JP2010218839A - El element, backlight device for liquid crystal display, lighting system, electronic signboard device, display device, and light extraction film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an EL element restraining abrupt luminance change due to change of angle of view, while highly maintaining light extraction efficiency. <P>SOLUTION: The EL element 10 has a light emitting layer 12 pinched by a pair of electrodes consisting of an anode 13 and a cathode 14, and laminated on one of the faces of a translucent base material 11, for irradiating light released by the light emitting layer 12 through the translucent material 11. A lens sheet 17 with a plurality of lens elements 19 arrayed thereon is laminated on a light irradiating face side of the translucent base material 11, and the lens elements 19 of the lens sheet 17 are made to contain diffusion elements. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an organic EL (electroluminescence) element used for a flat panel type display device, a light source for illumination such as a backlight unit for liquid crystal, an electric light source, a light source for a sign, and the like, and in particular, improves light extraction efficiency. The present invention relates to an EL element that can be achieved, a backlight device for a liquid crystal display using the EL element, an illumination apparatus using the EL element, a digital signage apparatus using the EL element, and a display apparatus using the EL element.

  In general, as shown in FIG. 7, the EL element has a structure in which a translucent substrate 1 and a light emitting layer 2 containing a fluorescent organic compound are sandwiched between an anode 3 and a cathode 4. The lens sheet 5 for light extraction is provided on the surface opposite to the light emitting layer 2 of the translucent substrate 1 through the adhesive layer 6. As shown in FIG. 8, the lens sheet 5 is configured by arranging a plurality of triangular lens elements 5b on a base material 5a (see, for example, Patent Document 1).

  In such an EL element, a direct-current voltage is applied between the anode 3 and the cathode 4 to inject electrons and holes into the light emitting layer 2 and recombine to generate excitons. It emits light using the emission of light when deactivated. Then, this light passes through the translucent substrate 1 and the lens sheet 5 and is emitted from the lens element 5b.

  Here, when it is set as the structure which remove | excluded the lens sheet 5 in the above EL elements, when the light ray which the light emitting layer 2 radiate | emitted is emitted from the translucent base material 1, a part of light rays will be translucent base material. The light is totally reflected on the exit surface of 1 and a loss of light energy occurs.

  In this case, the external extraction efficiency of light is generally said to be about 20%. Therefore, the higher the luminance, the more input power is required, the energy efficiency is poor, the load on the element increases, the reliability of the EL element itself decreases, and the life of the EL element is reduced. It will be shorter.

  Therefore, in the EL element, the lens sheet 5 is provided on the exit surface side of the translucent substrate 1 as described above for the purpose of improving the external extraction efficiency of light, and this causes loss due to total reflection. The light is taken out.

JP 2007-207471 A

However, in the conventional EL element, since the lens sheet 5 is configured by arranging a plurality of triangular lens elements 5b, the light passing through the lens sheet 5 is condensed in the viewer direction. The light and the light that is emitted unnecessarily in the lateral direction (sidelobe light) without traveling in the viewer direction are extremely divided and emitted.
Thereby, as shown in FIG. 9, the light intensity distribution emitted from the lens sheet has the highest light intensity when the viewing angle with respect to the visual direction F is 0 ° (on-axis direction), while the viewing angle is about ± 70 °. A peak of the light intensity is also observed in FIG. When such a light intensity distribution is shown, there has been a problem that a sudden luminance change occurs due to a change in the viewing angle of the viewer.

  The present invention has been made to solve the above-described problems, and uses an EL element capable of suppressing a rapid luminance change due to a change in viewing angle while maintaining a high light extraction efficiency and the same. An object of the present invention is to provide a backlight device for a liquid crystal display, an electronic signage device, an illumination device, a display device, and a light extraction film.

In order to solve the above problems, the following means are proposed.
That is, in the EL device according to the present invention, a light emitting layer sandwiched between a pair of electrodes composed of an anode and a cathode is disposed on one surface side of a light-transmitting substrate, and is emitted by the light emitting layer. In the EL element in which the emitted light is emitted through the base material, a lens sheet in which a plurality of lens elements are arranged on the exit surface side of the base material is laminated, and the lens element contains a diffusing element. It is characterized by having.

  According to the EL element having such a feature, since the diffusing element is contained in the lens element that constitutes the lens sheet, the light emitted from the light-emitting portion, passing through the base material, and incident on the lens sheet is the lens of the lens element. It is fully scattered before reaching the surface. Therefore, the scattered light is refracted and collected by the lens surface of the lens element, so that the light intensity distribution of the light emitted from the lens sheet can be made smooth. That is, since the light distribution characteristics can be adjusted to be uniform by the diffusing element, it is possible to reduce an abrupt luminance change due to a change in viewing angle.

  In the EL element according to the present invention, the lens surface of the lens element has a concave quadrangular pyramid shape.

  According to the EL element having such characteristics, it is difficult for a sudden luminance change such as a side lobe to occur in the viewing angle, and the rapid change due to the changing viewing angle can be further reduced, and the light distribution characteristic is further improved. Can be controlled.

  The EL element according to the present invention is characterized in that a volume percentage of the diffusing element contained in the lens element with respect to the lens element is set in a range of 1 vol% or more and 20 vol% or less.

Here, when the volume percentage of the diffusing element is less than 1 vol%, the effect of adjusting the light distribution characteristic by the diffusing element cannot be sufficiently obtained, and a rapid change in luminance due to a change in viewing angle cannot be reduced. . On the other hand, when the volume percentage of the diffusing element exceeds 20 vol%, the content of the diffusing element is too large, resulting in uneven appearance when producing a lens sheet, and the absorption of light by the diffusing element is increased, leading to a decrease in front luminance. End up.
In this regard, in the EL element of the present invention, since the volume percentage of the diffusing element is set to 1 vol% or more and 20 vol% or less, the light distribution characteristics are adjusted well, and the brightness changes rapidly due to the change of the viewing angle. While being able to reduce, appearance nonuniformity does not arise and it becomes possible to radiate | emit light with high brightness | luminance.

In the EL element according to the present invention, the volume percentage of the diffusing element contained in the lens element with respect to the lens element is preferably set in a range of 1.1 vol% or more and 19.8 vol% or less.
As a result, it is possible to more reliably reduce a sudden change in luminance due to a change in viewing angle, suppress occurrence of uneven appearance, and emit light with higher luminance.

The EL element according to the present invention is characterized in that the lens sheet is bonded to the base material via an adhesive layer.
Accordingly, the lens sheet can be reliably bonded to the base material, and it is possible to improve the luminance and adjust the light distribution by the lens sheet.

  A backlight device for a liquid crystal display according to the present invention is characterized by using the above-described EL element. Thereby, it is possible to emit backlight light having high luminance and having a uniform light distribution.

  An electronic signboard apparatus according to the present invention is characterized by using the above-described EL element. As a result, it is possible to perform digital signage display with high brightness and uniform light distribution.

  An illumination device according to the present invention is characterized by using the above-described EL element. As a result, it is possible to emit illumination light having a high luminance and a uniform light distribution.

A display device according to the present invention includes the backlight device or the illumination device described above, and an image display element that is irradiated by the backlight device or the illumination device and defines a display image according to transmission / light-shielding in pixel units. It is characterized by providing.
According to the display device having such a feature, it is possible to perform image display with high luminance and uniform light distribution.

  The light extraction film according to the present invention is characterized by using the above-described EL element. Thereby, it is possible to obtain light having a high luminance and a uniform light distribution according to the viewing angle.

According to the EL element of the present invention, since the diffusing element is contained in the lens element constituting the lens sheet, the light intensity distribution of the light emitted from the lens sheet can be made smooth. Therefore, it is possible to suppress a rapid luminance change due to a change in viewing angle while maintaining a high light extraction efficiency.
Further, according to the backlight device for liquid crystal display, the electronic signage device, the verification device, the display device, and the light extraction film of the present invention, it is possible to obtain emitted light and image display with high luminance and uniform light distribution according to the viewing angle. be able to.

It is a longitudinal cross-sectional view of the EL element which concerns on embodiment. It is a perspective view of a lens sheet. It is a perspective view of a lens element. It is a side view which shows an example of the production method of a lens sheet. It is a brightness | luminance measurement result of the EL element provided with the lens sheet of an Example and a comparative example. It is a graph which shows the light intensity distribution of the EL element provided with the lens sheet with an Example and a comparative example. It is a longitudinal cross-sectional view of the conventional EL element. It is a perspective view of the lens sheet in the EL element of a modification. It is a longitudinal cross-sectional view of the EL element of a modification. It is a figure which shows the light intensity distribution of the conventional EL element.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
As shown in FIG. 1, an EL element (electroluminescence element) 10 according to the embodiment includes a translucent substrate 11, a light emitting layer 12, an anode 13, a cathode 14, an adhesive layer 16, and a lens sheet. 17.

The translucent substrate 11 has a flat plate shape made of a translucent material such as a glass material or plastic. In addition to the glass material, a plastic material such as PMMA, polycarbonate, polystyrene or the like can be used as the material of the translucent substrate 11, and any other material may be used as long as it is transparent. .
In particular, it is preferable to use a cycloolefin polymer that is excellent in all of the material properties such as processability, heat resistance, water resistance and optical translucency.
The translucent substrate 11 is preferably formed of a material having a total light transmittance of 50% or more so that light from the light emitting layer 12 can be transmitted as much as possible.

Of the two plate surfaces of the translucent substrate 11, one of the surfaces facing the back side (the lower side in FIG. 1) is layered, and the anode 13 transmits light corresponding to the pixel to be formed. Are stacked.
The anode 13 is formed by a dry process such as vapor deposition or sputtering of ITO, IZO or the like. The material to be deposited is not limited to the above-described materials, and other materials may be used as long as they are transparent and have electrical conductivity.
The thickness of the anode 13 is preferably about 10,000 mm or less. If it is too thick, the electrical conductivity is improved, but local spikes are likely to occur, and the total light transmittance is lowered, which is not preferable. If the height of the spike exceeds, for example, about 100 nm, a problem may occur in the subsequent film formation process.

On the back side of the anode 13, a cathode 14 having a layer shape like the anode 13 is disposed so as to be spaced apart from each other.
The cathode 14 is formed of a material having electrical conductivity, and is not necessarily formed of a transparent material unlike the anode 13.
The cathode 14 and the anode 13 constitute an electrode capable of energizing the light emitting layer 12.

  A layered light emitting layer 12 is interposed between the anode 13 and the cathode 14. That is, the light emitting layer 12 is disposed so as to be sandwiched between a pair of electrodes including the anode 13 and the cathode 14.

  In the present embodiment, the light emitting layer 12 is made of a fluorescent organic compound that emits white light when energized. As an example of such a light emitting layer 12, ITO / CuPc (copper phthalocyanine) / α-NPD is doped with 1% rubrene / dioctylanthracene is doped with 1% perylene / Alq 3 / lithium fluoride / Al as a cathode. be able to.

The light emitting layer 12 is not limited to the fluorescent organic compound that emits white light having the above-described configuration, and may be a fluorescent organic compound that can emit light spontaneously in blue, red, yellow, and green. These colors can be realized by appropriately using a fluorescent organic compound that can change the wavelength of light emitted from the light emitting layer 12 to R (red), G (green), and B (blue).
In addition, when the EL element 10 is used for a full-color display, light emitted by separately applying three types of light emitting materials corresponding to R, G, and B, or by overlaying a color filter on white light. Can be colored, thereby enabling full color display.

  As the light emitting structure including the anode 13, the cathode 14, and the light emitting layer 12, various conventionally known structures can be adopted in addition to the above structure.

  Of the two plate surfaces of the translucent substrate 11, the other surface located on the opposite side of the one surface and facing the front side (the upper side in FIG. 1) is provided with an adhesive layer 16. A lens sheet 17 is laminated.

   The adhesive layer 16 is formed using an adhesive or an adhesive. As the pressure-sensitive adhesive or adhesive, urethane-based, acrylic-based, rubber-based, silicone-based, vinyl-based resins, or the like can be used. Furthermore, as a pressure-sensitive adhesive or adhesive, one that is pressed and adhered in a one-pack type, one that is cured by heat or light, and other one that is cured by mixing two or more liquids are used. It can also be used.

  As a method for forming the adhesive layer 16, there are a method in which the adhesive layer 16 is directly applied to a bonding surface, and a method in which a dry film prepared in advance is bonded. When the adhesive layer 16 is prepared as a dry film, it is preferable because it can be easily handled in the manufacturing process.

  As shown in FIGS. 1 and 2, the lens sheet 17 includes a translucent base film 18 whose back side surface is bonded to the translucent base 11 by the adhesive layer 16, and the base film 18. A plurality of lens elements 19 are provided on the front side surface.

As shown in detail in FIG. 2, the lens elements 19 are arranged in a two-dimensional direction at a constant pitch so as to cover the entire emission surface of the base film 18.
Each lens element 19 has a square shape when viewed from the front, and as shown in FIG. 3, the surface on the back side is a square shape and is a flat surface 19 a that is in contact with the emission surface of the substrate film 18. This surface is a concave quadrangular pyramid surface 19b that is recessed in a quadrangular pyramid shape with the outer peripheral four sides as the bottom four sides and the thickness of the lens element 19 as the height dimension. The concave quadrangular pyramid surface 19 b is formed of four triangular surfaces, and these triangular surfaces serve as the lens surface 19 c of the lens element 19.
That is, each lens element 19 has a concave quadrangular pyramid shape with a certain depth.

  The lens sheet 17 is configured by arranging such lens elements 19 on the base film 18 in a matrix. Accordingly, the concave and convex shape of the concave quadrangular pyramid surface 19b of each lens element 19 becomes a trough, and the concave and convex shape in which the bottom four sides of the concave quadrangular pyramid surface 19b in contact with adjacent lens elements 19 are peaks is the lens sheet 17. Formed on the exit surface side.

  A transparent material is used as a material for forming the lens sheet 17. As this transparent material, PET (polyethylene terephthalate), PC (polycarbonate), PMMA (polymethyl methacrylate), COP (cycloolefin polymer), acrylonitrile styrene copolymer, acrylonitrile polystyrene copolymer and the like can be used.

  In this embodiment, a diffusing element is added to the lens element 19 in the lens sheet 17. Examples of the diffusion element include polycarbonate resin, acrylic resin, fluorine acrylic resin, silicone acrylic resin, epoxy acrylate resin, polystyrene resin, cycloolefin polymer, methylstyrene resin, fluorene resin, PET, polypropylene, and other cured products. When the refractive index of the transparent resin as the main material of the lens sheet 17 is M and the refractive index of the diffusing element is N, the difference in refractive index between the two | MN− | It is desirable to satisfy the relationship of | ≧ 0.01. This is because if the difference in refractive index between the two is less than 0.01, the light scattering effect of the diffusing element cannot be sufficiently obtained. The volume percentage of the diffusing element in the lens element 19 can be controlled by adjusting the addition amount of the diffusing element.

  The diffusing element is added to the transparent material for molding the lens element 19 so that the volume percentage with respect to the lens element 19 is in the range of 1 vol% or more and 20 vol% or less, preferably 1.1 vol% or more and 19.8 vol% or less. ing.

  Here, as a method for forming the diffusing element in the lens element 19, for example, a method in which a filler such as resin or glass is disposed as a diffusing element inside the lens element 19 can be cited. Specifically, when forming an optical element pattern by pressure welding molding, extrusion molding, injection molding, or the like using a mold, a filler is mixed and taken into the lens element 19 and simultaneously formed.

  As another manufacturing method, there is a method in which bubbles are arranged inside the lens element 19 as a diffusing element. Here, as a method of creating the lens element 19 in the case where bubbles are arranged as a diffusing element, a pattern of the lens element 19 is formed on the base film 18 using a radiation curable resin, and the lens element 19 There is a method of providing a fine diffusion element inside, an example of which is shown below.

  In the pattern forming method of the lens element 19 in this case, as shown in FIG. 4, first, a radiation curable resin 32 is applied on the surface of the base film 18. Thereafter, radiation 31 is irradiated through the base film 18 while the resin application side is pressed against a roll-shaped mold 30 having a shape for forming the lens element 19 on the surface. Thereby, the lens element 19 having a desired shape is formed on the surface of the base film 18 by curing the radiation curable resin 32 applied on the surface of the base film 18.

  Here, after bubbles are mixed inside the radiation curable resin 32 using a bubble generation mechanism, the pattern is formed on the surface of the base film 18 to form the lens elements 19, thereby forming the lens elements 19. A diffusing element as a bubble can be provided in the inside. In the case where the diffusion element is provided in this way, it is necessary to adjust the amount of bubbles added to control the bubble generation mechanism. Specifically, the volume percentage of the diffusing element in the lens element 19 is adjusted by changing the amount of bubble generation in the generating mechanism, the pressure at the time of bubble ejection, and the shape of the bubble ejection port.

  In the EL element 10 configured as described above, when the electrode including the anode 13 and the cathode 14 is energized, the light emitting layer 12 sandwiched between the anode 13 and the cathode 14 emits light. The light emitted from the light emitting layer 12 passes through the translucent substrate 11 and enters the substrate film 18 of the lens sheet 17. The light rays incident on the base film 18 are scattered by the diffusing element in the lens element 19 and then emitted from the lens surface 19c.

According to the EL element 10 of the present embodiment, since the diffusing element is contained in the lens element 19 constituting the lens sheet 17, the light emitted from the light emitting layer 12 and emitted from the lens sheet 17 is the lens element 19. Before reaching the lens surface 19c. Therefore, the scattered light is refracted and collected by the lens surface 19c of the lens element 19, whereby the light intensity distribution of the light emitted from the lens sheet 17 can be made smooth.
That is, since the light distribution characteristics can be adjusted to be uniform by the diffusing element, it is possible to reduce an abrupt luminance change due to a change in viewing angle.

  Further, as described above, since the lens surface 19c of the lens element 19 of the lens sheet 17 has a concave quadrangular pyramid shape, a rapid luminance change such as sidelobe light due to a change in viewing angle is less likely to occur. Even if the lens sheet is on the viewer side, a sudden change in viewing angle can be further reduced, and the light distribution characteristics can be controlled more suitably.

Here, when the volume percentage of the diffusing element with respect to the lens element 19 is less than 1 vol%, the effect of adjusting the light distribution characteristic by the diffusing element cannot be sufficiently obtained, and a sudden change in luminance due to a change in viewing angle is reduced. I can't. On the other hand, when the volume percentage of the diffusing element exceeds 20 vol%, the content of the diffusing element is too large, resulting in uneven appearance when the lens sheet 17 is manufactured, and the light absorption by the diffusing element is increased, leading to a decrease in front luminance. Resulting in.
In this respect, in the EL element 10 of the present embodiment, the volume percentage of the diffusing element is set to 1 vol% or more and 20 vol% or less. The change can be reduced, the appearance non-uniformity does not occur, and light with high luminance can be emitted.
Furthermore, if the volume percentage of the diffusing element is set to 1.1 vol% or more and 19.8 vol% or less, the above effect can be obtained more reliably.

  Further, since the lens sheet 17 is bonded to the translucent substrate 11 via the adhesive layer 16, the lens sheet 17 can be reliably laminated on the translucent substrate 11, and the lens sheet 17. The luminance can be improved and the light distribution can be adjusted satisfactorily.

  The EL element 10 according to the embodiment of the present invention has been described above, but the present invention is not limited to this and can be appropriately changed without departing from the technical idea of the present invention.

  For example, a backlight for a liquid crystal display may be configured using the EL element 10. In the backlight for liquid crystal display, since the EL element 10 having high light extraction efficiency is used, high-intensity backlight light can be emitted with low input power.

  Moreover, you may comprise an electronic signboard apparatus using this backlight EL element 10. FIG. As a result, it is possible to perform digital signage display with high brightness and uniform light distribution.

  Furthermore, you may comprise an illuminating device using this backlight EL element 10. FIG. As a result, it is possible to emit illumination light having a high luminance and a uniform light distribution.

  Further, a liquid crystal display device equipped with a backlight using the EL element 10 may be configured. This liquid crystal display device is configured by disposing a liquid crystal panel on the front side of the backlight, that is, on a portion irradiated with the backlight light of the backlight. This liquid crystal panel is, for example, a polarizing plate that controls the polarization direction of light on the front side and the back side of a liquid crystal cell that controls the light transmission state according to an image signal for each of a plurality of pixel regions formed in a rectangular lattice shape. Are each laminated. Also in this liquid crystal display device, since the EL element 10 as described above is mounted, it is possible to perform image display with high luminance and uniform light distribution.

  Furthermore, the EL element 10 may be used as a light extraction film. As a result, it is possible to obtain light having a high luminance and a uniform light distribution.

(Production of lens sheet)
A lens sheet 17 in which concave lens element groups are arranged on a base film 18 of PET having a thickness of 188 μm using an acrylic UV curable resin as the lens element 19 by a UV curing molding method was produced. The lens elements 19 have a concave quadrangular pyramid shape with a height of 70 μm and are arranged in a matrix with a pitch of 140 μm.

  Here, when the radiation curable resin 32 is applied onto the PET substrate film 18, a bubble generation device is used to change the amount of bubble generation in the generation mechanism, the pressure at the time of bubble ejection, and the shape of the bubble ejection port. Thus, while adjusting the volume percentage of the diffusing element with respect to the lens element 19, the pattern of the lens element 19 was formed to form the lens sheet 17.

(Lens sheet of Example)
The lens sheet 17 is classified according to the difference in volume percentage of the diffusing element with respect to the lens element 19, the lens sheet 17 having a volume percentage of 1.1 vol% is Example 1, and the lens sheet 17 having a volume percentage of 10.1% is Example 2. The lens sheet 17 having a volume percentage of 19.8% was determined as Example 3.

(Comparative lens sheet)
Further, the volume percentage of the diffusing element with respect to the lens element 19 is 0%, that is, the lens sheet 17 to which no diffusing element is added is Comparative Example 1, and the lens sheet 17 with the volume percentage of 21.6 vol% is Comparative Example 2. 29.7 vol% of the lens sheet 17 as Comparative Example 3, and the volume percentage of 0.8 vol% of the lens sheet 17 as Comparative Example 4.

(Production of EL element and measurement of luminance)
The EL element 10 described in the embodiment was manufactured using the above Examples 1 to 3 and Comparative Examples 1 to 4.
Then, the electrode composed of the anode 13 and the cathode 14 was energized to cause the light emitting layer 12 to emit light, and the luminance of the light emitted from the lens sheet 17 at that time was measured. The luminance was measured from the front direction of the lens sheet 17 and from an oblique direction inclined by 45 ° from the front direction.

(Brightness measurement result)
The brightness measurement result data is shown in FIG. In addition, the brightness | luminance data of each Example and the comparative example were displayed by the ratio on the basis of the comparative example 1 (what does not add the diffusion element to the lens sheet 17).
In Comparative Example 4 in which the volume percentage of the diffusing element of the lens sheet 17 with respect to the lens element 19 is less than 1 vol%, the luminance is not changed as compared with the case where the diffusing element is not added, and the light distribution characteristics are adjusted. Was not recognized.
For Comparative Examples 2 and 3 in which the volume percentage of the diffusing element of the lens sheet 17 to the lens element 19 is larger than 20 vol%, unevenness in appearance occurs when the lens sheet 17 is created, and a sample deserving brightness measurement cannot be created. The luminance could not be evaluated.
From the above, when the volume percentage of the diffusing element of the lens sheet 17 to the lens element 19 is in the range of 1.1 vol% or more and 19.8 vol% or less, the appearance unevenness is recognized. The overall optical characteristics were adjustable. That is, as shown in FIG. 6, according to the EL element 10 including the lens sheet 17 of the example, while maintaining a high luminance as compared with the comparative example 1 in which the lens element 19 does not contain a diffusing element. A sudden change in luminance due to a difference in viewing angle can be suppressed. Such changes in front direction luminance and 45 degree direction luminance can greatly contribute to fine adjustment of optical characteristics in response to customer demands. In addition, it can be inferred that this effect is achieved even when the volume percentage of the diffusing element of the lens sheet 17 to the lens element 19 is in the range of 1 vol% or more and 20 vol% or less.

In addition, in the lens sheet 17 having the lens elements 19 having pitch widths other than those in Examples 1 to 3 and Comparative Examples 1 to 4, the range of the amount of change in the luminance ratio is different due to the difference in the condensing property of the lens elements 19. However, regarding the change of the optical characteristics with respect to the volume percentage of the diffusing element and the unevenness of the display state, the same tendency as the result shown above was shown.
Therefore, it was found that the overall optical characteristics can be adjusted within the above-described condition range regardless of the pitch width of the lens elements 19.

DESCRIPTION OF SYMBOLS 10 EL element 11 Translucent base material 12 Light emitting layer 13 Anode 14 Cathode 16 Adhesion layer 17 Lens sheet 18 Base film 19 Lens element 19a Flat surface 19b Concave quadrangular pyramid surface 19c Lens surface

Claims (10)

A light emitting layer sandwiched between a pair of electrodes composed of an anode and a cathode is disposed on one surface side of a light-transmitting base material, and light emitted by the light emitting layer passes through the base material. In the emitted EL element,
A lens sheet in which a plurality of lens elements are arranged is laminated on the emission surface side of the substrate,
An EL element, wherein the lens element of the lens sheet contains a diffusing element.   The EL element according to claim 1, wherein the lens surface of the lens element has a concave quadrangular pyramid shape.   3. The EL element according to claim 1, wherein a volume percentage of the diffusing element contained in the lens element with respect to the lens element is set in a range of 1 vol% or more and 20 vol% or less.   4. The volume percentage of the diffusing element contained in the lens element with respect to the lens element is set in a range of 1.1 vol% or more and 19.8 vol% or less. 5. EL element of description.   The EL element according to claim 1, wherein the lens sheet is bonded to the base material via an adhesive layer.   The backlight apparatus for liquid crystal displays which uses the EL element as described in any one of Claim 1 to 5.   The electronic signboard apparatus using the EL element as described in any one of Claims 1-5.   The illuminating device which uses the EL element as described in any one of Claim 1 to 5. A backlight device for a liquid crystal display according to claim 6 or an illumination device according to claim 8;
A display device comprising an image display element that is irradiated by the backlight device or the illuminating device and that defines a display image in accordance with transmission / shielding in pixel units.   The light extraction film which uses the EL element of any one of Claim 1 to 5.

Images