JP2010205512A - El element, display device using the same, display device, and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an EL element favorable to antifouling property, anti-friction property and optimizing color correction without deteriorating the efficiency of light extraction. <P>SOLUTION: When an average diameter of a micro unit lens 5 of a microlens sheet 7 is P1, an average height of the micro unit lens 5 is T1, the sum total of a bottom area of the micro unit lens 5 is S1, and the area of the remaining part taking the total S1 of the bottom area from the surface is S2, inorganic conductive particulates 5b are added to the lens sheet which has a region satisfying a conditional expression of 0.3≤(T1/P1)≤(S1/S2), and an average roughness Sa of the lens satisfies 10 nm<Sa<100 nm, so that the antifouling property and anti-friction property are improved without deteriorating the efficiency of light extraction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an EL element (electroluminescence element) used for a flat panel display, a backlight for liquid crystal, a light source for illumination, an illumination, a light source for signage, and the like, and a display device, a display device, and a liquid crystal display using the EL element It relates to the device.

  In general, an organic EL has a structure in which a light-emitting layer containing a fluorescent organic compound is sandwiched between an anode and a cathode on a translucent substrate. Then, a DC voltage is applied to the anode and the cathode, electrons and holes are injected into the light emitting layer and recombined to generate excitons, and light emission when the excitons are deactivated is used. Leads to light emission.

  Conventionally, in these EL elements, when the light emitted from the light emitting layer is emitted from the light transmitting substrate, there is a problem that the light is totally reflected on the light transmitting substrate and the light is lost. The light extraction efficiency at this time is generally said to be about 20%. Therefore, there is a problem that the higher the brightness is, the more input power is required. Not only that, the load on the element increases and the reliability of the element itself is lowered.

  In order to improve the external extraction efficiency of light, a method has been proposed in which fine irregularities are formed on an element substrate and a light beam lost due to total reflection is extracted to the outside. For example, 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 Patent Document 1).

JP 2002-260845 A

  However, the above-described prior art has a problem that the lens portion comes to the outermost surface (observer side), so that it is easily scratched and the surface of the lens portion is easily contaminated by being charged with static electricity. The present invention has been made in view of such circumstances, and has an EL element advantageous in antifouling property and abrasion resistance without reducing light extraction efficiency, and a display device, a display device, and a liquid crystal display using the EL device. An object is to provide an apparatus.

  In order to achieve the above object, the present invention takes the following measures.

That is, in the invention according to claim 1, in an EL element comprising a light-transmitting substrate and a light-emitting layer provided on one surface of the light-transmitting substrate and sandwiched between an anode and a cathode,
A microlens sheet is provided on the other surface of the translucent substrate, and the microlens sheet has a surface and fine unit lenses arranged on the surface.
In the microlens,
The average diameter of the fine unit lens is P1,
The average height of the fine unit lens is T1,
The total bottom area of the fine unit lens is S1,
When the area of the remaining part excluding the bottom area total S1 from the surface is S2,
Conditional expression: It is assumed to have a region satisfying 0.3 ≦ (T1 / P1) ≦ (S1 / S2).

  In the invention according to claim 2, in the EL element according to claim 1, the microlens sheet contains inorganic conductive fine particles, and the average roughness Sa of the microlens tip is 10 nm <Sa <100 nm. To do.

  In the invention according to claim 3, in the EL element according to claim 1, the fine unit lens has a convex spherical shape.

  In the invention according to claim 4, in the EL element according to claim 1, the fine unit lens has a convex aspherical shape.

  In the invention according to claim 5, in the EL element according to claim 1, the fine unit lens includes a straight portion and a curved portion.

  In the invention according to claim 6, in the EL element according to claim 1, the pitch of the fine unit lenses is random.

  In the invention according to claim 7, in the EL element according to claim 1, the arrangement of the fine unit lenses on the plane is a pattern.

  In the invention according to claim 8, in the EL element according to claim 1, the light diffusion member is disposed on the surface of the microlens sheet.

  In the invention according to claim 9, in the EL element according to claim 8, the surface of the microlens sheet and the light diffusing member are bonded together via an adhesive layer.

  In a display device according to a tenth aspect of the present invention, the EL element according to any one of the first to ninth aspects is used as a backlight.

  In the display device according to the eleventh aspect, the EL element according to any one of the first to ninth aspects is configured to be pixel-driven.

  In the liquid crystal display device according to the twelfth aspect, the EL element according to any one of the first to ninth aspects is used as a backlight on the back surface of the image display element.

  According to the present invention, the average diameter of the micro unit lens of the micro lens sheet is P1, the average height of the micro unit lens is T1, the total bottom area of the micro unit lens is S1, and the total bottom area S1 from the surface is calculated as S1. By adding inorganic conductive fine particles to the lens sheet having a region satisfying the conditional expression: 0.3 ≦ (T1 / P1) ≦ (S1 / S2) when the area of the remaining portion is S2, Further, by making the average roughness Sa of the lens portion satisfy 10 nm <Sa <100 nm, it becomes possible to improve the antifouling property and the abrasion resistance without reducing the light extraction efficiency. .

(A) is a top view of the microlens sheet | seat 7 of the EL element which is embodiment of this invention, (b) is a side view. It is a figure which shows the structure of the EL element which is embodiment of this invention. It is a figure which shows an example of the grid | lattice-like arrangement | positioning of the micro unevenness | corrugation shape of the micro lens sheet. 3 is a diagram showing an example of a substantially square pyramid honeycomb arrangement of a microlens sheet. FIG. It is a figure which shows an example of the substantially square pyramid-shaped random arrangement | positioning of the microlens sheet | seat. It is a figure which shows an example of the substantially square pyramid-shaped pattern arrangement | positioning of the microlens sheet | seat. It is a figure which shows the structure which provided the light-scattering means on the EL element which is embodiment of this invention. It is a figure which shows the structure which provided the light-scattering means on the EL element which is embodiment of this invention, and has arrange | positioned the contact bonding layer to the light-scattering means. It is a figure which shows an example which provided the example of the light ray from an EL element part on the EL element which is embodiment of this invention. It is a figure which shows an example which provided the light-scattering means on the EL element which is embodiment of this invention, arrange | positioned the contact bonding layer in the light-scattering means, and provided the example of the light ray from an EL element part. In the microlens sheet | seat of this invention, it is a figure which shows a measured value in case it is S2 / S1 = 0.785. In the microlens sheet | seat of this invention, it is a figure which shows a measured value in case it is S2 / S1 = 0.81. In the microlens sheet | seat of this invention, it is a figure which shows a measured value in case it is S2 / S1 = 0.92. It is a figure which shows the range L which implements average roughness measurement. It is a figure which shows the relationship between the average roughness Sa of the lens part of a microlens sheet | seat, and a front luminance increase rate. 3 is a schematic diagram of a microlens sheet 7. FIG.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 2 is a diagram showing a configuration of an EL element (electroluminescence element) according to an embodiment of the present invention. As shown in FIG. 2, the EL element includes first and second translucent substrates 1A and 1B, a light emitting layer 2, an anode 3, a cathode 4, a microlens sheet 7, and the like. Yes.

  An anode 3 is formed on one surface of the light emitting layer 2 and a cathode 4 is formed on the other surface. A light emitting structure is configured including the light emitting layer 2, the anode 3, and the cathode 4. Various known configurations can be employed as the light emitting structure.

  The light emitting layer 2 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 light emitting layer 2 is, for example, ITO / CuPc (copper phthalocyanine) / α-NPD doped with rubrene 1% / dinactylanthracene perylene 1% doped / Alq 3 / lithium fluoride. / The cathode may be made of Al.

  However, the present invention is not limited to this configuration, and any configuration using an appropriate material capable of setting the wavelength of light emitted from the light emitting layer to R (red), G (green), and B (blue) is adopted. Is possible. In addition, when used in a full color display application, full color display is possible by separately applying three types of light emitting materials corresponding to R, G, and B, or by overlaying a color filter on white light.

  The first translucent substrate 1 </ b> A is formed on the surface opposite to the surface where the anode 3 faces the light emitting layer 2. The second translucent substrate 1B is formed on the surface opposite to the surface on which the cathode 4 faces the light emitting layer 2.

  As materials for the first and second light-transmitting substrates 1A and 1B, various glass materials can be used, and plastic materials such as PMMA, polycarbonate, and polystyrene can be used. Although materials can be used, a cycloolefin-based polymer is particularly preferable, and this polymer is excellent in all of processability and material properties such as heat resistance, water resistance, and optical translucency. is there.

  Further, the first light-transmitting substrate 1A is formed of a material capable of making the total light transmittance 50% or more so that light from the light-emitting structure (light-emitting layer 2) can be transmitted as much as possible. Is preferred.

  The microlens sheet 7 is provided on the surface opposite to the surface on which the first transparent substrate 1 </ b> A faces the anode 3 with the adhesive layer 6 interposed therebetween. Examples of the adhesive / adhesive constituting the adhesive layer 6 include acrylic, urethane, rubber, and silicone adhesives / adhesives. In either case, since it is used in a high-temperature backlight, it is desirable that the storage elastic modulus G ′ is 1.0E + 04 (Pa) or more at 100 ° C. If the value is lower than this, the light diffusion layer 25 and the lens sheet 1 may be displaced during use.

  Further, in order to stably secure a gap, transparent fine particles such as beads may be mixed in the contact / adhesive layer. The adhesive may be a double-sided tape or a single layer.

  The microlens sheet 7 has a surface facing the side opposite to the first transmissive substrate 1 </ b> A and the fine unit lenses 5 arranged on the surface. In other words, the EL element includes a translucent substrate 1A and a light emitting layer 2 provided on one surface of the translucent substrate 1A and sandwiched between an anode 3 and a cathode 4. A microlens sheet 7 is provided on the other surface of the translucent substrate 1A, and the microlens sheet 7 has a surface and fine unit lenses 5 (microlenses) arranged on the surface.

  The substrate used for the microlens sheet is a transparent film, such as cellulose triacetate, polyester, polyamide, polyimide, polypropylene, polymethylpentene, polyvinyl chloride, polyvinyl acetal, polymethyl methacrylate, polycarbonate, polyurethane, etc. A stretched or unstretched film of a thermoplastic resin can be used.

  Although the thickness of a base film is based also on the rigidity which a film has, the thing of 50-300 micrometers is preferable from the handling surfaces, such as workability. In addition, it is preferable to perform easy adhesion treatment such as corona discharge treatment on the surface on which the microlenses are provided in order to firmly stabilize the adhesion.

  The microlenses are conventionally known, such as UV molding, extrusion molding, etc., using a mold made of a conductive resin composed of a binder 5a mainly composed of a thermoplastic resin or a reaction curable resin composition and inorganic conductive fine particles 5b. It can be formed by a method.

  The binder 5a is preferably selected from those having good adhesion to the base film, light resistance as the resin composition, and moisture resistance. When selecting the binder a mainly composed of a thermoplastic resin, linear polyester, polyurethane, acrylic resin, polyvinyl butyral, polyamide, vinyl chloride / vinyl acetate copolymer, etc. It is preferable to select from those added with a light stabilizer.

  When selecting a binder based on a reactive curable resin, in addition to polyester polyol / polyisocyanate, polyether polyol / polyisocyanate, polyacryl polyol polyol / polyisocyanate, epoxy / polyisocyanate, ionizing radiation curing type Resin can also be used. Of these, aromatic and / or aliphatic diisocyanates and triisocyanates are preferred as the polyisocyanate.

  As the conductive fine particles 5b, ultrafine particles such as antimony-containing tin oxide (hereinafter referred to as ATO) and tin-containing indium oxide (ITO) are used. These conductive fine particles 5b are mixed and used at a ratio of conductive fine particles 5b: 0.1 to 20 g with respect to the binder 5a: 100 g. When the proportion of the inorganic conductive fine particles 5b is lower than the above value, the antistatic performance is lowered. Conversely, when the proportion is higher than the above value, the transparency is lowered.

  In addition, when the microlens does not adhere firmly to the base film, or when the adhesive strength decreases due to external influences such as cold, moisture absorption and desorption, both materials are placed between the microlens and the base film. Alternatively, a primer layer having high adhesion may be provided, or the binder 5a may be appropriately selected to add the action of the primer layer to the microlens.

  Further, when the ionizing radiation curable resin is used as an ultraviolet curable resin, acetophenones, benzophenones, Michler benzoyl benzoate, α-amyloxime ester, thioxanthone, etc. It is preferable to use a mixture of n-butylamine, triethylamine, tri-n-butylphosphine or the like as a photosensitizer.

  The microlens shape includes a lenticular shape, a trapezoidal shape, a prism shape and the like extending in one direction; It may be a spherical (or hemispherical) or ellipsoidal structure.

  Depending on the method of manufacturing the microlens, the shape of the side surface may be an unspecified shape as long as the height of the microlens is constant. When ensuring a space | gap with these microlenses, you may use said 1 type of microlens structure for the whole, or may use it combining several types of microlens structure. Further, the arrangement of these microlenses may be periodic or random such as a stripe shape or a dotted line, and is appropriately selected according to the design.

  FIG. 1A is a top view of a microlens sheet 7 of an EL element according to an embodiment of the present invention, and FIG. 1B is a side view.

As shown in FIGS. 1A and 1B, the microlens sheet 7 has an average diameter of the fine unit lens 5 as P1, an average height of the fine unit lens 5 as T1, and When the total area of the bottom area is S1, and the area of the remaining portion excluding the total area of the bottom area S1 is S2, the area satisfying the following conditional expression (1) is formed.
0.3 ≦ (T1 / P1) ≦ (S1 / S2) (1)

  Further, when the area of the light emitting surface range a of the light emitting layer 2 shown in FIG. 2 is Sa and the area of the region where the microlens sheet 7 satisfies the conditional expression (1) is Sb, Sb is 50% of Sa. It is preferable to satisfy, and it is more preferable when Sb satisfies 90% of Sa. In addition, it is not so preferable when Sb satisfies 10% of Sa.

  Here, a method for measuring the areas S1 and S2, the height T1, and the average diameter P1 will be described.

  FIG. 16 is a schematic diagram of the microlens sheet 7. In FIG. 16, black portions indicate the fine unit lenses 5.

  Therefore, the total area of the black portions corresponds to the total bottom area S1 of the fine unit lens 5, and the total area of the white portions is the area of the remaining portion excluding S1 from the surface of the microlens sheet 7. This corresponds to S2. The height T1 is an average of 100 or more samples.

  The measurement of the areas S1 and S2 and the height T1 is not limited to this. For example, a confocal laser microscope such as a scanning confocal infrared laser microscope LEXT OLS3000-IR manufactured by Olympus is used. Can be used.

  When the number of the fine unit lenses 5 in a unit area having 100 or more fine unit lenses 5 is N, the average diameter P1 of the fine unit lenses 5 is expressed by the following formula.

  As shown in FIG. 9, the light emitted from the light emitting layer 2 is efficiently emitted not only in the front direction but also in various directions by the fine unit lens 5, and a wide field of view range is obtained.

  In order to efficiently extract the light emitted from the light emitting layer 2, in other words, in order to improve the light extraction efficiency, the fine unit lens 5 has a convex spherical shape, a convex aspherical shape, a linear portion, A shape including a curved portion is preferable.

  A random pitch of the fine unit lenses 5 is advantageous in optimizing the light extraction efficiency and improving the light extraction efficiency.

  Further, as shown in FIGS. 3 and 4, the arrangement of the fine unit lenses 5 on the plane may be periodic, or as shown in FIG. 5, the arrangement of the fine unit lenses 5 on the plane may be aperiodic. May be.

  If the arrangement of the fine unit lenses 5 on the plane is periodic, it is advantageous for increasing the density of the fine unit lenses 5. On the other hand, if the arrangement of the fine unit lenses 5 on the plane is aperiodic, EL emission defects are eliminated. It is advantageous in making it difficult to see.

  Further, as shown in FIG. 6, the arrangement on the plane of the fine unit lenses 5 may be a pattern, and in this case, the pattern can be displayed by the light emitted from each fine unit lens 5. Such a picture includes a logo, a mark, a pattern, and the like.

  As shown in FIG. 7, a light diffusion member 8 may be disposed on the surface of the microlens sheet 7. Further, as shown in FIG. 8, the surface of the microlens sheet 7 and the light diffusing member 8 may be bonded via an adhesive layer 6.

  As shown in FIG. 10, when the light diffusion member 8 is disposed on the surface of the microlens sheet 7, the light emitted from each fine unit lens 5 can be diffused by the light diffusion member 8. Therefore, it is even more advantageous in efficiently emitting light in various directions and obtaining a wide visual field range.

  Examples of such transparent resin for the diffusing member 8 include polycarbonate resin, acrylic resin, fluorine acrylic resin, silicone acrylic resin, epoxy acrylate resin, polystyrene resin, cycloolefin polymer, methylstyrene resin, fluorene resin, and PET. Polypropylene or the like can be used.

  Moreover, as the encapsulated transparent particles, transparent particles made of an inorganic oxide or transparent particles made of a resin can be used. For example, examples of the transparent particles made of an inorganic oxide include particles made of silica, alumina, or the like.

  Further, 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. These transparent particles may be used as a mixture of two or more.

  Next, an example of a manufacturing method of the microlens sheet 7 will be described.

  First, the ultraviolet curable resin for forming the pattern of the lens sheet 1 and the inorganic conductive fine particles are mixed on the base film in a weight ratio of 100 to 0.1-20, respectively, and applied to the film base. Subsequently, using a cylinder mold cut into the shape of the lens sheet 1, UV light is exposed from the PET film side while transporting a film coated with a mixture of conductive fine particles and an ultraviolet curable resin. As a result, the ultraviolet curable resin is cured. After curing the ultraviolet curable resin, the microlens group of the lens array can be produced by releasing the mold from the PET film.

  Also, a polycarbonate resin, which is a thermoplastic resin, and inorganic conductive fine particles are mixed in a ratio of 100 to 0.1-20, heated to about 300 ° C., and formed into a 0.3 mm thick film while being stretched along a roll. After that, use a cylinder mold with a concave microlens shape processed by etching into the cylinder, and cool the heated film while applying pressure (the cylinder mold itself is at room temperature: 25 ° C) to form the microlens shape. The cured film is completely cured. Thereby, the microlens group of a lens array can be produced.

  Next, examples will be described. FIG. 11 is a diagram showing measured values when S2 / S1 = 0.785 in the microlens sheet of the present invention. FIG. 12 is a diagram showing measured values when S2 / S1 = 0.81 in the microlens sheet of the present invention. FIG. 13 is a diagram showing measured values when S2 / S1 = 0.92 in the microlens sheet of the present invention.

  11, 12, and 13 are compared, the larger the numerical value of S2 / S1, the larger the lens area of the surface portion of the lens sheet 7 (lens area of the fine unit lens 5), and the lens effect. And the light extraction efficiency is increased. However, when S2 / S1 is less than T1 / P1, the influence amount of the fine unit lens 5 in the microlens sheet 7 is reduced, the light extraction efficiency is lowered, and flat portions other than the fine unit lens 5 are reduced. The extraction efficiency is attenuated, and just drops to around T1 / P1 = 0.785.

  In addition, it can be seen that the light extraction efficiency drops sharply when T1 / P1 is about 0.3, and when T1 / P1 is 0.3 or less, the microlens sheet 7 has almost no effect.

Next, the average roughness measured in the range of L of the microlens shown in FIG. 14 and the presence or absence of conductive fine particles are shown below. In addition, as a comparison object of each Example, the sample sheet | seat which set Sa = 10 nm and Sa = 100 nm of Sa of the measurement part L of the microlens sheet | seat shown in FIG. 14 was used.
<Example 1>
Average roughness Sa: 20 nm
Existence of inorganic conductive fine particles in the lens: Existence <Example 2>
Average roughness Sa: 100 nm
Presence / absence of light diffusing fine particles in adhesive: Existence <Comparative Example 1>
Average roughness Sa: 10 nm
Presence or absence of inorganic conductive fine particles in the lens: None <Comparative Example 2>
Average roughness Sa: 10 nm
Presence or absence of light diffusing fine particles in the adhesive: Yes

  As a result of the measurement under the above conditions, the results shown in Table 1 below were obtained.

Here, various measurements will be described.
[Measuring method of average roughness Sa]
The average roughness Sa was measured using a VertScan 2.0 non-contact surface / layer cross-sectional shape measurement system (manufactured by Ryoka System Co., Ltd.). Sa is a three-dimensional expansion of the two-dimensional arithmetic average roughness Ra, and is defined as the volume of the portion surrounded by the surface shape phase and the average surface divided by the measurement area.

[Surface resistance measurement]
Regarding the surface resistance value, a high resistivity meter Hi-Lester UP (manufactured by Mitsubishi Chemical Corporation) was used, and the measurement was performed in an environment of 25 ° C. and 50%.

[Powder test]
Regarding the powder test, the microlens sheet was placed in a corrugated cardboard containing soft flour and sealed, and then air was sent from the air blowing port, and the sample was covered with soft flour, and the unevenness was observed.

[Scratch test]
For the scratch test, a rubbing tester was used to rub the surface of the lens portion of the microlens sheet under the following rubbing conditions to confirm the presence or absence of scratches.
Environmental conditions: 25 ° C, 55% RH
Friction member: Wes (Technowipe C100 / Sanyu Corporation)
Contact area of the tip of the rubbing member to be brought into contact with the sample: 1 cm × 1 cm
Movement distance of rubbing member on sample (one way): 13 cm
Rubbing speed of rubbing member: 13 cm / sec Load applied to tip of rubbing member: 140 g / cm ²
Number of rubbing of rubbing member: 50 reciprocations

  As shown in Table 1 above, in Comparative Examples 1 and 2, the antistatic function was not obtained, and unevenness occurred in the powder test. The scratches were also conspicuous in terms of abrasion resistance. This is probably because the inorganic conductive fine particles did not come out on the lens surface and a sufficient effect was not obtained.

On the other hand, in Examples 1 and 2, the surface resistance value was 10 ¹⁰ or less, and no unevenness of the powder test was observed. Further, as a result of the scratch test, it was confirmed that the abrasion resistance was also improved.

  Next, FIG. 15 shows the relationship between the average roughness Sa of the lens portion of the microlens sheet and the front luminance increase rate.

  FIG. 15 shows the rate of increase when compared with the front luminance in a state where the microlens shape is not provided. The lens shape is produced under the condition that satisfies the conditional expression (1). From this result, it can be seen that when the value of Sa is 100 nm or more, the front luminance increase rate decreases.

  As described above, according to the EL element according to the embodiment of the present invention, the average diameter of the micro unit lens of the micro lens sheet is P1, the average height of the micro unit lens is T1, and the bottom area of the micro unit lens is When the total is S1 and the area of the remaining portion excluding the bottom area total S1 from the surface is S2, the lens portion is obtained by adding inorganic conductive fine particles to the lens sheet having a region satisfying the conditional expression (1). Since the roughness is provided and the average roughness Sa is in the range of 10 nm <Sa <100 nm, the antifouling property and the abrasion resistance can be improved without lowering the light extraction efficiency.

  In addition, by driving the EL element according to the present invention in pixels, in other words, the light emitting structure of the EL element has a pixel structure, whereby a display device can be configured. The display device configured as described above is also included in the technical scope of the present invention.

  Furthermore, since the EL device according to the present invention has excellent light extraction efficiency, it can be suitably used in various other applications. For example, the EL element according to the present invention can be suitably used as a backlight device for a display device or a liquid crystal display device, and the backlight device configured in this way also has the technical scope of the present invention. include.

DESCRIPTION OF SYMBOLS 1A 1st translucent board | substrate 1B 2nd translucent board | substrate 2 Light emitting layer 3 Anode 4 Cathode 5 Fine unit lens 5a Lens resin 5b Inorganic electroconductive fine particle 6 Adhesive layer 7 Microlens sheet 8 Light scattering means

Claims (12)

An EL device comprising: a light-transmitting substrate; and a light-emitting layer provided on one surface of the light-transmitting substrate and sandwiched between an anode and a cathode,
A microlens sheet is provided on the other surface of the translucent substrate, and the microlens sheet has a surface and fine unit lenses arranged on the surface,
In the microlens,
The average diameter of the fine unit lens is P1,
The average height of the fine unit lens is T1,
S1 is the total bottom area of the fine unit lens,
When the area of the remaining part excluding the bottom area total S1 from the surface is S2,
An EL element having a region satisfying conditional expression: 0.3 ≦ (T1 / P1) ≦ (S1 / S2).   2. The EL device according to claim 1, wherein the microlens sheet contains inorganic conductive fine particles, and the average roughness Sa of the tip portion of the microlens is 10 nm <Sa <100 nm.   The EL device according to claim 1, wherein the fine unit lens has a convex spherical shape.   The EL device according to claim 1, wherein the fine unit lens has a convex aspherical shape.   The EL device according to claim 1, wherein the fine unit lens has a shape including a straight portion and a curved portion.   The EL device according to claim 1, wherein the pitch of the fine unit lenses is random.   6. The EL element according to claim 1, wherein the arrangement of the fine unit lenses on a plane is a pattern.   The EL device according to claim 1, wherein a light diffusing member is disposed on a surface of the microlens sheet.   The EL element according to claim 8, wherein the surface of the microlens sheet and the light diffusing member are bonded via an adhesive layer. A display device comprising a backlight,
10. A display device using the EL element according to claim 1 as the backlight. A display device,
An EL element according to any one of claims 1 to 9 is provided,
A display device, wherein the EL element is configured to be driven by a pixel. A liquid crystal display device comprising a backlight on the back of the image display element,
10. A liquid crystal display device using the EL element according to claim 1 as the backlight.

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