JP2012212508A - Light-emitting element and illumination apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a see-through light-emitting element with high light extraction efficiency, in which stripe lines are less visible.SOLUTION: A light-emitting element 10 includes an organic EL element 140 and a structure layer 100 provided for a light-emitting surface 144 of the organic EL element 140. The structure layer 100 includes on a surface 10U opposite to the organic EL element 140, an uneven structure including a first line 113 extending in a first direction, a second line 114 extending in a second direction, which intersects with the first direction, and a third line 115 extending in a third direction, which intersects with the first direction and the second direction. A projection area formed by projecting a slope part of the uneven structure on a plane, which is parallel to a flat surface part of the uneven structure, in a direction perpendicular to the flat surface part is 0.1 times or less of the total area of the flat surface part.

Description

  The present invention relates to a light emitting device. Specifically, the present invention relates to a light-emitting element including an organic electroluminescence element (hereinafter referred to as “organic EL element” as appropriate).

  A light-emitting element including an organic EL element can have a planar shape, and the light color can be white or a color close thereto. For this reason, it is possible to use a light emitting element provided with an organic EL element for the use as a light source of the lighting fixture which illuminates spaces, such as a living environment, or as a backlight apparatus of a display apparatus.

However, currently known organic EL elements are low in efficiency for use in the above-described illumination applications. Therefore, it is desired to improve the light extraction efficiency of the organic EL element. As a method for improving the light extraction efficiency of an organic EL element, it is known to provide various uneven structures on the light emitting surface of a single-sided light emitting organic EL element. For example, it has been proposed to provide a structure layer having an uneven structure on the light emitting surface of an organic EL element (see Patent Document 1). With this concavo-convex structure, good light collection can be achieved, and the light extraction efficiency can be improved.
Further, techniques such as Patent Documents 2 and 3 are also known.

International Publication No. 2004/017106 JP 2010-164715 A JP 2005-221516 A

  In addition to the single-sided light-emitting type, a light-emitting element including an organic EL element includes a double-sided light-emitting type that extracts light from both sides. Since it is required to extract light with high efficiency even in a double-sided light emitting device, the inventor tried to provide a concavo-convex structure in a double-sided light emitting device as well as a single-sided light emitting device. . However, it has been found that the desired performance cannot be obtained even when the uneven structure for a single-sided light-emitting element is applied to a double-sided light-emitting element as it is.

  In general, each layer included in a double-sided light emitting element can transmit light. For this reason, a normal double-sided light emitting element is see-through, and the other side can be seen through the light emitting element. Since see-through can improve design and diversify applications, see-through is one of the advantages of a dual-side light emitting element. Therefore, even when a concavo-convex structure is provided so that light can be extracted with high efficiency, it is desirable to prevent the other side from being seen through the light emitting element.

  On the other hand, a single-sided light emitting device includes a reflective layer (for example, a reflective electrode) from the viewpoint of increasing light extraction efficiency, and reflects light emitted from the organic EL device on the side opposite to the light emitting surface. Reflected by the layer. For this reason, since the light that has entered the single-sided light emitting element from the outside is also reflected by the reflective layer, the other side cannot be seen through the light emitting element. For these reasons, the conventional concavo-convex structure provided in a single-sided light-emitting element is generally not studied for see-through like the double-sided light-emitting element. Therefore, when a conventional uneven structure is provided in a double-sided light emitting device, the haze is usually increased, and the other side cannot be seen through the light emitting device.

  Moreover, there exists a shape including the row | line | column extended in a fixed direction as an example of the shape of the uneven structure provided in the light emission surface of an organic EL element. When such a row is included in the concavo-convex structure, the above-mentioned row may be visually recognized depending on the observation angle in the double-sided light emitting device. For example, when the concavo-convex structure is observed at an oblique polar angle with respect to the light emitting surface of the organic EL element, a streak along the direction in which the line extends may be visually recognized. In particular, when the two groups of rows are in a lattice pattern, unevenness of reflected light on the surface of the concavo-convex structure may be observed by visually recognizing the stripes in a certain region. there were. Hereinafter, this unevenness may be referred to as “lattice unevenness”. The lattice unevenness is the light that is irradiated from the outside of the light emitting element and reflected on the surface of the concavo-convex structure is observed in the form of unevenness. Conceivable. However, the lattice unevenness which is a problem here does not mean that the intensity of the reflected light to be visually recognized is stronger or larger than the surroundings, and the streak of the above-mentioned row is visually recognized. , It means that the reflected light is unevenly visible to the extent that the direction in which the line extends can be recognized.

  The present invention has been made in view of the above, and is capable of taking out light with high efficiency while maintaining a see-through, and further, a light emitting element in which a streak of a row is hardly visually recognized, and its An object of the present invention is to provide a lighting fixture including a light emitting element.

As a result of intensive studies to solve the above-mentioned problems, the present inventor has a light emitting element having a concavo-convex structure on its light output surface, including three or more rows in which the concavo-convex structure extends in different directions, and By controlling the area ratio between the flat surface portion and the slope portion of the concavo-convex structure, it is possible to make the light emitting element capable of extracting light with high efficiency while making it difficult to see stripes in the row and maintaining the see-through. The present invention has been completed by finding out that it can be realized.
That is, the gist of the present invention is the following [1] to [6].

[1] An organic electroluminescence device that has a light emitting surface and emits light from the light emitting surface, and a structural layer provided directly or indirectly on the light emitting surface of the organic electroluminescence device,
The structural layer includes a first row extending in a first direction parallel to the surface on a surface of the structural layer opposite to the organic electroluminescence element, and the first parallel to the surface and the first A second row extending in a second direction intersecting with the direction of the second, and a third row extending in a third direction parallel to the surface and intersecting the first direction and the second direction. It has a concavo-convex structure including a row,
The concavo-convex structure has a flat surface portion parallel to the light emitting surface and a slope portion inclined with respect to the light emitting surface;
A projected area formed by projecting the slope portion in a direction perpendicular to the flat surface portion onto a plane parallel to the flat surface portion is 0.1 times or less of the total area of the flat surface portions. There is a light emitting element.
[2] The light emitting device according to [1], wherein the maximum value of the height difference of the flat surface portion in the uneven structure is 22 μm or less.
[3] The light emitting device according to [1] or [2], wherein the inclined surface portion is inclined at an inclination angle of 80 ° or more and less than 90 ° with respect to the flat surface portion.
[4] The light emitting device according to any one of [1] to [3], wherein a maximum height difference of the flat surface portion is 0.1 μm or more.
[5] A lighting fixture comprising the light emitting element according to any one of [1] to [4].

  According to the present invention, it is possible to extract light with high efficiency while maintaining see-through, and further to realize a light-emitting element in which a streak of stripes is difficult to visually recognize, and a lighting fixture including the light-emitting element. it can.

FIG. 1 is a perspective view schematically showing a light emitting device according to the first embodiment of the present invention. FIG. 2 is a diagram for explaining the light emitting element according to the first embodiment of the present invention, and schematically shows a cross section of the light emitting element shown in FIG. 1 cut along a plane including the lines 1a-1b and perpendicular to the light exit surface. FIG. FIG. 3 is an enlarged plan view schematically showing a light output surface of the light emitting device according to the first embodiment of the present invention as viewed from the thickness direction of the light emitting device. FIG. 4 is a plan view schematically showing an enlarged view of the light-emitting surface of the light-emitting element according to the first embodiment of the present invention viewed from the thickness direction of the light-emitting element. FIG. 5 is a plan view schematically showing an enlarged view of the light-emitting surface of the light-emitting element according to the first embodiment of the present invention viewed from the thickness direction of the light-emitting element. FIG. 6 is a plan view schematically showing an enlarged view of the light-emitting surface of the light-emitting element according to the first embodiment of the present invention viewed from the thickness direction of the light-emitting element. FIG. 7 is a plan view schematically showing an enlarged view of the light-emitting surface of the light-emitting element according to the first embodiment of the present invention viewed from the thickness direction of the light-emitting element. FIG. 8 is a partial cross-sectional view schematically showing a cross section of a part of the concavo-convex structure layer according to the first embodiment of the present invention, taken along a plane that includes the line 3a of FIG. 3 and is perpendicular to the light exit surface. . FIG. 9 schematically illustrates a state in which the slope portion of the light emitting surface of the light emitting element according to the first embodiment of the present invention is projected onto a plane parallel to the flat surface portion in a direction perpendicular to the flat surface portion. FIG. FIG. 10 shows a light emitting device according to the second embodiment of the present invention parallel to the point where the third row and the fourth row intersect and the direction in which the first row extends through the recess. It is sectional drawing which shows typically the cross section cut | disconnected by the surface perpendicular | vertical with respect to the light-emitting surface including a straight line. FIG. 11 is a perspective view schematically showing a light emitting device according to the third embodiment of the present invention. FIG. 12 is a plan view schematically showing an enlarged view of the light-emitting surface of the light-emitting element according to the modification of the first embodiment of the present invention when viewed from the thickness direction of the light-emitting element. FIG. 13 is a plan view schematically showing a part of the light exit surface according to the modification of the present invention as seen from the thickness direction of the light emitting element. FIG. 14 is a plan view schematically showing a part of the light exit surface according to the modification of the present invention as seen from the thickness direction of the light emitting element. FIG. 15 is a plan view schematically showing a part of the light exit surface according to the modification of the present invention as seen from the thickness direction of the light emitting element. FIG. 16 is a perspective view schematically showing a part of the concavo-convex structure layer obtained in Example 1 as seen from an oblique direction. FIG. 17 is a plan view schematically showing a part of the concavo-convex structure layer obtained in Example 1 as viewed from the thickness direction. FIG. 18 is a perspective view schematically showing a part of the concavo-convex structure layer obtained in Example 2 as seen from an oblique direction. FIG. 19 is a plan view schematically showing a part of the concavo-convex structure layer obtained in Example 2 as viewed from the thickness direction.

  Hereinafter, the present invention will be described in detail with reference to embodiments and examples, but the present invention is not limited to the embodiments and examples described below, and the gist of the present invention and its equivalent scope. The present invention may be implemented with any changes without departing from the scope.

[1. First embodiment]
1 and 2 are views for explaining a light emitting device according to the first embodiment of the present invention. FIG. 1 is a perspective view schematically showing the light emitting device, and FIG. 2 is a light emitting device shown in FIG. It is sectional drawing which shows typically the cross section which cut | disconnected the element | device by the surface perpendicular | vertical with respect to the light emission surface including line 1a-1b.

  As shown in FIG. 1, the light emitting element 10 according to the first embodiment of the present invention is an element having a rectangular flat plate structure, and includes a double-sided light emitting organic EL element 140. The organic EL element 140 includes at least a first electrode layer 141, a light emitting layer 142, and a second electrode layer 143 in this order. In the present embodiment, the first electrode layer 141 and the second electrode layer 143 are both transparent electrode layers. For this reason, the light generated in the light emitting layer 142 is transmitted through the first electrode layer 141 and the second electrode layer 143, respectively, and emitted outside through the surfaces 144 and 145. Therefore, in the following description, the surfaces 144 and 145 may be referred to as “light emitting surfaces”.

  At least one light emitting surface 144 of the organic EL element 140 is provided with a light emitting surface structural layer 100 as a structural layer according to the present invention. In the present embodiment, the light emitting surface structure layer 100 is provided directly so as to contact the light emitting surface 144. However, the light emitting surface structure layer 100 may be provided indirectly on the light emitting surface 144 via a layer such as an adhesive layer or a light diffusion layer.

  Furthermore, the light emitting element 10 of the present embodiment may include components other than the above-described members. In the present embodiment, it is assumed that the sealing substrate 151 is provided on the lower light emitting surface 145 of the organic EL element 140 in the drawing.

  Therefore, the light emitting element 10 includes the sealing substrate 151, the organic EL element 140, and the light emitting surface structure layer 100 in this order, and light passes through the surface 10U on the opposite side of the light emitting surface structure layer 100 from the organic EL element 140. The light can be emitted through the surface 10D of the sealing substrate 151 opposite to the organic EL element 140. The surfaces 10U and 10D are located on the outermost side of the light emitting element 10, and light is emitted to the outside of the light emitting element 10 through the surfaces 10U and 10D. May be called.

[1-1. Organic EL device]
For example, as exemplified as the organic EL element 140, the organic EL element is usually provided with two or more electrode layers and a light emitting layer that is provided between these electrode layers and emits light when a voltage is applied from the electrode layers; Is provided.

  An organic EL element forms layers such as an electrode layer and a light emitting layer constituting the organic EL element on a substrate, and further provides a sealing member that covers those layers, and a layer such as a light emitting layer is formed between the substrate and the sealing member. Generally, a sealed configuration is used.

  As a light emitting layer, it does not specifically limit but a known thing can be selected suitably. The light emitting material in the light emitting layer is not limited to one type, and two or more types may be used in combination at any ratio. Further, the light emitting layer is not limited to a single layer, and may be a single type of layer or a combination of a plurality of types of layers in order to suit the use as a light source. Thereby, light of white or a color close thereto can be emitted.

  The electrode layers of the organic EL element according to the present invention are all transparent electrode layers formed of a transparent material. Here, “transparent” means having a light transmittance of a degree suitable for use in an optical member. For example, an electrode layer having such a high light transmittance that the light-emitting element 10 has a desired total light transmittance described later as a whole may be used as the transparent electrode layer. By providing the transparent electrode layer having high transparency as described above, the extraction efficiency of light generated in the light emitting layer can be improved, and the other side can be clearly seen through the light emitting element. In addition, the material of a transparent electrode layer may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios. Further, the transparent electrode layer may be a single-layer structure including only one layer, or may be a multilayer structure including two or more layers.

  In addition to the light emitting layer 142, the organic EL element 140 includes other layers such as a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer (not shown) between the electrode layer 141 and the electrode layer 143. May be further included. Further, the organic EL element 140 may further include arbitrary components such as a wiring for energizing the electrode layers 141 and 143 and a peripheral structure for sealing the light emitting layer 142.

Although it does not specifically limit as a material which comprises an electrode layer and the layer provided in between, The following can be mentioned as a specific example.
Examples of the material for the transparent electrode layer include ITO (indium tin oxide).
Examples of the material for the hole injection layer include a starburst aromatic diamine compound.
Examples of the material for the hole transport layer include a triphenyldiamine derivative.
As a host material of a yellow light emitting layer, a triphenyldiamine derivative etc. can be mentioned, for example, As a dopant material of a yellow light emitting layer, a tetracene derivative etc. can be mentioned, for example.
Examples of the material for the green light emitting layer include pyrazoline derivatives.
Examples of the host material for the blue light emitting layer include anthracene derivatives and the like, and examples of the dopant material for the blue light emitting layer include perylene derivatives.
Examples of the material for the red light emitting layer include a europium complex.
Examples of the material for the electron transport layer include an aluminum quinoline complex (Alq).
As a material of the reflective electrode layer, for example, lithium fluoride and aluminum can be used, which are sequentially laminated by vacuum film formation.

  The above-described or other light-emitting layers may be combined as appropriate to form a light-emitting layer that generates a light emission color having a complementary color relationship, which is referred to as a stacked type or a tandem type. The combination of complementary colors may be, for example, yellow / blue or green / blue / red.

[1-2. (Light emitting surface structure layer)
The light emitting surface structure layer 100 is a layer provided on the light emitting surface 144 of the organic EL element 140, and the surface of the light emitting surface structure layer 100 opposite to the organic EL element 140 is the light emitting surface 10U. The light exit surface 10U is a surface exposed on the outermost surface of the light emitting element 10, and is a light exit surface as the light emitting element 10, that is, a light exit surface when light is emitted from the light emitting element 10 to the outside of the element.

When viewed macroscopically, the light exit surface 10 </ b> U is a surface parallel to the light emitting surface 144 of the organic EL element 140 and parallel to the main surface of the light emitting element 10. However, since the light exit surface 10U has an uneven structure when viewed microscopically, a portion corresponding to the surface of the concave portion or the convex portion can form an angle that is not parallel to the light emitting surface 144. Therefore, in the following description, being parallel or perpendicular to the light exit surface means that it is parallel or perpendicular to the light exit surface viewed macroscopically ignoring the recesses or projections unless otherwise specified. Say. Further, the light emitting element 10 will be described in a state where the light emitting surface 10U is placed so as to be parallel and upward with respect to the horizontal direction unless otherwise specified.
Further, the fact that the component is “parallel” or “vertical” may include an error within a range that does not impair the effects of the present invention, for example, ± 5 °. Further, “along” in a certain direction means “in parallel” in a certain direction unless otherwise specified.

The light exit surface structure layer 100 includes a multilayer body 110 including the concavo-convex structure layer 111 and the base film layer 112, a support substrate 131 as a substrate, and an adhesive layer 121 that adheres the multilayer body 110 and the support substrate 131. .
The uneven structure layer 111 is a layer located on the upper surface of the light emitting element 10 (that is, the outermost layer on the light emitting surface side of the light emitting element 10). The uneven structure layer 111 has an uneven structure including a first row 113, a second row 114, a third row 115, and a fourth row 116. Here, the “row” means a group of a plurality of rows of recesses or projections extending continuously for a certain length in a certain direction. Therefore, the direction in which the line extends means the direction in which the concave part or the convex part included in the line extends. The row may include, for example, only concave portions formed in a groove shape, for example, may include only convex portions formed in a bowl shape, or may include a combination thereof. . In the present embodiment, each of the first to fourth strips 113 to 116 is a convex portion that protrudes relatively from the surroundings. For this reason, a recessed portion 117 that is relatively recessed exists at a position between the first to fourth rows 113 to 116. In the concavo-convex structure layer 111 of the present embodiment, the concavo-convex structure includes the first to fourth rows 113 to 116 made of convex portions and the concave portion 117, and the outgoing surface 10U is defined by the concavo-convex structure. Yes.

  In addition, in this specification, since drawing is typical illustration, the number of the convex parts contained in the 1st-4th row | line | columns 113-116 shown on the light emission surface 10U is only a small number. In an actual light emitting element, a much larger number of convex portions may be provided on the light emitting surface 10U of one light emitting element.

(Description of uneven structure)
Hereinafter, the uneven structure of the light exit surface 10U will be described in detail with reference to the drawings.
3 to 7 are plan views schematically showing an enlarged view of the light exit surface 10U of the light emitting element 10 according to the first embodiment of the present invention viewed from the thickness direction of the light emitting element 10. FIG. Further, FIG. 8 is a portion schematically showing a cross section of a part of the concavo-convex structure layer 111 according to the first embodiment of the present invention cut by a plane including the line 3a of FIG. 3 and perpendicular to the light exit surface 10U. It is sectional drawing. In FIG. 3, the line 3 a passes through the point X where the third row 115 and the fourth row 116 intersect and the recess 117, and is parallel to the direction in which the first row 113 extends. It is. In FIG. 4, the first row 113 is hatched, the second row 114 is hatched, and the third row 115 is hatched in FIG. In FIG. 7, the fourth row 116 is indicated by hatching. Furthermore, in the following description, unless otherwise specified, “thickness direction” represents the thickness direction of the light emitting element 10.

  As shown in FIG. 3, the light-emitting surface structure layer 100 includes four rows extending on the light-emitting surface 10U in a direction parallel to the light-emitting surface 10U, that is, a first row 113 and a second row. 114, a third row 115 and a fourth row 116. The first row 113, the second row 114, the third row 115, and the fourth row 116 all extend in a direction parallel to the light exit surface 10U. However, the directions in which the first row 113, the second row 114, the third row 115, and the fourth row 116 extend are not parallel to each other but intersect each other. That is, when the direction in which the first row 113 extends is the first direction, the second row 114 extends in the second direction intersecting the first direction, and the third row 115 extends in a third direction intersecting the first direction and the second direction, and the fourth row 116 is a fourth direction intersecting the first direction, the second direction, and the third direction. It extends in the direction.

  As described above, since the rows 113 to 116 extending in three or more different directions are provided, in the light emitting element 10 of the present embodiment, the stripes of the rows 113 to 116 are observed even when the light exit surface 10U is viewed. Can be made difficult to see. As described above, the reason why the first to fourth rows 113 to 116 can be prevented from being visually recognized is not certain, but according to the study of the present inventor, it is assumed that the reason is as follows.

  In the conventional light emitting element, even when the uneven structure having the rows is provided, the rows are often provided only in one group or two groups. When the row is the first group or the second group, the regularity of the surface shape of the light emitting surface when viewed from the thickness direction becomes high. For this reason, it is considered that a certain regularity occurs in the way the reflected light is seen on the light exit surface according to the high regularity, and this regularity causes the streak of the line to be seen. In addition, when the regularity of the surface shape of the light exit surface is high as in the conventional case, interference and diffraction occur due to the periodic structure of the slope portion of the row, and light is strengthened or weakened by these interference and diffraction. It is thought that this was also one of the reasons for seeing streak lines. On the other hand, if the strips 113 to 116 extending in three or more different directions are provided as in the light emitting element 10, the regularity of the surface shape of the light exit surface 10U is lowered. It is inferred that the rows 113 to 116 can be suppressed from being visually recognized as streaks.

  In addition, in the conventional light emitting element having a concavo-convex structure, when the azimuth angle at which the observer views the light emitting element changes, the appearance of the light emitting surface of the light emitting element, such as the color and brightness, also changes. The appearance of the element sometimes fluctuated greatly. On the other hand, by providing the rows 113 to 116 extending in three or more different directions, in the light emitting element 10 of the present embodiment, the appearance according to the azimuth angle at which the observer normally looks at the light emitting element. It is also possible to suppress fluctuations in As described above, the reason why the change in appearance depending on the azimuth angle at which the observer looks at the light-emitting element can be reduced. However, according to the study by the present inventor, it is assumed that the reason is as follows.

  In the conventional light emitting device, as described above, since the unevenness is often provided only along one or two directions in the orthogonal plane, the optical characteristics observed at the azimuth angle according to the azimuth angle to be observed. (Luminance, color, etc.) are greatly different, and it is thought that the change in appearance due to the azimuth angle is large. On the other hand, when the rows 113 to 116 extending in three or more different directions as in the present embodiment are provided on the light exit surface 10U, the regularity of the concavo-convex structure of the light exit surface 10U is lowered, and from which azimuth angle Even if observed, the optical characteristics do not differ so much, and it is assumed that the appearance by the azimuth is uniform. Further, when the number of the rows 113 to 116 increases, more light is diffused by the rows 113 to 116 than in the prior art, so that such light diffusion is also a factor that can reduce the change in appearance due to the azimuth angle. It is inferred that

  In the case where the light exit surface has a flat surface portion, in the conventional light emitting device, unevenness may be observed on the light exit surface due to interference of light reflected by the flat surface portion. However, when the rows 113 to 116 extending in three or more different directions are provided on the light exit surface 10U as in the present embodiment, the interference by the flat surface portions 113U to 116U and 117B is dispersed, and unevenness due to the interference is expressed. Can be suppressed.

The angle formed by the directions in which the strips 113 to 116 extend may be arbitrarily set as long as the effect of the present invention is not significantly impaired. Specifically, the direction in which each row 113 to 116 extends is usually 4 ° or more, preferably 15 ° or more, more preferably 22.5 ° or more, and usually 176 ° or less, preferably 165 ° or less. More preferably, the crossing is performed so as to form an angle of 157.5 ° or less. Thereby, when there are four groups of lines, the stripes of the lines 113 to 116 can be effectively prevented from being visually recognized. Moreover, normally, the fluctuation | variation of the appearance by the azimuth which an observer looks at a light emitting element can be suppressed effectively.
Moreover, although the case of the 4th row was described here, the direction in which the mth row extends is expressed by a general formula as the Nth row (N represents an integer of 3 or more). When,
A range of 180 ° / N × (m−1) ± 180 ° / 1.1N is preferable,
The range of 180 ° / N × (m−1) ± 180 ° / 1.5N is more preferable,
A range of 180 ° / N × (m−1) ± 180 ° / 2N is particularly preferable.
Here, m represents an integer of 1 or more and N or less. The general formula represents an angle formed by the reference direction and a direction in which the m-th row extends when a certain reference direction is set to an angle of 0 °.

In the present embodiment, as shown in FIG. 4, the first row 113 is formed so as to extend in a first direction Di parallel to the light exit surface 10U. Further, as shown in FIG. 5, the second row 114 extends in a second direction Dii that forms an angle θ ₁ with respect to the first direction Di in which the first row 113 extends. Is formed. Further, as shown in FIG. 6, the third row 115 extends in a third direction Diii that forms an angle θ ₂ with respect to the first direction Di in which the first row 113 extends. Is formed. Furthermore, as shown in FIG. 7, the fourth row 116 extends in a fourth direction Div that forms an angle θ ₃ with respect to the first direction Di in which the first row 113 extends. Is formed. The angles θ _{1 to} θ ₃ may be all greater than 0 ° and less than 180 °, but the stripes 113 to 116 are less likely to be effectively visually recognized, and the direction in which the observer views the light emitting element is difficult. From the viewpoint of effectively suppressing variation in appearance due to corners, the angle is usually 4 ° or more and less than 176 °. However, the angles θ _{1 to} θ ₃ are different from each other, and are preferably different from each other by 4 ° or more as described above. In the present embodiment, θ ₁ is set to 90 °, θ ₂ is set to 45 °, and θ ₃ is set to 135 °.

  The shape of the cross section obtained by cutting the first to fourth rows 113 to 116 with a plane orthogonal to the direction in which the rows 113 to 116 extend may be, for example, a rectangle or a semicircle. From the viewpoints of good drawability and easy forming of the rows 113 to 116, and the objective optical characteristics strongly depending on the angles of the slope portions 113S to 116S, it is preferable that the polygon is a triangle or more. Here, the target optical characteristics strongly depend on the angles of the slopes 113S to 116S. It is easy to collect light when the angles of the slopes 113S to 116S are in the vicinity of 45 °, and light emission from the element is 55 ° or more. It means that it is easy to make the color uniform. Especially, it is preferable that it is a polygon more than a square from a viewpoint of making the row | line | columns 113-116 hard to chip and improving the durability of the uneven structure layer 111. Here, the shape of the cross section of the row means the shape of the concave portion or the convex portion (the convex portion in the present embodiment) constituting the row in the cross section of the row.

  In this embodiment, as shown in FIG. 8, the shape of the cross section obtained by cutting the first to fourth rows 113 to 116 with a plane orthogonal to the direction in which the rows 113 to 116 extend is any Is also a trapezoid (specifically an isosceles trapezoid) that is a square. Therefore, as shown in FIG. 3, each of the first to fourth rows 113 to 116 has flat surface portions 113U to 116U as the most projecting portions, and the flat surface portions 113U to 116U are the upper bases of the trapezoids. It corresponds to. The first to fourth strips 113 to 116 have a pair of slope portions 113S to 116S corresponding to opposite sides of the trapezoid, and the flat surface portions 113U to 116U are the slope portions 113S to 116S. It is to be sandwiched between.

  Here, the “slope portion” is a surface that is inclined with respect to the light exit surface 10U, that is, a surface that forms an angle that is not parallel to the light exit surface 10U. Further, the angle of the slope portion is an angle formed by the slope portion with respect to the light exit surface 10U. On the other hand, the flat surface portions 113U to 116U are flat surfaces parallel to the light exit surface 10U. As described above, the flat surface portions 113U to 116U have an effect of improving the durability of the uneven structure. For example, the light emitted from the organic EL element 140 and repeatedly reflected until taken out in the air in various directions. Reflecting has the effect of increasing the light extraction efficiency. Further, in the slope portions 113S to 116S, light that cannot be extracted by the flat surface portions 113U to 116U out of the light emitted from the organic EL element 140 can be extracted to the outside. Therefore, by providing the slope portions 113S to 116S, the light emitting element is provided. 10 light extraction efficiency can be improved.

As described above, each of the first to fourth rows 113 to 116 includes a plurality of convex portions, and these convex portions are provided at predetermined intervals. For this reason, a recess 117 that is relatively recessed from the surroundings exists between the rows 113 to 116. That is, the light exit surface 10U is provided with a plurality of concave portions 117, and the respective concave portions 117 are discretely formed so as to be separated by the rows 113 to 116.
As shown in FIG. 8, the bottom of the recess 117 is a flat surface portion 117B that is a flat surface parallel to the light exit surface 10U. If dust and debris accumulate in the concave portion 117, the light extraction efficiency may be reduced and bright spots may be generated. However, the bottom of the concave portion 117 is a flat surface portion 117B. In addition, it is possible to make it difficult to collect debris and the like.

  FIG. 9 shows flat surface portions 113U to 116U and 117B in a direction perpendicular to the flat surface portions 113U to 116U and 117B of the slope portions 113S to 116S of the light emitting surface 10U of the light emitting element 10 according to the first embodiment of the present invention. It is a projection figure which shows a mode that it projected on the plane 901 parallel to with respect to. In the present embodiment, the direction perpendicular to the flat surface portions 113U to 116U and 117B coincides with the direction perpendicular to the light exit surface 10U and the direction parallel to the thickness direction of the light emitting element 10. Further, the plane 901 parallel to the flat surface portions 113U to 116U and 117B is a plane parallel to the light exit surface 10U. However, the plane 901 that is parallel to the flat surface portions 113U to 116U and 117B is not a plane that the light emitting element 10 has, but a projection plane that is set to measure the projected areas of the slope portions 113S to 116S. In addition, in FIG. 9, the inclined surfaces 113S to 116S of the light emitting surface 10U of the light emitting element 10 are arranged in a plane perpendicular to the flat surface portions 113U to 116U and 117B and parallel to the flat surface portions 113U to 116U and 117B. A projected image 902 projected onto the head is shown with diagonal lines.

  As shown in FIG. 9, in the light emitting element 10 of this embodiment, the slope portions 113S to 116S are parallel to the flat surface portions 113U to 116U and 117B in a direction perpendicular to the flat surface portions 113U to 116U and 117B. The projected area formed by projecting onto the plane 901 is usually 0.1 times or less, preferably 0.05 times or less, more preferably 0.01 times or less of the total area of the flat surface portions 113U to 116U and 117B. is there. In addition, the lower limit of the ratio of the projected area of the slope portions 113S to 116S to the total area of the flat surface portions 113U to 116U and 117B is usually 0.0001 times or more, preferably 0.0005 times or more, more preferably 0.001 times or more. It is.

  Thereby, the other side of the light emitting element 10 can be seen. When the uneven structure provided in the conventional single-sided light emitting device is applied to the double-sided light emitting device, the haze increases due to the increase in the ratio of the slope portion, and the other side of the light emitting device cannot be seen. On the other hand, when the ratio of the projected area of the inclined surface portions 113S to 116S to the total area of the flat surface portions 113U to 116U and 117B is within the above range, the uneven structure when viewed from the direction perpendicular to the light exit surface 10U. The improvement of haze can be suppressed. Therefore, according to the light emitting device 10 of the present embodiment, the haze increase can be suppressed while having the concavo-convex structure, so that see-through is not impaired.

  Furthermore, as shown in FIG. 8, the maximum value of the height difference H between the flat surface portions 113U to 116U and 117B on the light exit surface 10U is preferably 22 μm or less, and may be 21.5 μm or less or 21.0 μm or less. The lower limit is usually 0.1 μm or more, and may be 0.15 μm or more or 0.2 μm or more. Here, the height difference means a distance in the thickness direction. Therefore, the height difference H between the flat surface portions 113U to 116U and the flat surface portion 117B in the present embodiment means the height of the convex portions included in the first to fourth rows 113 to 116, and It means depth.

  By keeping the maximum value of the height difference H of the flat surface portions 113U to 116U and 117B within such a range, the light emitting element 10 can be seen even when viewed from a direction (oblique direction) inclined with respect to the normal direction of the light exit surface 10U. You can see the other side. When the area ratio of the slope portions 113S to 116S is large, the haze tends to increase when the light exit surface 10U is viewed from an oblique direction. On the other hand, the ratio of the projected area of the slope portions 113S to 116S to the total area (total area) of the flat surface portions 113U to 116U and 117B is within the above range, and the height difference H of the flat surface portions 113U to 116U and 117B is When the maximum value falls within the above range, improvement in haze when viewed from an oblique direction can be suppressed, so that see-through can be prevented from being impaired even when the light emitting element 10 is viewed from an oblique direction.

  As shown in FIG. 8, the slope portions 113S to 116S are usually 80 ° or more, preferably 81 ° or more, more preferably 82 ° or more, and usually less than 90 °, with respect to the flat surface portions 113U to 116U and 117B. Preferably, it is inclined at an inclination angle φ of 89 ° or less, more preferably 88 ° or less. That is, the slope portions 113S to 116S are all surfaces that are not parallel to the flat surface portions 113U to 116U and 117B. It is preferable to be within the range. Thus, since the inclination angle φ of the slope portions 113S to 116S is large, the light extraction efficiency can be stably increased. In addition, when the inclination angle φ is large, the projected area per one of the slope portions 113S to 116S can be reduced as compared with the case where the inclination angle φ is small, and thus light emission occurs when viewed from the thickness direction perpendicular to the light exit surface 10U. The other side of the element 10 is more clearly visible. The thickness direction perpendicular to the light emitting surface 10U corresponds to the front direction of the light emitting element 10, and since it is normally assumed that the frequency of looking through the light emitting element 10 from the front direction is high, the above advantages are practically useful. It is.

  Moreover, in this embodiment, although inclination-angle (phi) of all the slope parts 113S-116S is set to the same magnitude | size, it does not specifically limit and may differ.

  The thickness T of the concavo-convex structure layer 111 is preferably in an appropriate range in relation to the maximum value of the height difference H of the flat surface portions 113U to 116U and 117B. For example, in the case where a hard material advantageous for maintaining the durability of the uneven structure layer 111 is used as the material of the uneven structure layer 111, the flexibility of the light emitting element 10 is improved by reducing the thickness T of the uneven structure layer 111. This makes it possible to easily handle the uneven structure layer 111 in the manufacturing process of the light emitting element 10, which is preferable. Specifically, the difference between the maximum value of the height difference H of the flat surface portions 113U to 116U and 117B and the thickness T of the uneven structure layer 111 is preferably 0 to 30 μm.

  In the first to fourth strips 113 to 116, the dimensions such as the width W and the pitch P of the concave portions or the convex portions included in the respective strips 113 to 116 are arbitrary as long as the effects of the present invention are not significantly impaired. . For example, the width W is usually 1 μm or more, preferably 2 μm or more, and is usually 60 μm or less, preferably 50 μm or less. Furthermore, the pitch P is usually 0.5 μm or more, preferably 1 μm or more, and is usually 2 mm or less, preferably 1 mm or less.

In each of the concave portions or the convex portions included in the first to fourth rows 113 to 116, the height (that is, the height difference between the flat surface portions 113U to 116U and 117B) H, the width W, the pitch P, and the like are constant. For example, it may change according to the position in the extending direction. In this embodiment, the dimension of a convex part shall be constant in the extension direction in any row 113-116.
Moreover, the dimension of the recessed part or convex part contained in the same row | line | column 113-116 may be the same, and may differ. In the present embodiment, the dimensions of the convex portions included in the same row 113 to 116 are all constant.
Furthermore, the dimension of the recessed part or convex part contained in different rows 113-116 may be the same, and may differ. In this embodiment, the height H and the width W of the convex portions are constant in any of the rows 113 to 116. The size of the pitch P is adjusted so that any of the third row 115 and the fourth row 116 pass through the point where the first row 113 and the second row 114 intersect. . For this reason, the shape of the concave portion 117 viewed from the thickness direction is the same in any concave portion 117, and the flat surface portion 117B at the bottom of each concave portion 117 is triangular.

(Description of the material of the multilayer)
The light exit surface structure layer 100 may be composed of a plurality of layers, but may be composed of a single layer. From the viewpoint of easily obtaining the light-emitting surface structure layer 100 having desired characteristics, it is preferable that the light-emitting surface structure layer 100 is composed of a plurality of layers. In the present embodiment, as shown in FIG. 1, the light exit surface structure layer 100 includes a multilayer body 110 in which an uneven structure layer 111 and a base film layer 112 are combined. Thereby, the light emission surface structure layer 100 with high performance can be obtained easily.

  The concavo-convex structure layer 111 and the base film layer 112 are usually formed of a resin composition containing a transparent resin. Here, that the transparent resin is “transparent” means having a light transmittance suitable for use in an optical member. In the present embodiment, each layer constituting the light exit surface structure layer 100 may have a light transmittance suitable for use in an optical member. For example, the light exit surface structure layer 100 as a whole has a total light transmittance of 80% or more. It is good also as what has a rate.

  The transparent resin is not particularly limited, and various resins that can form a transparent layer may be used. Examples thereof include a thermoplastic resin, a thermosetting resin, an ultraviolet curable resin, and an electron beam curable resin. Among these, thermoplastic resins are preferable because they can be easily deformed by heat, and ultraviolet curable resins have high curability and high efficiency, so that the uneven structure layer 111 can be efficiently formed.

  Examples of the thermoplastic resin include polyester-based, polyacrylate-based, and cycloolefin polymer-based resins. In addition, examples of the ultraviolet curable resin include epoxy resins, acrylic resins, urethane resins, ene / thiol resins, isocyanate resins, and the like. As these resins, those having a plurality of polymerizable functional groups can be preferably used. In addition, the said resin may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

  Among them, the material of the concavo-convex structure layer 111 constituting the multilayer body 110 is a material having a high hardness at the time of curing from the viewpoint of easily forming the concavo-convex structure of the light exit surface 10U and easily obtaining scratch resistance of the concavo-convex structure. Is preferred. Specifically, when a resin layer having a film thickness of 7 μm is formed on a substrate without a concavo-convex structure, a material having a pencil hardness of HB or higher is preferable, and a material of H or higher is more preferable. The material which becomes 2H or more is more preferable. On the other hand, as the material of the base film layer 112, in order to facilitate the handling when forming the concavo-convex structure layer 111 and the handling of the multilayer body 110 after forming the multilayer body 110, a certain degree of flexibility is provided. There are preferred. By combining such materials, the multilayer body 110 that is easy to handle and excellent in durability can be obtained, and as a result, the high-performance light-emitting element 10 can be easily manufactured.

  Such a combination of materials can be obtained by appropriately selecting the transparent resin exemplified above as the resin constituting each material. Specifically, as the transparent resin constituting the material of the concavo-convex structure layer 111, for example, an ultraviolet curable resin such as acrylate is used, while as the transparent resin constituting the material of the base film layer 112, for example, an alicyclic olefin It is preferable to use a polymer film (for example, ZEONOR film manufactured by Nippon Zeon Co., Ltd.) or a polyester film.

  When the light-emitting surface structure layer 100 includes the concavo-convex structure layer 111 and the base film layer 112 as in the present embodiment, the refractive index of the concavo-convex structure layer 111 and the base film layer 112 may be as close as possible. . In this case, the refractive index difference between the uneven structure layer 111 and the base film layer 112 is preferably within 0.1, and more preferably within 0.05.

  As a material of a layer that is a constituent element of the light exit surface structure layer 100 such as the uneven structure layer 111 and the base film layer 112, a material having light diffusibility may be used as long as the see-through property is not hindered. Thereby, it is possible to diffuse the light transmitted through the light exit surface structure layer 100 while maintaining the see-through property, and it is possible to further reduce the change in color depending on the observation angle.

  Examples of the light diffusing material include a material containing particles, and an alloy resin that diffuses light by mixing two or more kinds of resins. Among these, from the viewpoint that the light diffusibility can be easily adjusted, a material including particles is preferable, and a resin composition including particles is particularly preferable.

  The particles may be transparent or opaque. Examples of the material of the particles include metals and metal compounds, and resins. Examples of the metal compound include metal oxides and nitrides. Specific examples of metals and metal compounds include metals having high reflectivity such as silver and aluminum; metal compounds such as silicon oxide, aluminum oxide, zirconium oxide, silicon nitride, tin-added indium oxide, and titanium oxide. be able to. On the other hand, examples of the resin include methacrylic resin, polyurethane resin, and silicone resin. In addition, the particle | grain material may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

The shape of the particles can be, for example, a spherical shape, a cylindrical shape, a needle shape, a cubic shape, a rectangular parallelepiped shape, a pyramid shape, a conical shape, a star shape, or the like.
The particle diameter of the particles is preferably 0.1 μm or more, preferably 10 μm or less, more preferably 5 μm or less. Here, the particle diameter is a 50% particle diameter in an integrated distribution obtained by integrating the volume-based particle amount with the particle diameter as the horizontal axis. The larger the particle size, the larger the content ratio of particles necessary for obtaining the desired effect, and the smaller the particle size, the smaller the content. Therefore, as the particle size is smaller, desired effects such as a reduction in change in color depending on the observation angle and an improvement in light extraction efficiency can be obtained with fewer particles. When the particle shape is other than spherical, the diameter of the sphere having the same volume is used as the particle size.

  In the case where the particles are transparent particles and the particles are contained in the transparent resin, the difference between the refractive index of the particles and the refractive index of the transparent resin is preferably 0.05 to 0.5. More preferably, it is 07-0.5. Here, either the particle or the refractive index of the transparent resin may be larger. If the refractive index of the particles and the transparent resin is too close, the diffusion effect cannot be obtained and the color unevenness may be difficult to be suppressed. Conversely, if the difference is too large, the diffusion becomes large and the color unevenness is suppressed, but light Extraction effect may be reduced.

  The content ratio of the particles is a volume ratio in the total amount of the layer containing the particles, preferably 1% or more, more preferably 5% or more, 80% or less, and more preferably 50% or less. By setting the content ratio of the particles to be equal to or higher than the lower limit, desired effects such as reduction of a change in color depending on the observation angle can be obtained. Moreover, by setting it as this upper limit or less, aggregation of particle | grains can be prevented and particle | grains can be disperse | distributed stably.

  Furthermore, the resin composition may contain arbitrary components as necessary. Examples of the optional component include additives such as phenol-based and amine-based degradation inhibitors; surfactant-based, siloxane-based antistatic agents; triazole-based, 2-hydroxybenzophenone-based light-resistant agents; Can be mentioned.

The thickness T of the uneven structure layer 111 is not particularly limited, but is preferably 1 μm to 70 μm. In the present embodiment, the thickness T of the concavo-convex structure layer 111 is a distance between the surface on the base film layer 112 side where the concavo-convex structure is not formed and the flat surface portions 113U to 116U of the concavo-convex structure.
Moreover, it is preferable that the thickness of the base film layer 112 is 20 micrometers-300 micrometers.

(Support substrate)
The light emitting element 10 of this embodiment includes a support substrate 131 between the organic EL element 140 and the multilayer body 110. By providing the support substrate 131, the light emitting element 10 can be given rigidity for suppressing deflection. Further, the supporting substrate 131 is provided with a substrate that is excellent in the performance of sealing the organic EL element 140 and that can easily form the layers constituting the organic EL element 140 on the manufacturing process in order. As a result, the durability of the light emitting element 10 can be improved and the manufacture can be facilitated.

As a material constituting the support substrate 131, a transparent material is usually used. Examples of the material include glass and resin. In addition, the material of the support substrate 131 may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
The refractive index of the support substrate 131 is not particularly limited, but is preferably 1.4 to 2.0.
The thickness of the support substrate 131 is not particularly limited, but is preferably 0.1 mm to 5 mm.

(Adhesive layer)
The light emitting element 10 of this embodiment includes an adhesive layer 121 between the multilayer body 110 and the support substrate 131. The adhesive layer 121 is a layer that is interposed between the base film layer 112 of the multilayer body 110 and the support substrate 131 and adheres these two layers.
The adhesive that is the material of the adhesive layer 121 is not only a narrowly defined adhesive (a so-called hot melt type adhesive having a shear storage modulus of 1 to 500 MPa at 23 ° C. and not exhibiting tackiness at room temperature), A pressure-sensitive adhesive having a shear storage modulus at 23 ° C. of less than 1 MPa is also included. Specifically, a material having a refractive index close to that of the support substrate 131 or the base film layer 112 and transparent can be used as appropriate. More specifically, an acrylic adhesive or a pressure-sensitive adhesive can be used. The thickness of the adhesive layer is preferably 5 μm to 100 μm.

(Sealing substrate)
The light emitting element 10 of the present embodiment includes a sealing substrate 151 on the light emitting surface 145. The sealing substrate 151 may be provided so as to be in direct contact with the light emitting surface 145. Further, an arbitrary substance such as a filler or an adhesive may be present between the light emitting surface 145 and the sealing substrate 151, or a gap may be present. As long as there is no inconvenience such as greatly impairing the durability of the light emitting layer 142, air or other gas may be present in the space, or the space may be evacuated.

  As the sealing substrate 151, any member that can seal the organic EL element 140 and transmits light emitted from the light emitting surface 145 can be used. For example, a member similar to the support base 131 can be used.

(Production method)
Although the manufacturing method of the light emitting element 10 is not particularly limited, for example, each layer constituting the organic EL element 140 is laminated on one surface of the support substrate 131, and after or before that, the other surface of the support substrate 131 is uneven. You may manufacture by sticking the multilayer body 110 which has the structure layer 111 and the base film layer 112 through the contact bonding layer 121. FIG.

For the production of the multilayer body 110 having the concavo-convex structure layer 111 and the base film layer 112, for example, a mold such as a mold having a desired shape is prepared, and this mold is a layer of a material for forming the concavo-convex structure layer 111. You may carry out by transferring to. As a more specific method, for example,
(Method 1) An unprocessed multilayer having a layer of the resin composition A constituting the base film layer 112 and a layer of the resin composition B constituting the concavo-convex structure layer 111 (the concavo-convex structure is not yet formed) A method for preparing and forming a concavo-convex structure on the surface of the raw multilayer body on the resin composition B side; and (Method 2) applying the resin composition B in a liquid state on the base film layer 112 Then, a method may be mentioned in which a mold is applied to the applied layer of the resin composition B, the resin composition B is cured in that state, and the concavo-convex structure layer 111 is formed.

In Method 1, the raw multilayer body may be obtained by, for example, extrusion molding in which the resin composition A and the resin composition B are coextruded. An uneven structure can be formed by pressing a mold having a desired surface shape onto the surface of the unprocessed multilayer body on the resin composition B side.
More specifically, a long raw multilayer body is continuously formed by extrusion molding, and the raw multilayer body is pressed with a transfer roll and a nip roll having a desired surface shape, thereby continuously. Manufacturing can be performed efficiently. The pinching pressure between the transfer roll and the nip roll is preferably several MPa to several tens of MPa. The temperature at the time of transfer is preferably Tg or more (Tg + 100 ° C.) or less, where Tg is the glass transition temperature of the resin composition B. The contact time between the unprocessed multilayer body and the transfer roll can be adjusted by the film feed speed, that is, the roll rotation speed, and is preferably 5 seconds or more and 600 seconds or less.

  In Method 2, as the resin composition B constituting the concavo-convex structure layer 111, it is preferable to use a composition that can be cured by energy rays such as ultraviolet rays. The resin composition B is applied on the base film layer 112, and in a state where the mold is applied, the resin composition B is located on the back side of the application surface (the side opposite to the surface on which the resin composition B is applied). By irradiating energy rays such as ultraviolet rays from a light source, curing the resin composition B, and then peeling the mold, the coating film of the resin composition B can be used as the concavo-convex structure layer 111 to obtain a multilayer body 110. it can.

(Main advantages of light-emitting elements)
Since the light emitting element 10 of the present embodiment is configured as described above, light emitted from the light emitting surface 144 of the organic EL element 140 is transmitted through the light emitting surface structure layer 100 and extracted through the light emitting surface 10U. In addition, the light emitted from the light emitting surface 145 passes through the sealing substrate 151 and is extracted through the light emitting surface 10D.

  At this time, since the light exit surface 10U has a concavo-convex structure including the first to fourth strips 113 to 116 and the concave portion 117, even if the light cannot be extracted from the flat surface portions 113U to 116U and 117B, the slope portions 113S to 116S. Therefore, the light extraction efficiency through the light exit surface 10U can be increased as compared with the case without the uneven structure.

  Moreover, when the light-emitting element 10 is observed by having a concavo-convex structure including three or more groups of rows 113 to 116 extending in different directions on the light emitting surface 10U, the first to fourth rows 113 to 116 are observed. It is possible to prevent the streaks from being visually recognized, and consequently to prevent lattice unevenness.

  In addition, since the light emitting element 10 has the first to fourth rows 113 to 116 on the light exit surface 10U, usually, the change in appearance due to the azimuth angle at which the observer views the light emitting element is small.

  These effects can be achieved if there are at least three groups of rows, but it is considered that a remarkable effect can be obtained if there are more rows, so rather than providing only three groups of rows. It is preferable to have four or more rows as in the present embodiment. In addition, since a sufficient effect can be obtained without excessively increasing the number of groups in the row, the number of rows in the eight groups or less may be usually provided.

  Furthermore, since all the layers included in the light emitting element 10 are transparent, in the light emitting element 10, the light incident on one light exit surface 10U can pass through the light emitting element 10 and exit through the other light exit surface 10D. In addition, the light incident on the other light exit surface 10D can be transmitted through the light emitting element 10 and emitted through one light exit surface 10U. Furthermore, in this embodiment, since the ratio of the projection area of slope part 113S-116S with respect to the total area of flat surface part 113U-116U and 117B is contained in the predetermined range, haze can be suppressed. Therefore, the opposite side can be clearly seen through the light emitting element 10 with the naked eye, and a see-through type light emitting element can be realized.

  Specifically, the light emitting element 10 as a whole has a total light transmittance of 60% or more, preferably 70% or more, more preferably 80% or more as a whole. The upper limit is ideally 100%, but is usually 90% or less.

  Furthermore, since the shape of the concavo-convex structure is appropriately set in the light emitting element 10, the haze of the light emitting element 10 is generally 10% or less, preferably 8% or less, more preferably 6% or less as the whole light emitting element 10. It is a small value. The lower limit value is ideally zero, but is usually 0.1% or more.

  Furthermore, in the light emitting element 10 according to the present embodiment, it is possible to prevent the light exit surface 10U from being chipped due to an external impact, thereby improving the mechanical strength of the light exit surface 10U. In general, when a surface has a concavo-convex structure, when an impact is applied to the surface, the force concentrates on a part of the concavo-convex structure and tends to cause breakage. However, the light emitting element 10 according to the present embodiment has the flat surface portions 113U to 116U at the outermost position in the thickness direction. For this reason, it is possible to prevent the force from being concentrated on a part of the concavo-convex structure layer 111 due to the force or impact applied to the light exit surface 10U from the outside. The mechanical strength of 10 can be increased. Therefore, damage to the concavo-convex structure layer 111 can be prevented, and both good light extraction efficiency and high mechanical strength of the light output surface 10U of the light emitting element 10 can be achieved at the same time.

[2. Second embodiment]
In the first embodiment, since the height difference H between the flat surface portions 113U to 116U and 117B on the same light exit surface 10U is made constant, the uneven structure of the light exit surface 10U has two different heights. However, in the light emitting device of the present invention, the uneven structure on the light exit surface may have three or more different heights by making the height difference H uneven, for example.
At this time, it is preferable that the height of the concavo-convex structure is different from each other by 0.1 μm or more regardless of which height is compared. When the uneven structure of the light exit surface has three or more heights different by 0.1 μm or more, the uneven structure of the light exit surface is one or both of the outgoing light that exits through the light exit surface and the reflected light that is reflected by the light exit surface. It will have a dimensional difference that exceeds the difference that causes interference. Thereby, the rainbow nonuniformity by interference of the one or both of the said emitted light and reflected light can be suppressed effectively. Here, the rainbow unevenness means a rainbow-like color unevenness observed when the light exit surface is viewed. Further, the height difference of the concavo-convex structure may be, for example, 0.15 μm or more or 0.2 μm or more in addition to 0.1 μm or more. The upper limit of the height difference of the concavo-convex structure is not particularly limited, but if it is too large, the light emitting element tends to be thick. Therefore, the upper limit of the height difference of the concavo-convex structure is preferably 50 μm or less, for example, 25 μm. Or may be 10 μm or less.

Here, the height of the concavo-convex structure means the position in the thickness direction of the light exit surface other than the slope portion, and usually the position in the thickness direction of the most protruding portion of the convex portion included in the row, and the row The position in the thickness direction of the bottom of the recessed part provided between the convex parts contained in is said. In addition, the outgoing light emitted through the light emitting surface is not only the light emitted from the organic EL element, but also enters the light emitting element through the light emitting surface, is reflected inside the light emitting element, and is again emitted. Also includes light that exits through.
Hereinafter, the example is demonstrated using drawing.

  FIG. 10 shows the light emitting device 20 according to the second embodiment of the present invention, in which the first row 113 extends through the point where the third row 115 and the fourth row 116 intersect and the recess 117. It is sectional drawing which shows typically the cross section cut | disconnected by the surface perpendicular | vertical with respect to the light emission surface 10U including a line parallel to a direction. In addition, in 2nd embodiment, the element similar to 1st embodiment is shown with the code | symbol similar to 1st embodiment.

As shown in FIG. 10, the light emitting element 20 according to the second embodiment of the present invention includes the height of the convex portions included in the first row 113 (see FIG. 1) and the second row 114, and the third row. Except that the heights of the convex portions included in the first row 115 and the fourth row 116 are different, the light emitting element 10 according to the first embodiment has the same configuration. Specifically, the height of the convex portion included in the third row 115 and the fourth row 116 is higher than the height of the convex portion included in the first row 113 and the second row 114. It is low. Thereby, as the height of the concavo-convex structure of the light exit surface 10U, the position T _I in the thickness direction of the flat surface portion 117B at the bottom of the recess 117, the flat surface portion 115U of the third row 115 and the flatness of the fourth row 116 are obtained. There are three positions T _{II in} the thickness direction of the surface portion 116 U, and a position T _{III in} the thickness direction of the flat surface portion 113 U of the first row 113 and the flat surface portion 114 U of the second row 114.

Moreover, the height of the convex part contained in the 3rd row | line 115 and the 4th row | line 116 is set to 0.1 micrometer or more. Furthermore, the difference between the height of the convex portion included in the first row 113 and the second row 114 and the height of the convex portion included in the third row 115 and the fourth row 116 is also 0. It is set to 1 μm or more. Accordingly, the three heights T _{I to} T _III of the uneven structure of the light exit surface 10U are different from each other by 0.1 μm or more.

In this case, the difference between the three heights T _{I to} T _III of the concavo-convex structure of the light exit surface 10U is a dimensional difference of the concavo-convex structure exceeding the difference that causes interference of one or both of the emitted light and the reflected light. Unevenness can be suppressed. That is, interference of the emitted light and reflected light at the flat surface portions 113U and 114U, the flat surface portions 115U and 116U, and the flat surface portion 117B located at different heights can be suppressed, and rainbow unevenness can be effectively suppressed. At this time, the dimensional difference T _III -T _II and T _II -T _I of the above, but exhibits the effects even by the size difference exceeding the difference resulting in interference of the emitted light, typically reflective than the emitted light Since the light tends to have a greater influence on the rainbow unevenness, a remarkable effect is exhibited by the dimensional difference exceeding the difference that causes interference of reflected light.

  The dimensional difference exceeding the difference that causes the interference is, for example, interference of outgoing light emitted from the organic EL element 140, for example, usually 0.62 times or more of the center wavelength of outgoing light, preferably 1 Dimensional difference more than 5 times. By providing this dimensional difference, the occurrence of rainbow unevenness can be suppressed. The upper limit of the dimensional difference is not particularly limited, but is preferably 60 times or less of the center wavelength of the emitted light.

  The above numerical range is confirmed from the knowledge shown below. In other words, in a structural layer designed in such a manner that all the depths of the recesses are made uniform, if an error of 170 nm or more occurs in the depth of the recesses, interference occurs and rainbow unevenness appears. It has been found that the generation of rainbow unevenness can be suppressed by daringly providing a dimensional difference that is twice or more the minimum value. Further, in the structure layer designed in such a manner that all the depths of the recesses are made uniform, if a variation of σ1 nm (≈60 nm) with a standard deviation occurs in the depth of the recesses, interference occurs and rainbow unevenness appears. = 360 nm) It is known that the generation of rainbow unevenness can be suppressed by intentionally providing a dimensional difference of not less than 360 nm. Based on the above two findings, it can be shown that the dimensional difference exceeding the difference that causes interference of the emitted light is 0.62 or more times the center wavelength of the light emitted from the light emitting element.

  For the same reason, in the interference between transmitted light and reflected light, the dimensional difference exceeding the difference that causes interference is usually 0.62 times or more, preferably 1.5 times or more the center wavelength of transmitted light and reflected light. And a dimensional difference of usually 60 times or less. However, normally, since transmitted light and reflected light are natural light and include light having an arbitrary wavelength, it is difficult to determine the center wavelength of the reflected light. Therefore, in view of the fact that the light that causes rainbow unevenness is visible light, the dimensional difference may be set as the center wavelength of light that normally reflects the center wavelength of visible light at 550 nm.

Even when the concavo-convex structure has three or more heights T _I , T _II and T _III different from each other by 0.1 μm or more as in the present embodiment, the same advantages as those of the first embodiment can be obtained. When the heights H of the convex portions included in all the rows 113 to 116 can be made uniform as in the first embodiment, rainbow unevenness due to interference is unlikely to occur, but in an actual product, manufacturing such as temperature and humidity It may be difficult to make the height H of the convex portions included in the rows 113 to 116 highly uniform due to a change in the conditions. Therefore, by making the uneven structure positively have different heights T _I , T _II and T _III as described above, rainbow unevenness can be more easily suppressed.

  Moreover, the same effect can be obtained even when the dimensional difference is provided in the elements other than the height of the concavo-convex structure. For example, if there is a dimensional difference in one or more elements of the group of elements such as the height, width, and pitch of the row, rainbow unevenness can be similarly suppressed.

[3. Third Embodiment]
In the first and second embodiments described above, the example in which the light emitting surface structure layer is disposed on one light emitting surface of the two light emitting surfaces of the organic EL element has been described. However, the light emitting surface structure layer is disposed on both light emitting surfaces. May be. Hereinafter, the example is demonstrated using drawing.

FIG. 11 is a perspective view schematically showing a light emitting device according to the third embodiment of the present invention. In the third embodiment, the same elements as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment.
As shown in FIG. 11, the light emitting element 30 according to the third embodiment is the same as the light emitting element 10 according to the first embodiment except that the light emitting surface structure layer 100 is provided instead of the sealing base material 151. Accordingly, the light emitting element 30 includes the light emitting surface structure layer 100 on both of the two light emitting surfaces 144 and 145 of the organic EL element 140. Therefore, the light emitting element 30 has an uneven structure on both of the two light exit surfaces 10U. In the present embodiment, the two light exit surfaces are provided with the uneven structure layer having the same shape. However, the present invention is not necessarily limited to such a form, and the shape of the uneven structure on one light output surface and the other The shape of the concavo-convex structure on the light exit surface may be different. In addition, an arbitrary substance such as a filler or an adhesive may exist between the light emitting surface structure layer 100 on the lower side in the drawing and the second electrode 143, and a void exists. Also good. As long as there is no inconvenience such as greatly impairing the durability of the light emitting layer 142, air or other gas may be present in the space, or the space may be evacuated.

  Since the light emitting element 30 of the present embodiment is configured as described above, the light emitted from the light emitting surface 144 of the organic EL element 140 is emitted through the light emitting surface 10U on the upper side in the drawing and emitted from the light emitting surface 145. The light exits through the lower exit surface 10U in the figure. At this time, light can be extracted with high efficiency while maintaining see-through. Further, it is possible to prevent the streaks of the first to fourth rows 113 to 116 from being visually recognized on both of the two light exit surfaces 10U. Furthermore, the same effect as the first embodiment can be obtained.

[4. Others]
As mentioned above, although embodiment of this invention was described, this invention is not limited to embodiment mentioned above, You may implement it further changing.
For example, although the light emitting surface structure layer 100 is provided so as to be in direct contact with the light emitting surface 144 in the above-described embodiment, the light emitting surface structure layer 100 may be provided on the light emitting surface 144 via another layer. Examples of the other layers include a gas barrier layer that protects the organic EL element 140 from the outside air and moisture, and an ultraviolet cut layer that blocks ultraviolet rays.

  Further, for example, in the above-described embodiment, the light exit surface structure layer 100 includes the uneven structure layer 111, the base film layer 112, the adhesive layer 121, and the support substrate 131. These layers may be composed of fewer layers than these, or conversely may include any layers in addition to these layers. For example, a coating layer may be further provided on the surface of the concavo-convex structure layer 111, and this may define the concavo-convex structure of the light exit surface U10.

  Further, for example, in the above-described embodiment, any third row 115 and fourth row 116 pass through a point where the first row 113 and the second row 114 intersect. Thus, the first to fourth rows 113 to 116 intersect each other at one intersection, but the first to fourth rows 113 to 116, for example, as in the light emitting element 40 shown in FIG. It is possible not to intersect at one intersection. As a specific example, the pitch of any row may be made nonuniform, or the position or extending direction of the row may be shifted from the above-described embodiment. Thereby, the regularity of the light emission surface 10U can be reduced more and it can suppress more effectively that the stripe of the 1st-4th strips 113-116 is visually recognized. FIG. 12 is a plan view schematically showing an enlarged view of the light emitting surface 10U of the light emitting element 40 according to the modification of the first embodiment of the present invention as viewed from the thickness direction of the light emitting element 40. FIG. In FIG. 12, the same elements as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment.

Further, for example, in the above-described embodiment, the first to fourth rows 113 to 116 each include a protruding portion that protrudes from the surroundings, but the first to fourth rows are from the surroundings. Also, it may include a depressed recess. Moreover, the row | line | column which consists of a convex part, and the row | line | column which consists of a recessed part may coexist on the same light-emitting surface.
Further, for example, the concave portions or the convex portions included in the first to fourth rows may be formed in a shape with rounded corners.
Further, for example, the slope portion may be a curved surface.

  Furthermore, the number, position, extending direction and length of the rows provided on the light exit surface, and combinations thereof are not limited to the above-described embodiments. For example, as shown in FIG. 13, strips 413, 414, and 415 of the same length intersecting at an angle of 120 ° are provided on the light exit surface 410U so as to form a regular hexagon when viewed from the thickness direction. Rows 416 and 417 intersecting the columns 413, 414 and 415 may be provided. For example, as shown in FIG. 14, the rows 513 and 514 intersecting at a certain angle are provided on the light exit surface 510U so as to form a parallelogram when viewed from the thickness direction, and these rows 513 and 514 are further provided. Rows 515 and 516 intersecting with each other may be provided. Further, for example, as shown in FIG. 15, strips 613, 614, and 615 having the same length intersecting at an angle of 60 ° are provided on the light exit surface 610U so as to form an equilateral triangle when viewed from the thickness direction. Rows 616 and 617 that intersect the rows 614, 614, and 615 may be provided. Even such a complicated arrangement of rows can be formed by using a technique such as etching.

  Moreover, in 2nd embodiment, the convex part contained in the 1st row | line | column 113 and the 2nd row | line | column 114 is made high, and the convex part contained in the 3rd row | line 115 and the 4th row | line 116 is used. Although the height is made lower so that the uneven structure of the light exit surface 10U has a different height, the uneven structure of the light output surface 10U may have a different height by other configurations. For example, only the convex portions included in the first strip 113 may be increased, and the convex portions included in the second to fourth strips 114 to 116 may be decreased. Further, for example, the position in the thickness direction of the flat surface portion 117B at the bottom of the concave portion 117 is made non-uniform so that the position of the flat surface portion 117B at the bottom of one concave portion 117 and the position of the flat surface portion 117B at the bottom of another concave portion 117 The thickness direction may differ by 0.1 μm or more. Further, for example, the height of the convex portions belonging to the same row is made non-uniform, or the height of a certain convex portion is made non-uniform in the extending direction, so that the height of the uneven structure of the light exit surface 10U is different. You may give it.

[5. Lighting equipment and backlight device]
The light emitting device of the present invention may be used for applications such as lighting equipment and backlight devices.
The luminaire includes the light-emitting element of the present invention as a light source, and further includes optional components such as a member for holding the light source and a circuit for supplying power as necessary.
Further, the backlight device includes the light-emitting element of the present invention as a light source, and further includes a casing, a circuit for supplying power, a diffusion plate, a diffusion sheet, and a prism for making light emitted more uniform as necessary. Including optional components such as sheets. Applications of the backlight device include a display device such as a liquid crystal display device that displays an image by controlling pixels, and a backlight of a display device that displays a fixed image such as a signboard.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the following examples, and can be arbitrarily changed without departing from the gist of the present invention and the equivalent scope thereof. May be implemented. In addition, the refractive index of the resin described in the following description represents the refractive index after curing. Further, “parts” and “%” indicating amounts are based on weight unless otherwise specified. Further, the operations described below were performed under normal temperature and normal pressure conditions unless otherwise specified. An azimuth angle direction refers to a direction parallel to the surface on which the concavo-convex structure is formed.

[Example 1]
(Manufacture of multilayers)
UV film composed mainly of urethane acrylate on a roll-shaped film substrate (trade name “ZEONOR FILM”, Nippon Zeon Co., Ltd., alicyclic structure-containing polymer resin film, thickness 100 μm, refractive index 1.53) A cured resin (refractive index of 1.54) was applied to form a coating film, and a metal mold was pressed onto the coating film. In this state, ultraviolet rays were irradiated at 1.5 mJ / cm ² to cure the coating film, thereby forming an uneven structure layer (thickness 25 μm) having an uneven structure. The metal mold for forming the concavo-convex structure was prepared by cutting in three azimuth directions using a cutting tool having an apex angle of 5 ° and a tip width of 50 μm.

The three azimuth directions were 0 °, 45 °, and 90 °.
Cutting in the direction of azimuth angle 0 ° was performed with a cutting pitch of 200 μm and a groove depth of 19.4 μm, 19.7 μm, 20.0 μm, 20.3 μm, and 20.6 μm, and random for each groove.
In the azimuth angle 45 ° direction and 90 ° direction cutting, the cutting pitch was 400 μm, and the groove depth was constant at 20.0 μm.

  16 is a perspective view schematically showing a part of the concavo-convex structure layer obtained in Example 1 as viewed obliquely, and FIG. 17 shows a part of the concavo-convex structure layer obtained in Example 1. It is a top view which shows typically a mode that it saw from the thickness direction. As shown in FIGS. 16 and 17, the surface of the obtained concavo-convex structure layer was formed with a concavo-convex structure having a number of convex portions having a trapezoidal cross section corresponding to the grooves formed in the metal mold. On the surface of the concavo-convex structure layer on which the concavo-convex structure was formed, the average inclination angle of the inclined portion with respect to the flat surface portion was 87.5 °. Further, the ratio of the projected area of the slope portion to the total area (total area) of the flat surface portion was 0.03, and the maximum height difference of the flat surface portion was 20.6 μm.

(Manufacture of transparent organic EL elements)
A hole injection layer, a hole transport layer, a light emitting layer, a hole blocking layer, a charge generation layer, a metal oxide layer, and a cathode were formed in this order on a glass substrate having a transparent electrode layer formed on the main surface. The material and film thickness for forming each layer are as follows.

-Transparent electrode layer: ITO 300nm
Hole injection layer: Molybdenum trioxide (MoO ₃ ) 5 nm
-Hole transport layer: NS-21 [manufactured by Nippon Steel Chemical Co., Ltd.] and MoO ₃ 20 nm, NS-21 5 nm, total 25 nm
-Light emitting layer: NS-21 and EY52 (manufactured by e-Ray Optoelectronics Technology (hereinafter referred to as e-Ray)) 20 nm, EB43 and EB52 (both manufactured by e-Ray) 30 nm, total 50 nm
Hole blocking layer: bis (2-methyl-8-quinolinolato) (p-phenylphenolate) aluminum (BAlq) 5 nm
Charge generation layer: Liq and DPB 35 nm, further aluminum 1.5 nm, further NS-21 and MoO ₃ 10 nm, total 37.5 nm
Metal oxide layer: MoO ₃ 5 nm
-Cathode: ITO 100nm

For the formation from the hole injection layer to the metal oxide layer, a glass substrate on which a transparent electrode layer has already been formed is placed in a vacuum evaporation apparatus, and the materials from the hole transport layer to the metal oxide layer are sequentially applied by resistance heating. This was done by vapor deposition. The system internal pressure was 5 × 10 ⁻³ Pa and the evaporation rate was 0.1 to 0.2 nm / s. Thereafter, ITO of the cathode layer was formed by facing target sputtering. This was sealed with another glass plate using a UV curable resin to obtain a transparent organic EL element 1. When the obtained transparent organic EL element 1 was energized and driven, good white light emission was obtained, and both the front direction and the oblique direction were excellent in transparency. Here, the front direction refers to a direction parallel to the normal direction of the light emitting surface, and the oblique direction refers to a direction inclined by 45 ° with respect to the light emitting surface.

(Manufacture of light-emitting element 1)
The obtained transparent organic EL element 1 is bonded with a film substrate on which an uneven structure layer is formed via an adhesive layer (acrylic resin, refractive index 1.49, manufactured by Nitto Denko Corporation, CS9621), and the transparent organic EL element The light emitting element 1 having a layer structure of 1-adhesive layer-film substrate-uneven structure layer was obtained. When the obtained light emitting device 1 was energized to emit light and the transparency of the light emitting device 1 was visually evaluated, the transparency from the front direction and the oblique direction was excellent.

[Example 2]
Using a cutting tool with an apex angle of 25 ° and a tip width of 50 μm and a cutting tool with an apex angle of 25 ° and a tip width of 150 μm, the metal mold was manufactured by cutting in four azimuth directions. The four azimuth directions were 0 °, 45 °, 90 ° and 135 °.
Cutting at an azimuth angle of 0 ° was performed using a cutting tool having a tip width of 150 μm, and the cutting pitch was 360 μm, 380 μm, 400 μm, 420 μm, and 440 μm so that each groove was random.
Cutting in the azimuth 45 ° direction and 90 ° direction was performed using a cutting tool having a tip width of 50 μm and a constant cutting pitch of 400 μm.
For cutting in the direction of azimuth 135 °, a cutting tool having a tip width of 150 μm was used, and the cutting pitch was made constant at 400 μm.
Further, the depth of any groove was set to 18.0 μm.
A light-emitting element 2 was produced by forming a concavo-convex structure layer (thickness 25 μm) in the same manner as in Example 1 except that the metal mold produced as described above was used.

  18 is a perspective view schematically showing a part of the concavo-convex structure layer obtained in Example 2 as viewed obliquely, and FIG. 19 shows a part of the concavo-convex structure layer obtained in Example 2. It is a top view which shows typically a mode that it saw from the thickness direction. As shown in FIGS. 18 and 19, the surface of the obtained concavo-convex structure layer was formed with a concavo-convex structure having many trapezoidal convex sections corresponding to the grooves formed in the metal mold. On the surface of the concavo-convex structure layer on which the concavo-convex structure was formed, the average inclination angle of the slope portion with respect to the flat surface portion was 77.5 °. Further, the ratio of the projected area of the slope portion to the total area of the flat surface portion was 0.08, and the maximum height difference of the flat surface portion was 18.1 μm. When the obtained light emitting device 2 was energized to emit light and the transparency of the light emitting device 2 was visually evaluated, the transparency from the front direction and the oblique direction was excellent.

Example 3
Cutting is performed in six azimuth directions using a cutting bit having an apex angle of 20 ° and a tip width of 75 μm, a cutting bit having an apex angle of 20 ° and a tip width of 100 μm, and a cutting bit having an apex angle of 20 ° and a tip width of 125 μm. This produced a metal mold. The six azimuth directions were 0 °, 45 °, 60 °, 90 °, 120 ° and 135 °.
For cutting in the direction of 0 ° azimuth, a cutting tool having a tip width of 100 μm is used, the cutting pitch is 360 μm, 380 μm, 400 μm, 420 μm, and 440 μm so that each groove is random, and the groove depth is 24.4 μm, 24 .7 μm, 25.0 μm, 25.3 μm, and 25.5 μm were made random for each groove.
Cutting in the direction of 45 ° azimuth uses a cutting tool with a tip width of 125 μm, the cutting pitch is made constant at 800 μm, and the groove depths are 24.4 μm, 24.7 μm, 25.0 μm, 25.3 μm and It was made random for every groove | channel at 25.6 micrometers.
Cutting at an azimuth angle of 60 ° uses a cutting tool with a tip width of 75 μm, and the cutting pitch is set to 720 μm, 760 μm, 800 μm, 840 μm, and 880 μm to be random for each groove, and the groove depth is constant at 25.0 μm. It was made to become.
Cutting in the direction of 90 ° azimuth uses a cutting tool having a tip width of 100 μm, the cutting pitch is made constant at 400 μm, and the groove depths are 24.4 μm, 24.7 μm, 25.0 μm, 25.3 μm and It was made random for every groove | channel at 25.6 micrometers.
For cutting in the direction of azimuth 120 °, a cutting tool having a tip width of 125 μm was used, the cutting pitch was made constant at 800 μm, and the groove depth was made 25.1 μm.
Cutting in the direction of 135 ° azimuth uses a cutting tool with a tip width of 75 μm, and the cutting pitch is set to 720 μm, 760 μm, 800 μm, 840 μm, and 880 μm so as to be random for each groove, and the groove depth is constant at 25.0 μm. It was made to become.
A light-emitting element 3 was manufactured by forming a concavo-convex structure layer (thickness 30 μm) in the same manner as in Example 1 except that the metal mold manufactured as described above was used.

  On the surface of the manufactured concavo-convex structure layer on which the concavo-convex structure was formed, the average inclination angle of the slope portion with respect to the flat surface portion was 80.0 °. Further, the ratio of the projected area of the inclined surface portion to the total area of the flat surface portion was 0.09, and the maximum height difference of the flat surface portion was 25.6 μm. When the obtained light emitting device 3 was energized to emit light, and the transparency of the light emitting device 3 was visually evaluated, the transparency from the front direction and the oblique direction was excellent.

Example 4
Cutting tool with apex angle 25 ° and tip width 40 μm, cutting tool with apex angle 25 ° and tip width 80 μm, cutting tool with apex angle 25 ° and tip width 120 μm, cutting tool with apex angle 25 ° and tip width 160 μm Were cut into eight azimuthal directions to produce a metal mold. The eight azimuth directions were 0 ° direction, 20 ° direction, 45 ° direction, 60 ° direction, 90 ° direction, 115 ° direction, 135 ° direction, and 165 ° direction.
Cutting at an azimuth angle of 0 ° is performed by using a cutting tool having a tip width of 160 μm, with a cutting pitch of 720 μm, 760 μm, 800 μm, 840 μm, and 880 μm so that each groove is random, and the groove depth is constant at 25.0 μm. It was made to become.
Cutting in the direction of the azimuth angle of 20 ° uses a cutting tool having a tip width of 120 μm, the cutting pitch is made constant at 800 μm, and the groove depths are 24.4 μm, 24.7 μm, 25.0 μm, 25.3 μm and It was made random for every groove | channel at 25.6 micrometers.
Cutting in the direction of 45 ° azimuth is performed using a cutting tool having a tip width of 40 μm, and the cutting pitch is set to 720 μm, 760 μm, 800 μm, 840 μm, and 880 μm so as to be random for each groove, and the groove depth is 24.4 μm, 24 It was made to become random for every groove | channel at 0.7 micrometer, 25.0 micrometer, 25.3 micrometer, and 25.6 micrometers.
Cutting at an azimuth angle of 60 ° is performed using a cutting tool having a tip width of 160 μm, the cutting pitch is kept constant at 800 μm, and the groove depths are 24.4 μm, 24.7 μm, 25.0 μm, 25.3 μm, and It was made random for every groove | channel at 25.6 micrometers.
Cutting in the direction of 90 ° azimuth angle uses a cutting tool with a tip width of 80 μm, the cutting pitch is 720 μm, 760 μm, 800 μm, 840 μm and 880 μm so that each groove is random, and the groove depth is constant at 25.0 μm. It was made to become.
Cutting at an azimuth angle of 115 ° is performed using a cutting tool having a tip width of 120 μm, with the cutting pitches being 720 μm, 760 μm, 800 μm, 840 μm, and 880 μm so that each groove is random, and the groove depth is 24.4 μm, 24 It was made to become random for every groove | channel at 0.7 micrometer, 25.0 micrometer, 25.3 micrometer, and 25.6 micrometers.
Cutting at an azimuth angle of 135 ° is performed using a cutting tool having a tip width of 80 μm, the cutting pitch is set to 720 μm, 760 μm, 800 μm, 840 μm, and 880 μm so as to be random for each groove, and the groove depth is constant at 25.0 μm. It was made to become.
Cutting in the direction of azimuth angle 165 ° uses a cutting tool having a tip width of 40 μm, the cutting pitch is made constant at 800 μm, and the groove depths are 24.4 μm, 24.7 μm, 25.0 μm, 25.3 μm and It was made random for every groove | channel at 25.6 micrometers.
From this metal mold, a transfer mold having a shape in which the concavo-convex shape was inverted was produced by Ni electroforming (thickness: about 300 μm).
Except that this transfer mold was used as a mold, a concavo-convex structure layer (thickness 30 μm) was formed in the same manner as in Example 1 to manufacture the light-emitting element 4.

  On the surface of the manufactured concavo-convex structure layer on which the concavo-convex structure was formed, the average inclination angle of the slope portion with respect to the flat surface portion was 77.5 °. Further, the ratio of the projected area of the inclined surface portion to the total area of the flat surface portion was 0.09, and the maximum height difference of the flat surface portion was 25.6 μm. When the obtained light emitting device 4 was energized to emit light, and the transparency of the light emitting device 4 was visually evaluated, the transparency from the front direction and the oblique direction was excellent.

[Comparative Example 2]
A metal mold was manufactured by cutting in two azimuth directions using a cutting tool having an apex angle of 20.0 ° and a tip width of 10 μm. The two azimuth directions were 0 ° and 90 °.
In any azimuth direction, the cutting is random for each groove with a cutting pitch of 90.0 μm, 95.0 μm, 100.0 μm, 105.0 μm and 110.0 μm, and the groove depth is 20.0 μm. To be constant.
A light-emitting element 5 was manufactured by forming a concavo-convex structure layer (thickness 25 μm) in the same manner as in Example 1 except that the metal mold manufactured as described above was used.

  On the surface of the manufactured concavo-convex structure layer on which the concavo-convex structure was formed, the ratio of the projected area of the inclined surface portion to the total area of the flat surface portion was 0.32, and the maximum height difference of the flat surface portion was 20.1 μm. . When the obtained light-emitting element 5 was energized to emit light and the transparency of the light-emitting element 5 was visually evaluated, the transparency from the front direction and the oblique direction was inferior.

[Comparative Example 3]
A metal mold was manufactured by cutting in two azimuth directions using a cutting tool having an apex angle of 40.0 ° and a tip width of 10.0 μm. The two azimuth directions were 0 ° and 90 °.
Cutting is performed so that the cutting pitch is constant at 35.0 μm in any azimuth direction, and the groove depth is 4.4 μm, 4.7 μm, 5.0 μm, 5.3 μm and 5.6 μm for each groove. To be random.
A light-emitting element 6 was produced by forming a concavo-convex structure layer (thickness: 10 μm) in the same manner as in Example 1 except that the metal mold produced as described above was used.

  In the surface of the manufactured concavo-convex structure layer on which the concavo-convex structure was formed, the ratio of the projected area of the inclined surface portion to the total area of the flat surface portion was 0.40, and the maximum height difference of the flat surface portion was 5.6 μm. . When the obtained light emitting element 6 was energized to emit light and the transparency of the light emitting element 6 was visually evaluated, the transparency from the front direction and the oblique direction was inferior.

[Comparative Example 4]
A metal mold was manufactured by cutting in two azimuth directions using a cutting tool having an apex angle of 20.0 ° and a tip width of 30.0 μm. The two azimuth directions were 0 ° and 90 °.
In any azimuth direction, the cutting is random for each groove with a cutting pitch of 90.0 μm, 95.0 μm, 100.0 μm, 105.0 μm and 110.0 μm, and the depth of the groove is 24.4 μm. 24.7 μm, 25.0 μm, 25.3 μm, and 25.6 μm so that each groove is random.
A light-emitting element 7 was manufactured by forming a concavo-convex structure layer (thickness: 30 μm) in the same manner as in Example 1 except that the metal mold manufactured as described above was used.

  In the surface of the manufactured concavo-convex structure layer on which the concavo-convex structure was formed, the ratio of the projected area of the inclined surface portion to the total area of the flat surface portion was 0.28, and the maximum height difference of the flat surface portion was 25.6 μm. . When the obtained light-emitting element 7 was energized to emit light and the transparency of the light-emitting element 7 was visually evaluated, the transparency from the front direction and the oblique direction was inferior.

[Comparative Example 5]
A metal mold was manufactured by cutting in two azimuth directions using a cutting tool having an apex angle of 30.0 ° and a tip width of 75.0 μm. The two azimuth directions were 0 ° and 90 °.
In any azimuth direction, the cutting is random for each groove with a cutting pitch of 90.0 μm, 95.0 μm, 100.0 μm, 105.0 μm and 110.0 μm, and the depth of the groove is 24.4 μm. 24.7 μm, 25.0 μm, 25.3 μm, and 25.6 μm so that each groove is random.
A light-emitting element 8 was produced by forming a concavo-convex structure layer (thickness 30 μm) in the same manner as in Example 1 except that the metal mold produced as described above was used.

  On the surface of the manufactured concavo-convex structure layer on which the concavo-convex structure was formed, the ratio of the projected area of the inclined surface portion to the total area of the flat surface portion was 0.26, and the maximum height difference of the flat surface portion was 25.6 μm. . When the obtained light-emitting element 8 was energized to emit light and the transparency of the light-emitting element 8 was visually evaluated, the transparency from the front direction and the oblique direction was inferior.

[Evaluation]
(Light extraction amount)
For the transparent organic EL device 1 obtained in Example 1, Examples 1 to 4 and the light-emitting devices 1 to 8 obtained in Comparative Examples 2 to 5, a program (program name: ASAP, manufactured by Breath Research) was used. In the optical simulation, the luminous intensity of the light emitting layer was set to 1 lm, and the luminous intensity emitted from both sides was calculated. The obtained values are shown in Tables 1 and 2. In Tables 1 and 2, the numerical value in the “light extraction amount of the bonding surface” column represents the light extraction amount from the light emission surface having the concavo-convex structure layer provided with the concavo-convex structure layer, and “the light extraction amount of the back surface”. The numerical value in the column represents the amount of light extracted from the glass surface without the uneven structure layer. Further, the transparent organic EL element 1 is handled as Comparative Example 1. In Comparative Example 1, each of the numerical value in the “light extraction amount on the bonding surface” column and the numerical value in the “back light extraction amount” column represents the light extraction amount from the glass surface without the uneven structure layer.

(Transparency of uneven structure layer)
For the concavo-convex structure layers obtained in Examples 1 to 4 and Comparative Examples 2 to 5, the parallel light transmittance and the diffuse light transmittance are calculated by optical simulation using a program (program name: ASAP, manufactured by Breath Research). Then, (diffuse light transmittance) / (parallel light transmittance + diffuse light transmittance) × 100 was calculated as a numerical value representing the transparency of the uneven structure layer. It represents that it is excellent in the transparency seen from the thickness direction, so that this figure is low. The obtained values are shown in Tables 1 and 2.

(Lattice unevenness)
The light-emitting elements 1 to 8 obtained in Examples 1 to 4 and Comparative Examples 2 to 5 were visually observed to confirm the presence or absence of lattice unevenness. In Examples 1 to 4, since three or more groups included in the concavo-convex structure layer were included, the lattice unevenness was hardly observed and was excellent. In Tables 1 and 2, “excellent” indicates that lattice unevenness is hardly observed, and “defect” indicates that lattice unevenness is observed.

(Visibility)
The transparent organic EL element 1 and the light emitting elements 1 to 8 are arranged in a non-lighting state 50 cm in front of the display surface on which characters of 5 mm × 5 mm size are arranged. Through the transparent organic EL element 1 and the light emitting elements 1 to 8, the front direction The characters were observed from an oblique direction. Characters that are clearly visible with no blurring or distortion are classified as “excellent”, while those with blurring or distortion are “good”, while those that can read characters are “good”, and those that have many blurring or distortion and are not clearly readable are “bad”. The results are shown in Tables 1 and 2.

(Rainbow unevenness)
The light emitting elements obtained in Examples 1 to 4 and Comparative Examples 2 to 5 were visually observed to confirm the presence or absence of rainbow unevenness. In each of Examples 1 to 4 and Comparative Examples 2 to 5, since the unevenness of the uneven structure is uneven within a predetermined range, rainbow unevenness based on interference in the reflected light on the front and back surfaces of the uneven structure layer Was not observed and was excellent.

Example 5
A metal mold was manufactured by cutting in three azimuth directions using a cutting tool having an apex angle of 5 ° and a tip width of 50 μm. The three azimuth directions were 0 °, 45 ° and 90 °.
Cutting pitch in azimuth angle 0 ° direction is constant at 200 μm, cutting pitch in azimuth angle 45 ° direction and 90 ° direction is constant at 400 μm, and groove depth is constant at 20.0 μm in all azimuth directions. .
A light-emitting element 9 was manufactured by forming a concavo-convex structure layer (thickness: 25 μm) in the same manner as in Example 1 except that the metal mold manufactured as described above was used.

On the surface of the manufactured concavo-convex structure layer on which the concavo-convex structure was formed, the average inclination angle of the inclined portion with respect to the flat surface portion was 87.5 °. Further, the ratio of the projected area of the inclined surface portion to the total area of the flat surface portion was 0.03, and the maximum height difference of the flat surface portion was 20.1 μm.
When the obtained light emitting device 9 was energized to emit light and the transparency of the light emitting device 9 was visually evaluated, the transparency from the front direction and the oblique direction was excellent.

Example 6
Using a cutting tool with an apex angle of 25 ° and a tip width of 50 μm and a cutting tool with an apex angle of 25 ° and a tip width of 150 μm, the metal mold was manufactured by cutting in four azimuth directions. The four azimuth directions were 0 °, 45 °, 90 ° and 135 °.
Cutting in the azimuth angle 0 ° direction and 135 ° direction was performed using a cutting tool having a tip width of 150 μm. Further, cutting in the azimuth 45 ° direction and 90 ° direction was performed using a cutting tool having a tip width of 50 μm. In any of the grooves, the cutting pitch was made constant at 400 μm, and the groove depth was made constant at 18.0 μm.
A light-emitting element 10 was manufactured by forming a concavo-convex structure layer (thickness: 25 μm) in the same manner as in Example 1 except that the metal mold manufactured as described above was used.

  On the surface of the manufactured concavo-convex structure layer on which the concavo-convex structure was formed, the average inclination angle of the slope portion with respect to the flat surface portion was 77.5 °. Further, the ratio of the projected area of the slope portion to the total area of the flat surface portion was 0.08, and the maximum height difference of the flat surface portion was 18.1 μm. When the obtained light emitting device 10 was energized to emit light and the transparency of the light emitting device 10 was visually evaluated, the transparency from the front direction and the oblique direction was excellent.

Example 7
Cutting is performed in six azimuth directions using a cutting bit having an apex angle of 20 ° and a tip width of 75 μm, a cutting bit having an apex angle of 20 ° and a tip width of 100 μm, and a cutting bit having an apex angle of 20 ° and a tip width of 125 μm. This produced a metal mold. The six azimuth directions were 0 °, 45 °, 60 °, 90 °, 120 ° and 135 °.
Cutting in the azimuth 0 ° direction and 90 ° direction was performed using a cutting tool having a tip width of 100 μm and a constant cutting pitch of 400 μm.
Cutting in the azimuth 45 ° direction and 120 ° direction was performed using a cutting tool having a tip width of 125 μm, and the cutting pitch was kept constant at 800 μm.
Cutting in the azimuth 60 ° direction and 135 ° direction was performed using a cutting tool with a tip width of 75 μm, and the cutting pitch was kept constant at 800 μm.
The depth of the groove was fixed at 25.0 μm in any groove.
A light-emitting element 11 was manufactured by forming a concavo-convex structure layer (thickness of 30 μm) in the same manner as in Example 1 except that the metal mold manufactured as described above was used.

  On the surface of the manufactured concavo-convex structure layer on which the concavo-convex structure was formed, the average inclination angle of the slope portion with respect to the flat surface portion was 80.0 °. The ratio of the projected area of the slope portion to the total area of the flat surface portion was 0.09, and the maximum height difference of the flat surface portion was 25.1 μm. When the obtained light emitting element 11 was energized to emit light and the transparency of the light emitting element 11 was visually evaluated, the transparency from the front direction and the oblique direction was excellent.

Example 8
Cutting tool with apex angle 25 ° and tip width 40 μm, cutting tool with apex angle 25 ° and tip width 80 μm, cutting tool with apex angle 25 ° and tip width 120 μm, cutting tool with apex angle 25 ° and tip width 160 μm Were cut into eight azimuthal directions to produce a metal mold. The eight azimuth directions were 0 °, 20 °, 45 °, 60 °, 90 °, 115 °, 135 ° and 165 °.
For cutting in the azimuth angle 0 ° direction and azimuth angle 60 ° direction, a cutting tool having a tip width of 160 μm was used. For cutting in the azimuth 20 ° direction and 115 ° direction, a cutting tool having a tip width of 120 μm was used. For cutting in the azimuth 45 ° direction and 165 ° direction, a cutting tool having a tip width of 40 μm was used. For cutting in the azimuth 90 ° direction and 135 ° direction, a cutting tool having a tip width of 80 μm was used. In any groove, the cutting pitch was made constant at 800 μm, and the groove depth was made constant at 25.0 μm.
From this metal mold, a transfer mold having a shape in which the concavo-convex shape was inverted was produced by Ni electroforming (thickness: about 300 μm).
Except that this transfer mold was used as a mold, a concavo-convex structure layer (thickness 30 μm) was formed in the same manner as in Example 1, and the light emitting device 12 was manufactured.

  On the surface of the manufactured concavo-convex structure layer on which the concavo-convex structure was formed, the average inclination angle of the slope portion with respect to the flat surface portion was 77.5 °. The ratio of the projected area of the slope portion to the total area of the flat surface portion was 0.09, and the maximum height difference of the flat surface portion was 25.1 μm. When the obtained light emitting device 12 was energized to emit light and the transparency of the light emitting device 12 was visually evaluated, the transparency from the front direction and the oblique direction was excellent.

[Comparative Example 6]
A metal mold was manufactured by cutting in two azimuth directions using a cutting tool having an apex angle of 20.0 ° and a tip width of 10 μm. The two azimuth directions were 0 ° and 90 °.
In the cutting, the cutting pitch was made constant at 100.0 μm and the groove depth was made constant at 20.0 μm in any azimuth direction.
A light-emitting element 13 was manufactured by forming a concavo-convex structure layer (thickness: 25 μm) in the same manner as in Example 1 except that the metal mold manufactured as described above was used.

  On the surface of the manufactured concavo-convex structure layer on which the concavo-convex structure was formed, the ratio of the projected area of the inclined surface portion to the total area of the flat surface portion was 0.32, and the maximum height difference of the flat surface portion was 20.1 μm. . When the obtained light-emitting element 13 was energized to emit light and the transparency of the light-emitting element 13 was visually evaluated, the transparency from the front direction and the oblique direction was poor.

[Comparative Example 7]
A metal mold was manufactured by cutting in two azimuth directions using a cutting tool having an apex angle of 40.0 ° and a tip width of 10.0 μm. The two azimuth directions were 0 ° and 90 °.
In the cutting, the cutting pitch was made constant at 35.0 μm and the groove depth was made constant at 5.0 μm in any azimuth direction.
A light-emitting element 14 was manufactured by forming a concavo-convex structure layer (thickness: 10 μm) in the same manner as in Example 1 except that the metal mold manufactured as described above was used.

  On the surface of the manufactured concavo-convex structure layer on which the concavo-convex structure was formed, the ratio of the projected area of the inclined surface portion to the area of the flat surface portion was 0.40, and the maximum height difference of the flat surface portion was 5.1 μm. When the obtained light emitting element 14 was energized to emit light and the transparency of the light emitting element 14 was visually evaluated, the transparency from the front direction and the oblique direction was inferior.

[Comparative Example 8]
A metal mold was manufactured by cutting in two azimuth directions using a cutting tool having an apex angle of 20.0 ° and a tip width of 30.0 μm. The two azimuth directions were 0 ° and 90 °.
In the cutting, the cutting pitch was made constant at 100.0 μm and the groove depth was made constant at 25.1 μm in any azimuth direction.
A light-emitting element 15 was manufactured by forming a concavo-convex structure layer (thickness of 30 μm) in the same manner as in Example 1 except that the metal mold manufactured as described above was used.

  In the surface of the manufactured concavo-convex structure layer on which the concavo-convex structure was formed, the ratio of the projected area of the inclined surface portion to the area of the flat surface portion was 0.28, and the maximum height difference of the flat surface portion was 25.1 μm. When the obtained light-emitting element 15 was energized to emit light and the transparency of the light-emitting element 15 was visually evaluated, the transparency from the front direction and the oblique direction was inferior.

[Comparative Example 9]
A metal mold was manufactured by cutting in two azimuth directions using a cutting tool having an apex angle of 30.0 ° and a tip width of 50.0 μm. The two azimuth directions were 0 ° and 90 °.
In the cutting, the cutting pitch was made constant at 100.0 μm and the groove depth was made constant at 25.0 μm in any azimuth direction.
A light-emitting element 16 was manufactured by forming a concavo-convex structure layer (thickness: 30 μm) in the same manner as in Example 1 except that the metal mold manufactured as described above was used.

  In the surface of the manufactured concavo-convex structure layer on which the concavo-convex structure was formed, the ratio of the projected area of the inclined surface portion to the area of the flat surface portion was 0.26, and the maximum height difference of the flat surface portion was 25.1 μm. When the obtained light-emitting element 16 was energized to emit light and the light-emitting element 16 transparency was evaluated visually, the transparency from the front direction and the oblique direction was poor.

[Evaluation]
The light emitting elements 9 to 16 obtained in Examples 5 to 8 and Comparative Examples 6 to 9 were evaluated in the manner described above. The results are shown in Tables 3 and 4.

  When the light-emitting elements obtained in Examples 5 to 8 and Comparative Examples 6 to 9 were visually observed, although some rainbow unevenness was present, it was of a level that was not regarded as a problem depending on the use mode. .

DESCRIPTION OF SYMBOLS 10 Light emitting element 20 Light emitting element 30 Light emitting element 40 Light emitting element 10U Light emission surface 10D Light emission surface 100 Light emission surface structure layer 110 Multilayer body 111 Concavity and convexity structure layer 112 Base film layer 113 First row 113U Flat surface part 113S Slope part 114 1st Second row 114U Flat surface portion 114S Slope portion 115 Third row 115U Flat surface portion 115S Slope portion 116 Fourth row 116U Flat surface portion 116S Slope portion 117 Concave portion 117B Flat surface portion 121 Adhesive layer 131 Support substrate 140 Organic EL element 141 First electrode layer 142 Light emitting layer 143 Second electrode layer 144 Light emitting surface 145 Light emitting surface 151 Sealing substrate 410U Light emitting surface 413, 414, 415, 416 and 417 row 510U Light emitting surface 513, 514, 515 and 516 Row 610U Light exit surface 613, 614, 615, 616, and 617 row 901 projection plane 902 projection image

Claims (5)

An organic electroluminescence device that has a light emitting surface and emits light from the light emitting surface; and a structural layer provided directly or indirectly on the light emitting surface of the organic electroluminescence device,
The structural layer includes a first row extending in a first direction parallel to the surface on a surface of the structural layer opposite to the organic electroluminescence element, and the first parallel to the surface and the first A second row extending in a second direction intersecting with the direction of the second, and a third row extending in a third direction parallel to the surface and intersecting the first direction and the second direction. It has a concavo-convex structure including a row,
The concavo-convex structure has a flat surface portion parallel to the light emitting surface and a slope portion inclined with respect to the light emitting surface;
A projected area formed by projecting the slope portion in a direction perpendicular to the flat surface portion onto a plane parallel to the flat surface portion is 0.1 times or less of the total area of the flat surface portions. There is a light emitting element.   The light emitting element according to claim 1, wherein the maximum value of the height difference of the flat surface portion in the uneven structure is 22 μm or less.   The light emitting element of Claim 1 or 2 in which the said slope part inclines with the inclination angle of 80 degrees or more and less than 90 degrees with respect to the said flat surface part.   The light emitting element as described in any one of Claims 1-3 whose maximum value of the height difference of the said flat surface part is 0.1 micrometer or more.   A lighting fixture provided with the light emitting element as described in any one of Claims 1-4.

Images