JP2011060472A - Light-emitting element and display device as well as lighting system using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting element and a display device with high light extraction efficiency. <P>SOLUTION: For the light-emitting element 10 provided with a lamination structure made by laminating a first electrode layer 12, a light-emitting layer 14a, a second electrode layer 15, and an optical layer 16 equipped with an optical system consisting of one or a plurality of lenses 16a in that order, when a width in one direction vertical to the lamination direction in the lamination structure is denoted by w, an object-side focal distance of the optical system is denoted by f, and a distance from a point where a light axis of the optical system and the light-emitting layer cross to an object-side main point is denoted by d, the structure is to satisfy following formulae 1 to 5. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a light emitting element such as an organic EL light emitting element, and a display device and an illumination device using the light emitting element.

2. Description of the Related Art In recent years, organic EL light-emitting elements for use as displays and flat light sources have been actively put into practical use with the expectation that they are excellent in thinning, high brightness, and energy saving.
In general, an organic EL light emitting device has a laminated structure in which a first electrode layer, a light emitting layer, a second electrode layer, a sealing layer, a glass plate, and the like are laminated. Since the above light is totally reflected at the interface between the layers and the interface between the glass plate and the air, it is not extracted to the outside, which causes a problem that the light extraction efficiency is low in the conventional organic EL light emitting device.

  In order to solve this problem, for example, in the light emitting device according to Patent Document 1, by providing an optical layer having a lens on the light extraction side of the light emitting layer, the divergence angle of the light emitted from the light emitting layer is controlled, The light extraction efficiency is improved by suppressing the total reflection at the interface.

JP2007-280699A

However, simply providing an optical layer did not improve the light extraction efficiency as expected, so there is room for improvement in optimizing the optical characteristics of the optical layer in order to actually improve the light extraction efficiency. It is thought that it is left. However, Patent Document 1 does not mention at all such optimization of optical characteristics.
In view of the above problems, an object of the present invention is to provide a light-emitting element with high light extraction efficiency, and a display device and an illumination device with high light extraction efficiency using the light-emitting element.

  In order to achieve the above object, a light-emitting element according to one embodiment of the present invention includes a first electrode layer, a light-emitting layer, a second electrode layer, and an optical layer provided with an optical system including one or more lenses. Are stacked in this order, the width in one direction perpendicular to the stacking direction in the stacked structure is w, the object-side focal length of the optical system is f, the optical axis of the optical system and the light emission When the distance from the point where the layer intersects to the object side principal point of the optical system is defined as d, the following Expressions 1 to 5 are satisfied.

  In the light-emitting element according to one embodiment of the present invention, the width in one direction perpendicular to the stacking direction in the stacked structure is w, the object-side focal length of the optical system is f, and the optical axis of the optical system and the light-emitting layer intersect. When the distance from the point to the object side principal point of the optical system is d, the light extraction efficiency is high in order to satisfy the relationship of the above formulas 1 to 5.

2A and 2B are diagrams illustrating a pixel structure of a display device according to one embodiment of the present invention, in which FIG. 3A is a plan view viewed from a light extraction side, and FIG. Sectional drawing which shows the lamination | stacking state of each layer of the light emitting element which concerns on 1 aspect of this invention. The figure for explaining the concept of the light extraction efficiency calculation method The figure which shows the calculation result of light extraction efficiency The figure which shows the calculation result of light extraction efficiency 1A and 1B illustrate a lighting device according to one embodiment of the present invention, in which FIG. It is a figure which shows the light emitting element which concerns on the modification 1, Comprising: (a) is the top view seen from the light extraction side, (b) is the sectional view on the AA line in (a), (c) is in (a). BB sectional view It is a figure which shows the light emitting element which concerns on the modification 2, Comprising: (a) is the top view seen from the light extraction side, (b) is the sectional view on the AA line in (a), (c) is in (a). BB sectional view

[Outline of Light-Emitting Element, Display Device, and Lighting Device according to One Embodiment of the Present Invention]
In a light-emitting element according to one embodiment of the present invention, a first electrode layer, a light-emitting layer, a second electrode layer, and an optical layer provided with an optical system including one or more lenses are stacked in this order. From the point where the width in one direction perpendicular to the stacking direction in the stacked structure is w, the object-side focal length of the optical system is f, and the optical axis of the optical system and the light emitting layer intersect each other. When the distance to the object side principal point of the optical system is d, the above-described Expressions 1 to 5 are satisfied, so that the light extraction efficiency is high.

  In the light-emitting element according to one embodiment of the present invention, the width in one direction perpendicular to the stacking direction in the stacked structure is w, the object-side focal length of the optical system is f, the optical axis of the optical system, and the light emission. When the distance from the point where the layer intersects to the object side principal point of the optical system is d, the light extraction efficiency is higher when the following Expressions 6 to 10 are satisfied.

また、本発明の一態様に係る発光素子は、前記積層構造における積層方向に垂直且つ前記一の方向にも垂直な他の方向の幅をｖとするとき、下記の式１１〜式１５を満足する場合は、幅ｗと幅ｖとの大きさに差があっても光取り出し効率が高い。

In addition, the light-emitting element according to one embodiment of the present invention satisfies the following formulas 11 to 15 where v is a width in another direction perpendicular to the stacking direction and also perpendicular to the one direction in the stacked structure. In this case, even if there is a difference between the width w and the width v, the light extraction efficiency is high.

また、本発明の一態様に係る発光素子は、前記積層構造における積層方向に垂直且つ前記一の方向にも垂直な他の方向の幅をｖとするとき、下記の式１６〜式２０を満足する場合は、幅ｗと幅ｖとの大きさに差があってもより光取り出し効率が高い。

In addition, the light-emitting element according to one embodiment of the present invention satisfies Expressions 16 to 20 below where v is a width in another direction perpendicular to the stacking direction and also perpendicular to the one direction in the stacked structure. In this case, the light extraction efficiency is higher even if there is a difference between the width w and the width v.

また、本発明の一態様に係る発光素子は、前記光学系が前記一の方向と前記他の方向とでパワーが異なる１のレンズからなる場合、及び、前記光学系が前記一の方向にのみパワーを有する第１のレンズと、前記他の方向のみにパワーを有する第２のレンズとからなる場合は、幅ｗと幅ｖとの大きさに差があっても、式１〜式５と式１１〜式１５とを同時に満足させ易い。

In the light-emitting element according to one embodiment of the present invention, the optical system includes one lens having different powers in the one direction and the other direction, and the optical system is only in the one direction. In the case where the first lens having power and the second lens having power only in the other direction are used, even if there is a difference between the width w and the width v, Formula 1 to Formula 5 It is easy to satisfy Equations 11 to 15 at the same time.

Since the display device according to one embodiment of the present invention includes a plurality of the light-emitting elements as pixels, light extraction efficiency is high.
The lighting device according to one embodiment of the present invention includes a light-emitting element as a light source, and thus has high light extraction efficiency.
Hereinafter, a light-emitting element according to one embodiment of the present invention, and a display device and a lighting device using the light-emitting element will be described with reference to the drawings.

[Configuration of display device]
1A and 1B are diagrams illustrating a pixel structure of a display device according to one embodiment of the present invention, in which FIG. 1A is a plan view viewed from a light extraction side, and FIG. 1B is a cross-sectional view taken along line AA in FIG. It is. A display device according to one embodiment of the present invention is an organic EL display in which pixels that emit R, G, or B light are regularly arranged in a matrix in a row direction and a column direction, Is composed of the light-emitting element according to one embodiment of the present invention. As shown in FIG. 1A, each of the pixels 10 (R), 10 (G), and 10 (B) of the display device 100 has substantially the same width v in the row direction and width w in the column direction. The shape of the XY plane viewed from the light extraction side is a substantially square of v × w.

In FIG. 1, the X-axis indicates the row direction, the Y-axis indicates the column direction, and the Z-axis indicates the depth direction (light emitting element stacking direction). The X axis and the Y axis are each perpendicular to the Z axis, and the X axis is also perpendicular to the Y axis. The same applies to FIG. 2 and FIGS.
As shown in FIG. 1B, each pixel 10 (R), 10 (G), 10 (B) has a functional layer 14 (R), 14 (G), 14 that emits light to R, G, or B. (B) and an optical layer 16 having a lens 16a as an optical system are provided. The width of each lens 16a is substantially the same as the width of each pixel 10 (R), 10 (G), 10 (B) in order to increase the light extraction efficiency, and the shape of the XY plane of each lens 16a. Is approximately square.

[Schematic configuration of light-emitting element]
FIG. 2 is a cross-sectional view illustrating a stacked state of each layer of the light-emitting element according to one embodiment of the present invention. As shown in FIG. 2, a light emitting element 10 according to one embodiment of the present invention is, for example, a top emission type organic EL element, and a drain electrode of the TFT is provided on a substrate 11 on which a TFT (not shown) is arranged. A first electrode (reflection anode) 12 connected to the first electrode layer 12 is formed, and a bank 13 is formed so as to surround the first electrode layer 12. In the region partitioned by the bank 13, a stacked structure is formed in which the first electrode layer 12, the functional layer 14 including the light emitting layer 14a, the second electrode layer 15, and the optical layer 16 are stacked in that order. . The light emitting layer 14a is an organic EL layer containing an organic light emitter, for example.

  The width (width v and width w) in the direction perpendicular to the stacking direction in the stacked structure is basically the width of the pixel of the light emitting element 10, but the bank 13 is formed as shown in FIG. In this case, it is defined by the opening width of the bank 13. As a specific example, the width w in the column direction (Y-axis direction) in the stacked structure is the distance between the light extraction side ends of the banks 13 (between the upper ends of the banks 13 in FIG. 2).

On the optical layer 16, a sealing layer 17 and a glass plate 18 are laminated so as to be continuous with the adjacent pixels beyond the region partitioned by the bank 13. The sealing layer 17 adheres and fixes the glass plate 18 and the optical layer 16 to prevent moisture and oxygen in the outside air from entering the functional layer 14 and the like. An upper surface 18 a of the glass plate 18 serves as a light extraction surface of the light emitting element 10.
[Configuration of each layer]
<Board>
Examples of the material of the substrate 11 include glass plates and quartz plates such as soda glass, non-fluorescent glass, phosphate glass, and borate glass, acrylic resins, styrene resins, polycarbonate resins, epoxy resins, and polyethylene. Further, a plastic plate or plastic film such as polyester or silicone resin, and a metal plate or metal foil such as alumina can be used.

When the light emitting element 10 is a so-called bottom emission type that extracts light from the substrate 11 side, the substrate 11 is required to be a transparent substrate such as a glass substrate.
<First electrode>
As the material of the first electrode layer 12, for example, a simple alkali metal such as sodium or lithium, or an alloy thereof can be used. In addition, alkaline earth metals such as calcium and magnesium, or alloys thereof can be used. Also, some Group III metals such as gallium and indium can be used. The alloy is aluminum, silver, indium or the like.

<Bank>
The bank 13 may be formed of an insulating material, and preferably has organic solvent resistance. Moreover, since the bank 13 may be subjected to an etching process, a baking process, or the like, it is preferable that the bank 13 be formed of a material having high resistance to these processes. The material of the bank 13 may be an organic material such as resin or an inorganic material such as glass. As the organic material, an acrylic resin, a polyimide resin, a novolac-type phenol resin, or the like can be used. As the inorganic material, silicon oxide (SiO ₂ ), silicon nitride (Si ₃ N ₄ ), or the like can be used. it can.

<Functional layer>
The functional layer 14 may have a single layer structure including only the light emitting layer 14a, or may have a multilayer structure in which an electron transport layer and a hole transport layer are stacked so as to sandwich the light emitting layer 14a. Further, it may have a multilayer structure further including an electron injection layer, a hole injection layer, and the like. The electron injection layer and the hole injection layer can be formed by vapor deposition, spin coating, casting, or the like.

  Examples of the material of the organic EL layer as the light emitting layer 14a include oxinoid compounds, perylene compounds, coumarin compounds, azacoumarin compounds, oxazole compounds, oxadiazole compounds, perinone compounds, pyrrolopyrrole compounds described in JP-A-5-163488, Naphthalene compounds, anthracene compounds, fluorene compounds, fluoranthene compounds, tetracene compounds, pyrene compounds, coronene compounds, quinolone compounds and azaquinolone compounds, pyrazoline derivatives and pyrazolone derivatives, rhodamine compounds, chrysene compounds, phenanthrene compounds, cyclopentadiene compounds, stilbene compounds, diphenyl Quinone compounds, styryl compounds, butadiene compounds, dicyanomethylenepyran compounds, dicyanomethylenethiopyran compounds, fluoresceins Compound, pyrylium compound, thiapyrylium compound, serenapyrylium compound, telluropyrylium compound, aromatic ardadiene compound, oligophenylene compound, thioxanthene compound, anthracene compound, cyanine compound, acridine compound, 8-hydroxyquinoline compound metal chain, Fluorescent materials such as metal chains of 2′-bipyridine compounds, chains of Schiff salts and Group III metals, oxine metal chains, and rare earth chains can be used. The organic EL layer can be formed by vapor deposition, spin coating, casting, or the like.

  Examples of the material for the hole transport layer include triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino acids described in Japanese Patent Application No. 3-333517. Substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, porphyrin compounds, aromatic tertiary amine compounds and styrylamine compounds, butadiene compounds, polystyrene derivatives, hydrazone derivatives, triphenylmethane derivatives, tetraphenyl derivatives Phenyl benzine derivatives and the like can be used, and in particular, porphyrin compounds, aromatic tertiary amine compounds and styryl amine compounds are preferable.

  The material for the electron transport layer includes a nitro-substituted fluorenone derivative, a thiopyrandioxide derivative, a diphequinone derivative, a perylenetetracarboxyl derivative, an anthraquinodimethane derivative, a fluorenylidenemethane derivative, an anthrone derivative of JP-A-5-163488. Oxadiazole derivatives, perinone derivatives, quinoline complex derivatives, and the like can be used.

<Second electrode>
The second electrode layer 15 is made of a conductive material having sufficient translucency with respect to the light generated in the light emitting layer 14a. As a material, indium tin oxide (Indium Tin Oxide: ITO), indium zinc oxide (Indium Zinc Oxide: IZO), or the like is preferable. This is because good conductivity can be obtained even if the film is formed at room temperature.

<Optical layer>
The optical layer 16 includes a high refractive index portion and a low refractive index portion 16b that constitute the lens 16a. For example, a high refractive index resin such as an episulfide resin or a thiourethane resin, a high refractive index ceramic such as flint glass or TiO ₂ can be used as the material of the lens 16a. For example, PMMA (Polymethylmethacrylate), low refractive index resin such as urethane resin, crown glass, quartz glass, and the like can be used.

<Sealing layer>
The sealing layer 17 has a function of suppressing exposure of the functional layer 14 and the like to moisture and air, and is made of, for example, a material such as silicon nitride (SiN) or silicon oxynitride (SiON). Preferably it is formed. In particular, when the light emitting element is a top emission type, since the sealing layer 17 is on the emission path of the light beam generated from the light emitting layer 14a, it is also required that the light transmittance is good.

[Detailed configuration of optical layer]
<Optical characteristics of optical layer>
In the optical layer 16, the interface 16c between the lens 16a and the low refractive index portion 16b is a spherical surface. Specifically, in order to give the optical layer 16 positive power, for example, the lens 16a side has a convex surface and a low refractive index. The part 16b side is a concave surface. For example, the lens 16a is made of TiO ₂ and the low refractive index portion 16b is made of SiO ₂ . The refractive index of TiO ₂ is 2.53, and the refractive index of SiO ₂ is 1.46.

  When the radius of curvature of the interface 16c is r, the refractive index of the lens 16a is nh, and the refractive index of the low refractive index portion 16b is nl, the object-side focal length f of the optical layer 16 is given by the following equation (21). The sign of the radius of curvature r is positive when the lens 16a side is convex.

積層構造の幅ｗ、レンズ１６ａの物体側焦点距離ｆ、前記レンズ１６ａの光軸Ｊと発光層１４ａとが交わる点Ｏから前記レンズ１６ａの物体側主点Ｈまでの距離ｄは、式１〜式５を満足するように設計されている。

The width w of the laminated structure, the object-side focal length f of the lens 16a, and the distance d from the point O where the optical axis J of the lens 16a intersects the light-emitting layer 14a to the object-side principal point H of the lens 16a Designed to satisfy Equation 5.

Similarly, the width v of the laminated structure, the object-side focal length f of the lens 16a, and the distance from the point O where the optical axis J of the lens 16a intersects the light-emitting layer 14a to the object-side principal point H of the lens 16a. d is designed to satisfy Expressions 11 to 15.
As shown in FIG. 2, when the parallel light L1 is incident on the lens 16a from the image side (upper side in FIG. 2), the object side principal point H is an extension line of the incident light and the outgoing light from the lens 16a. An intersection point where the extension line intersects is defined as G, a perpendicular line is drawn from the intersection point G toward the optical axis J, and the perpendicular line and the optical axis J intersect each other. Since the object side focal length f is a distance from the object side principal point H to the object side focal point F, the object side principal point H can be calculated backward from the object side focal length f and the object side focal point F.

Strictly speaking, the point O where the optical axis J and the light emitting layer 14a intersect is on the optical axis J and an intermediate position in the stacking direction (Z direction) of the light emitting layer 14a.
<Function of optical layer>
Next, the function of the optical layer 16 will be described. As shown in FIG. 2, the light beam L <b> 2 emitted along the optical axis J is emitted from the upper surface 18 a of the glass plate 18. On the other hand, the light beam L 3 emitted in an oblique direction having an angle with respect to the optical axis J is refracted by the optical layer 16 and emitted from the upper surface 18 a of the glass plate 18. Considering the case where the optical layer 16 is not provided, the light beam L4 that has not been refracted by the optical layer 16 is incident obliquely on the upper surface 18a that serves as the interface between the glass plate 18 and the outside, so this incident angle is the critical angle. If it is above, it is totally reflected and is not taken out to the outside world. Thus, the direction of the light emitted from the light emitting layer 14a is controlled by the optical layer 16, and the light extraction efficiency is improved.

<Calculation of light extraction efficiency>
FIG. 3 is a diagram for explaining the concept of the light extraction efficiency calculation method. 4 and 5 are diagrams showing calculation results of light extraction efficiency.
In order to estimate the effect according to one embodiment of the present invention, the following numerical calculation was performed. The ray tracing by geometric optics was used for the calculation. As shown in FIG. 3, the light emitting layer 14 a is considered as a collection of point light sources (i = 1, 2, 3...), And n lines are equiangularly divided into 0 to 360 degrees from each point light source. Are emitted (j = 1, 2, 3...). The energy after the light beam emitted from the j-th angle of the i-th light source is emitted from the upper surface 18a when the number of point light sources is m and the energy per light beam immediately after being emitted from the point light source is 1. Is Eij, the light extraction efficiency η is given by Equation 22 below.

式２２により、光学層１６を設けた場合と設けない場合との光取り出し効率をそれぞれ計算し、設けた場合の設けない場合に対する改善率を求めたところ、図４及び図５に示すような計算結果が得られた。

The light extraction efficiency with and without the optical layer 16 was calculated from the equation 22, and the improvement rate with respect to the case where the optical layer 16 was not provided was calculated. As shown in FIGS. Results were obtained.

  In addition, the part considered to be a collection of point light sources in the light emitting layer 16 was assumed to have a top emission type, and the width in the row direction and the column direction were set to 0.75 v and 0.75 w, respectively. This is because in the top emission type EL display, the width of the portion contributing to light emission of the light emitting layer 14a is about 3/4 times the width of the pixel. Therefore, the shape of the XY plane of the part contributing to the light emission of the light emitting layer 14a is a substantially square of 3 / 4v × 3 / 4w.

  In FIG. 4, the object-side focal length f is in the range of 0.2 w (0.2 v) to 1.4 w (1.4 v), and the distance d is in the range of 0.05 w (0.05 v) to 0.7 w (0.7 v). The ratio of improvement at that time is shown by a contour map. Contour lines showed improvement rates of 1.1 times, 1.2 times, and 1.3 times. Moreover, the boundary line which satisfy | fills Formula 1-Formula 5 and Formula 11-Formula 15 was shown with the dotted line. If the object-side focal length f and the distance d are determined so as to satisfy the conditions of Equations 1 to 5 and Equations 11 to 15, the improvement rate falls within the region surrounded by the dotted line in FIG. Compared with the case where 16 is not provided, the light extraction efficiency is improved to 1.2 times or more, and as a result, high light extraction efficiency is obtained.

Further, as shown in FIG. 5, satisfying Expressions 6 to 10 and Expressions 16 to 20, the light extraction efficiency is improved by 1.3 times or more compared to the case where the optical layer 16 is not provided, and as a result Higher light extraction efficiency can be obtained.
<Method for forming optical layer>
The optical layer 16 can be formed by applying a normal photolithography process and an etching process. Below, an example of the formation method of the optical layer 16 is demonstrated easily.

First, a TiO ₂ layer to be a lens 16a later is formed on the second electrode layer 15, a photoresist is applied on the upper surface of the TiO ₂ layer, and the lens 16a is formed at a position where the lens 16a is to be formed using a predetermined mask. Exposure and development are performed so that a substantially square resist layer remains. Next, the TiO ₂ layer is etched with an isotropic etchant using the resist layer as a mask. As the isotropic etching solution, for example, a mixed solution of hydrogen fluoride (HF) solution and nitric acid (HNO ₃ ) is used. Since the etching solution penetrates into the interface between the resist layer and the TiO ₂ layer, the etched TiO ₂ layer is formed into a plano-convex lens 16a. Since the degree of penetration of the etching solution varies depending on the composition ratio of the hydrogen fluoride solution and nitric acid, the shape of the lens 16a can be controlled by adjusting this composition ratio. Also, the shape of the lens 16a can be controlled by controlling the size of the resist layer without changing the etching conditions.

Thereafter, if the resist layer is removed, the lens 16a is completed. Therefore, the low refractive index portion 16b is formed so as to fill the lens 16a, and the optical layer 16 is completed.
[Lighting device]
6A and 6B are diagrams illustrating a lighting device according to one embodiment of the present invention, in which FIG. 6A is a longitudinal sectional view, and FIG. 6B is a longitudinal sectional view.

  As illustrated in FIG. 6, the lighting device 200 includes a base 201, a plurality of light emitting elements 10 according to one embodiment of the present invention arranged on the base 201, and a reflective member 202. Each light emitting element 10 is electrically connected to a conductive pattern formed on the base 201, and emits light by driving power supplied by the conductive pattern. The light distribution of a part of the light emitted from each light emitting element 10 is controlled by the reflecting member 202.

Since the lighting device 200 having the above structure includes the light-emitting element 10 according to one embodiment of the present invention, light extraction efficiency is high.
[Modification]
As described above, the light-emitting element according to one embodiment of the present invention and the display device and the lighting device using the light-emitting element have been specifically described. However, the content of the present invention is not limited to the above, and for example, the following modifications may be considered. It is done.

<Light Emitting Element According to Modification 1>
Although the shape of the XY plane of the light-emitting element 10 according to one embodiment of the present invention is substantially square, the shape of the XY plane of the light-emitting element is not limited to a substantially square, and may be, for example, a substantially rectangular shape. good.
7A and 7B are diagrams illustrating a light-emitting element according to Modification Example 1. FIG. 7A is a plan view viewed from the light extraction side, FIG. 7B is a cross-sectional view taken along the line AA in FIG. It is a BB line sectional view in (a). As shown in FIG. 7, the light-emitting element 20 according to Modification 1 includes a substrate 21, a first electrode 22, a bank 23, a functional layer 24 including a light-emitting layer 24a, a second electrode 25, an optical layer 26, and a sealing layer 27. The optical layer 26 includes a high refractive index layer and a low refractive index layer 26b that function as a lens 26a.

The light-emitting element 20 basically has the same configuration as that of the light-emitting element 10 according to one embodiment of the present invention, except that the shape of the XY plane is substantially rectangular and the aspect of the optical layer 26 is different. Have. Therefore, description of common configurations is omitted, and only different points are described.
Since the light emitting element 20 has a substantially rectangular shape on the XY plane, the pixel width differs between the X direction and the Y direction. That is, since the width v in the row direction and the width w in the column direction are different, the optimum values of the object side focal length f and the distance d are also different in the X direction (row direction) and the Y direction (column direction). Therefore, in the optical layer 16, a lens 26a having different powers in the X direction and the Y direction is formed as an optical system. As the lens 26a having different powers in the X direction and the Y direction, for example, a toric lens, a zone plate or the like can be considered.

<Light-emitting device according to Modification 2>
8A and 8B are diagrams showing a light-emitting element according to Modification Example 2. FIG. 8A is a plan view seen from the light extraction side, FIG. 8B is a cross-sectional view taken along the line AA in FIG. It is a BB line sectional view in (a). As shown in FIG. 8, the light emitting element 30 according to Modification 2 includes a substrate 31, a first electrode 32, a bank 33, a functional layer 34 including a light emitting layer 34 a, a second electrode 35, an optical layer 36, and a sealing layer 37. And the glass plate 38, the optical layer 36 is a first high refractive index layer that functions as a first lens 36a, a first low refractive index layer 36b, and a second lens 36c that functions as a second lens 36c. The light refractive index layer and the second low refractive index layer 36d are laminated in this order.

The light emitting element 30 basically has the same configuration as that of the light emitting element 10 according to one embodiment of the present invention, except that the shape of the XY plane is substantially rectangular and the aspect of the optical layer 36 is different. Have. Therefore, description of common configurations is omitted, and only different points are described.
Since the light emitting element 30 has a substantially rectangular shape on the XY plane, the pixel width is different between the X direction and the Y direction. That is, since the width v in the row direction and the width w in the column direction are different, the optimum values of the object side focal length f and the distance d are also different in the X direction (row direction) and the Y direction (column direction). Therefore, in the optical layer 16, a first lens 36a having power in the X direction and a second lens 36c having power in the Y direction are formed as an optical system.

  Each of the first lens 36a and the second lens 36c is a cylindrical lens, has a shape obtained by dividing a column into two in the axial direction, and has a cylindrical refracting surface. The first lens 36a and the second lens 36c are arranged at different distances from the light emitting layer 14a, respectively, in the direction in which the axis of the cylinder is orthogonal. As the first lens 36a and the second lens 36c, for example, a zone plate may be adopted in addition to the cylindrical lens.

<Other variations>
In the light-emitting element 10 according to one embodiment of the present invention, a curved lens is used as the lens 16a of the optical layer 16, and the lens of the optical layer is a diffractive lens, a refractive index distribution lens, a Fresnel lens, or a Selfoc lens (registered trademark). The lens may be of a type other than a curved lens, and the same high light extraction efficiency can be obtained if the above conditions are satisfied.

  The light-emitting element according to the present invention can be used in, for example, a passive matrix type or active matrix type display device, and can be widely used in the fields of display devices and lighting devices.

12 First electrode layer 14a Light emitting layer 17 Second electrode layer 16a Lens 16 Optical layer 100 Display device 200 Illumination device

Claims (8)

A laminated structure in which a first electrode layer, a light-emitting layer, a second electrode layer, and an optical layer provided with an optical system including one or more lenses are laminated in this order; The width in one direction perpendicular to the direction is w, the object-side focal length of the optical system is f, and the distance from the point where the optical axis of the optical system and the light emitting layer intersect to the object-side principal point of the optical system is A light emitting element satisfying the following formulas 1 to 5 when d.

The width of one direction perpendicular to the laminating direction in the laminated structure is w, the object side focal length of the optical system is f, and the object side main of the optical system intersects with the optical axis of the optical system and the light emitting layer. The light emitting device according to claim 1, wherein when the distance to the point is d, the following formulas 6 to 10 are satisfied.

The following formulas 11 to 15 are satisfied, where v is a width in another direction perpendicular to the stacking direction and also perpendicular to the one direction in the stacked structure. Light emitting element.

The following formulas 16 to 20 are satisfied, where v is a width in another direction perpendicular to the stacking direction and also perpendicular to the one direction in the stacked structure. 2. A light emitting device according to item 1.

  The light-emitting element according to claim 3, wherein the optical system includes one lens having different powers in the one direction and the other direction.   5. The light-emitting element according to claim 3, wherein the optical system includes a first lens having power in the one direction and a second lens having power in the other direction. 6.   A display device comprising a plurality of light emitting elements according to claim 1 as pixels.   An illumination device comprising the light emitting element according to claim 1 as a light source.

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