JP5830887B2 - Illumination device and liquid crystal display device including the same - Google Patents

Description

  The present invention includes, for example, an illuminating device including an EL element (electroluminescence element) and a light extraction sheet, which are used for a flat panel display, a backlight for liquid crystal, a light source for illumination, an electric decoration, a light source for signage, and the like, and this The present invention relates to a display device using a lighting device, a display device, and a liquid crystal display 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. 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. Note that the light extraction efficiency at this time is generally said to be about 20%. Therefore, there is a problem that the higher the luminance is, the more input power is required. In this case, the load on the element is increased and the reliability of the element itself is lowered. .

  In order to improve the light extraction efficiency of such light, a technique has been proposed in which fine irregularities are formed on the element substrate and light rays lost due to total reflection are extracted to the outside. This technique is, for example, a technique for forming a microlens array in which a plurality of microlens elements are arranged in a plane on one surface of a translucent substrate, as described in Patent Document 1.

JP 2002-260845 A

However, the above-described conventional techniques are not sufficient for improving the light extraction efficiency and suppressing the chromaticity change due to the emission angle of the emitted light.
The present invention has been made in order to solve the above-described problem, and it is possible to improve the light extraction efficiency by optimizing the light extraction efficiency, and to change the chromaticity coordinates depending on the emission angle of the emitted light. It is an object of the present invention to provide an EL element, a lighting device, a display device, and a liquid crystal display device that are advantageous for improvement.

In order to solve the above problems, the present invention proposes the following means.
That is, of the present invention, the invention described in claim 1 includes a first electrode formed on at least a second substrate and one of an anode and a cathode, and facing the first electrode and the anode and A surface light source having a second electrode which is the other of the cathodes, and a light emitting layer sandwiched between the first electrode and the second electrode and containing a fluorescent organic compound,
A first substrate on which light emitted from the surface light source is incident on one surface and the first electrode is formed on a surface opposite to the surface facing the light emitting layer ;
A second substrate on which light emitted from the surface light source is incident on one surface and the second electrode is formed on a surface opposite to the surface facing the light emitting layer;
A light extraction sheet provided on a surface opposite to a surface on which light emitted from the surface light source of the first substrate is incident;
Comprising a surface light source, and said first substrate, said second substrate, and a light emitting unit formed by disposing the light extraction sheet to an EL element provided with,
A first lens array having a plurality of first lenses spaced apart and arranged in parallel on a surface opposite to the surface facing the first substrate of the light extraction sheet, and adjacent to each other. And a second lens array comprising a plurality of second lenses arranged in parallel,
The plurality of first lenses extend along one direction and are arranged in parallel.
The plurality of second lenses are arranged adjacent to and parallel to each other along a direction intersecting the first lens array,
The maximum height of the first lens array is H1, the maximum height of the second lens array is H2, the arrangement pitch between the adjacent first lenses is P1, and the arrangement pitch between the adjacent second lenses is the P2, the lens width of the first lens L1, a lens width of the second lens L2, the from the surface opposite the light-transmitting substrate and the opposing surfaces of the light extraction sheet of the first lens When the maximum inclination angle is θ1, and the maximum inclination angle from the surface of the light extraction sheet of the second lens opposite to the surface facing the light-transmitting substrate is θ2, the following relational expression (1) To (8) holds,
The cross-sectional shape seen from the direction orthogonal to the arrangement direction of the first lens is a prism shape,
The apex angle θ1a of the first lens has a curvature in the range of 0% to 50% with respect to the lens width L1 of the first lens,
A cross-sectional shape viewed from a direction orthogonal to the arrangement direction of the second lenses is a prism shape,
The illumination device, wherein the apex angle θ2a of the second lens has a curvature in the range of 0% to 50% with respect to the lens width L2 of the second lens.
H2 <H1 (1)
0.01 <(H2 / H1) <1 (2)
0.2 <(L1 / P1) <0.9 (3)
L2 = P2 (4)
0.3 <(H1 / L1) <2 (5)
0.3 <(H2 / L2) <2 (6)
30 ° ≦ θ1 ≦ 75 ° (7)
30 ° ≦ θ2 ≦ 75 ° (8)

Next, of the present invention, the invention described in claim 2 is a display device including an EL element in which a light extraction sheet included in the illumination device described in claim 1 is arranged,
The EL element is a display device that is pixel driven.

Next, of the present invention, the invention described in claim 3 is a liquid crystal display device including a light extraction sheet provided in the illumination device described in claim 1 and an image display element,
In the display device, the light extraction sheet is disposed on a back surface of the image display element.

Next, among the present inventions, the invention described in claim 4 is a liquid crystal display device including an EL element on which a light extraction sheet provided in the illumination device described in claim 1 is arranged, and an image display element. ,
The EL element is pixel driven,
In the liquid crystal display device, the light extraction sheet is disposed on a back surface of the image display element.

According to the EL element of the present invention, the first lens array and the second lens array are arranged so as to intersect each other, and the maximum height H1 of the first lens array and the maximum height H2 of the second lens array. And the ratio of the lens width L1 of the first lens to the arrangement pitch P1 of the first lens array is L1 / P1, and the lens width L1 of the first lens and the lens of the second lens By optimizing H1 / L1 and H2 / L2, which are the ratios of the maximum heights H1 and H2 with respect to the width L2, it is possible to improve the change in chromaticity coordinates due to the external light extraction efficiency and the emission angle. Become.
Furthermore, it is possible to provide a lighting device, a display device, and a liquid crystal display device that have high design efficiency and use efficiency of light by using a lighting device, a display device, and a liquid crystal display device that include the EL element of the present invention. Become.

It is sectional drawing which shows schematic structure of the illuminating device in 1st embodiment of this invention. It is sectional drawing which shows schematic structure of the illuminating device of the structure which is not provided with the structure layer. It is a figure which shows the structure of a light extraction sheet | seat. It is a figure which shows the structure of a light extraction sheet | seat. It is a light ray figure when changing the incident angle of the light which injects into a unit lens when the cross-sectional shape of the lens array in the light extraction sheet | seat of 1st embodiment of this invention is made into the triangular prism shape of 90 degrees of apex angles. . It is a light ray diagram when changing the incident angle of the light which injects into a unit lens when the cross-sectional shape of the lens array in the light extraction sheet | seat of 1st embodiment of this invention is aspherical shape. It is a graph which shows the ratio (light utilization efficiency) of the emitted light quantity with respect to incident light quantity when the light which changed the incident angle from 0 degree to 85 degree was made to inject into a light extraction sheet | seat. It is a light distribution characteristic figure of emitted light. It is a figure which shows a relative light quantity and a relative color difference. It is a figure which shows a relative light quantity and a relative color difference. It is a figure which shows a relative light quantity and a relative color difference. It is a figure showing relative luminance and relative light quantity.

(First embodiment)
Hereinafter, a first embodiment of the present invention (hereinafter referred to as “the present embodiment”) will be described with reference to the drawings. Note that this embodiment is an example of the present invention and does not limit the present invention.
(Constitution)
First, the structure of the decorative film of this embodiment is demonstrated using FIG.
FIG. 1 is a cross-sectional view illustrating a schematic configuration of a lighting device according to the present embodiment.
As shown in FIG. 1, an EL element 101 (electroluminescence element), a first substrate 1A, a second substrate 1B, a light emitting layer 2, an anode 3, a cathode 4, and a light extraction sheet 7 It has. In FIG. 1, the light extraction sheet 7 has an irradiation direction F on the side opposite to the surface on which the light emitting layer 2 is installed.

  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. Here, when the light emitting layer 2 is 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 with perylene 1%. What is necessary is just to set it as Al as dope / Alq3 / lithium fluoride / cathode.

An anode 3 is formed on one surface of the light emitting layer 2, and a cathode 4 is formed on the other surface. The light emitting layer 2 emits light by applying a voltage to the anode 3 and the cathode 4, and the light emitting structure 100 includes the light emitting layer 2, the anode 3, and the cathode 4. As the light emitting structure 100, various conventionally known configurations can be employed.
That is, the illuminating device of the first embodiment includes light emitting means formed using the EL element 101 on which the light extraction sheet 7 is arranged.

  The configuration of the light emitting structure 100 is not limited to this configuration, and the wavelength of light emitted from the light emitting layer 2 can be R (red), G (green), and B (blue). It is possible to adopt any configuration using appropriate materials. In addition, 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 overlaying a color filter on white light.

The first substrate 1A is formed on the surface opposite to the surface where the anode 3 faces the light emitting layer 2. On the other hand, the second substrate 1B is formed on the surface opposite to the surface where the cathode 4 faces the light emitting layer 2.
That is, the translucent substrates (the first substrate 1A and the second substrate 1B) are formed so that light emitted from the light source (the light emitting structure 100) is incident on one surface.
As a material of the first substrate 1A and the second substrate 1B, various glass materials can be used. Moreover, as materials for the first substrate 1A and the second substrate 1B, plastic materials such as PMMA, polycarbonate, and polystyrene, or metal materials such as aluminum can be used, and various other materials can be used. Although it 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.

In addition, the first substrate 1A is a material that can have a total light transmittance of 50% or more so that light (emitted light) emitted from the light emitting structure 100 (light emitting layer 2) can be transmitted as much as possible. It is preferable to form by.
The light extraction sheet 7 is provided on the surface opposite to the surface on which the first substrate 1 </ b> A faces the anode 3 via the adhesive layer 6.

  Examples of the adhesive / adhesive constituting the adhesive layer 6 include acrylic, urethane, rubber, and silicone adhesives. In any case, since it is used adjacent to a light source having a high temperature, it is desirable that the storage elastic modulus G ′ is 1.0E + 04 (Pa) or more at 100 ° C. This is because if the value is lower than this, the light extraction sheet 7 and the first substrate 1A may be displaced during use. If the light extraction sheet 7 and the first substrate 1 </ b> A are greatly displaced, light from the light emitting layer 2 is not efficiently incident on the light extraction sheet 7, so that the light use efficiency decreases.

In order to stably secure a gap between the light emitting layer 2 and the light extraction sheet 7, transparent fine particles such as beads may be mixed in the contact / adhesive layer constituting the adhesive layer 6. . The adhesive / adhesive constituting the adhesive layer 6 may be a double-sided tape or a single layer.
The light extraction sheet 7 has a function of deflecting the light from the light emitting layer 2 and emitting it in the irradiation direction F to improve the external extraction efficiency of the light.

Further, the light extraction sheet 7 has a surface facing the side opposite to the first substrate 1A and a structural layer 5 arranged on the surface.
In other words, the EL element 101 includes a substrate 1A and a light emitting layer 2 provided on one surface of the substrate 1A and sandwiched between the anode 3 and the cathode 4. Furthermore, a light extraction sheet 7 is provided on the other surface of the substrate 1A, and the light extraction sheet 7 has a surface and a structural layer 5 arranged on the surface.

As shown in FIG. 1, the light B0 emitted from the light emitting layer 2 passes through the substrate 1A (light B1), enters the structural layer 5, and a part of the light B1 incident on the structural layer 5 is the structural layer. 5 is emitted from the exit surface 5 to the outside.
Here, as shown in FIG. 2, when the configuration of the lighting device is a flat surface without the structural layer 5, most of the light B <b> 1 is reflected by the flat surface and incident on the light emitting layer 2 again. Light B12 to be transmitted. Since the light B12 is not deflected in the irradiation direction F, the light B12 is lost. Therefore, in order to improve the light extraction efficiency of the EL element 101, it is important to reduce the light B12 and increase the light B1. FIG. 2 is a cross-sectional view showing a schematic configuration of an illuminating device that does not include the structural layer 5.

In the EL element 101, the color of light B0 (see FIG. 1) emitted from the light emitting layer 2 changes in color (fine hue in the medium) depending on the emission angle. Here, by providing the structural layer 5 on the light emitting surface side of the EL element 101, the light B0 emitted from the light emitting layer 2 is deflected by the structural layer 5 and emitted in the irradiation direction F as the emitted light B2. At this time, by changing the shape of the structural layer 5 and changing the emission direction of the emission light B2, it is possible to suppress a change in color due to the emission angle.
Here, as a method for improving the external light extraction efficiency and the color difference of the EL element, conventionally, a method of forming a structure such as a prism, or a diffusion film in which an uneven surface is formed by applying a filler to a transparent substrate is installed. And a method of forming a substantially hemispherical microlens.

However, the method for forming a structure such as a prism as described above has the following problems.
In a structure in which a linear shape such as a prism forms a large part, the inclination angle is constant due to the linear shape. Therefore, it is possible to improve the external extraction efficiency only for light having a specific angle. However, light other than the specific angle described above has a problem that the external extraction efficiency of the light is reduced, and overall, the external extraction efficiency is reduced. Further, the change in chromaticity coordinates depending on the emission angle of the EL element 101 has a constant inclination angle in the case of a prism shape, and deflects incident light at a specific angle into emission light at a specific angle. The improvement effect to the change by is low.

Moreover, in the method of installing the diffusion film which formed the uneven | corrugated surface by apply | coating a filler to the above transparent base materials, there exists a problem described below.
In the case of forming an uneven surface by applying a filler, the shape of the uneven surface is determined by the degree of bulging of the filler, so that it is impossible to form an uneven surface with high accuracy. Therefore, there arises a problem that a sufficient shape for controlling light cannot be formed on the uneven surface. For example, when an approximately semicircular shape is formed by raising the filler, the filler is not sufficiently raised, and only a part of the approximately hemispherical shape is formed. That is, when the ratio of the substantially hemispherical height to the width is the aspect ratio (height / width), the aspect ratio becomes small, resulting in a problem that the external extraction efficiency becomes small.

Further, the method for forming a microlens as described above has the following problems.
The microlens can be molded with higher accuracy than the above-described diffusion filler, and can have a substantially hemispherical shape with an increased aspect ratio. However, since the light from the light emitting layer of the EL element is isotropic, a substantially hemispherical type is preferable. However, in a substantially hemispherical microlens, the entire surface cannot be filled and a flat surface is generated. When a flat surface is generated, light B12 is generated and is not emitted in the irradiation direction F, as shown in FIG.

  In addition, a close-packed structure such as a hexagonal arrangement can fill the entire surface, but when creating such a shape, more precise molding is required, and there are problems such as overlapping microlenses. Likely to happen. Further, if the microlens is molded with a small gap, a slight gap between the microlenses appears as macro unevenness, which is not preferable. Therefore, the substantial area ratio is around 76%. As a result, since about 24% has a flat surface, there arises a problem that the external extraction efficiency of light is insufficient.

  As described above, the light extraction sheet 7 shown in FIG. 3 is provided on the surface of the EL element 101 in order to improve the light extraction efficiency of the EL element 101. 3 is a diagram showing the configuration of the light extraction sheet 7. FIG. 3 (a) is an upper perspective view of the light extraction sheet 7. FIG. 3 (b) is a B line arrow in FIG. 3 (a). FIG. 3C is a view taken along the line C in FIG. FIG. 3A is a perspective view when the cross-sectional shapes of the first lens array 40 and the second lens array 50 are convex aspheric lens shapes.

  As shown in FIG. 3, the structural layer 5 of the light extraction sheet 7 has a first surface of the light-transmitting substrate 8, that is, a surface in the irradiation direction F (this surface is defined as a surface) 8 a on the first surface. The lens array 40 includes a first lens array 40 that extends along one direction and has a flat surface between adjacent first lenses and is spaced apart from each other and arranged in parallel. The structural layer 5 is adjacent to each other and arranged in parallel along the direction intersecting the first lens array 40 so as to occupy the flat surface of the first lens array 40. A second lens array 50 having these lenses is formed. The first lens array 40 and the second lens array 50 may be arranged separately on the base material 8, or the first lens array 40 and the second lens array 50 may be The base material 8 may be integrally molded.

Further, as the first lens array 40 and the second lens array, for example, a lens having a convex section or a triangular prism shape can be used.
The plurality of first lenses included in the first lens array 40 may be configured to extend along one direction and be arranged in parallel.
Further, the plurality of second lenses provided in the second lens array 50 may be configured such that they are adjacent to each other and arranged in parallel along the direction intersecting the first lens array 40.

Further, the first lens array 40 and the second lens array 50 are arranged so as to intersect each other.
The reason is described below.
When the first lens array 40 and the second lens array 50 have a strip shape extending in one direction without intersecting each other, the first lens array 40 and the second lens array 40 are arranged in one extending direction. Since the lens array 50 does not have an inclination angle, that is, is equivalent to a planar effect and becomes light that cannot be extracted to the outside like the light B12 illustrated in FIG. There arises a problem that becomes smaller.

Therefore, the first lens array 40 and the second lens array 50 form a lens or prism shape having a convex cross section, exhibit a belt shape extending in one direction, and the belt-shaped convex lens or prism shape. However, it is possible to provide an inclination angle with respect to the two-dimensional direction by arranging so as to cross each other, which is preferable because the light extraction efficiency is increased.
Furthermore, by arranging as described above, the light distribution of the light emitted from the first lens array 40 and the second lens array 50 in the irradiation direction F can be adjusted in a two-dimensional direction. Therefore, by making the first lens array 40 and the second lens array 50 have arbitrary shapes, it becomes possible to make the emitted light have a symmetrical light distribution, or to improve the color difference due to the emission angle. Is preferable.

In addition, when the EL element 101 is used for illumination, it is necessary to adjust the light distribution distribution at least two-dimensionally.
The reason is that, for example, depending on the installation location of the lighting device, there is no need to irradiate in a specific direction, and there is a case where a luminance improvement in the front direction is required instead of a wide light distribution.
Alternatively, the light B1 incident on the structural layer 5 has an asymmetric light distribution and the light distribution emitted from the lighting device is required to be a symmetric light distribution. Since it is difficult to make the light distribution of the light emitted from the lighting device into a symmetric light distribution by adjusting only in the one-dimensional direction, the configuration of this embodiment can be adjusted in the two-dimensional direction. Is preferred.

In addition, in the configuration in which the first lens array 40 and the second lens array 50 are arranged substantially perpendicularly as in the configuration of the present embodiment, a new lens sheet is added to spread light in a two-dimensional manner. Therefore, it is possible to adjust the light distribution to an appropriate light distribution without reducing the weight, thickness and cost of the lighting device.
In particular, the light emitted from the light emitting layer 2 is light having a broad directivity with a wide light distribution. Therefore, it is preferable that the first lens array 40 and the second lens array 50 are designed so as to deflect the wide light distribution described above in the irradiation direction F.

  In the first lens array 40, the lens width of the first lens that contacts the surface 8a of the substrate 8 is L1, the maximum height from the surface 8a to the top is H1, and the first lens array 40 is located between the vertices of the first lens array 40. The distance (arrangement pitch between the first lenses) is P1, and the maximum inclination angle is θ1. Here, the maximum inclination angle θ1 is the maximum inclination angle of the first lens from the surface opposite to the surface facing the light-transmitting substrate of the light extraction sheet 7.

The second lens array 50 has a bottom width (lens width of the second lens) in contact with the surface 8a as L2, a maximum height from the surface 8a to the top as H2, and the second lens array 50. The distance between the vertices (arrangement pitch between the second lenses) is P2, and the maximum inclination angle is θ2. Here, the maximum inclination angle θ2 is the maximum inclination angle of the second lens from the surface opposite to the surface of the light extraction sheet 7 facing the light-transmitting substrate.
Here, in the first embodiment, the arrangement pitch P2 between the second lenses is equal to the lens width L2 of the second lens. That is, in the first embodiment, the relational expression L2 = P2 is established.
Further, the shapes of the first lens array 40 and the second lens array 50 may be the same or different. Here, by making the shapes of the first lens array 40 and the second lens array 50 orthogonal to each other, when the light B1 incident on the structural layer 5 is emitted in the irradiation direction F, the light orientation distribution is obtained. Can be adjusted in two dimensions.

  Furthermore, the cross-sectional shapes of the first lens array 40 and the second lens array 50 may be polygonal shapes, complete semicircular shapes (spherical lenses), semielliptical shapes (elliptical lenses), or parabolic shapes, in addition to triangular shapes. Non-semicircular shape (so-called secondary aspherical shape) such as (parabolic lens), high-order aspherical shape having second and subsequent terms, high-order aspherical shape and polygon It may be a combination of shapes, and the combination is free. 4 is a diagram showing the configuration of the light extraction sheet 7. FIG. 4 (a) is an upper perspective view of the light extraction sheet 7, and FIG. 4 (b) is a line B arrow in FIG. 4 (a). FIG. 4C is a view taken along the line C in FIG. 4A. 4A shows that the cross-sectional shapes of the first lens array 40 and the second lens array 50 are triangular, the apex angle θ1a of the first lens array 40 and the apex of the second lens array 50. It is a perspective view when a curved surface shape is formed at the angle θ2a.

Here, by making the cross-sectional shapes of the first lens array 40 and the second lens array 50 polygonal or aspherical, the area having an appropriate inclination of the lens side surface can be adjusted. It becomes possible to adjust the light beam direction of the emitted light at higher order.
In addition, since the cross-sectional shapes of the first lens array 40 and the second lens array 50 have a plurality of lens side surface inclinations, the emission angle from the light extraction sheet 7 changes depending on the lens side surface inclinations. The angle dependency of the color of the emitted light can be controlled.

Furthermore, improvement in abrasion resistance is expected by making the lens shape having a curved surface at the lens apex.
In the light extraction sheet 7 of the present embodiment, since two types of lens shapes, the first lens array 40 and the second lens array 50, are present in the structure 5, a triangular prism having an apex angle of 90 degrees is crossed. It is possible to improve the light use efficiency and the color difference due to the emission angle, rather than the arranged cross prism shape.

  FIG. 5 is a ray diagram when the incident angle of light incident on the unit lens is changed when the cross-sectional shape of the lens array in the light extraction sheet 7 of the present embodiment is a triangular prism shape with an apex angle of 90 degrees. Indicates. 5A is a ray diagram when the incident angle of light incident on the unit lens is 10 degrees, and FIG. 5B is a diagram when the incident angle of light incident on the unit lens is 30 degrees. FIG. 5C is a ray diagram when the incident angle of light incident on the unit lens is 50 degrees.

FIG. 6 shows a ray diagram when the incident angle of light incident on the unit lens is changed when the cross-sectional shape of the lens array in the light extraction sheet 7 of the present invention is an aspherical shape. FIG. 6A is a ray diagram when the incident angle of light incident on the unit lens is 10 degrees, and FIG. 6B is a diagram when the incident angle of light incident on the unit lens is 30 degrees. FIG. 6C is a ray diagram when the incident angle of light incident on the unit lens is 50 degrees.
As shown in FIG. 5, when the cross-sectional shape of the lens array is a triangular prism shape, the emitted light travels substantially linearly regardless of the angle of the incident light. In FIG. 5, light (at least one of incident light and emitted light) is indicated by reference numerals 501, 502, and 503.

On the other hand, as shown in FIG. 6, when the cross-sectional shape of the lens array is an aspherical lens shape, the emitted light travels to a wide-angle region or is narrowed to a plurality of emission angles depending on the angle of the incident light. There are a wide variety of behaviors of the emitted light. In FIG. 6, light (at least one of incident light and emitted light) is indicated by reference numerals 601, 602, and 603.
Further, when the light emitted from the EL element 101 has a light emission distribution that varies depending on the emission angle, there is a problem that when the EL element 101 is observed from the irradiation direction F side, the color difference changes depending on the viewing angle.
On the other hand, in the light extraction sheet 7 of the present embodiment, the angle dependency of the color is obtained by optimizing the inclination angle of the lens in the cross-sectional shape of the lens array according to the emission angle of the light emitted from the EL element 101. It is possible to manufacture an EL element with low properties.

  FIG. 7 is a graph showing the ratio of the emitted light quantity to the incident light quantity (light utilization efficiency) when light having an incident angle changed from 0 degree to 85 degrees is incident on the light extraction sheet 7. In FIG. 7, the horizontal axis represents the incident angle of light incident on the incident surface of the unit lens. In FIG. 7, the vertical axis represents the light use efficiency, which is the ratio of light emitted from the exit surface of the unit lens when the intensity of light incident on the unit lens is 100%. In FIG. 7, the light utilization efficiency when the cross-sectional shapes of the first lens array 40 and the second lens array 50 are 90-degree prisms is indicated as A, and the first lens array 40 and The light utilization efficiency when the cross-sectional shape of the second lens array 50 is an aspherical lens shape is indicated as B.

When the cross-sectional shapes of the first lens array 40 and the second lens array 50 are prism shapes with an apex angle of 90 degrees, the light near the incident angle of 0 degrees is totally reflected and is not emitted in the front direction. The light utilization efficiency in the range of 30 degrees to 60 degrees is high, and the light near the incident angle of 30 degrees is deflected in the front direction, so that the light extraction sheet 7 having a high light collection effect is obtained.
On the other hand, when the cross-sectional shapes of the first lens array 40 and the second lens array 50 are aspherical lens shapes, the light use efficiency in the region of the incident angle of 0 degrees to 30 degrees is high, and the incident angle is around 0 degrees. Since the light is diffused and emitted in the front direction, the light extraction sheet 7 is more diffusive than the triangular prism shape described above.

  Therefore, by optimizing the cross-sectional shapes of the first lens array 40 and the second lens array 50 according to the light distribution characteristics of the incident light of the light B1 incident on the light extraction sheet 7, the luminous efficiency of the EL element is obtained. Will improve. For example, if the incident light B1 has a light distribution characteristic with a large amount of light in the region of 30 degrees to 60 degrees, the first lens array 40 and the second lens array 50 have a prism shape with an apex angle of 90 degrees. If the incident light B1 has a light distribution characteristic in which the incident light B1 has a large amount of light in the region of 0 degrees to 30 degrees, the lens array having a cross-sectional shape having an aspheric lens shape is more efficient.

The ratio H2 / H1 of the maximum height H2 of the second lens array 50 to the maximum height H1 of the first lens array 40 is less than 1. That is, the maximum height H2 of the second lens array 50 is lower than the maximum height H1 of the first lens array 40.
This is due to the reason described below.
When the above ratio H2 / H1 is 1, the accuracy in producing the mold and the sheet for producing the light extraction sheet 7 becomes very difficult. For this reason, when the height accuracy is displaced (shifted) even in a small or high direction, the portion where the maximum height H1 of the first lens array 40 is higher than the maximum height H2 of the second lens array 50. And a low part mixes in the surface of the light extraction sheet | seat 7, and visibility falls.

Further, when the ratio H2 / H1 is larger than 1, the maximum height H2 of the second lens array 50 in which the plurality of second lenses are adjacently arranged closely is set to be larger than that of the plurality of first lenses. Since it becomes higher than the maximum height H1 of the sparsely arranged first lens array 40 and the second lens array 50 is located on the outermost layer of the light extraction sheet 7, the abrasion resistance is lowered, which is not preferable.
When the maximum height H1 of the first lens array 40 or the maximum height H2 of the second lens array 50 is larger than 0.300 mm, the shape of the lens (first lens, second lens) is visually observed. It is not preferable because it is observed at. Furthermore, when the maximum height H1 or the maximum height H2 is smaller than 0.030 mm, diffracted light is generated and the effect as a lens is reduced. Therefore, the maximum height H1 of the first lens array 40 is reduced. The ratio H2 / H1 of the maximum height H2 of the second lens array 50 is preferably larger than 0.01.
That is, it is desirable that the relational expression of 0.01 <(H2 / H1) <1 holds.

  FIG. 8 shows the ratio L1 / P1 of the lens width L1 of the first lens with respect to the arrangement pitch P1 of the first lens array 40 and the maximum of the second lens array 50 with respect to the maximum height H1 of the first lens array 40. It is a light distribution characteristic figure of the emitted light when ratio H2 / H1 of height H2 is made into a set value, respectively. 8A is a light distribution characteristic diagram of the emitted light when the ratio L1 / P1 is 1 and the ratio H2 / H1 is 0.5. FIG. It is a light distribution characteristic view of the emitted light when said ratio L1 / P1 is 0.6 and said ratio H2 / H1 is 0.5. FIG. 8C is a light distribution characteristic diagram of emitted light when the ratio L1 / P1 is 0.4 and the ratio H2 / H1 is 0.5. Here, in FIG. 8, the light distribution characteristic in the extending direction of the first lens array 40 is set to 0 deg, the light distribution characteristic in the direction orthogonal to the extending direction of the first lens array 40 is set to 90 deg, and the oblique direction The light distribution characteristic was 45 deg.

Normally, when a lens array whose cross-sectional shape is an aspherical shape or a triangular prism shape is arranged in a direction orthogonal to the outside, the emitted light B2 is collected in the 0 deg direction, 45 deg direction, and 90 deg direction, respectively. Since the light characteristics are different, the light distribution characteristics of the emitted light at the azimuth angle are different when observed from the exit surface F side.
For example, when the ratio H2 / H1 is 0.5 and the ratio L1 / P1 is 1, the dominant ratio of the lenses of the first lens array 40 in the light extraction sheet 7 is increased. Therefore, the condensing effect of the emitted light in the direction orthogonal to the extending direction of the first lens array 40, that is, in the 0 deg direction is increased (see FIG. 8A).

On the other hand, as the ratio L1 / P1 decreases, the lens effect of the second lens array 50 on the light extraction sheet 7 increases, so that the direction orthogonal to the extending direction of the second lens array 50, that is, , The condensing effect of the emitted light in the 90 deg direction is increased (see FIG. 8C).
In the light extraction sheet 7 of the present embodiment, the ratio L1 / P1 and the ratio H2 / H1 are optimized to arbitrary values, whereby the lens effect of the first lens array 40 in the light extraction sheet 7 and the first effect are obtained. Since the lens effect of the second lens array 50 can be controlled, it is possible to control the light distribution characteristics of the emitted light in the azimuth direction when observed from the emission direction F (FIG. 8 ( b)).

  In FIG. 9, the ratio H2 / H1 of the maximum height H2 of the second lens array 50 to the maximum height H1 of the first lens array 40 is 0.5, and the lens width L1 and the first width of the first lens array 40 are shown. The maximum height ratios H1 / L1 and H2 / L2 with respect to the lens width L2 of the second lens array 50 are set to 0.7, respectively, and the maximum inclination angle θ1 of the first lens array 40 and the second lens array 50 is set. , Θ2 are set to 70 degrees, and the relative light quantity and relative color difference when the ratio L1 / P1 of the lens width L1 of the first lens to the arrangement pitch P1 of the first lens array 40 is changed from 0 to 1 are set. FIG.

In FIG. 9A, the horizontal axis indicates the ratio L1 / P1 of the lens width L1 with respect to the arrangement pitch P1, and the vertical axis indicates the relative light quantity when the ratio L1 / P1 is changed.
Here, the relative light quantity refers to the integrated light quantity of light emitted from the incident light B1 in the irradiation direction F when the light extraction film having a cross prism shape with an apex angle of 90 degrees is used for the EL element 101. This is the value when

In FIG. 9B, the horizontal axis represents the ratio L1 / P1 of the lens width with respect to the arrangement pitch P1, and the vertical axis represents the measurement field of view from 0 degrees to 80 degrees when the light extraction sheet 7 is not used. The relative color difference when the maximum change amount of the chromaticity coordinates (u ′, v ′) is 1.00.
As shown in FIG. 9, when the ratio L1 / P1 of the lens width L1 with respect to the arrangement pitch P1 of the first lens array 40 is increased, the relative light amount is increased and the ratio L1 / P1 is 0.5. The relative color difference decreases and becomes minimum when the ratio L1 / P1 is 0.4.

  This is because when the ratio L1 / P1 is 1, that is, when the arrangement pitch P1 of the first lens array 40 and the lens width L1 are the same, the first lens array 40 is continuously densely arranged. Even if the second lens array 50 is arranged in a direction intersecting with the first lens array 40, the ratio of the second lens array 50 occupying the light extraction sheet 7 is small, so that the incident light B1 On the other hand, since the lens effect in the direction in which the first lens array 40 extends is low, the relative light amount is reduced and the effect of improving the color difference is small.

  On the other hand, when the value of the ratio L1 / P1 is reduced, the lens width L1 with respect to the arrangement pitch P1 of the first lens array 40 is reduced, and the convex portions in the first lens array 40 are arranged with a constant interval. Therefore, when the second lens array 50 is arranged in a direction intersecting with the first lens array 40, the ratio of the second lens array 50 occupying the light extraction sheet 7 is increased, and the second lens array 50 with respect to the incident light B1 is increased. Since the lens effect of the lens array 50 is increased, the relative light amount is increased and the color difference is improved.

Further, as the ratio L1 / P1 is decreased, the lens effect of the first lens array 40 is decreased, so that the relative light amount is decreased and the color difference is deteriorated.
For the above reasons, the ratio L1 / P1 of the lens width L1 with respect to the arrangement pitch P1 of the first lens array 40 is changed between 0 and 1 to increase the integrated light amount and improve the color difference. It is desirable that the reduction rate from the maximum value of the integrated light quantity is within a range of 0.2 <(L1 / P1) <0.9, which is within 2%.
In addition, since it is preferable that the rate of increase of the integrated light amount is high, it is more preferable that the decrease rate from the maximum value of the integrated light amount is within 1%, 0.35 <L1 / P1 <0.75.

  FIG. 10 shows that the ratio H2 / H1 of the lens height H2 of the second lens array 50 to the maximum height H1 of the first lens array 40 is 0.5, and the lens with respect to the arrangement pitch P1 of the first lens array 40. The ratio L1 / P1 of the width L1 is 0.4, the maximum inclination angle θ1 of the first lens array 40 and the maximum inclination angle θ2 of the second lens array 50 are each 70 degrees, and the lens width of the first lens It is a figure which shows the relative light quantity and relative color difference when changing ratio H1 / L1 of the maximum height H1 with respect to L1, and ratio H2 / L2 of the maximum height H2 with respect to the lens width L2 of a 2nd lens.

In FIG. 10A, the horizontal axis indicates the ratio H / L of the maximum height H (H1, H2) to the lens width L (L1, L2), and the vertical axis indicates the relative light quantity.
Here, the relative light quantity refers to the integrated light quantity of light emitted from the incident light B1 in the irradiation direction F when the light extraction film having a cross prism shape with an apex angle of 90 degrees is used for the EL element 101. This is the value when

In FIG. 10B, the horizontal axis indicates the ratio H / L of the maximum height H (H1, H2) to the lens width L (L1, L2), and the vertical axis uses the light extraction sheet 7. The relative color difference when the maximum change amount of the chromaticity coordinates (u ′, v ′) in the range of 0 to 80 degrees in the measurement visual field is set to 1.00 is shown.
As shown in FIG. 10, as the ratio H / L increases, the relative light quantity increases and the relative color difference decreases. Therefore, it is preferable that the ratio H / L is large, but the change amount of the color difference is small. If the ratio H / L is increased as well as improvement by 20% or more, it becomes difficult to produce the light extraction sheet 7. For this reason, it is more preferable that the range is 0.3 <H / L <2.

That is, it is desirable that the relational expression of 0.3 <H1 / L1 <2 and the relational expression of 0.3 <H2 / L2 <2 are satisfied.
Here, when used as an illuminating device, it is preferable that the deviation of the chromaticity due to the viewing angle is small, and more preferably, the change amount of the color difference is improved by 40% or more, and the rate of increase of the ratio H / L is increased. The effect of improving the relative color difference with respect to is decreased as H / L increases, and becomes almost constant when H / L is greater than 1.6. Therefore, within the range of 0.7 <H / L <1.6. It is desirable to be.

  FIG. 11 shows that the ratio H2 / H1 of the maximum height H2 of the second lens array 50 to the maximum height H1 of the first lens array 40 is 0.5, and the lens with respect to the arrangement pitch P1 of the first lens array 40. The relative light quantity and the relative color difference when the ratio L1 / P1 of the width L1 is 0.4 and the maximum inclination angle θ1 of the first lens array 40 and the maximum inclination angle θ2 of the second lens array 50 are changed are shown. FIG.

In FIG. 11, the horizontal axis indicates the maximum inclination angle θ1 of the first lens array 40 and the maximum inclination angle θ2 of the second lens array 50, and the vertical axis indicates measurement when the light extraction sheet 7 is not used. The relative color difference is shown when the maximum amount of change in chromaticity coordinates (u ′, v ′) in the range of 0 to 80 degrees of view is 1.00.
As shown in FIG. 11, the relative color difference decreases as the maximum inclination angle θ (θ1, θ2) increases. Therefore, it is desirable that the maximum inclination angle θ is large, but the improvement rate of the relative color difference is 20% or more. In addition, when the maximum inclination angle θ is large, it is difficult to produce the light extraction sheet 7.
For this reason, more preferably, it is within the range of 30 degrees ≦ θ1 ≦ 75 degrees and within the range of 30 degrees ≦ θ2 ≦ 75 degrees.

That is, it is desirable that the relational expression 30 ° ≦ θ1 ≦ 75 ° and the relational expression 30 ° ≦ θ2 ≦ 75 ° are established.
Here, when used as an illumination device, it is preferable that the deviation of the chromaticity due to the viewing angle is small, and more preferably, the change amount of the color difference is improved by 40% or more. It is desirable to be within a range of ≦ 75 degrees.
FIG. 12 shows a case where the first lens array 40 has a prism shape and the apex angle θ1a has a curvature shape, or the second lens array 50 has a prism shape. It is the figure which showed the relative brightness | luminance and relative light quantity when giving a curvature shape to apex angle (theta) 1a.

In FIG. 12, the horizontal axis indicates the ratio of curvature to the lens widths L1 and L2 in the lens array, and the vertical axis indicates the relative light quantity (FIG. 12 (a)) and the relative luminance (FIG. 12 (b)). Yes. Here, the relative luminance and the relative light amount are values when the luminance and the light amount when the curvature shapes are not given to the apex angles θ1a and θ2a are 1.00.
As shown in FIG. 12A, as the ratio of the curvature of the apex angle to the lens widths L1 and L2 is increased, the relative light quantity increases, and the maximum is obtained when a curvature of 40% is formed with respect to the lens widths L1 and L2. The efficiency decreases as the curvature is further increased. This is because, if no curvature is applied, the amount of transmitted light increases when the light beam that has been totally reflected by the inclined surface of the triangular prism imparts a curvature to the apex angle.

In addition, as shown in FIG. 12B, when the ratio of the curvature of the apex angle with respect to the lens widths L1 and L2 is increased, the relative luminance decreases.
As described above, even if the relative light amount increases, the visibility decreases when the relative luminance decreases, so the ratio of the curvature with respect to the lens widths L1 and L2 is a range from 0% to 50% in which the relative luminance decreases by 10%. It is preferable to be within.

That is, it is preferable that the apex angle θ1a of the first lens has a curvature in the range of 0% to 50% with respect to the lens width L1 of the first lens.
Similarly, the apex angle θ2a of the second lens preferably has a curvature in the range of 0% to 50% with respect to the lens width L2 of the second lens.
Note that a microlens array having a lens height higher than the maximum height H1 of the first lens array 40 may be formed on the substrate surface 8a of the light extraction sheet 7.

In this case, by forming the microlens array as described above, the highest position in the light extraction sheet 7 becomes a microlens shape, so that it becomes point contact when contacting with an obstacle, and the abrasion resistance is improved. improves.
As a material for molding the light extraction sheet 7, it is possible to use a material having light transmittance with respect to the wavelength of the light emitted from the light emitting layer 2, for example, a plastic material that can be used for an optical member. It is possible to use.

  Examples of such materials include polyester resins, acrylic resins, polycarbonate resins, polystyrene resins, MS (acrylic and styrene copolymer) resins, thermoplastic resins such as polymethylpentene resins and cycloolefin polymers, or And transparent resins such as radiation curable resins composed of oligomers such as polyester acrylates, urethane acrylates, epoxy acrylates, or acrylates.

  Depending on the application, fine particles may be dispersed in the transparent resin. In this case, by dispersing the fine particles in the transparent resin, when the light incident on the light extraction sheet 7 is emitted in the irradiation direction F, the diffusibility is further increased, so that the change of the chromaticity due to the viewing angle is improved. In addition, when used as a lighting device, there is an advantage that defects are hardly observed.

  As the fine particles, particles made of an inorganic oxide or particles made of a resin can be used. In this case, for example, transparent particles made of an inorganic oxide include particles made of silica, alumina, titanium oxide, or the like. 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). Examples thereof include fluorine-containing polymer particles such as fluoroethylene monohexafluoropropylene copolymer), PVDF (polyfluorovinylidene), and ETFE (ethylene monotetrafluoroethylene copolymer), and silicone resin particles. These fine particles may be used as a mixture of two or more.

And the light extraction sheet | seat 7 is shape | molded by pouring the above materials into a metal mold | die and solidifying.
As a method of manufacturing such a mold, the mold is cut using a cutting tool having various lens shapes, and the cross-sectional shape is formed on the uneven portions of the first lens array 40 and the second lens array 50. A part having a corresponding shape is produced.

  In addition to the method of producing the light extraction sheet 7 with such a mold, the method of forming the uneven portion of the first lens array 40, the uneven portion of the second lens array 50, and the base material 8 includes: It is possible to mold by extrusion molding, injection molding, UV molding method or the like using a plastic resin or an ultraviolet curable resin and a mold formed with the above-mentioned shape. At this time, the concavo-convex portion of the first lens array 40, the concavo-convex portion of the second lens array 50, and the base material 8 may be molded separately or may be molded (integrated molding) as an integrated product. Good. Further, when the concave and convex portions of the first lens array 40, the second lens array 50, and the base material 8 are molded, it is also possible to mold by dispersing a diffusing agent such as a filler therein.

As the antistatic agent, ultrafine particles such as antimony-containing tin oxide (hereinafter referred to as ATO) or tin-containing indium oxide (ITO), which are conductive fine particles, may be dispersed. In this case, the antifouling property of the light extraction sheet 7 can be improved by dispersing the antistatic agent.
Moreover, when the structural layer 5 forms the base material 8 separately as in the UV molding method, the base material 8 is a transparent film, such as cellulose triacetate, polyester, polyamide, polyimide, polypropylene, poly It is possible to use stretched or unstretched films of thermoplastic resins such as methylpentene, polyvinyl chloride, polyvinyl acetal, polymethyl methacrylate, polycarbonate, polyurethane and the like.

Moreover, although the thickness of the base material 8 is based on the rigidity which the base material 8 has, it is preferable from a handling surface, such as workability, to set it as the range of 50 micrometers or more and 300 micrometers or less.
In addition, when the structural layer 5 does not adhere firmly to the base material 8 or when the adhesive force decreases due to external influences such as cold, moisture absorption and desorption, between the structural layer 5 and the base material 8, A primer layer having high adhesion to both materials may be provided, or the action of the primer layer may be added to the structural layer 5. Alternatively, an easy adhesion process such as a corona discharge process may be performed.
As described above, the representative example of the light extraction sheet 7 has been described. However, if the optical characteristics of the present embodiment can be achieved, the light extraction may be performed using materials, structures, processes, and the like other than those described above. It is also possible to produce the sheet 7.

(Display device)
As a configuration of the display device formed using the illumination device of the first embodiment, for example, the display device includes an EL element 101 on which the light extraction sheet 7 included in the illumination device of the first embodiment is arranged. It is good also as a structure to be made.
Moreover, as a structure of the display apparatus formed using the illuminating device of 1st embodiment, it is equipped with the light extraction sheet | seat 7 with which the illuminating device of 1st embodiment is equipped, and an image display element, for example on the back surface of an image display element. The light extraction sheet 7 may be arranged.
Moreover, as a structure of the display apparatus formed using the illuminating device of 1st embodiment, for example, it has the EL element 101 which has arrange | positioned the light extraction sheet | seat 7 with which the illuminating device of 1st embodiment is equipped, and an image display element, The EL element 101 may be pixel driven, and the light extraction sheet 7 may be disposed on the back surface of the image display element.

(Example)
Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. In addition, this invention is not limited only to these Examples. Specifically, two types of comparative example (Comparative Examples 1 and 2) samples and 11 types of samples of the present invention were prepared, and the results of comparing these physical properties will be described. The configuration of the sample of the present invention includes the same configuration as the configuration of the first embodiment described above.

(Comparative Example 1)
As Comparative Example 1, a sample having a configuration in which the light extraction sheet 7 is not attached to the glass surface of the EL element 101 was used.
(Comparative Example 2)
The sample of Comparative Example 2 was produced by the following procedure.
First, the light extraction sheet 7 is a cylinder in which a UV curable acrylic resin having a refractive index of 1.50 is applied on a transparent PET base material having a thickness of 188 μm, and a cross prism shape having an apex angle of 90 degrees is cut. The UV curable resin was cured by exposing the UV light from the transparent PET side while conveying a film coated with the ultraviolet curable resin using a mold. Furthermore, the light extraction sheet | seat 7 was produced by peeling a metal mold | die from the transparent PET film for the cured UV curable resin.

The sample of the comparative example 2 was produced by bonding the light extraction sheet | seat 7 obtained as mentioned above to the EL element 101 of 1st embodiment through an adhesive.
At this time, the configuration of the lens shape of the first lens array 40 is a convex cylindrical shape with an arrangement pitch of 140 μm, and the configuration of the lens shape of the second lens array 50 is an arrangement pitch of 30 μm. This is a triangular prism with an apex angle of 90 degrees.

(Example of the present invention)
The sample of the present invention example was produced by the following procedure.
First, on a transparent PET substrate having a thickness of 188 μm, a UV curable acrylic resin having a refractive index of 1.50 that forms the pattern of the structural layer 5 was applied, and the cylinder mold cut into the shape of the structural layer 5 was formed. In use, the UV curable resin was cured by exposing UV light from the transparent PET side while conveying the film coated with the ultraviolet curable resin. Furthermore, the light extraction sheet | seat 7 was produced by peeling a metal mold | die from the transparent PET film for the cured UV curable resin.
The light extraction sheet 7 obtained as described above was bonded to the EL element 101 of the first embodiment described above via an adhesive to produce 11 types of samples of the present invention.

In the following, 11 types of inventive examples were prepared according to the following parameters, respectively.
(Invention Example 1)
The maximum height H1 of the first lens array 40 was 0.070 mm, the lens width L1 was 0.100 mm, the arrangement pitch P1 was 0.400 mm, and the maximum inclination angle θ1 was 70 degrees. In addition, the lens height H2 of the second lens array 50 is 0.035 mm, the lens width L2 is 0.050 mm, the arrangement pitch P2 is 0.050 mm, and the maximum inclination angle θ2 is 70 degrees.

(Invention Example 2)
The maximum height H1 of the first lens array 40 was 0.070 mm, the lens width L1 was 0.100 mm, the arrangement pitch P1 was 0.200 mm, and the maximum inclination angle θ1 was 70 degrees. In addition, the lens height H2 of the second lens array 50 is 0.035 mm, the lens width L2 is 0.050 mm, the arrangement pitch P2 is 0.050 mm, and the maximum inclination angle θ2 is 70 degrees.

(Invention Example 3)
The maximum height H1 of the first lens array 40 was 0.070 mm, the lens width L1 was 0.100 mm, the arrangement pitch P1 was 0.111 mm, and the maximum inclination angle θ1 was 70 degrees. In addition, the lens height H2 of the second lens array 50 is 0.035 mm, the lens width L2 is 0.050 mm, the arrangement pitch P2 is 0.050 mm, and the maximum inclination angle θ2 is 70 degrees.
And each light extraction sheet | seat 7 of Example 1-3 of this invention was each arrange | positioned in the EL element 101 of 1st embodiment, and the integrated light quantity was measured. The results are shown in Table 1 below. Here, the relative light amount shown in Table 1 is a value when the integrated light amount in Comparative Example 2 is 1.00.

  As shown in Table 1, it is clear that the relative light quantity increases when the value of L1 / P1 in the lens array is in the range of 0.25 to 0.90.

(Invention Example 4)
The maximum height H1 of the first lens array 40 was 0.030 mm, the lens width L1 was 0.100 mm, the arrangement pitch P1 was 0.150 mm, and the maximum inclination angle θ1 was 55 degrees. In addition, the lens height H2 of the second lens array 50 is 0.015 mm, the lens width L2 is 0.050 mm, the arrangement pitch P2 is 0.500 mm, and the maximum inclination angle θ2 is 55 degrees.

(Invention Example 5)
The maximum height H1 of the first lens array 40 was 0.100 mm, the lens width L1 was 0.100 mm, the arrangement pitch P1 was 0.500 mm, and the maximum inclination angle θ1 was 75 degrees. In addition, the lens height H2 of the second lens array 50 was 0.050 mm, the lens width L2 was 0.050 mm, the arrangement pitch P2 was 0.050 mm, and the maximum inclination angle θ2 was 75 degrees.
And each light extraction sheet | seat 7 of this invention example 4 and 5 was each arrange | positioned to the EL element 101 of 1st embodiment, and chromaticity was measured. The results are shown in Table 2. Here, the relative color difference shown in Table 2 is a value when the color difference in Comparative Example 1 is 1.00.

  As shown in Table 2, the ratio H / L of the maximum height H to the lens width L is set to 0.30 or less so that the light extraction sheet 7 of the first embodiment is not used. It is clear that the color difference is improved by 20% or more compared to the time.

(Invention Example 6)
The maximum height H1 of the first lens array 40 was 0.023 mm, the lens width L1 was 0.100 mm, the arrangement pitch P1 was 0.500 mm, and the maximum inclination angle θ1 was 25 degrees. In addition, the lens height H2 of the second lens array 50 is 0.012 mm, the lens width L2 is 0.050 mm, the arrangement pitch P2 is 0.050 mm, and the maximum inclination angle θ2 is 25 degrees.

(Invention Example 7)
The maximum height H1 of the first lens array 40 was 0.029 mm, the lens width L1 was 0.100 mm, the arrangement pitch P1 was 0.500 mm, and the maximum inclination angle θ1 was 30 degrees. In addition, the lens height H2 of the second lens array 50 is 0.014 mm, the lens width L2 is 0.050 mm, the arrangement pitch P2 is 0.050 mm, and the maximum inclination angle θ2 is 30 degrees.

(Invention Example 8)
The maximum height H1 of the first lens array 40 was 0.137 mm, the lens width L1 was 0.100 mm, the arrangement pitch P1 was 0.500 mm, and the maximum inclination angle θ1 was 70 degrees. In addition, the lens height H2 of the second lens array 50 is 0.068 mm, the lens width L2 is 0.050 mm, the arrangement pitch P2 is 0.050 mm, and the maximum inclination angle θ2 is 70 degrees.
And each light extraction sheet | seat 7 of the invention examples 6-8 was each arrange | positioned to the EL element 101 of 1st embodiment, and chromaticity was measured. The results are shown in Table 3. Here, the relative color difference shown in Table 3 is a value when the color difference in Comparative Example 1 is 1.00.

  As shown in Table 3, by setting the maximum inclination angle θ (θ1, θ2) of the lens to 30 degrees or more, it is compared with Comparative Example 1, that is, when the light extraction sheet 7 of the first embodiment is not used. It is apparent that the color difference is improved by 20% or more.

(Invention Example 9)
The maximum height H1 of the first lens array 40 was 0.087 mm, the lens width L1 was 0.100 mm, the arrangement pitch P1 was 0.500 mm, and the maximum inclination angle θ1 was 70 degrees. In addition, the lens height H2 of the second lens array 50 is 0.043 mm, the lens width L2 is 0.050 mm, the arrangement pitch P2 is 0.050 mm, and the maximum inclination angle θ2 is 70 degrees.
Further, 0% curvature with respect to the lens width L1 was given to the apex angle θ1a of the first lens array 40, and 0% curvature with respect to the lens width L2 was given to the apex angle θ2a of the second lens array 50.

(Invention Example 10)
The maximum height H1 of the first lens array 40 was 0.087 mm, the lens width L1 was 0.100 mm, the arrangement pitch P1 was 0.500 mm, and the maximum inclination angle θ1 was 70 degrees. In addition, the lens height H2 of the second lens array 50 is 0.043 mm, the lens width L2 is 0.050 mm, the arrangement pitch P2 is 0.050 mm, and the maximum inclination angle θ2 is 70 degrees.
Further, a curvature of 50% with respect to the lens width L1 was given to the apex angle θ1a of the first lens array 40, and a curvature of 50% with respect to the lens width L2 was given to the apex angle θ2a of the second lens array 50.

(Invention Example 11)
The maximum height H1 of the first lens array 40 was 0.087 mm, the lens width L1 was 0.100 mm, the arrangement pitch P1 was 0.500 mm, and the maximum inclination angle θ1 was 70 degrees. In addition, the lens height H2 of the second lens array 50 is 0.043 mm, the lens width L2 is 0.050 mm, the arrangement pitch P2 is 0.050 mm, and the maximum inclination angle θ2 is 70 degrees.

Further, a curvature of 60% with respect to the lens width L1 was given to the apex angle θ1a of the first lens array 40, and a curvature of 60% with respect to the lens width L2 was given to the apex angle θ2a of the second lens array 50.
And each light extraction sheet | seat 7 of this invention example 9-11 was each arrange | positioned to the EL element 101 of 1st embodiment, and the brightness | luminance was measured. The results are shown in Table 4. Here, the relative light quantity and the relative luminance shown in Table 4 are values when the luminance in Example 9 of the present invention is 1.00.

  As shown in Table 4, when the curvature is given to the apex angle of the lens, the relative light quantity increases, but the relative luminance decreases. Therefore, even if the relative light quantity was increased, it was confirmed that the visibility decreased when the relative luminance decreased by 10% or more.

1A substrate (translucent substrate)
1B substrate (translucent substrate)
DESCRIPTION OF SYMBOLS 2 Light emitting layer 3 Anode 4 Cathode 5 Structure layer 6 Adhesive layer 7 Light extraction sheet 8 Base material 8a Base material surface 8b Base material back surface 40 1st lens array 50 2nd lens array 100 Light emitting structure 101 EL element B0, B1 , B2, B12 Light 501, 502, 503, 601, 602, 603 Light P1 Arrangement pitch of the first lens array P2 Arrangement pitch of the second lens array L1 Lens width of the first lens array L2 Second lens array Lens width H1 maximum height of the first lens array H2 maximum height of the second lens array θ1 maximum tilt angle of the first lens array θ1a apex angle of the first lens array θ2 maximum of the second lens array Tilt angle θ2a Vertex angle of the second lens array

Claims (4)

A first electrode formed on at least a second substrate and being one of an anode and a cathode; a second electrode facing the first electrode and being the other of the anode and the cathode; and the first electrode A surface light source having a light emitting layer sandwiched between and a second electrode and containing a fluorescent organic compound,
A first substrate on which light emitted from the surface light source is incident on one surface and the first electrode is formed on a surface opposite to the surface facing the light emitting layer ;
A second substrate on which light emitted from the surface light source is incident on one surface and the second electrode is formed on a surface opposite to the surface facing the light emitting layer;
A light extraction sheet provided on a surface opposite to a surface on which light emitted from the surface light source of the first substrate is incident;
Comprising a surface light source, and said first substrate, said second substrate, and a light emitting unit formed by disposing the light extraction sheet to an EL element provided with,
A first lens array having a plurality of first lenses spaced apart and arranged in parallel on a surface opposite to the surface facing the first substrate of the light extraction sheet, and adjacent to each other. And a second lens array comprising a plurality of second lenses arranged in parallel,
The plurality of first lenses extend along one direction and are arranged in parallel.
The plurality of second lenses are arranged adjacent to and parallel to each other along a direction intersecting the first lens array,
The maximum height of the first lens array is H1, the maximum height of the second lens array is H2, the arrangement pitch between the adjacent first lenses is P1, and the arrangement pitch between the adjacent second lenses is the P2, the lens width of the first lens L1, a lens width of the second lens L2, the from the surface opposite the light-transmitting substrate and the opposing surfaces of the light extraction sheet of the first lens When the maximum inclination angle is θ1, and the maximum inclination angle from the surface of the light extraction sheet of the second lens opposite to the surface facing the light-transmitting substrate is θ2, the following relational expression (1) To (8) holds,
The cross-sectional shape seen from the direction orthogonal to the arrangement direction of the first lens is a prism shape,
The apex angle θ1a of the first lens has a curvature in the range of 0% to 50% with respect to the lens width L1 of the first lens,
A cross-sectional shape viewed from a direction orthogonal to the arrangement direction of the second lenses is a prism shape,
The illumination device, wherein the apex angle θ2a of the second lens has a curvature in the range of 0% to 50% with respect to the lens width L2 of the second lens.
H2 <H1 (1)
0.01 <(H2 / H1) <1 (2)
0.2 <(L1 / P1) <0.9 (3)
L2 = P2 (4)
0.3 <(H1 / L1) <2 (5)
0.3 <(H2 / L2) <2 (6)
30 ° ≦ θ1 ≦ 75 ° (7)
30 ° ≦ θ2 ≦ 75 ° (8) A display device comprising an EL element in which a light extraction sheet provided in the illumination device according to claim 1 is disposed,
The display device, wherein the EL element is pixel driven. A liquid crystal display device comprising a light extraction sheet provided in the illumination device according to claim 1 and an image display element,
A liquid crystal display device, wherein the light extraction sheet is disposed on a back surface of the image display element. A liquid crystal display device comprising: an EL element on which a light extraction sheet provided in the illumination device according to claim 1 is disposed; and an image display element.
The EL element is pixel driven,
A liquid crystal display device, wherein the light extraction sheet is disposed on a back surface of the image display element.

Images