JP4300751B2 - ORGANIC ELECTROLUMINESCENCE ELEMENT, DISPLAY DEVICE USING SAME, AND PORTABLE TERMINAL - Google Patents

Description

【０１７８】
ここで、（表１）の評価項目における評価方法及びその評価基準について説明する。
【０１７９】
素子の発光効率は、有機エレクトロルミネッセンス素子に一定電流を流したときの全方位における発光輝度の和を評価した。その評価基準は、比較例１の発光効率に対して、◎：非常に優れている、○：優れている、△：許容できるである。
【０１８０】
素子の正面輝度は、有機エレクトロルミネッセンス素子に一定電流を流したときの正面方向での発光輝度を評価した。その評価基準は、比較例１の正面輝度に対して、◎：非常に優れている、○：優れている、△：許容できるである。
【０１８１】
発光面の視認性は、有機エレクトロルミネッセンス素子を３００μｍ×３００μｍの画素からなる表示装置としたときの、正面方向における光のにじみ、ぼけについて、視認性の程度を目視にて評価した。評価は、◎、○、△の三段階評価であり、その評価基準は、◎：非常に優れている、○：優れている、△：許容できるである。
【０１８２】
【発明の効果】
以上のように、本発明によれば、有機エレクトロルミネッセンス素子表面に光の角度変換パネルを貼り付けることで、高効率の発光輝度特性を有する有機エレクトロルミネッセンス素子、それを用いた表示装置及び携帯端末、および照明装置を提供することができる。また、メサ型構造の対称性や光取り出し面における散乱を調整することで、にじみや光ぼけの少ない、あるいは、特定の視野角特性を持った有機エレクトロルミネッセンス素子、それを用いた表示装置及び携帯端末を提供することができる。
【図面の簡単な説明】
【図１】本発明の実施の形態における光の角度変換パネルの一例を示す図
【図２】本発明の実施の形態における光の角度変換パネルの一例を示す図
【図３】本発明の実施の形態における光の角度変換パネルに形成される溝の断面形状を示す図
【図４】本発明の実施の形態における光の角度変換パネルに形成される溝の断面形状を示す図
【図５】本発明の実施の形態における有機エレクトロルミネッセンス素子の要部断面図
【図６】本発明の実施の形態における有機エレクトロルミネッセンス素子の要部断面図
【図７】本発明の実施の形態における有機エレクトロルミネッセンス素子の要部断面図
【図８】本発明の実施の形態における有機エレクトロルミネッセンス素子を用いた表示装置の概略斜視図
【図９】本発明の有機エレクトロルミネッセンス素子を用いた表示装置を備えた携帯端末を示す斜視図
【図１０】本発明の有機エレクトロルミネッセンス素子を用いた表示装置を備えた携帯端末を示すブロック図
【図１１】従来の有機エレクトロルミネッセンス素子の要部断面図
【図１２】従来の有機エレクトロルミネッセンス素子の要部断面における代表的な光線経路を示す模式図
【符号の説明】
１ 基板
２ 陽極
３ 正孔輸送層
４ 発光層
５ 陰極
６ 光の角度変換パネル
７，８ 溝
９ マイク
１０ スピーカー
１１ 操作部
１２ 表示部
１３ アンテナ
１４ 送信部
１５ 受信部
１６ 制御部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to various display devices, light sources or backlights of display devices, organic electroluminescence elements used for light-emitting elements used in optical communication devices, and the like, and display devices and portable terminals using the same.
[0002]
[Prior art]
An electroluminescence element is a light-emitting device that utilizes electroluminescence of a solid fluorescent substance. Currently, an inorganic electroluminescence element using an inorganic material as a light emitter has been put into practical use, and is used for backlights and flat displays of liquid crystal displays. The application development of is partly planned. However, since the inorganic electroluminescence element has a high voltage required for light emission of 100 V or higher and is difficult to emit blue light, it is difficult to achieve full color using the three primary colors of RGB. In addition, since the inorganic electroluminescent element has a very large refractive index of the material used as the light emitter, it is strongly influenced by total reflection at the interface, and the light extraction efficiency into the air with respect to actual light emission is 10-20. It is difficult to achieve high efficiency as low as about%.
[0003]
On the other hand, research on electroluminescent devices using organic materials has attracted attention for a long time, and various studies have been made. However, since the luminous efficiency is very low, full-scale practical research has not progressed.
[0004]
However, in 1987, Kodak's C.I. W. Tang et al. Proposed an organic electroluminescence device having a function-separated stacked structure in which an organic material is divided into two layers, a hole transport layer and a light-emitting layer, and 1000 cd / m despite a low voltage of 10 V or less. ² It became clear that the above high luminance can be obtained [C. W. Tang and S.M. A. Vanslyke: Appl. Phys. Lett, 51 (1987) 913, etc.]. Since then, organic electroluminescence devices have attracted a great deal of attention, and research on organic electroluminescence devices having a similar functionally separated type laminated structure has been actively conducted, especially for practical application of organic electroluminescence devices. High efficiency and long life, which are indispensable for this, have been sufficiently studied. In recent years, displays using organic electroluminescence elements have been realized.
[0005]
Here, the structure of the conventional general organic electroluminescent element is demonstrated using FIG. FIG. 11 is a cross-sectional view of a main part of a conventional organic electroluminescence element. In FIG. 11, 1 is a substrate, 2 is an anode, 3 is a hole transport layer, 4 is a light emitting layer, and 5 is a cathode.
[0006]
As shown in FIG. 11, the organic electroluminescence element includes an anode 2 made of a transparent conductive film such as ITO formed on a substrate 1 made of glass or the like by a sputtering method, a resistance heating vapor deposition method, or the like, and an anode N, N′-diphenyl-N, N′-bis (3-methylphenyl) -1,1′-diphenyl-4,4′-diamine (hereinafter referred to as TPD), which is also formed on the substrate 2 by resistance heating vapor deposition or the like. And a light emitting layer 4 composed of 8-hydroxyquinoline aluminum (hereinafter abbreviated as Alq3) formed on the hole transport layer 3 by a resistance heating vapor deposition method or the like. And a cathode 5 made of a metal film having a thickness of about 100 nm to 300 nm formed on the light emitting layer 4 by a resistance heating vapor deposition method or the like.
[0007]
When a direct current voltage or direct current is applied with the anode 2 of the organic electroluminescence element having the above configuration as a positive electrode and the cathode 5 as a negative electrode, holes are generated from the anode 2 to the light emitting layer 4 through the hole transport layer 3. Then, electrons are injected from the cathode 5 into the light emitting layer 4. In the light-emitting layer 4, recombination of holes and electrons occurs, and a light emission phenomenon occurs when excitons generated thereby shift from the excited state to the ground state.
[0008]
[Problems to be solved by the invention]
In such an organic electroluminescence device, light emitted from the phosphor in the light emitting layer 4 is normally emitted in all directions centering on the phosphor and passes through the hole transport layer 3, the anode 2, and the substrate 1. And radiated into the air. Alternatively, the light is once reflected in the direction opposite to the light extraction direction (substrate 1 direction), reflected by the cathode 5, and radiated into the air via the light emitting layer 4, the hole transport layer 3, the anode 2, and the substrate 1. The
[0009]
However, when light passes through the boundary surface of each medium, if the refractive index of the medium on the incident side is larger than the refractive index on the outgoing side, the angle at which the outgoing angle of the refracted wave becomes 90 °, that is, the critical angle, However, light incident at a large angle cannot pass through the boundary surface, is totally reflected, and is not extracted into the air.
[0010]
Here, the relationship between the refraction angle of light and the refractive index of the medium at the interface between different media follows Snell's law. According to Snell's law, when light travels from a medium having a refractive index n1 to a medium having a refractive index n2, a relationship of n1sinθ1 = n2sinθ2 holds between the incident angle θ1 and the refractive angle θ2. Therefore, when n1> n2 holds, the incident angle θ1 = sin−1 (n2 / n1) where θ2 = 90 ° is well known as the critical angle, and when the incident angle is larger than this, the light is transmitted through the medium. It will be totally reflected at the interface between them.
[0011]
Therefore, in an organic electroluminescence device that emits light isotropically, light emitted at an angle larger than the critical angle repeats total reflection at the boundary surface, is confined inside the device, and is emitted into the air. Disappear.
[0012]
FIG. 12 is a schematic diagram showing a typical light path in a cross section of a main part of a conventional organic electroluminescence element. In FIG. 12, the same parts as those described in FIG. 11 are denoted by the same reference numerals.
[0013]
As shown in FIG. 12, the light emitted from the light emitting layer 4 is emitted from the interface between the anode 2 and the substrate 1 (ITO / glass interface) and the interface between the substrate 1 and air (glass / air interface). Total reflection is performed at each boundary surface.
[0014]
This does not radiate light emitted from the light emitting layer to the outside of the device, and causes an apparent decrease in efficiency as an organic electroluminescence device. In general, most of the radiated light obtained from the light emitting layer of an organic electroluminescence device is confined inside the device by total reflection, and it is known that the effective radiated light is about 17% to 20%. [Refer to Advanced Material 6 (1994) 491 etc.].
[0015]
Accordingly, it has been proposed to solve the above-described problems by providing means for converting the light emission angle on the substrate of the organic electroluminescence element.
[0016]
For example, Japanese Patent No. 2773720 discloses an invention that improves the light extraction efficiency by forming a lens structure on the light extraction side of the substrate.
[0017]
Japanese Patent No. 2911183 discloses an invention that improves the light extraction efficiency by forming a diffraction grating or the like at a position where total reflection at the element interface is suppressed. Japanese Patent Laid-Open No. 9-129375 discloses a light extraction side. Inventions have been made to improve the light extraction efficiency by causing disturbance on the irregular reflection surface or reflection / refraction angle of the surface.
[0018]
Furthermore, Japanese Patent Laid-Open No. 10-189251 discloses a means for converting the light emission angle in a transparent substrate, or Japanese Patent Laid-Open No. 10-308286 forms a light reflecting layer on the side surface of the lower electrode. Thus, an invention for improving the light extraction efficiency has been made.
[0019]
However, in any of the above measures, since measures for improving the light extraction efficiency are taken on the substrate or on the substrate itself, there are significant restrictions in terms of forming materials and methods. In particular, when these light extraction efficiency improvement measures are used for an image forming apparatus such as a display, the degree of freedom for the light extraction efficiency improvement measure is important because each pixel is small.
[0020]
The present invention has been made in view of the above problems, and an object thereof is to provide an organic electroluminescence element capable of maintaining high-efficiency light-emitting performance, a display device using the same, and a portable terminal.
[0021]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, an organic electroluminescent device according to the first aspect of the present invention includes an anode for injecting holes, a cathode for injecting electrons, and the anode and the cathode on a substrate. A light emitting portion that emits light by recombination of holes injected by the anode and electrons injected by the cathode, and a groove portion that is provided on the opposite side of the light emitting portion with respect to the cathode and opens to the cathode side The opening area of the groove is in contact with the cathode Light angle conversion panel It was set as the structure which has.
[0044]
[ BEST MODE FOR CARRYING OUT THE INVENTION ]
Hereinafter, the organic electroluminescence element of the present invention will be described in detail.
[0045]
First, the function of the light angle conversion panel will be described.
[0046]
As described above, the relationship between the refractive angle of light and the refractive index of the medium at the interface between different media follows Snell's law and is larger than the critical angle in an organic electroluminescence device that emits light isotropically. Light emitted at an angle repeats total reflection at the boundary surface, is confined inside the device, and is not emitted into the air.
[0047]
Therefore, by changing the angle of light using a means for changing the angle of light at the interface, the angle of light reaching the light extraction surface / air interface is changed, and the angle and amount of light emitted into the air are changed. The change is important for improving the efficiency of the organic electroluminescence element.
[0048]
In addition, as the light angle conversion means, structures such as a lens structure, a concavo-convex structure, and a prism structure on the substrate have been proposed, but when these structures are formed on the substrate surface, the supporting ability as the substrate is maintained, Appropriately designed structures need to be formed, and there are restrictions on the materials and forming methods used for the structures, and there are structures on the top of the substrate, and the light emitting layer can be formed without damaging the structures. Since the necessity for forming a restriction on the formation method of the light emitting layer and the like occurs, it is difficult to realize. In particular, it is difficult to form a display device using an organic electroluminescence element in this structure. For example, in the case of a simple matrix display device, an electrode facing the substrate is formed in a strip shape on the substrate on which the structure is formed. It is very difficult to form.
[0049]
On the other hand, in the organic electroluminescence element in the present invention, an organic electroluminescence light-emitting unit composed of elements such as an anode, a light-emitting layer, and a cathode formed on the substrate, including the substrate, and a light angle conversion panel are provided. By making them separately and joining them together, light angle conversion can be realized without being subject to various restrictions on the organic electroluminescence element part and the light angle conversion panel.
[0050]
Such a light angle conversion panel has a structure in which a lens structure, a concavo-convex structure, a prism structure, or the like is arranged in the panel surface, or a structure in which a refractive index distribution is provided inside the panel to change the light angle. Can be considered.
[0051]
Among these, the manufacturing process is easy, and as a configuration effective in improving the light extraction efficiency, the angle conversion of light having a flat panel as a base material and having a plurality of grooves parallel to one direction in the in-plane direction. The panel is effective. By using the light angle conversion panel having such a configuration, highly efficient light extraction can be realized. Here, FIG. 1 is a view showing an example of a light angle conversion panel in the embodiment of the present invention, FIG. 1 (a) is a top perspective view, and FIG. 1 (b) is a bottom perspective view. . In FIG. 1, 6 is a light angle conversion panel, and 7 is a groove. As shown in FIG. 1, the light angle conversion panel 6 uses a flat panel as a base material and has a plurality of grooves 7 parallel to one of the in-plane directions.
[0052]
In the case of a panel having a plurality of grooves parallel to one direction, the angle conversion of light is performed only in one direction, and therefore it is difficult to perform effective light angle conversion. Therefore, by using a light angle conversion panel having a flat panel as a base material and having a plurality of grooves parallel to two directions orthogonal to each other in the plane, the manufacturing process is easy and very efficient. Light extraction can be realized. Here, FIG. 2 is a view showing an example of a light angle conversion panel in the embodiment of the present invention, FIG. 2 (a) is a top perspective view, and FIG. 2 (b) is a bottom perspective view. . As shown in FIG. 2, the light angle conversion panel 6 uses a flat panel as a base material and has a plurality of grooves 7 parallel to two directions orthogonal to each other in the plane.
[0053]
Further, the groove formed in the light angle conversion panel may be any shape as long as it includes a surface that is not parallel to at least the panel surface. From the viewpoint of easiness of design and the like, the groove formed in the light angle conversion panel is preferably a linear V-shaped groove having two substantially straight V-shaped cross sections. Here, FIG. 3 is a diagram showing a cross-sectional shape of a groove formed in the light angle conversion panel according to the embodiment of the present invention. As shown in FIG. 3, the groove 7 is substantially V-shaped and has a linear V-shape.
[0054]
In order to further improve the light extraction efficiency, the grooves formed in the light angle conversion panel can extract light efficiently according to the angle of light reaching the side surface, or the light intensity in the front direction is strong. A cross-sectional shape that can freely design the orientation of light is preferable, and it is preferably a curved V-shaped groove formed of two curves that are substantially V-shaped. Here, FIG. 4 is a diagram showing the cross-sectional shape of the groove formed in the light angle conversion panel in the embodiment of the present invention, and 8 shows the groove. As shown in FIG. 4, the groove 8 is substantially V-shaped, and has a V-shape that is convex in a curved line.
[0055]
In addition, the substantially V shape in the present invention is a cross-sectional shape of a groove composed of two surfaces that are non-parallel to the panel surface and the panel surface, has a substantially triangular shape, and has a vertex portion. May be a substantially triangular shape having a planar shape such as a flat surface or a curved surface. Further, the straight V-shaped groove is a groove whose cross-sectional shape is substantially the above-mentioned V shape, characterized in that two surfaces that are non-parallel to the panel surface are flat surfaces. A curved V-shaped groove consisting of a convex curve is characterized in that two surfaces that are non-parallel to the panel surface are curved surfaces whose cross-sections are convex inside the triangle. Is a groove whose cross-sectional shape is substantially V-shaped.
[0056]
By providing such a light angle conversion panel, light emitted from the light-emitting layer, particularly light inclined with respect to the light-emitting surface that is confined inside the element by total reflection, is a panel in the V-shaped groove of the panel. / The angle is changed by total reflection at the air interface, and the light is extracted into the air, so that the light extraction efficiency and the light intensity in the front direction are increased. In other words, since light angle conversion is not performed for light that is totally reflected before reaching the light angle conversion panel, the light passes through the air layer from the light emitting layer to the light angle conversion panel. It is preferable not to pass through, more preferably, it is preferable not to pass through a layer having a low refractive index before reaching.
[0057]
When forming such an angle conversion panel of light, it goes without saying that attention is paid to the light extraction efficiency that directly affects the efficiency of the organic electroluminescence element. Therefore, it is necessary to pay attention to the contact area between the organic electroluminescence light emitting part and the light angle conversion means or the distance between the organic electroluminescence light emission part and the light angle conversion means. is there.
[0058]
When joining an angle conversion panel of light to an image display device such as a display using an organic electroluminescence element, it is important to effectively use the light emitted from the pixel, and the direction of the pixel and the direction of the V-shaped groove If they are matched, the V-shaped groove can be arranged without reducing the area of the light emitting portion in the pixel, and an efficient angle conversion effect of light can be performed.
[0059]
Here, FIG. 5 is a fragmentary cross-sectional view of the organic electroluminescence element according to the embodiment of the present invention. In FIG. 5, the substrate 1, the anode 2, the hole transport layer 3, the light emitting layer 4, and the cathode 5 are the same as those described in the prior art, so the same reference numerals are given and the description is omitted. In addition, 6 is a light angle conversion panel, and 7 is a groove.
[0060]
As shown in FIG. 5, the pitch in each direction of the V-shaped groove 7 is made equal to the pitch in each direction of the light emitting section corresponding to each pixel, and the center of the substantially V-shaped groove 7 is connected to the center of each pixel. By being at the intermediate point, the positional relationship between the light emitting portion and the V-shaped groove 7 can be made the same, and the same extraction efficiency improvement effect can be obtained in any pixel, and a good image can be obtained. .
[0061]
Further, FIG. 6 is a cross-sectional view of a main part of the organic electroluminescence element in the embodiment of the present invention.
[0062]
As shown in FIG. 6, by making the pitch in each direction of the V-shaped groove 7 smaller than the pitch in each direction of the light emitting part corresponding to each pixel, a plurality of V-shaped grooves 7 can be formed in the light emitting part. Therefore, it is not necessary to perform precise alignment, and the positional relationship between the light emitting portion and the V-shaped groove 7 can be made the same, and the same extraction efficiency improvement effect can be obtained in any pixel, and a good image can be obtained. .
[0063]
Further, FIG. 7 is a cross-sectional view of a main part of the organic electroluminescence element in the embodiment of the present invention.
[0064]
As shown in FIG. 7, by making the pitch in each direction of the V-shaped groove 7 larger than the pitch in each direction of the light emitting portion corresponding to each pixel, the size of the V-shaped groove 7 can be increased. Panels can be easily formed and the alignment process is facilitated.
[0065]
In addition, when an organic electroluminescence element having a light angle conversion panel formed on a substrate is used as an image forming apparatus such as a display, light emitted from an arbitrary pixel is different until the light reaches the light angle conversion panel. This may cause so-called stray light that reaches the angle conversion panel of light arranged in the pixel and is emitted from the pixel into the air, and may cause problems such as a decrease in contrast and blurring or blurring of light.
[0066]
Therefore, the thickness from the light emitting layer to the light angle conversion panel is preferably sufficiently thin, and the distance from the light emitting layer to the convex surface formed by the V-shaped groove is preferably smaller than the length of one side of the pixel. Thus, the influence of stray light can be reduced.
[0067]
Furthermore, in order to extend the life of the organic electroluminescence element, it is effective to increase the area of the light emitting portion relative to the size of the pixel. However, when converting the angle of light by the V-shaped groove, the area of the convex surface formed by the V-shaped groove is smaller than that of the pixel, and therefore the area of the convex surface and the area of the light emitting layer in the pixel should be the same. Is disadvantageous for extending the life of the device. Therefore, by making the area of the convex surface formed by the V-shaped groove smaller than the area of the light emitting layer in the pixel, a highly efficient and long-life organic electroluminescence element can be realized.
[0068]
Moreover, when using an organic electroluminescent element as illumination apparatuses, such as display apparatuses, such as a display, and a printer light source, the design about the above-mentioned light orientation becomes important. For example, when it is used as a display of a portable terminal or a cash dispenser, the display state only needs to be recognized by the user himself, and the visibility from the surroundings is preferably low. In addition, when used as a printer light source, since it is required that strong light can be irradiated only to the portion of the photoconductor corresponding to the opening, it is sufficient that there is luminance in the front direction from the opening, and light is emitted in the peripheral direction. Less is preferred. In such a case, the light radiated from the opening is preferably radiated substantially strongly in the front direction and weakly in the peripheral direction, and light extraction with high directivity is preferably performed.
[0069]
In addition, for example, when used as a display for a plurality of people such as a television or an advertising display, the display state preferably has high visibility from the surroundings in the same manner as the visibility in the front direction. Moreover, when using as light sources, such as indoor lighting, it is preferable that light is uniformly irradiated to a lighting object. In such a case, the light emitted from the opening is preferably emitted uniformly in all directions, and it is preferable that uniform light extraction without directivity is performed.
[0070]
In the case of using the light angle conversion panel or the like in the present invention, the cross-sectional shape of the V-shaped groove is made symmetrical so that the light orientation has a strong directivity in the front direction, or the same for all pixels. The light orientation can be designed. Further, by making the cross-sectional shape of the V-shaped groove asymmetrical, the orientation direction of light can be changed, and the orientation according to the arrangement of pixels such as the peripheral portion and the central portion can be designed, or V It is also possible to emit light isotropically by arranging the cross-sectional shapes of the letter-shaped grooves asymmetrically and randomly. Furthermore, by making the light extraction surface of the light angle conversion panel a scattering surface, the extracted light can be scattered, the light orientation can be made uniform, and light can be emitted isotropically. is there.
[0071]
By using the light angle conversion panel having the above-described configuration, it is possible to design visual characteristics such as the orientation of light, and to maintain a high-efficiency light-emitting performance that can extend the life by increasing the light-emitting area. An organic electroluminescence element can be realized.
[0072]
Furthermore, when joining a light angle conversion panel, if the panel is joined directly on the transparent electrode, for example, it affects the life and efficiency of the organic electroluminescence device due to the influence of moisture and reactive gas contained in the adhesive to be joined. If the panel is subjected to force or force is applied to the panel during or after bonding, the transparent electrode may be peeled off from the light emitting layer, or the electrodes may be short-circuited, causing problems such as the element not emitting light. .
[0073]
Therefore, by forming a protective film for mitigating damage on the transparent electrode and attaching a light angle conversion panel on the upper surface, it is possible to realize efficient light emission without causing the above-mentioned problems. it can.
[0074]
Further, when the light angle conversion panel is bonded using a bonding material such as an adhesive capable of optical coupling or a liquid medium such as an optical coupling liquid, the coupling material may enter the V-shaped groove. In particular, as the pitch of the V-shaped grooves decreases, the ratio of the binding material entering increases because it becomes difficult to apply the binding material or the capillary phenomenon easily occurs.
[0075]
Note that the optical coupling material has a refractive index similar to that of the light angle conversion panel or the light emitting layer in order to prevent the light from being totally reflected before entering the light angle conversion panel as described above. Material is used. When a material having such a refractive index enters the V-shaped groove, the angle conversion effect of light in the V-shaped groove is reduced. In order to reduce such influence, it is effective to preserve the light path on the side surface of the V-shaped groove, and a light reflecting surface is formed on the side surface of the V-shaped groove, or the side surface of the V-shaped groove. Further, by forming a surface made of a medium having a refractive index smaller than that of the angle conversion panel, efficient light emission can be realized.
[0076]
When the light angle conversion panel and the substrate are made of different materials, thermal expansion of each member may be a problem. In other words, in the practical temperature range of the organic electroluminescence element, the size of the light angle conversion panel and the substrate changes due to thermal expansion, which causes problems such as peeling of the light angle conversion panel attachment portion. Therefore, in order to suppress the harmful effects caused by these thermal expansions, it is important to make the thermal expansion coefficient of the light angle conversion panel and the thermal expansion coefficient of the substrate as close as possible to form the light angle conversion panel. The thermal expansion coefficient of the medium is preferably 80% or more and within 120% of the thermal expansion coefficient of the substrate. Furthermore, it is preferable that the light angle conversion panel is not formed as an integral panel, but can be divided into one or more pixels.
[0077]
By using the light angle conversion panel having the above-described configuration, it is possible to realize an organic electroluminescence element that can be easily joined and can maintain high-efficiency light-emitting performance.
[0078]
Next, each structural part which comprises the organic electroluminescent element of this invention is demonstrated.
[0079]
First, the substrate will be described. Since the substrate of the organic electroluminescence element of the present invention is not used as a light extraction surface, either a transparent or opaque substrate can be used as long as it has a strength capable of holding the organic electroluminescence element. In the present invention, the definition of transparent or translucent indicates transparency to the extent that the visual recognition of light emission by the organic electroluminescence element is not hindered.
[0080]
The substrate is, for example, transparent or translucent soda lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, quartz glass, etc., inorganic oxide glass, inorganic fluoride glass , Etc., or polymer films such as transparent or translucent polyethylene terephthalate, polycarbonate, polymethyl methacrylate, polyether sulfone, polyvinyl fluoride, polypropylene, polyethylene, polyacrylate, amorphous polyolefin, fluorine resin, etc. Etc., or transparent or translucent As ₂ S _Three , As ₄₀ S _Ten , S ₄₀ Ge _Ten Such as chalcogenoid glass, ZnO, Nb ₂ O _Five , Ta ₂ O _Five , SiO, Si _Three N _Four , HfO ₂ TiO ₂ Insulating treatment on the surface of the transparent substrate material containing pigment, etc., or a material such as opaque metal, germanium, silicon carbide, gallium arsenide, gallium nitride, etc. It can be used by appropriately selecting from applied metal materials, etc., and a laminated substrate in which a plurality of substrate materials are laminated can also be used.
[0081]
Further, a circuit composed of a resistor, a capacitor, an inductor, a diode, a transistor, or the like for driving the organic electroluminescence element may be formed on the substrate surface or inside the substrate.
[0082]
Next, the light angle conversion panel will be described. The light angle conversion panel can be appropriately selected from transparent or translucent substrate materials among the substrate materials, and is preferably made of a material that can efficiently extract light emitted from the light emitting layer. It is preferable to easily form a structure such as a V-shaped groove on the panel surface. In addition, as a V-shaped groove forming method, a V-shaped groove is directly formed on the substrate material by using, for example, a cutting tool such as a cutting tool or a grinding wheel, and a V-shaped groove is formed in a mold by using the processing tool, for example. Then, it is possible to use a method of forming it by molding such as transferring it to a secondary mold by cold and hot working and forming the light angle conversion panel by the secondary mold.
[0083]
The light angle conversion panel is a transparent or translucent member that can be optically coupled between the light extraction layer and the panel before the panel is attached, and light is transmitted between the light extraction layer. It is preferable that no total reflection occurs. The material for the affixing member is appropriately selected from a curable optical coupling material such as a transparent resist and a transparent optical adhesive, or a non-curable optical coupling material such as an optical coupling liquid such as ethylene glycol. be able to. In order to effectively use the effect of the light angle conversion panel, it is preferable to select a material having a higher refractive index than the panel or the light emitting layer.
[0084]
The anode is an electrode for injecting holes, and it is necessary to efficiently inject holes into the light emitting layer or the hole transport layer. A transparent electrode can be used as the anode. Transparent electrode materials include indium tin oxide (ITO) and tin oxide (SnO). ₂ ), A metal oxide such as zinc oxide (ZnO), a transparent conductive film made of a mixture such as SnO: Sb (antimony), ZnO: Al (aluminum), or Al (thickness not to impair transparency). A metal thin film such as aluminum), Cu (copper), Ti (titanium), or Ag (silver), a metal thin film such as a mixed thin film or a laminated thin film of these metals, or a conductive polymer such as polypyrrole can be used. . It is also possible to form a transparent electrode by laminating a plurality of the aforementioned transparent electrode materials, and it is formed by various polymerization methods such as resistance heating vapor deposition, electron beam vapor deposition, sputtering method or electric field polymerization method. Further, it is desirable that the transparent electrode has a thickness of 1 nm or more in order to provide sufficient conductivity or to prevent uneven light emission due to unevenness on the substrate surface. In addition, it is desirable that the thickness be 500 nm or less in order to provide sufficient transparency.
[0085]
Furthermore, as the anode, in addition to these transparent electrodes, metals having a large work function such as Cr (chromium), Ni (nickel), Cu (copper), Sn (tin), W (tungsten), Au (gold), Alternatively, an alloy, oxide, or the like can be used, and a laminated structure of a plurality of materials using these anode materials can also be used. However, when a transparent electrode is not used as the anode, the anode is preferably formed of a material that reflects light in order to make the most of the effect of the light angle conversion means. In addition, when not using a transparent electrode as an anode, a cathode should just be a transparent electrode.
[0086]
Further, an amorphous carbon film may be provided on the anode. In this case, both have a function as a hole injection electrode. That is, holes are injected from the anode into the light emitting layer or the hole transport layer through the amorphous carbon film. The amorphous carbon film is formed by sputtering between the anode and the light emitting layer or the hole transport layer. Examples of the carbon target by sputtering include isotropic graphite, anisotropic graphite, glassy carbon, and the like. Although not particularly limited, isotropic graphite having high purity is suitable. Specifically, when the work function of the amorphous carbon film is measured using a surface analyzer AC-1 manufactured by Riken Keiki, the work of the amorphous carbon film is shown. The function is W _C = 5.40 eV. Here, the work function of ITO, which is generally used as an anode, is W _ITO = 5.05 eV, it is possible to inject holes into the light emitting layer or the hole transport layer more efficiently by using the amorphous carbon film. Further, when the amorphous carbon film is formed by sputtering, reactive sputtering is performed in an atmosphere of nitrogen or a mixed gas of hydrogen and argon in order to control the electric resistance value of the amorphous carbon film. Furthermore, in the thin film formation technique by sputtering or the like, when the film thickness is 5 nm or less, the film becomes an island structure and a uniform film cannot be obtained. For this reason, when the film thickness of the amorphous carbon film is 5 nm or less, efficient light emission cannot be obtained, and the effect of the amorphous carbon film cannot be expected. Further, when the film thickness of the amorphous carbon film is 200 nm or more, the color of the film becomes dark and light emitted from the organic electroluminescence element cannot be sufficiently transmitted.
[0087]
In addition, the light emitting layer material is preferably made of a phosphor having a fluorescent property in the visible region and a good film forming property. _Three And Be-benzoquinolinol (BeBq ₂ ), 2,5-bis (5,7-di-t-pentyl-2-benzoxazolyl) -1,3,4-thiadiazole, 4,4′-bis (5,7-pentyl- 2-Benzoxazolyl) stilbene, 4,4′-bis [5,7-di- (2-methyl-2-butyl) -2-benzoxazolyl] stilbene, 2,5-bis (5,7 -Di-t-benzyl-2-benzoxazolyl) thiophene, 2,5-bis ([5-α, α-dimethylbenzyl] -2-benzoxazolyl) thiophene, 2,5-bis [5, 7-di- (2-methyl-2-butyl) -2-benzoxazolyl] -3,4-diphenylthiophene, 2,5-bis (5-methyl-2-benzoxazolyl) thiophene, 4, 4′-bis (2-benzoxazolyl) biphenyl, 5-methyl-2- [2 Benzoxazoles such as-[4- (5-methyl-2-benzoxazolyl) phenyl] vinyl] benzoxazolyl, 2- [2- (4-chlorophenyl) vinyl] naphtho [1,2-d] oxazole Benzothiazoles such as 2,2 '-(p-phenylenedivinylene) -bisbenzothiazole, 2- [2- [4- (2-benzimidazolyl) phenyl] vinyl] benzimidazole, 2- [2- ( 4-carboxyphenyl) vinyl] benzimidazole and other fluorescent whitening agents, bis (8-quinolinol) magnesium, bis (benzo-8-quinolinol) zinc, bis (2-methyl-8-quinolinolate) Aluminum oxide, tris (8-quinolinol) indium, tris (5-methyl-8-quinolinol) a 8 such as luminium, 8-quinolinol lithium, tris (5-chloro-8-quinolinol) gallium, bis (5-chloro-8-quinolinol) calcium, poly [zinc-bis (8-hydroxy-5-quinolinyl) methane] -Metal chelated oxinoid compounds such as hydroxyquinoline-based metal complexes and dilithium ependridione, 1,4-bis (2-methylstyryl) benzene, 1,4- (3-methylstyryl) benzene, 1,4 -Bis (4-methylstyryl) benzene, distyrylbenzene, 1,4-bis (2-ethylstyryl) benzene, 1,4-bis (3-ethylstyryl) benzene, 1,4-bis (2-methylstyryl) ) A styrylbenzene compound such as 2-methylbenzene, 2,5-bis (4-methylstyryl) pyrazine, 2, -Bis (4-ethylstyryl) pyrazine, 2,5-bis [2- (1-naphthyl) vinyl] pyrazine, 2,5-bis (4-methoxystyryl) pyrazine, 2,5-bis [2- (4 -Biphenyl) vinyl] pyrazine, distil pyrazine derivatives such as 2,5-bis [2- (1-pyrenyl) vinyl] pyrazine, naphthalimide derivatives, perylene derivatives, oxadiazole derivatives, aldazine derivatives, A cyclopentadiene derivative, a styrylamine derivative, a coumarin derivative, an aromatic dimethylidin derivative, or the like is used. Furthermore, anthracene, salicylate, pyrene, coronene and the like are also used. Alternatively, a phosphorescent material such as fac-tris (2-phenylpyridine) iridium may be used.
[0088]
In addition to the single-layer structure of only the light-emitting layer, any of a two-layer structure of a hole transport layer and a light-emitting layer or a light-emitting layer and an electron transport layer, or a three-layer structure of a hole transport layer, a light-emitting layer, and an electron transport layer The structure of may be sufficient. However, in the case of such a two-layer structure or a three-layer structure, the hole transport layer and the anode are stacked or the electron transport layer and the cathode are in contact with each other.
[0089]
And as a positive hole transport layer, a hole mobility is high, and a transparent and favorable film forming property is preferable. Besides TPD, porphyrin compounds such as porphine, tetraphenylporphine copper, phthalocyanine, copper phthalocyanine, titanium phthalocyanine oxide, 1,1-bis {4- (di-P-tolylamino) phenyl} cyclohexane, 4,4 ′, 4 ″ -trimethyltriphenylamine, N, N, N ′, N′-tetrakis (P-tolyl) -P-phenylenediamine, 1- (N, N-di-P-tolylamino) naphthalene, 4,4 ′ -Bis (dimethylamino) -2-2'-dimethyltriphenylmethane, N, N, N ', N'-tetraphenyl-4,4'-diaminobiphenyl, N, N'-diphenyl-N, N'- Di-m-tolyl-4, N, N-diphenyl-N, N′-bis (3-methylphenyl) -1,1′-4,4′-diamine, 4′-diaminobiphenyl, N Aromatic tertiary amines such as -phenylcarbazole, 4-di-P-tolylaminostilbene, 4- (di-P-tolylamino) -4 '-[4- (di-P-tolylamino) styryl ] Stilbene compounds such as stilbene, triazole derivatives, oxazizazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, annealed amine derivatives, amino-substituted chalcone derivatives, Oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, silazane derivatives, polysilane aniline copolymers, polymer oligomers, styrylamine compounds, aromatic dimethylidin compounds, poly 3- Organic such as methylthiophene Material is used. Further, a polymer-dispersed hole transport layer in which an organic material for a low-molecular hole transport layer is dispersed in a polymer such as polycarbonate is also used.
[0090]
As the electron transport layer, oxadiazole derivatives such as 1,3-bis (4-tert-butylphenyl-1,3,4-oxadiazolyl) phenylene (OXD-7), anthraquinodimethane derivatives, diphenylquinone Derivatives and the like are used.
[0091]
The cathode is an electrode for injecting electrons, and it is necessary to efficiently inject electrons into the light emitting layer or the electron transport layer, and Al (aluminum), In (indium), Mg (magnesium), Ti having a small work function. Metals such as (titanium), Ag (silver), Ca (calcium), and Sr (strontium), oxides or fluorides of these metals, alloys thereof, and laminates are generally used. In order to make the most of the effect of angle conversion of light, the cathode is preferably formed of a material that reflects light.
[0092]
When the light angle conversion panel is pasted, it is difficult to perform effective angle conversion for all light, so light that has not been taken out by one angle conversion of light is at the interface with air. It is totally reflected, propagates again into the device, and reaches the cathode. Alternatively, since light is emitted isotropically in the light emitting layer, half of the light emitted from the light emitting layer reaches the cathode before reaching the light extraction surface. At this time, if the cathode is made of a material that reflects light, the light that reaches the cathode is reflected and can propagate again toward the light extraction surface, and can be used as effective light. There is sex. In order to make this effect effective, the cathode is preferably formed of a material that reflects light, and the light reflectance is preferably 50% or more. This is because the efficiency improvement rate by the angle conversion of light is about twice, so that effective light extraction is possible if the light reflectance is 50% or more, that is, the light loss at the cathode is 50% or less. . Conventional organic electroluminescence devices are required to have a very high reflectance of the cathode, but by improving the light extraction efficiency, it is possible to expand the selectivity of the cathode material, film thickness, formation method, etc. It is. Needless to say, the above applies to the anode when the cathode is used as a transparent electrode.
[0093]
Alternatively, in order to suppress a decrease in contrast due to external light such as sunlight or a fluorescent lamp incident from the light extraction surface of the organic electroluminescence element, either the anode or the cathode should be an electrode that absorbs light. Is valid.
[0094]
In addition, as the cathode, an ultra-thin film using a metal having a small work function is formed at the interface in contact with the light emitting layer or the electron transport layer, and a transparent electrode is laminated on the upper surface to form a transparent cathode. It is also possible to form. In particular, Mg, Mg—Ag alloy having a small work function, Al—Li alloy, Sr—Mg alloy, Al—Sr alloy, Al—Ba alloy, etc. described in JP-A-5-121172, or LiO ₂ A laminated structure such as / Al or LiF / Al is suitable as a cathode material.
[0095]
Furthermore, resistance heating vapor deposition, electron beam vapor deposition, and sputtering are used as a method for forming these cathodes.
[0096]
Note that at least one of the anode and the cathode may be a transparent electrode. Furthermore, both may be transparent electrodes, but in order to improve the light extraction efficiency, if one is a transparent electrode, it is preferable that the other be formed of a material that reflects light.
[0097]
In addition, a protective film may be formed on the surface of the element in order to block the organic electroluminescence element from the outside air and ensure long-term stability. As the material of the protective film, SiON, SiO, SiN, SiO ₂ , Al ₂ O _Three A thin film made of inorganic oxide such as LiF, inorganic nitride, inorganic fluoride, glass film made of inorganic oxide, inorganic nitride, inorganic fluoride, etc., or a mixture thereof, or thermosetting Examples thereof include a photocurable resin and a silane polymer material having a sealing effect, and are formed by vapor deposition, sputtering, or a coating method.
[0098]
The organic electroluminescence element of the present invention can be used as a display device for displaying an image. These display devices include a display of a portable information terminal such as a mobile phone, PHS, PDA, television, personal computer, car navigation system. It can be used for a display of AV equipment such as a stereo and a radio.
[0099]
Further, it can be used in an illumination device as a light source such as a laser printer or a scanner. Or it can also be used as a lighting device as a simple light source such as a lighting fixture such as a room lamp or a light stand.
[0100]
Among these, in consideration of advantages such as low power consumption, light weight and thinning of organic electroluminescence elements, and high response speed, display devices and laser printers as displays for displaying images in various electronic devices In addition, it is preferably used for a lighting device as a light source such as a scanner.
[0101]
Embodiments of the present invention will be described below.
[0102]
(Embodiment 1)
The organic electroluminescence element in the embodiment of the present invention will be described. Here, description will be made with reference to FIG.
[0103]
The organic electroluminescence element in the present embodiment includes a light angle conversion panel 6 in which a V-shaped groove 7 is formed on the element side surface of the substrate 1 as light extraction efficiency improving means. The light angle conversion panel 6 converts the angle of the light emitted from the light emitting layer 4 to an angle smaller than the critical angle that causes total reflection at the boundary surface between the light extraction surface and the air. Preferably it is. The constituent material and the forming method of the light angle conversion panel can be appropriately selected from the constituent materials, the forming method, and the conventionally known materials described above so as not to prevent the emission of light emission from the light emitting layer 4.
[0104]
It should be noted that the constituent materials, forming methods, and conventionally known materials described above can be used as the constituent materials and forming methods of the substrate 1, the anode 2, the hole transport layer 3, the light emitting layer 4, and the cathode 5.
[0105]
Further, in the present embodiment, the case of a two-layer structure including the hole transport layer 3 and the light emitting layer 4 has been described, but the structure is not particularly limited as described above.
[0106]
In the present embodiment, the case where the anode 2 is formed on the upper surface of the substrate 1 has been described. However, the structure is not particularly limited as described above, and the cathode 5 is formed on the upper surface of the substrate 1. It is also possible to form
[0107]
In addition, the sealing mode can be realized by adhering the glass cap to the substrate with UV curable resin or the like so that the light extraction surface and the glass cap are not in close contact with each other, or it is protected on the surface of the organic electroluminescence element. Appropriate means such as forming a film and sealing can be employed. There is no problem even if it is a combination of a protective film and a shielding material. Moreover, the structure which forms a protective film and affixes the angle conversion panel of light on the upper surface may be sufficient.
[0108]
As described above, according to the present embodiment, light that has been wasted in the conventional configuration can be extracted, so that the light extraction efficiency is improved and high-efficiency light-emitting performance can be maintained.
[0109]
And it cannot be overemphasized that the organic electroluminescent element in this Embodiment can be used as an illuminating device or a display apparatus.
[0110]
(Embodiment 2)
Next, a display device using the organic electroluminescence element of the present invention will be described.
[0111]
FIG. 8 is a schematic perspective view of a display device using the organic electroluminescence element in the embodiment of the present invention.
[0112]
In FIG. 8, the substrate 1, the anode 2, the hole transport layer 3, the light emitting layer 4, and the cathode 5 are denoted by the same reference numerals as those in Embodiment 1 and description thereof is omitted here.
[0113]
In the present embodiment, as shown in FIG. 8, the anode 2 is linearly patterned, and the cathode 5 is similarly linearly patterned so as to be substantially orthogonal thereto.
[0114]
Then, the anode 2 of this display device is set to the positive side and the cathode 5 is set to the negative side, and connected to a driving circuit (driver) as driving means (not shown), and a DC voltage or a DC current is applied to the selected anode 2 and cathode 5. For example, the light emitting layer 4 in the orthogonal portion emits light and can be used as a simple matrix display device.
[0115]
In the present embodiment, a panel having a V-shaped groove is provided as the light angle conversion panel 6 on the element forming surface of the substrate 1. The light angle conversion panel preferably converts the angle of light emitted from the light emitting layer to an angle smaller than the critical angle causing total reflection at the interface between the substrate and air. .
[0116]
In addition, the constituent material, formation method, and conventionally well-known thing mentioned above can also be used for the constituent material and formation method of the anode 2, the hole transport layer 3, the light emitting layer 4, and the cathode 5.
[0117]
As described above, also in the display device of this embodiment mode, light that has been wasted in the conventional configuration can be extracted, so that the light extraction efficiency can be improved and high-efficiency light-emitting performance can be maintained. Further, in the display device of this embodiment, since the light orientation becomes stronger in the front direction, light propagation in the light-transmitting substrate on the light extraction surface can be suppressed, and highly efficient light emission performance is maintained. In addition, it is possible to realize a display device with high visibility and no blurring of light.
[0118]
In this embodiment mode, a simple matrix type display device has been described. However, an active matrix type display device may be used, and a V-shaped portion may be formed on a non-light-emitting portion such as a TFT used for driving on the element formation surface of the substrate. By disposing the grooves, the area of the light emitting portion can be used effectively, and the same high efficiency light emitting performance as in the case of the simple matrix method can be maintained.
[0119]
The organic electroluminescence element of the present invention can be used not only as a display device for displaying an image but also as an illumination device such as a light source such as a laser printer or a scanner. Further, the anode 2 and the cathode 5 may be used as a simple lighting device by emitting light over the entire surface without patterning them linearly.
[0120]
(Embodiment 3)
Next, a portable terminal using the organic electroluminescence element of the present invention will be described. FIG. 9 is a perspective view showing a portable terminal equipped with a display device using the organic electroluminescence element of the present invention, and FIG. 10 is a block diagram showing a portable terminal equipped with a display device using the organic electroluminescence element of the present invention. FIG.
[0121]
9 and 10, reference numeral 9 denotes a microphone that converts voice into a voice signal, 10 denotes a speaker that converts voice signals into voice, 11 denotes an operation unit including dial buttons, and 12 denotes a display unit that displays an incoming call or the like. The antenna is constituted by the display device using the organic electroluminescence of the present invention, 13 is an antenna, 14 is a transmission unit for converting an audio signal from the microphone 9 into a transmission signal, and a transmission signal produced by the transmission unit 14 Is emitted to the outside through the antenna 13. Reference numeral 15 denotes a reception unit that converts a reception signal received by the antenna 13 into an audio signal. The audio signal created by the reception unit 15 is converted into audio by the speaker 10. A control unit 16 controls the transmission unit 14, the reception unit 15, the operation unit 11, and the display unit 12.
[0122]
The microphone 9 receives the voice of the user (sender) during a call, and the other party's voice or notification sound is output from the speaker 10 and transmitted to the user (recipient). Note that in the case where a pager is used as the portable terminal, the microphone is not particularly required.
[0123]
Further, the operation unit 11 includes a numeric keypad as a dial button and various function keys. Moreover, not only a numeric keypad and various function keys but a character key etc. may be provided. From the operation unit 11, predetermined data such as a telephone number, name, time, setting of various functions, an e-mail address, and a URL are input. Further, the operation unit 11 may use not only such an operation by the keyboard but also a pen input device, a voice input device, a magnetic or optical input device.
[0124]
The display unit 12 displays predetermined data input from the operation unit 11, data such as a telephone number, an e-mail address, a URL, or a character icon stored in a memory.
[0125]
The antenna 13 performs at least one of transmission and reception of radio waves. Note that in this embodiment mode, transmission and reception of signals are performed by radio waves, and thus antennas (helical antennas, planar antennas, etc.) are provided. It may be provided instead. In this case, the light emitting element transmits a signal to another communication device or the like, and the light receiving element receives an external signal.
[0126]
The transmission unit 14 and the reception unit 15 each convert an audio signal into a transmission signal, and convert the received reception signal into an audio signal.
[0127]
Further, the control unit 16 is configured by a conventionally known method using a CPU, a memory, or the like not shown, and controls the transmission unit 14, the reception unit 15, the operation unit 11, and the display unit 12. More specifically, a command is given to each control circuit, drive circuit, etc. (not shown) provided in each of these units. For example, the display control circuit that has received a display command from the control unit 16 drives the display drive circuit and displays on the display unit 12.
[0128]
An example of the operation will be described below.
[0129]
First, when there is an incoming call, the receiving unit 15 sends an incoming signal to the control unit 16, and the control unit 16 displays a predetermined character or the like on the display unit 12 based on the incoming signal, and further performs an operation. When a button or the like for receiving an incoming call from the unit 11 is pressed, a signal is sent to the control unit 16, and the control unit 16 sets each unit to the incoming mode. That is, the signal received by the antenna 13 is converted into an audio signal by the receiving unit 15, the audio signal is output as audio from the speaker 10, and the audio input from the microphone 9 is converted into an audio signal, and the transmitting unit 14 And is transmitted to the outside through the antenna 13.
[0130]
Next, the case of making a call will be described.
[0131]
First, when making a call, a signal to the effect that the operation unit 11 sends is input to the control unit 16. Subsequently, when a signal corresponding to the telephone number is transmitted from the operation unit 11 to the control unit 16, the control unit 16 transmits a signal corresponding to the telephone number from the antenna 13 via the transmission unit 14. When communication with the other party is established by the transmission signal, when a signal to that effect is sent to the control unit 16 through the reception unit 15 via the antenna 13, the control unit 16 sets each unit to the transmission mode. That is, the signal received by the antenna 13 is converted into an audio signal by the receiving unit 15, the audio signal is output as audio from the speaker 10, and the audio input from the microphone 9 is converted into an audio signal, and the transmitting unit 14 And is transmitted to the outside through the antenna 13.
[0132]
In the present embodiment, an example in which voice is transmitted and received is shown. However, the same effect is obtained not only for voice but also for a mobile terminal that transmits and / or receives data other than voice, such as character data. be able to.
[0133]
In such a portable terminal according to the present embodiment, high-efficiency light emission performance can be maintained, so that the amount of power used by a battery or the like can be suppressed. This makes it possible to use the portable terminal for a long time, or to reduce the weight by reducing the size of the battery. In particular, in recent years, display elements used in portable terminals have been required to have higher image quality and lower power consumption, and higher image quality and higher efficiency compared with conventional light extraction of organic electroluminescence elements are significant advantages. Bring. And by high efficiency, the battery capacity can be reduced, and the weight can be reduced and the usage time can be increased. In addition, if a polymer film is used as the substrate of the organic electroluminescence element, it is possible to bring about a dramatic reduction in weight.
[0134]
In addition, in a portable terminal intended for personal use such as a portable terminal, a characteristic that only the user himself / herself can recognize information and cannot recognize information from the surroundings is required. Since it is possible to design such that the light orientation is strengthened in the front direction, it is very effective for the above-described applications.
[0135]
【Example】
Example 1
After forming an Al film having a thickness of 160 nm on a transparent substrate made of glass, a resist material (OFPR-800, manufactured by Tokyo Ohka Kogyo Co., Ltd.) is applied onto the Al film by a spin coating method to form a resist film having a thickness of 10 μm. The resist film was patterned into a predetermined shape by forming, masking, exposing and developing. Next, the substrate is immersed in 50% hydrochloric acid at 50 ° C. to etch the Al film where the resist film is not formed. Then, the resist film is also removed, and an anode made of an Al film having a predetermined pattern is formed. A patterning substrate on which was formed was obtained.
[0136]
Next, this patterning substrate was washed by ultrasonic cleaning for 5 minutes with pure water at 70 ° C., and then the water adhering to the substrate was removed with a nitrogen blower, and further heated and dried.
[0137]
Next, 2 × 10 ^-6 Alq as a light emitting layer on the cathode in a resistance heating vapor deposition apparatus depressurized to a degree of vacuum below Torr. _Three Was formed with a thickness of about 60 nm, and TPD was formed with a thickness of about 50 nm as a hole transport layer on the light emitting layer. The vapor deposition rates of TPD and Alq3 were both 0.2 nm / s.
[0138]
Next, 2 × 10 ^-6 In a low damage sputtering apparatus reduced in vacuum to Torr or less, masked with a metal mask, an ITO film having a film thickness of 160 nm was formed on the hole transport layer to form a transparent anode.
[0139]
Next, a silicon oxide film having a thickness of 3 μm was formed as a protective film on the ITO film in the same manner in a low damage sputtering apparatus.
[0140]
Next, the transparent resin plate made of polycarbonate is cut in one direction with a symmetrical V-shaped steel cutting tool formed at a pitch corresponding to the pixel formed by the patterned anode and cathode, and the in-plane 1 A light angle conversion panel in which V-shaped grooves parallel to the direction were formed.
[0141]
Next, an optical adhesive was uniformly applied to the surface of the protective film, and the light angle conversion panel was attached.
[0142]
(Example 2)
A transparent substrate made of glass is subjected to ultrasonic cleaning for 5 minutes with a detergent (Semico Clean, manufactured by Furuuchi Chemical Co., Ltd.), ultrasonic cleaning for 10 minutes with pure water, and aqueous hydrogen peroxide 1 with respect to ammonia water 1 (volume ratio). After washing in the order of ultrasonic cleaning for 5 minutes with a mixed solution of water and water 5 and ultrasonic cleaning for 5 minutes with pure water at 70 ° C., moisture attached to the substrate was removed with a nitrogen blower and dried.
[0143]
Next, the substrate is 2 × 10 ^-6 A cathode patterned with a metal mask was formed to a thickness of 150 nm using an Al—Li alloy containing 15 at% Li as a vapor deposition source in a resistance heating vapor deposition apparatus whose pressure was reduced to a vacuum level of Torr or less.
[0144]
Next, in the same manner, in the resistance heating vapor deposition apparatus, Alq as a light emitting layer on the cathode. _Three Was formed with a thickness of about 60 nm, and TPD was formed with a thickness of about 50 nm as a hole transport layer on the light emitting layer. TPD and Alq _Three The vapor deposition rate of was 0.2 nm / s.
[0145]
Next, 2 × 10 ^-6 An ITO film having a film thickness of 160 nm was formed on the hole transport layer by masking with a metal mask in a low damage sputtering apparatus reduced in vacuum to Torr or less.
[0146]
Next, a silicon nitride film having a film thickness of 3 μm was formed as a protective film on the uneven organic electroluminescence element in the same manner in a low damage sputtering apparatus.
[0147]
Next, a transparent resin plate made of PMMA (acrylic) is cut in one direction by a symmetrical V-shaped steel cutting tool formed at a pitch corresponding to the pixel formed by the patterned anode and cathode, Further, the transparent resin plate on which the V-shaped groove is formed is rotated by 90 °, and is similarly cut by the steel cutting tool, and the angle of the light on which the V-shaped groove parallel to two directions perpendicular to each other is formed. A conversion panel was used.
[0148]
Next, an optical binder made of ethylene glycol is uniformly applied to the surface of the protective film, and the light angle conversion panel is attached using surface tension, and then the four corners of the light angle conversion panel are bonded. It was fixed using an agent.
[0149]
(Example 3)
An opaque substrate made of silicon is subjected to ultrasonic cleaning for 5 minutes with detergent (Semico Clean, manufactured by Furuuchi Chemical Co., Ltd.), ultrasonic cleaning for 10 minutes with pure water, hydrogen peroxide solution 1 to ammonia water 1 (volume ratio). After washing in the order of ultrasonic cleaning for 5 minutes with a mixed solution of water and water 5 and ultrasonic cleaning for 5 minutes with pure water at 70 ° C., moisture attached to the substrate was removed with a nitrogen blower and dried.
[0150]
Next, the substrate is 2 × 10 ^-6 A cathode patterned with a metal mask was formed to a thickness of 150 nm using an Al—Li alloy containing 15 at% Li as a vapor deposition source in a resistance heating vapor deposition apparatus whose pressure was reduced to a vacuum level of Torr or less.
[0151]
Next, in the same manner, in the resistance heating vapor deposition apparatus, Alq as a light emitting layer on the cathode. _Three Was formed with a thickness of about 60 nm, and TPD was formed with a thickness of about 50 nm as a hole transport layer on the light emitting layer. TPD and Alq _Three The vapor deposition rate of was 0.2 nm / s.
[0152]
Next, 2 × 10 ^-6 An ITO film having a film thickness of 160 nm was formed on the hole transport layer by masking with a metal mask in a low damage sputtering apparatus reduced in vacuum to Torr or less.
[0153]
Next, a silicon oxide film having a thickness of 3 μm was formed as a protective film on the concavo-convex organic electroluminescence element in a low damage sputtering apparatus.
[0154]
Next, a steel mold having symmetric V-shaped projections parallel to two directions perpendicular to each other in a plane is formed at a pitch corresponding to the pixel formed by the patterned anode and cathode, and hot working is performed. A light angle conversion panel made of polycarbonate was formed.
[0155]
Next, a light scattering film was attached to the surface of the light angle conversion panel opposite to the surface on which the V-shaped grooves were formed, thereby obtaining a light angle conversion panel in which the light extraction surface was a scattering surface.
[0156]
Next, an optical adhesive was uniformly applied to the surface of the protective film, and the light angle conversion panel was attached.
[0157]
(Example 4)
After forming an Al film having a thickness of 160 nm on a transparent substrate made of glass, a resist material (OFPR-800, manufactured by Tokyo Ohka Kogyo Co., Ltd.) is applied onto the Al film by a spin coating method to form a resist film having a thickness of 10 μm. The resist film was patterned into a predetermined shape by forming, masking, exposing and developing. Next, the substrate is immersed in 50% hydrochloric acid at 50 ° C. to etch the Al film where the resist film is not formed. Then, the resist film is also removed, and an anode made of an Al film having a predetermined pattern is formed. A patterning substrate on which was formed was obtained.
[0158]
Next, this patterning substrate was washed by ultrasonic cleaning for 5 minutes with pure water at 70 ° C., and then the water adhering to the substrate was removed with a nitrogen blower, and further heated and dried.
[0159]
Next, 2 × 10 ^-6 Alq as a light emitting layer on the cathode in a resistance heating vapor deposition apparatus depressurized to a degree of vacuum below Torr. _Three Was formed with a thickness of about 60 nm, and TPD was formed with a thickness of about 50 nm as a hole transport layer on the light emitting layer. TPD and Alq _Three The vapor deposition rate of was 0.2 nm / s.
[0160]
Next, 2 × 10 ^-6 In a low damage sputtering apparatus reduced in vacuum to Torr or less, masked with a metal mask, an ITO film having a film thickness of 160 nm was formed on the hole transport layer to form a transparent anode.
[0161]
Next, a silicon oxide film having a thickness of 3 μm was formed as a protective film on the ITO film in the same manner in a low damage sputtering apparatus.
[0162]
Next, a steel mold formed with asymmetric V-shaped protrusions parallel to two directions perpendicular to each other in a plane is formed at a pitch corresponding to the pixel formed by the patterned anode and cathode, and hot working is performed. A light angle conversion panel made of polycarbonate was formed.
[0163]
Next, an optical adhesive was uniformly applied to the surface of the protective film, and the light angle conversion panel was attached.
[0164]
(Example 5)
After forming an Al film having a thickness of 160 nm on a transparent substrate made of glass, a resist material (OFPR-800, manufactured by Tokyo Ohka Kogyo Co., Ltd.) is applied onto the Al film by a spin coating method to form a resist film having a thickness of 10 μm. The resist film was patterned into a predetermined shape by forming, masking, exposing and developing. Next, the substrate is immersed in 50% hydrochloric acid at 50 ° C. to etch the Al film where the resist film is not formed. Then, the resist film is also removed, and an anode made of an Al film having a predetermined pattern is formed. A patterning substrate on which was formed was obtained.
[0165]
Next, this patterning substrate was washed by ultrasonic cleaning for 5 minutes with pure water at 70 ° C., and then the water adhering to the substrate was removed with a nitrogen blower, and further heated and dried.
[0166]
Next, 2 × 10 ^-6 Alq as a light emitting layer on the cathode in a resistance heating vapor deposition apparatus depressurized to a degree of vacuum below Torr. _Three Was formed with a thickness of about 60 nm, and TPD was formed with a thickness of about 50 nm as a hole transport layer on the light emitting layer. TPD and Alq _Three The vapor deposition rate of was 0.2 nm / s.
[0167]
Next, 2 × 10 ^-6 In a low damage sputtering apparatus reduced in vacuum to Torr or less, masked with a metal mask, an ITO film having a film thickness of 160 nm was formed on the hole transport layer to form a transparent anode.
[0168]
Next, a silicon oxide film having a thickness of 3 μm was formed as a protective film on the ITO film in the same manner in a low damage sputtering apparatus.
[0169]
Next, a transparent resin plate made of PMMA (acrylic) is cut in one direction by a symmetrical V-shaped steel cutting tool formed at a pitch corresponding to the pixel formed by the patterned anode and cathode, Further, the transparent resin plate on which the V-shaped groove is formed is rotated by 90 °, and is similarly cut by the steel cutting tool, and the angle of the light on which the V-shaped groove parallel to two directions perpendicular to each other is formed. A conversion panel was used.
[0170]
Next, the light angle conversion panel is set to 2 × 10. ^-6 In a resistance heating vapor deposition apparatus whose pressure is reduced to a vacuum level of Torr or less, Al is formed as a light reflecting layer with a thickness of about 100 nm on the surface where the V-shaped groove is formed, and further, an Al light reflecting layer is formed. The surface on the V-shaped groove side was cut by 1 μm using a polishing apparatus to obtain a light angle conversion panel whose side surface is a light reflecting surface.
[0171]
Next, an optical binder made of ethylene glycol is uniformly applied to the surface of the protective film, and the light angle conversion panel is attached using surface tension, and then the four corners of the light angle conversion panel are bonded. It was fixed using an agent.
[0172]
(Comparative Example 1)
An Al film having a film thickness of 160 nm was formed on a transparent substrate made of glass in the same manner as in Example 1, and then a resist material (manufactured by Tokyo Ohka Co., Ltd., OFPR-800) was applied on the Al film by a spin coating method. A resist film having a thickness of 10 μm was formed, and the resist film was patterned into a predetermined shape by masking, exposure and development. Next, the substrate is immersed in 50% hydrochloric acid at 60 ° C. to etch the portion of the Al film where the resist film is not formed. Then, the resist film is also removed, and an anode made of an Al film having a predetermined pattern A patterning substrate on which was formed was obtained.
[0173]
Next, this patterning substrate was washed by ultrasonic cleaning for 5 minutes with pure water at 70 ° C., and then the water adhering to the substrate was removed with a nitrogen blower, and further heated and dried.
[0174]
Next, 2 × 10 ^-6 Alq as a light emitting layer on the cathode in a resistance heating vapor deposition apparatus depressurized to a degree of vacuum below Torr. _Three Was formed with a thickness of about 60 nm, and TPD was formed with a thickness of about 50 nm as a hole transport layer on the light emitting layer. TPD and Alq _Three The vapor deposition rate of was 0.2 nm / s.
[0175]
Next, 2 × 10 ^-6 In a low damage sputtering apparatus reduced in vacuum to Torr or less, masked with a metal mask, an ITO film having a film thickness of 160 nm was formed on the hole transport layer to form a transparent anode.
[0176]
Next, a silicon oxide film having a thickness of 3 μm was formed as a protective film on the concavo-convex organic electroluminescence element in a low damage sputtering apparatus.
[0177]
[Table 1]

[0178]
Here, the evaluation method and the evaluation criteria in the evaluation items of (Table 1) will be described.
[0179]
The light emission efficiency of the device was evaluated by summing the light emission luminance in all directions when a constant current was passed through the organic electroluminescence device. The evaluation criteria are ◎: excellent, ◯: excellent, and Δ: acceptable for the luminous efficiency of Comparative Example 1.
[0180]
The front luminance of the element was evaluated by the light emission luminance in the front direction when a constant current was passed through the organic electroluminescence element. The evaluation criteria are 正面: excellent, ◯: excellent, and Δ: acceptable with respect to the front luminance of Comparative Example 1.
[0181]
The visibility of the light emitting surface was evaluated by visual observation of the degree of visibility of blurring and blurring of light in the front direction when the organic electroluminescence element was a display device composed of 300 μm × 300 μm pixels. The evaluation is a three-stage evaluation of ◎, ○, and Δ, and the evaluation criteria are ◎: very good, ○: excellent, Δ: acceptable.
[0182]
【The invention's effect】
As described above, according to the present invention, an organic electroluminescence element having high-efficiency emission luminance characteristics by attaching an angle conversion panel of light to the surface of the organic electroluminescence element, a display device using the same, and a mobile terminal , And a lighting device can be provided. In addition, by adjusting the symmetry of the mesa structure and the scattering at the light extraction surface, the organic electroluminescence element has less blur and light blur or has a specific viewing angle characteristic, a display device using the same, and a mobile phone. A terminal can be provided.
[Brief description of the drawings]
FIG. 1 is a view showing an example of a light angle conversion panel according to an embodiment of the present invention.
FIG. 2 is a view showing an example of a light angle conversion panel according to the embodiment of the present invention.
FIG. 3 is a diagram showing a cross-sectional shape of a groove formed in the light angle conversion panel according to the embodiment of the present invention.
FIG. 4 is a diagram showing a cross-sectional shape of a groove formed in the light angle conversion panel according to the embodiment of the present invention.
FIG. 5 is a cross-sectional view of a main part of an organic electroluminescence element in an embodiment of the present invention.
FIG. 6 is a cross-sectional view of a main part of an organic electroluminescence element in an embodiment of the present invention.
FIG. 7 is a cross-sectional view of a main part of an organic electroluminescence element in an embodiment of the present invention.
FIG. 8 is a schematic perspective view of a display device using an organic electroluminescence element in an embodiment of the present invention.
FIG. 9 is a perspective view showing a portable terminal equipped with a display device using the organic electroluminescence element of the present invention.
FIG. 10 is a block diagram showing a portable terminal equipped with a display device using the organic electroluminescence element of the present invention.
FIG. 11 is a cross-sectional view of a main part of a conventional organic electroluminescence element.
FIG. 12 is a schematic diagram showing a typical light beam path in a cross section of a main part of a conventional organic electroluminescence element.
[Explanation of symbols]
1 Substrate
2 Anode
3 Hole transport layer
4 Light emitting layer
5 Cathode
6 Light angle conversion panel
7,8 groove
9 Microphone
10 Speaker
11 Operation unit
12 Display section
13 Antenna
14 Transmitter
15 Receiver
16 Control unit

Claims (18)

An anode for injecting holes on the substrate;
A cathode for injecting electrons;
A light emitting portion that emits light by recombination of holes injected by the anode and electrons injected by the cathode, between the anode and the cathode;
An organic electroluminescence device comprising: a light angle conversion panel provided on a side opposite to the light emitting portion with respect to the cathode and having a groove opening to the cathode side, and an opening area of the groove contacting the cathode. 2. The organic electroluminescence element according to claim 1, wherein the light angle conversion panel is bonded via a protective film provided on an element formation surface of the substrate. The organic electroluminescence element according to claim 1, wherein the light angle conversion panel has a light extraction surface formed of a scattering surface. The organic light-emitting device according to claim 1, wherein the light angle conversion panel includes a plurality of grooves parallel to one direction in the in-plane direction. 5. The organic electroluminescence element according to claim 1, wherein the groove portion of the light angle conversion panel is a plurality of grooves parallel to two directions orthogonal to each other in an in-plane direction. 6. The organic electroluminescence according to claim 1, wherein the groove portion of the light angle conversion panel is a linear V-shaped groove having two substantially straight V-shaped cross sections. element. 6. The organic material according to claim 1, wherein the groove portion of the light angle conversion panel is a curved V-shaped groove whose cross-sectional shape is a substantially V-shaped convex curve. Electroluminescence element. The organic electroluminescence element according to claim 1, wherein the groove portion of the light angle conversion panel has a symmetrical shape. The organic electroluminescence element according to claim 1, wherein the groove portion of the light angle conversion panel has an asymmetric shape. The organic electroluminescence device according to claim 1, wherein the groove portion of the light angle conversion panel is formed with a light reflection surface at least on a side surface thereof. Groove of the optical angle conversion panel, at least on that side, according to any one of claims 1 to 9, characterized in that by forming a surface consisting of small medium having a refractive index than the optical angle conversion panel Organic electroluminescence element. The organic material according to any one of claims 1 to 11, wherein a thermal expansion coefficient of a medium forming the light angle conversion panel is 80% or more and within 120% of a thermal expansion coefficient of the substrate. Electroluminescence element. An organic electroluminescence device according to any one of claims 1 to 12, wherein the anode is individually electrically separated in a stripe shape, and the cathode is individually electrically separated in a stripe shape, thereby forming an image. a display arrangement, the direction of the groove of the optical angle conversion panel, an organic electroluminescence display device characterized by the direction of the pixels formed by one of the stripe electrodes are the same. Direction of the groove of the optical angle conversion panel, column wherein each pixel is formed or an organic electroluminescent display device according to claim 1 3, characterized in that equal to the direction of the row. Area of the convex surface formed by the groove portion of the optical angle conversion panel, an organic electroluminescence display device according to any one of claims 13 to 14, characterized in that less than the area of the light-emitting layer of the pixel. 16. The organic electroluminescence according to claim 13, wherein a distance from the light emitting layer to a convex surface formed by the groove portion of the light angle conversion panel is smaller than a length of one side of the pixel. Display device. The optical angle conversion panel, an organic electroluminescence display device according to any one of claims 13 to 16, characterized in that formed by divided for each one or more of said pixels. Voice signal conversion means for converting voice to voice signals, operation means for inputting telephone numbers, display means for displaying incoming calls and telephone numbers, communication means for converting voice signals to transmission signals, received signals 18. A portable terminal comprising: receiving means for converting a sound signal into an audio signal; an antenna for transmitting and receiving the transmission signal and the received signal; and a control means for controlling each part, wherein the display means is any one of claims 13 to 17 . mobile terminal characterized in that it is composed of an organic electroluminescent display device according to.

Images