystyrene resins; resins having an alicyclic structure; Among them, a resin having an alicyclic structure is suitable because it has excellent light transmittance, heat stability, water absorption properties, mechanical properties and the like.

In a resin having an alicyclic structure, the alicyclic structure may have a deviation of! / ° between the main chain and the side chain. Examples of the resin having an alicyclic structure include a cycloalkane structure and a cycloalkene structure. The number of carbon atoms forming the alicyclic structure is usually 4 to 30, preferably 5 to 20, and more preferably 5 to 15. When the number of carbon atoms constituting the alicyclic structure is in this range, excellent heat resistance and flexibility are obtained. The proportion of the repeating unit having an alicyclic structure in the resin having an alicyclic structure may be appropriately selected depending on the purpose of use.

[0044] Specific examples of the resin having an alicyclic structure include a norbornene-based polymer, a monocyclic cyclic olefin polymer, a cyclic conjugated diene polymer, a vinyl alicyclic hydrocarbon polymer, Examples thereof include hydrides thereof, and mixtures thereof. Among these, norbornene-based polymers and their hydrides, vinyl alicyclic hydrocarbon polymers and their hydrides, and the like are preferred from the viewpoints of light transmittance, thermal stability, water absorption properties, heat resistance, and mechanical strength. ,

(1) Norbornene-based polymer

Examples of the norbornene-based polymer used in the present invention include a ring-opening polymer of a norbornene-based monomer, a ring-opening copolymer of a norbornene-based monomer and another monomer capable of ring-opening copolymerizing the same, a hydride thereof, and a norbornene-based polymer. Examples include an addition polymer of a monomer, and an addition copolymer of a norbornene-based monomer and another monomer copolymerizable therewith. Among these, from the viewpoints of heat resistance and mechanical strength, a hydrogenated ring-opened polymer of a norbornene-based monomer is most preferred. Examples of the norbornene-based monomer include bicyclo [2.2.1] 1-hept-2-ene (common name: norbornene) and a derivative having a substituent on the ring, and tricyclo [4. 3. 0. I ² ' ⁵ ] deca- 3,7-Gen (common name: dicyclopentadiene) and its derivatives, 7,8-Benzotricyclo [4.3.0. I ² ' ⁵ ] deca-one (common name: methanotetrahydrofluorene) and its derivatives , tetracyclo ^{^{[4. 4. 0. I 2 '5}} l 7.' 10] de de force - 3 E down (inertia for name: tetracyclododecene), and the like, and derivatives thereof. Examples of the substituent include an alkyl group, an alkylene group, a butyl group, an alkoxycarbol group, and the like. The norbornene-based monomer may have two or more of these. These norbornene monomers may be used alone or in combination of two or more. The ring-opening polymer of these norbornene-based monomers or the ring-opening copolymer of a nonolevonorenene-based monomer and another monomer can be obtained by polymerization in the presence of a known ring-opening polymerization catalyst. Examples of other monomers include, for example, monocyclic cyclic olefin monomers such as cyclohexene, cycloheptene, and cyclootaten.

[0046] The hydrogenated ring-opening polymer of a norbornene-based monomer is usually prepared by adding a known hydrogenation catalyst containing a transition metal such as nickel or radium to a polymerization solution of the above-mentioned ring-opening polymer to obtain a carbon-carbon unsaturated polymer. It can be obtained by hydrogenating the bond. An addition polymer of a norbornene-based monomer or an addition polymer or copolymer of a norbornene-based monomer and another monomer is obtained by polymerizing these monomers using a known polymerization catalyst. be able to. Examples of other monomers that can be copolymerized with norbornene-based monomers include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, —Α-olefins having 2 to 20 carbon atoms, such as tetradecene, 1-hexadecene, 1-octadecene, 1 eicosene, and derivatives thereof; cyclobutene, cyclopentene, cyclohexene, cyclootaten, 3a, 5, 6, 7a— Cycloolefins such as tetrahydro-4,7-methano 1H-indene and derivatives thereof; 1,4-hexanegen, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, 1,7-octadiene, etc. And the like. Of these, a-olefins, particularly ethylene, are preferred.

These other monomers copolymerizable with the norbornene-based monomer can be used alone or in combination of two or more. When the addition of a norbornene-based monomer and another monomer copolymerizable therewith is carried out, the structural unit derived from the norbornene-based monomer in the addition copolymer and the structural unit derived from the other copolymerizable monomer may be used. Is appropriately selected so as to be in the range of 30:70 to 99: 1 by weight.

(2) Vinyl alicyclic hydrocarbon polymer

Examples of the bur alicyclic hydrocarbon polymer include butyl alicyclic hydrocarbon monomers such as bulcyclohexene and bursik hexane and hydrides thereof; and vinyl aromatic monomers such as styrene and _a- methylstyrene. Hydrides of the aromatic ring portion of the solid polymer; and other polymers that can be copolymerized with vinyl alicyclic hydrocarbon monomers and vinyl aromatic monomers and these monomers. And copolymers such as random copolymers and block copolymers with the above-mentioned monomers, and hydrides thereof. Examples of the block copolymer include diblock, triblock, and higher multiblock and inclined block copolymers, but there is no particular limitation! /.

(3) Monocyclic Cyclic Olefin Polymer, Cyclic Conjugated Gen-Based Polymer

As the monocyclic cyclic olefin polymer, for example, an addition polymer of a monocyclic cyclic olefin monomer such as cyclohexene, cycloheptene, and cyclootaten can be used. Examples of the cyclic conjugated polymer include cyclopentadiene and cyclohexadiene. Polymers obtained by addition polymerization of cyclic conjugated monomers such as 1,2 or 1,4, and hydrides thereof can be used.

[0049] The molecular weight of the resin having an alicyclic structure suitably used in the present invention can be appropriately selected depending on the purpose of use. Gel "permeation" chromatograph of cyclohexane solution and toluene solution It can be measured by the method. The molecular weight of the resin having an alicyclic structure is usually 5,000 to 500,000, preferably 8,000 to 200,000, more preferably <000, 100 to 100, in terms of polystyrene equivalent weight average molecular weight. , 000 range. By setting the molecular weight in the above range, the mechanical strength of the resin and the moldability are improved. The glass transition temperature of the resin having an alicyclic structure suitably used in the present invention is a force appropriately selected according to the purpose of use, preferably from 80 to 350 ° C, more preferably from 130 to 250 ° C. It is. By setting the glass transition temperature within the above range, even when used at a high temperature, deformation and stress concentration do not occur and durability is improved. The thickness of the transparent substrate 1 used in the present invention is preferably from 0.03 to: LOmm, and more preferably from 0.1 to 3 mm. In addition, since the uneven structure on the surface of the transparent substrate 1 is smaller than the thickness, the thickness may be measured based on the convex portions or the concave portions.

[0050] The first electrode layer 2, the light emitting layer 3, and the second electrode layer 4 may have the same configuration as that of a normal electroluminescent device. That is, the first electrode layer 2, the light-emitting layer 3, and the second electrode layer 4 are sequentially stacked below in FIG. The first electrode layer 2 may be a normal transparent electrode for an electroluminescent device, but needs to have an adhesive property with the adjacent intermediate refractive index layer 5 or gas barrier layer 5 '. For example, even when the surface of the intermediate refractive index layer 5 is not flat, the junction between the first electrode layer 2 and the intermediate refractive index layer 5 needs to be in close contact. In the first electrode layer 2 which is usually used, zinc-added indium oxide called IZO or indium stannic oxide called ITO is adhered to the intermediate refractive index layer side by a sputtering method or the like. The thickness of the first electrode layer 2 usually ranges from 0.01 to 10111, preferably from 0.1 to 0.5 m.

The light-emitting layer 3 is formed by laminating a layer of an arylamine-based material such as TPD and an aluminum complex such as Alq3, or a single layer or a plurality of layers of an inorganic compound such as zinc sulfate and an organic compound such as Alq3. Are laminated. Usually, the light emitting layer can be formed by using a vacuum evaporation method. Wear. The thickness of the light-emitting layer 3 is usually 0.01 to 2111, preferably 0.1 to 0.1. Since the second electrode layer 4 may have a role of reflecting emitted light to the transparent substrate side, the second electrode layer 4 is also referred to as a back electrode, and is formed of, for example, an aluminum vapor-deposited film. The second electrode layer 4 can be formed by using an evaporation method. The thickness of the second electrode layer 4 is usually 0.01 to: L0 m, and preferably 0.1 to 0.5 m. When a voltage is applied between the first electrode layer 2 and the second electrode layer 4, the light emitting layer 3 emits light by electroluminescence, and the light is emitted from the first electrode layer 2, the intermediate refractive index layer 5, and the transparent substrate. Light emitted through 1 or reflected on the second electrode layer 4 is emitted to the outside of the electroluminescent element, that is, usually to the atmosphere, through the first electrode layer 2, the intermediate refractive index layer 5, and the transparent substrate 1. It is.

[0052] The electroluminescent device of the present invention may have another layer in addition to the transparent substrate, the first electrode layer, the light emitting layer, and the second electrode layer. Other layers include a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer, and a sealing layer. As a material forming these layers, a material known as a material forming each layer in the conventional electroluminescent device can be used.

The electroluminescent element 50 according to the embodiment of the present invention is configured as described above. For example, in FIG. 10, between the first electrode layer 2 and the second electrode layer 4, When a predetermined driving voltage is applied, the light-emitting layer 3 emits light due to the electroluminescence effect, and the light is transmitted to the transparent first electrode layer 2, gas nolia layer 5 ', intermediate refractive index layer 5, transparent The light passes through the substrate 1 and is emitted above the transparent substrate 1. Various types of lighting devices can be provided using the emitted light. As a characteristic of the electoran luminescence element, it can also be used as a lighting device as a surface light emitter. Further, it can be used directly as a display device, and can be various suitable display devices instead of liquid crystal. Further, the electroluminescent element has a suitable function as a backlight device for a liquid crystal or the like, and a suitable display device can be provided by combining with the liquid crystal display device.

Example

(Example 1)

An electorifice luminescence device 10 having the configuration shown in FIG. 1 was produced. The material of the transparent substrate 1 is norbornene based with a refractive index of n = 1.5, a water absorption of 0.05%, and a linear thermal expansion coefficient of 70 ppm ZK. Fat was used. The transparent substrate 1 has a length of 40 mm, a width of 40 mm, and a thickness of lmm. The intermediate refractive index layer 5 is made of alumina having a refractive index of n = 1.6, and has a thickness of 100 nm by DC sputtering.

M

The film was formed as follows. The water vapor transmission rate of the intermediate refractive index layer 5 of alumina was 0.1 lgZm ² days, and it could also function as a gas nolia layer. The first electrode layer 2 has a refractive index n =

E

The zinc-added indium oxide (IZO) of No. 2 was formed by DC sputtering so as to have a thickness of 100 nm. The light-emitting layer 3 was formed by using a laminated body of an arylamine-based material, TPD, and an aluminum complex, Alq3, to a thickness of about 100 nm by a vacuum evaporation method. The second electrode layer 4 was formed by vacuum deposition of aluminum to a thickness of 100 nm. A voltage of 5 V was applied between the first electrode layer 2 and the second electrode layer 4 of the electroluminescent device to emit electroluminescent light. The light emitted from the upper surface of the electroluminescent element was measured with a luminance meter manufactured by Prometric. The light extraction efficiency was expressed as a ratio based on Comparative Example 1 described later. The half-life was expressed in days as the emission time until the luminance measured by a luminance meter was reduced by half. The measurement results are shown in Table 1.

(Example 2)

An electroluminescent device 30 having a transparent substrate having a structure shown in FIG. 3 instead of the transparent substrate 1 of Example 1 was produced. The difference from the first embodiment is that the upper surface of the transparent substrate 1 has a quadrangular pyramid-shaped uneven structure that is continuous vertically and horizontally. Each of the concavities and convexities was a quadrangular pyramid having an apex on the upper side, that is, on the opposite side to the light emitting layer, with a base of 50 m and a height of 25 / z m. In addition, the base of the quadrangular pyramid corresponds to the arrangement pitch 7 of the microlenses of the microlens array. The lower part of FIG. 3 shows an enlarged plan view of a part of the microlens array. The transparent substrate 1 was manufactured by injection molding into a mold having a resin uneven structure. The configuration and manufacturing method of the other parts are the same as in the first embodiment. Measurements of light extraction efficiency and half-life were performed in the same manner, and the measurement results are shown in Table 1.

(Example 3)

Instead of the electorifice luminescent element 30 having the configuration of Example 2, an electoral luminescent element 50 having a configuration shown in FIG. 10 was produced. The difference from Example 2 is that between the transparent substrate 1 and the first electrode layer 2, an intermediate refractive index layer 5, which is an AlO layer with n = 1.6,

This is a two-layer structure in which an intermediate refractive index layer 5 ′, which is an M2 23 Ml 23 layer, is sequentially laminated from the transparent substrate 1 side. The The thickness of each intermediate refractive index layer is 50 nm. The water vapor transmission rate of the intermediate refractive index layer is 0.08 gZm for ² days in total. The configuration and manufacturing method of the other parts are the same as in the second embodiment. Measurements of light extraction efficiency and half-life were performed in the same manner, and the measurement results are shown in Table 1.

(Example 4)

Instead of the electorifice luminescent element 50 having the configuration of Example 3, an electoral luminescent element having a configuration shown in FIG. 7 was produced. The difference from the third embodiment is that the side surface structure of the transparent substrate 1 has a cross-sectional structure in which small convex arcs are stacked on all four sides. The concavo-convex structure provided on the upper surface of the transparent substrate 1 was a quadrangular pyramid having an apex at an upper side, a base 50 m, and a height 25 m. The small arc provided on the side of the transparent substrate has a radius of curvature of about 20 mm and a height of about 25 / z m. Other configurations and manufacturing methods are the same as those of the third embodiment. Measurements of light extraction efficiency and half-life were performed in the same manner, and the measurement results are shown in Table 1.

(Example 5)

Instead of the electroluminescent device 10 having the structure of Example 1, an electroluminescent device having the structure shown in FIG. 9 was produced. The difference from the first embodiment is that a glossy 0.2 mm thick aluminum foil 8 is provided on the four side surfaces of the electorifice luminescence element, and the side surface of the transparent substrate has a mirror surface structure. Other configurations and manufacturing methods are the same as those of the first embodiment. Measurements of light extraction efficiency and half-life were performed in the same manner, and the measurement results are shown in Table 1.

(Comparative Example 1)

Instead of the electroluminescent device 10 having the structure of Example 1, an electroluminescent device having the structure shown in FIG. 12 was manufactured. The difference from Example 1 is that only the intermediate refractive index layer 5 is provided, and the configuration and manufacturing method of the other parts are the same as in Example 1. That is, it has the same structure as a normal electroluminescent device. The measurement of light extraction efficiency, half-life and the like were performed in the same manner as in Example 1, and the measurement results are shown in Table 1.

(Comparative Example 2)

Instead of the electroluminescent element 30 having the configuration of Example 2, an electroluminescent element having the configuration shown in FIG. 13 was manufactured. The difference from the second embodiment is only the absence of the intermediate refractive index layer 5, and the configuration of the other parts and the manufacturing method are the same as those of the second embodiment. Extraction efficiency, half-life The measurement was performed in the same manner as in Example 1, and the measurement results are shown in Table 1.

(Comparative Example 3)

An electorescence luminescence element having a configuration shown in FIG. 11 was produced instead of the electoration luminescence element 30 having the configuration of Example 2. The difference from Example 2 is that instead of the intermediate refractive index layer 5 of alumina, a gaseous silica layer 6 of silica having a refractive index of n = 1.45 was formed by DC sputtering.

M

Thus, the structure and manufacturing method of the other parts are the same as in Example 2 except that the film was formed to have a thickness of 100 nm. The water vapor transmission rate of the intermediate refractive index layer 5 is 0.1 lgZm ² days. The extraction efficiency and half-life were measured in the same manner as in Example 1, and the measurement results are shown in Table 1.

[Table 1]

The following can be seen from the results in Table 1. As shown in Examples 1 to 5, the electorophore luminescent device of the present invention has a high half-life in which emission luminance and light extraction efficiency are high. On the other hand, in some cases, the half-life power S of the electorophore luminescent element of the comparative example is low because the luminous efficiency and the light extraction efficiency are low.

Industrial applicability

According to the present invention, it is possible to provide a high-brightness, power-saving electorifice luminescence element. In addition, since the light emission efficiency of the electoran luminescent element of the present invention is improved, the electoral luminescent element is suitable for use in various high-luminance lighting devices and display devices. In addition, when used as a backlight of a display device such as a liquid crystal display, it is possible to easily cope with higher luminance and power saving of the display device.

Claims

The scope of the claims

[I] An electroluminescent device having an intermediate refractive index layer, a first electrode layer, a light emitting layer, and a second electrode layer in this order on a transparent substrate, wherein the transparent substrate has a refractive index of n, During

S

When the refractive index of the inter-refractive index layer is n and the refractive index of the first electrode layer is n, n <n <n

M E S M E

A certain electorifice luminescence element.

2. The difference in refractive index between the first electrode layer and the intermediate refractive index layer and the difference in refractive index between the intermediate refractive index layer and the transparent substrate are each 0.5 or less. Electroluminescence device.

[3] The intermediate refractive index layer is composed of two or more layers, and the refractive index of each of the layers constituting the intermediate refractive index layer is n, n,... Η in order from the layer closest to the first electrode layer. Then, η> η

Ml M2 Mk E Ml

2. The electroluminescent device according to claim 1, wherein> n> n> n.

M2 Mk S

4. The electroluminescent device according to claim 3, wherein a difference in refractive index between adjacent layers constituting the intermediate refractive index layer is 0.3 or less.

[5] A plurality of uneven structures are provided on at least one surface of the transparent substrate.

2. The electoluminescent device according to 1 above.

6. The electoran luminescence element according to claim 1, wherein a reflection structure is provided on a side surface of the transparent substrate.

7. The electroluminescent device according to claim 6, wherein the reflection structure has a concave-convex structure.

8. The electroluminescent device according to claim 6, wherein the reflection structure is a mirror surface.

9. The electroluminescent device according to claim 1, further comprising a gas barrier layer having a water vapor transmission rate of 0.1 lg / m ² day or less between the transparent substrate and the first electrode layer.

10. The electroluminescent device according to claim 1, wherein the transparent substrate has a water absorption of 0.1% or less and a linear thermal expansion coefficient of 0 to 80 ppmZK or less.

[2] The electroluminescent device according to claim 1, wherein the transparent substrate is made of a resin having an alicyclic structure.

[12] A lighting device provided with the elect-opening luminescent element according to claim 1.

[13] A display device provided with the elect-opening luminescence element according to claim 1.