JP2009272068A - El element, backlight apparatus for liquid crystal display using el element, lighting device using el element, electronic signboard device using el element, and display device using el element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the moire and blurring of an image in an EL display device with a microlens array provided on one face of a translucent substrate. <P>SOLUTION: An interval t between a light-emitting layer 22 in an optical axis direction of a microlens element 28 and the microlens element 28, a pitch P1 of a microlens array 30, and a pitch Pe of a pixel structure are to satisfy at least one of the following conditions (1), (2), (3). (1) t≥Pe, and Pe=m×P1 (provided, m is a natural number); (2) t<Pe, and Pe=m×P1 (provided, m is a natural number); (3) t<Pe, and Pe≥5×P1. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an EL (electroluminescence) element, and also, a backlight device for a liquid crystal display using the EL element, an illumination device using the EL element, a digital signage device using the EL element, and a display using the EL element Relates to the device. The EL device according to the present invention has excellent light extraction efficiency.

  EL display devices are widely used for main displays of mobile phones, TV monitors, etc. because they have excellent visibility and good viewing angle distribution regardless of whether the illuminant is organic or inorganic. ing.

  Many EL display devices include a light-transmitting substrate and a light-emitting structure having a pixel structure including an EL light-emitting layer, and light emitted from the pixel structure of the light-emitting structure is incident on the light-transmitting substrate and is light-transmitting. It is configured to exit through the substrate. Conventionally, in such an EL display device, when a light beam incident on a light-transmitting substrate from a pixel structure attempts to exit the air through the light-transmitting substrate, a considerable part of the light beam is light-transmitting. Since the light is totally reflected on the surface of the substrate, 60% to 80% of the light cannot be emitted, resulting in a loss.

  In order to cope with this problem, it has been proposed to form a microlens array in which a plurality of microlens elements are arranged in a plane on one surface of a translucent substrate (see, for example, Patent Document 1). ).

JP 2002-260845 A

  However, in the conventional EL display device in which the microlens array is provided on one surface of the translucent substrate, both the pixel structure and the microlens array have a periodic structure, so that moire and blurring of images occur. There was a problem. The object of the present invention is to solve this problem. Another object of the present invention is to solve the same problem not only in the EL display device but also in the EL element itself or various other devices using the EL element.

  The present invention has been made to solve the above problems, and an EL display device according to the present invention includes a light-transmitting substrate and a light-emitting structure having a pixel structure including an EL (electroluminescence) light-emitting layer. In the EL display device configured such that light emitted from the pixel structure of the light emitting structure is incident on the light-transmitting substrate and is emitted through the light-transmitting substrate, the light-transmitting substrate includes: A microlens array having a plurality of microlens elements arranged in a plane is provided on one surface thereof, and a distance between the light emitting layer and the microlens element in the optical axis direction of the microlens element. t, the pitch Pl of the microlens array, and the pitch Pe of the pixel structure are (1) t ≧ Pe and Pe = m × Pl (where m (Natural number), (2) t <Pe, and Pe = m × Pl (where m is a natural number), (3) t <Pe, and Pe ≧ 5 × P1, the above conditions (1), (2), and Any one of (3) is satisfied.

  The invention according to claim 2 is further characterized in that the microlens element has a spherical lens shape.

  The invention according to claim 3 is further characterized in that the shape of the microlens element is an aspherical lens shape.

  The invention according to claim 4 is further characterized in that the microlens array is a lenticular lens.

  The invention according to claim 5 is further characterized in that the microlens array is a cross lenticular lens.

  The invention according to claim 6 is further characterized in that the shape of the microlens element is a polygonal prism shape.

  The invention according to claim 7 is further characterized in that the top of the microlens element has a flat shape.

  The invention according to claim 8 is further characterized in that the translucent substrate is made of a cycloolefin polymer.

  The invention according to claim 9 is further characterized in that a silica airgel layer is coated on the surface of the microlens array.

  The invention according to claim 10 is further characterized in that the microlens array is provided on a surface of the translucent substrate on the light emitting structure side.

  The invention according to claim 11 is further characterized in that the microlens array is provided on a surface of the translucent substrate opposite to the light emitting structure.

  The invention according to claim 12 is further characterized in that a light shielding layer having a one-to-one relationship with the pixels of the pixel structure of the light emitting structure is provided.

  The invention according to claim 13 is further characterized in that a color filter having a one-to-one relationship with the pixels of the pixel structure of the light emitting structure is provided.

  Furthermore, the invention according to claim 14 includes a light-transmitting substrate and a light-emitting structure having a pixel structure including an EL (electroluminescence) light-emitting layer, and light emitted from the pixel structure of the light-emitting structure. In the EL element that is configured to enter the light-transmitting substrate, pass through the light-transmitting substrate, and exit the light-transmitting substrate, the light-transmitting substrate has a plurality of microlens elements on a plane. A microlens array arranged in the direction of the optical axis of the microlens element, an interval t between the light emitting layer and the microlens element, a pitch Pl of the microlens array, and the pixels The pitch of the structure Pe is (1) t ≧ Pe and Pe = m × Pl (where m is a natural number), (2) t <Pe and Pe = m × Pl (where m is a natural number) Number), (3) t <Pe, and Pe ≧ 5 × P1, and any one of the above conditions (1), (2), and (3) is satisfied. is there.

  According to a fifteenth aspect of the present invention, there is provided an EL element wherein the microlens element has a spherical lens shape.

  The invention according to claim 16 is the EL element characterized in that the shape of the micro lens element is an aspherical lens shape.

  The invention according to claim 17 is the EL element characterized in that the microlens array is a lenticular lens.

  The invention according to claim 18 is the EL element characterized in that the microlens array is a cross lenticular lens.

  The invention according to claim 19 is the EL element characterized in that the microlens element has a polygonal prism shape.

  The invention according to claim 20 is the EL device characterized in that the top of the microlens element has a flat shape.

  The invention according to claim 21 is the EL device characterized in that the translucent substrate is made of a cycloolefin polymer.

  The invention according to claim 22 is the EL device characterized in that the surface of the microlens array is coated with a silica airgel layer.

  The invention according to claim 23 is the EL element further characterized in that the microlens array is provided on a surface of the translucent substrate on the light emitting structure side.

  The invention according to claim 24 is the EL element characterized in that the microlens array is provided on a surface of the translucent substrate opposite to the light emitting structure.

  According to a twenty-fifth aspect of the present invention, there is provided an EL element further comprising a light shielding layer having a one-to-one relationship with a pixel of the pixel structure of the light emitting structure.

  According to a twenty-sixth aspect of the present invention, there is provided an EL device further comprising a color filter having a one-to-one relationship with a pixel of the pixel structure of the light emitting structure.

  A twenty-seventh aspect of the present invention is a backlight device for a liquid crystal display device using the EL element according to any one of the first to fifteenth aspects as a light source.

  A twenty-eighth aspect of the invention is an illuminating device using the EL element according to any one of the first to fifteenth aspects as a light source.

  A twenty-ninth aspect of the present invention is an electronic signage apparatus using the EL element according to any one of the first to fifteenth aspects as a light-emitting source.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In all the drawings, even if the embodiments are different, the same or corresponding components are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a cross-sectional view of an EL display device 10-1 according to the first embodiment of the present invention. As shown in this figure, the EL display device 10-1 includes a translucent substrate 12 and a light emitting structure 14, which are attached to each other by a transparent adhesive layer 16.

  The adhesive layer 16 is formed using an adhesive or a pressure-sensitive adhesive. As the pressure-sensitive adhesive or adhesive, urethane-based, acrylic-based, rubber-based, silicone-based, vinyl-based resin, or the like can be used. In addition, as the pressure-sensitive adhesive and the adhesive, those which are pressed and adhered in a one-pack type, those which are cured by heat or light can be used, and those which are cured by mixing two liquids or a plurality of liquids are used. be able to. Moreover, as a formation method of the adhesive layer 16, there are a method of directly applying to the bonding surface and a method of pasting together those prepared in advance as a dry film. When the adhesive layer is prepared as a dry film, it is preferable because it can be easily handled in the manufacturing process.

  As a material of the translucent substrate 12, various glass materials can be used, plastic materials such as PMMA, polycarbonate, and polystyrene can be used, and various other materials can be used. Particularly preferred is a cycloolefin-based polymer, which is excellent in all of the processability and material properties such as heat resistance, water resistance and optical translucency. Moreover, it is preferable to form the translucent substrate 12 with the material which can make a total light transmittance 50% or more so that the light from the light emitting laminated structure 14 can permeate | transmit as much as possible.

  The light emitting structure 14 has a pixel structure and includes a first electrode layer 18, a second electrode layer 20, an EL light emitting layer 22, a TFT (thin film transistor) layer 24, and a lower substrate 26. The light-emitting structure 14 may be further provided with a hole transport layer, a hole injection layer, an electron transport layer, an electron injection layer, etc., but these are well known and are very important in the present invention. Since it is not important and may be provided as necessary, description thereof will be omitted here.

  The first electrode layer 18 is a transparent electrode layer, and this transparent electrode layer can be, for example, a layer in which an ITO film, an IZO film or the like is formed by a dry process such as a vapor deposition method or a sputtering method. However, the film forming material is not limited to these, and other materials can be used as long as they are transparent and have electrical conductivity. The film thickness is desirably 1 μm or less. This is because, although the electrical conductivity is improved as the film thickness is increased, there is a problem that local spikes easily enter the transparent electrode layer and the total light transmittance is reduced. When the height of the protrusion reaches 100 nm, for example, the local spike may cause a problem in the subsequent film formation process.

  The EL light emitting layer 22 may be a white light emitting layer, or may be a light emitting layer of blue, red, yellow, green, or the like. In the case of a white light emitting layer, the structure of the EL light emitting layer 20 is, for example, ITO / CuPc (copper phthalocyanine) / α-NPD doped with rubrene 1% / dinactylanthracene perylene 1% doped / Alq 3 / fluorinated. What is necessary is just to set it as Al as lithium / cathode. However, the present invention is not limited to this configuration, and an arbitrary configuration using an appropriate material that can set the wavelength of light emitted from the light emitting layer to R (red), G (green), and B (blue) is adopted. It is possible. Further, when used in a full-color display application, full-color display can be performed by separately applying three types of light emitting materials corresponding to R, G, and B, or by superimposing a color filter on white light.

  The translucent substrate 12 is provided with a microlens array 30 in which a plurality of microlens elements 28 are arranged in a plane on one surface (the upper surface in the drawing). In the illustrated example, the microlens array 30 is directly formed on the upper surface of the translucent substrate 12. However, the present invention is not limited to this, and the optical sheet on which the microlens array is formed is transmitted through the adhesive layer. The microlens array can be provided on the translucent substrate also by sticking to the surface of the transparent substrate. In the illustrated example, the microlens array 30 is provided on the opposite surface of the light-transmitting substrate 12 to the light-emitting structure 14, but opposite to the light-transmitting substrate. A microlens array can also be provided on the side surface, and such an embodiment will be described later.

  The microlens array 30 may be a lenticular lens, a triangular prism array, or a microlens array of another shape. When the microlens array 30 is formed as a triangular prism array, the microlens element 28 has a triangular prism shape. Since the triangular prism has a high light condensing property in the front direction, the luminance in the front direction can be increased thereby. Further, the shape of the microlens element may be a convex curved surface. In such a case, light is emitted not only in the front direction but also in various directions, so that a wide field of view can be obtained. The shape of the microlens element is not limited to the shape described above, and can be selected as appropriate depending on the light distribution characteristics required for the display to be used. For example, a polygonal pyramid shape such as a triangular pyramid or a quadrangular pyramid Also good. As a material for forming the microlens array 30, PET (polyethylene terephthalate), PC (polycarbonate), PMMA (polymethyl methacrylate), COP (cycloolefin polymer), acrylonitrile styrene copolymer, acrylonitrile polystyrene copolymer, or the like is used. be able to.

  Further, in FIG. 1, the distance between the microlens element 28 and the light emitting layer 22 in the optical axis direction (vertical direction in the drawing) of the microlens element 28 is t, the pitch of the microlens array 30 is Pl, and the light emission The pitch of the pixel structure of the structure 14 is indicated by Pe. The pitch Pe of the pixel structure is usually 10 μm or more and 500 μm or less, and in many cases, it is 10 μm or more and 400 μm or less.

  In the EL display device 10-1 of FIG. 1, t> Pe and Pe = Pl. More generally speaking, by satisfying the condition of t ≧ Pe and Pe = m × Pl (where m is a natural number), light beams emitted from adjacent pixels of the EL light-emitting layer 22 interfere with each other. It can be prevented from fitting. As a result, it is possible to prevent the occurrence of moire and image blur while securing the advantage of the EL display device using the microlens array that suppresses the loss of total reflection and achieves an increase in luminance.

  FIG. 2 is a cross-sectional view of an EL display device 10-2 according to the second embodiment of the present invention. The EL display device 50-2 differs from the EL display device 10-1 in FIG. 1 in that the pitch Pl of the microlens array 30 is made smaller than that in FIG. 1, that is, the EL display device. In 10-2, t> Pe and Pe = 2 × Pl. Also in the embodiment of FIG. 2, the condition that t ≧ Pe and Pe = m × Pl (where m is a natural number) is satisfied. Therefore, the same effects as the embodiment of FIG. 1 are obtained. It is supposed to be

  FIG. 3 is a sectional view of an EL display device 10-3 according to the third embodiment of the present invention. The EL display device 10-3 is different from the EL display device 10-1 in FIG. 1 in that the surface on which the microlens array 30 is formed is on the side of the light emitting structure 14 out of both surfaces of the translucent substrate 12. This is the surface (the lower surface in the figure). Therefore, the interval t between the microlens element 28 and the light emitting layer 22 in the optical axis direction (vertical direction in the drawing) of the microlens element 28 is considerably smaller than that of the embodiment of FIG. It is smaller than Pe, that is, t <Pe. On the other hand, regarding the pitch Pl of the microlens array 30 and the pitch Pe of the pixel structure, Pe = Pl. To further generalize, a microlens array that achieves an increase in luminance while suppressing the loss of total reflection by satisfying the condition of t <Pe and Pe = m × Pl (where m is a natural number). While securing the advantages of the EL display device used, it is possible to prevent the occurrence of moire and image blur.

  FIG. 4 is a cross-sectional view of an EL display device 10-4 according to the fourth embodiment of the present invention. The EL display device 10-4 has the same configuration as the EL display device 10-3 of FIG. 3, except that the pitch Pl of the microlens array 30 is smaller than that of FIG. In the EL display device 10-4 of FIG. 4, t <Pe and Pe = 2 × Pl. In the embodiment of FIG. 4 as well, the condition that t <Pe and Pe = m × Pl (where m is a natural number) is satisfied, as in the embodiment of FIG. The same effect as that of the embodiment can be obtained.

  FIG. 5 is a cross-sectional view of an EL display device 10-5 according to the fifth embodiment of the present invention. The EL display device 10-5 has the same configuration as the EL display device 50-3 in FIG. 3 and the EL display device 10-4 in FIG. 4, except that the pitch Pl of the microlens array 30 is that in FIG. It is even smaller, that is, t <Pe and Pe> 5 × Pl. To further generalize, an EL display device using a microlens array that achieves an increase in luminance by suppressing the loss of total reflection by satisfying the conditions t <Pe and Pe ≧ 5 × Pl. It is possible to prevent the occurrence of moire and image blur while securing the advantage.

  Regarding the embodiment of FIG. 5, it is clear from experimental results that the image quality becomes better as the Pe / Pl ratio value increases, and the experimental results are shown in Table 1 below. This experiment was conducted with Pe = 350 μm, where x represents poor image quality, Δ represents slightly poor image quality, and ◯ represents good image quality.

  FIG. 6 is a cross-sectional view of an EL display device 10-6 according to the sixth embodiment of the present invention. The EL display device 10-6 has the same configuration as that of the EL display device 10-2 of FIG. 2, except that the thickness of the translucent substrate 12 is smaller than that of the EL display device 10-2 of FIG. The distance t between the microlens element 28 and the light emitting layer 22 in the optical axis direction (vertical direction in the drawing) of the lens element 28 is small and smaller than the pitch Pe of the pixel structure, that is, t <Pe. It has become. On the other hand, regarding the pitch Pl of the microlens array 30 and the pitch Pe of the pixel structure, Pe = 2 × Pl as in the embodiment of FIG. Therefore, as in the embodiments of FIGS. 3 and 4, the condition that t <Pe and Pe = m × Pl (where m is a natural number) is satisfied, whereby the same operation as those of the embodiments is performed. The effect is obtained.

  In the various EL display devices described above, a light diffusing layer is further laminated on the translucent substrate 12 provided with the microlens array 30 so that the light extracted through the microlens array 30 is diffused. As a result, the angle dependency and the wavelength dependency of the viewing angle can be relaxed. Such a light diffusing layer is also effective when the viewing angle is simply expanded or controlled. The light diffusion layer is preferably a layer having a haze value of 20% or more. If the haze value is less than 20%, the light diffusion performance is insufficient and the uniformity of in-plane luminance is deteriorated. May occur. Such a light diffusing layer may be, for example, a layer containing fine particles of an inorganic material or an organic material. Examples of the fine particles in this case include titanium oxide, barium sulfate, magnesium carbonate, zinc oxide, clay, water White or transparent fine particles such as aluminum oxide, zinc sulfide, silica, and silicone can also be used, and metal particles such as aluminum and silver can also be used. Further, only one type of white or transparent particles or metal particles may be used, or a plurality of types may be mixed and used.

  Such a light diffusion layer can also be formed by sticking a sheet-like light diffusion member. The sheet-like light diffusion member is formed, for example, by dispersing light diffusion particles in a transparent resin. It can also be. Moreover, as a transparent resin in that case, a thermoplastic resin, a thermosetting resin, or the like can be used. More specifically, for example, a polycarbonate resin, an acrylic resin, a fluorine-based acrylic resin, a silicone-based acrylic resin, Epoxy acrylate resins, polystyrene resins, cycloolefin polymers, methyl styrene resins, fluorene resins, polyethylene terephthalate (PET), polypropylene, acrylonitrile styrene copolymers, acrylonitrile polystyrene copolymers, and the like can be used. As the light diffusing particles, transparent particles made of an inorganic oxide or a resin can be used. As the transparent particles made of an inorganic oxide, for example, silica, alumina or the like can be used. The transparent particles made of resin include acrylic particles, styrene particles, styrene acrylic particles and cross-linked products thereof, melamine / formalin condensate particles, PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxy resin), FEP (tetrafluoroethylene). Fluoropolymer particles such as fluoroethylene / hexafluoropropylene copolymer), PVDF (polyfluorovinylidene), and ETFE (ethylene / tetrafluoroethylene copolymer), silicone resin particles, and the like can be used. Moreover, you may use combining 2 or more types of transparent particles from the transparent particle mentioned above. Furthermore, the size and shape of the transparent particles are not particularly defined. The thickness of the sheet-like light diffusing member having the above configuration is preferably 0.05 mm to 5 mm. By doing so, suitable diffusion performance and luminance can be obtained. If the thickness of the light diffusing member is less than 0.05 mm, the diffusing performance may be insufficient. On the other hand, if the thickness exceeds 5 mm, the amount of resin is so large that the luminance may decrease due to absorption. .

  Alternatively, when the light diffusing layer is formed by sticking a sheet-like light diffusing member, the sheet-like light diffusing member is formed as a sheet in which fine bubbles are included in a thermoplastic resin. It can also be. That is, the inner surface of fine bubbles formed inside the thermoplastic resin causes diffused reflection of light, and a light diffusing function equivalent to or higher than that when light diffusing particles are dispersed can be exhibited. Therefore, it becomes possible to make the film thickness of the light diffusing member thinner. Examples of such a light diffusing member include white PET and white PP. For white PET, a resin that is incompatible with PET, titanium oxide (TiO2), barium sulfate (BaSO4), fillers such as calcium carbonate are dispersed in PET, and then the PET is stretched by a biaxial stretching method. Thus, bubbles are generated around the filler. In addition, the light diffusing member made of the thermoplastic resin having such a configuration may be extended at least in the uniaxial direction, and bubbles may be generated around the filler by extending in the at least uniaxial direction. it can. Examples of the thermoplastic resin in this case include polyethylene terephthalate (PET), polyethylene-2,6-naphthalate, polypropylene terephthalate, polybutylene terephthalate, cyclohexane dimethanol copolymer polyester resin, isophthalic acid copolymer polyester resin, Polyester resins such as low-glycol copolymer polyester resin and fluorene copolymer polyester resin, polyolefin resins such as polyethylene, polypropylene, polymethylpentene, and alicyclic olefin copolymer resins, acrylic resins such as polymethyl methacrylate, polycarbonate, polystyrene , Polyamides, polyethers, polyesteramides, polyetheresters, polyvinyl chloride, cycloolefin polymers, and their components Copolymers, also can be used as mixtures of these resins are not particularly limited. Moreover, it is preferable that the thickness of the sheet-like light diffusing member enclosing such fine bubbles is 25 μm to 500 μm. When the thickness of the light diffusing member is less than 25 μm, the sheet is insufficiently squeezed and wrinkles are likely to occur in the manufacturing process and display. On the other hand, when the thickness exceeds 500 μm, there is no particular problem with optical performance, but there is a possibility that inconveniences such as difficulty in processing into a roll shape due to increase in rigidity.

  In the various EL display devices described above, the shape of the top of the microlens element 28 is a flat shape. The microlens element 28 having a flat top portion is advantageous in securing a bonding strength because a large adhesion area or adhesive area can be obtained when the microlens array 30 is bonded to the light emitting structure or the light diffusion layer. It is. However, when it is desired to further increase the sticking strength, an embodiment as described below may be adopted.

  FIG. 7 is a sectional view of an EL display device 10-7 according to the seventh embodiment of the present invention. This EL display device 10-7 has the same configuration as that of the EL display device 10-3 of FIG. 3, except that the surface of the microlens array 30 is coated with a silica airgel layer. The space around the microlens element 28 is filled with silica aerogel. Since silica airgel is a low refractive index material, even if the space around the microlens element 28 is filled with silica airgel, the surface of the microlens element 28 is optically similar to that when the space is an air layer. Characteristics can be maintained. By setting it as this structure, the adhesion strength at the time of adhere | attaching or sticking a microlens array to another member can be increased. This can also improve the abrasion resistance of the microlens array. There are other materials that can be used as low-refractive-index materials used to fill the space around the microlens element, but silica airgel has a refractive index very close to that of air, making it translucent. Is also a particularly preferred material.

  FIG. 8 is a cross-sectional view of an EL display device 10-8 according to the eighth embodiment of the present invention. This EL display device 10-8 has the same configuration as the EL display device 10-3 of FIG. 3, except that a light shielding layer 34 having a one-to-one relationship with the pixels of the pixel structure of the light emitting structure 14 is provided. Is different. By providing such a light shielding layer 34, it is possible to improve the contrast when viewed from the observer side. Further, the position of the light shielding layer 34 is not limited to the position illustrated in FIG.

  FIG. 9 is a cross-sectional view of an EL display device 10-9 according to the ninth embodiment of the present invention. This EL display device 10-9 has the same configuration as the EL display device 10-3 in FIG. 3, except that a color filter 36 having a one-to-one relationship with the pixels of the pixel structure of the light emitting structure is provided. ing. When the light emitted from the EL light emitting layer 22 is white light, a color filter 36 is required to display a full color image. The position where the color filter 36 is arranged is not limited to the position shown in FIG.

  Among the EL display devices described above, the microlens array 30 is provided on the surface of the translucent substrate 12 on the light emitting structure 14 side, and the light emitting structure 14 of the translucent substrate 12. Was provided on the opposite side. In the former, since the microlens array 30 is positioned between the translucent substrate 12 and the light emitting structure 14, there is an advantage that the microlens array 30 is protected by the translucent substrate 12. On the other hand, in the latter, since the microlens array 30 is located on the entire surface of the EL display device, there is an advantage that the manufacture of the microlens array 30 becomes easy.

  The microlens array 30 in the EL display device described above has a shape of the microlens element 28 in the shape of a truncated pyramid or a truncated cone, but the shape of the microlens element 28 is not limited thereto. For example, the shape of the microlens element 28 may be a spherical lens shape. In such a case, the viewing angle distribution can be smoothed by a spherical curve. The shape of the microlens element 28 may be an aspherical lens shape. In such a case, the viewing angle distribution can be controlled more finely. The microlens array 30 may be a lenticular lens. In such a case, the microlens element 28 may be a lens element having a different curvature and pitch in the horizontal and vertical directions. The microlens array 30 may be a cross lenticular lens, and the cross lenticular lens in that case may be a lens in which lenticular lenses are arranged in parallel in the horizontal and vertical directions. The shape of the microlens element 28 may be a polygonal prism shape, and the polygonal prism may have a triangular shape, a quadrangular shape, or the like.

  Although the case where the present invention is applied to an EL display device has been described above, the present invention can also be applied to EL elements used for purposes other than the EL display device. In that case, the EL element according to the present invention includes a light-transmitting substrate and a light-emitting structure including an EL light-emitting layer and having a pixel structure, and light emitted from the pixel structure of the light-emitting structure is the light-transmitting light. In an EL device configured to enter a light-transmitting substrate and pass through and pass through the light-transmitting substrate, the light-transmitting substrate has a plurality of microlens elements arranged in a plane on one surface thereof. The microlens array is provided, and an interval t between the light emitting layer and the microlens element in the optical axis direction of the microlens element, a pitch Pl of the microlens array, and a pitch Pe of the pixel structure (1) t ≧ Pe and Pe = m × P1 (where m is a natural number), (2) t <Pe and Pe = m × P1 (where m is a natural number), (3) t < Pe and An EL element is characterized in that Pe ≧ 5 × Pl and any one of the above conditions (1), (2), and (3) is satisfied. Further, the EL element can have various features of the EL display device described above.

  Furthermore, since the EL element according to the present invention has excellent light extraction efficiency, it is also suitable for use as a light source of a lighting device, and the lighting device configured as such is also included in the scope of the present invention. . Moreover, the EL element according to the present invention can be suitably used for various other applications. For example, the EL element according to the present invention can be suitably used as a light emission source of a backlight device for a liquid crystal display device, and the backlight device configured as such is also included in the scope of the present invention. By using the EL element according to the present invention as a light source of a backlight device for a liquid crystal display device, the structure is made thinner and the power consumption is reduced as compared with a backlight device using a cold cathode fluorescent lamp as a light source. Can also be reduced. In addition, since there is virtually no light source unevenness, a diffusion plate and a lens sheet for reducing the lamp image are not required, which contributes to cost reduction. The EL element according to the present invention can also be suitably used as a light emission source of a digital signage apparatus, and the electronic signage apparatus configured as such is also included in the scope of the present invention.

1 is a cross-sectional view of an EL display device according to a first embodiment of the present invention. It is sectional drawing of the EL display apparatus which concerns on the 2nd Embodiment of this invention. It is sectional drawing of the EL display apparatus which concerns on the 3rd Embodiment of this invention. It is sectional drawing of the EL display apparatus which concerns on the 4th Embodiment of this invention. It is sectional drawing of the EL display apparatus which concerns on the 5th Embodiment of this invention. It is sectional drawing of the EL display apparatus which concerns on the 6th Embodiment of this invention. It is sectional drawing of the EL display apparatus which concerns on the 7th Embodiment of this invention. It is sectional drawing of the EL display apparatus which concerns on the 8th Embodiment of this invention. It is sectional drawing of the EL display apparatus which concerns on the 9th Embodiment of this invention.

Explanation of symbols

10-1 to 10-9 EL display device 12 Translucent substrate 14 Light emitting structure 16 Adhesive layer 18 First electrode layer 20 Second electrode layer 22 EL light emitting layer 24 TFT layer 26 Lower substrate 28 Micro lens element 30 Micro lens array 32 Silica airgel layer 34 Light shielding layer 36 Color filter

Claims (29)

A light-transmitting substrate and a light-emitting structure having a pixel structure including an EL (electroluminescence) light-emitting layer, and light emitted from the pixel structure of the light-emitting structure is incident on the light-transmitting substrate and the light-transmitting substrate. In an EL display device configured to emit through a light substrate,
The translucent substrate is provided on one surface thereof with a microlens array in which a plurality of microlens elements are arranged in a plane.
An interval t between the light emitting layer and the microlens element in the optical axis direction of the microlens element, a pitch Pl of the microlens array, and a pitch Pe of the pixel structure,
(1) t ≧ Pe and Pe = m × Pl (where m is a natural number),
(2) t <Pe and Pe = m × Pl (where m is a natural number),
(3) t <Pe and Pe ≧ 5 × Pl,
Satisfies any one of the above conditions (1), (2), and (3),
An EL display device.   The EL display device according to claim 1, wherein the microlens element has a spherical lens shape.   2. The EL display device according to claim 1, wherein the microlens element has an aspheric lens shape.   The EL display device according to claim 1, wherein the microlens array is a lenticular lens.   The EL display device according to claim 1, wherein the microlens array is a cross lenticular lens.   The EL display device according to claim 1, wherein the microlens element has a polygonal prism shape.   The EL display device according to claim 1, wherein a top portion of the microlens element has a flat shape.   The EL display device according to claim 1, wherein the translucent substrate is made of a cycloolefin-based polymer.   2. The EL display device according to claim 1, wherein a surface of the microlens array is coated with a silica airgel layer.   2. The EL display device according to claim 1, wherein the microlens array is provided on a surface of the translucent substrate on the light emitting structure side.   The EL display device according to claim 1, wherein the microlens array is provided on a surface of the translucent substrate opposite to the light emitting structure.   The EL display device according to claim 1, further comprising a light shielding layer having a one-to-one relationship with the pixels of the pixel structure of the light emitting structure.   2. The EL display device according to claim 1, further comprising a color filter having a one-to-one relationship with a pixel of the pixel structure of the light emitting structure. A light-transmitting substrate and a light-emitting structure having a pixel structure including an EL (electroluminescence) light-emitting layer, and light emitted from the pixel structure of the light-emitting structure is incident on the light-transmitting substrate and the light-transmitting substrate. In an EL device configured to pass through a light substrate and emit,
The translucent substrate is provided on one surface thereof with a microlens array in which a plurality of microlens elements are arranged in a plane.
An interval t between the light emitting layer and the microlens element in the optical axis direction of the microlens element, a pitch Pl of the microlens array, and a pitch Pe of the pixel structure,
(1) t ≧ Pe and Pe = m × Pl (where m is a natural number),
(2) t <Pe and Pe = m × Pl (where m is a natural number),
(3) t <Pe and Pe ≧ 5 × Pl,
Satisfies any one of the above conditions (1), (2), and (3),
An EL element.   The EL element according to claim 14, wherein the microlens element has a spherical lens shape.   The EL element according to claim 14, wherein the microlens element has an aspheric lens shape.   The EL device according to claim 14, wherein the microlens array is a lenticular lens.   The EL device according to claim 14, wherein the microlens array is a cross lenticular lens.   The EL element according to claim 14, wherein the microlens element has a polygonal prism shape.   The EL element according to claim 14, wherein a top portion of the microlens element has a flat shape.   The EL device according to claim 14, wherein the translucent substrate is made of a cycloolefin-based polymer.   15. The EL device according to claim 14, wherein the surface of the microlens array is coated with a silica airgel layer.   The EL device according to claim 14, wherein the microlens array is provided on a surface of the translucent substrate on the light emitting structure side.   The EL device according to claim 14, wherein the microlens array is provided on a surface of the translucent substrate opposite to the light emitting structure.   15. The EL element according to claim 14, further comprising a light shielding layer having a one-to-one relationship with the pixel having the pixel structure of the light emitting structure.   The EL element according to claim 14, further comprising a color filter having a one-to-one relationship with a pixel of the pixel structure of the light emitting structure.   27. A backlight device for a liquid crystal display device, wherein the EL element according to claim 14 is used as a light emission source.   27. An illuminating device comprising the EL element according to claim 14 as a light source.   27. An electronic signboard apparatus, wherein the EL element according to any one of claims 14 to 26 is used as a light source.

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