JP6167883B2 - Surface emitting unit - Google Patents

Description

  The present invention relates to a surface light emitting unit, and more particularly to a surface light emitting unit including a plurality of surface light emitting panels arranged so that each light emitting surface is arranged in a planar shape.

  2. Description of the Related Art In recent years, surface emitting units that include a surface emitting panel as a light source have attracted attention. The surface light emitting unit is not limited to a lighting device, and is also used as a backlight for a liquid crystal display, a computer monitor, or outdoor advertising (signage). Generally, a surface light-emitting panel such as an organic EL (organic electro luminescence) element is used for the surface light-emitting panel. The organic EL element can obtain high luminance with low power consumption, and exhibits excellent performance in terms of responsiveness and life.

  In the surface light emitting panel, it is necessary to seal the light emitting part of the surface light emitting element or to connect the wiring to the light emitting part. Therefore, a non-light emitting part is formed around the light emitting part. When an organic EL element is used as the surface light emitting element, the surface light emitting element includes a transparent electrode and a reflective electrode for flowing a current through the light emitting layer. In order to secure a portion where the bonding wire is connected to the transparent electrode and the reflective electrode, a non-light emitting portion is formed on the outer periphery of the light emitting portion.

  Therefore, in a surface light emitting unit including a plurality of surface light emitting panels, a reduction in luminance in the front direction of these non-light emitting portions and portions corresponding to the surrounding portions is inevitable. Therefore, when no countermeasure is taken, this appears as uneven luminance, and a dark portion is generated along the non-light emitting portion.

  Japanese Patent Application Laid-Open No. 2010-092866 (Patent Document 1) discloses an invention related to a light emitting element. The light emitting device has a first light extraction region having a first light scattering ability and a second light extraction region having a second light scattering ability larger than the first light scattering ability as a light emitting surface. Have. The publication states that according to this light emitting element, the light extraction efficiency can be optimized.

  Japanese Patent Laying-Open No. 2005-158369 (Patent Document 2) discloses an invention related to a lighting device. This illumination device includes an optical member and a plurality of light emitting elements. This publication states that according to this optical member and the illumination device, illumination light can be irradiated in a state where there is little luminance unevenness over an area larger than the front surface of each light emitting element by using a plurality of light emitting elements.

JP 2010-092866 A JP 2005-158369 A

  An object of this invention is to provide the surface emitting unit which improves the brightness | luminance of the front direction of the part applicable to a non-light-emitting part and its peripheral part.

According to one embodiment, the surface light emitting unit is arranged such that each light emitting surface is arranged in a plane, and a plurality of surface light emitting panels that emit light toward the front side, and a plurality of adjacent surface light emitting panels. A transmissive member that is disposed to face the light emitting surface and reflects and propagates the light emitted from the surface light emitting panel, and a light scattering portion that scatters the light propagated by the transmissive member toward the front side. Each light emitting surface of the plurality of surface light emitting panels has a light emitting region that emits light and a non-light emitting region that is located on the outer periphery of the light emitting region and does not emit light. The light scattering portion emits light in a pattern shape that matches the shape of the surface light emitting panel so that it extends along the outer edge of the light emitting surface of the surface light emitting panel at a portion facing the non-light emitting region on the light incident surface of the transmitting member. It is printed on the surface.

  Preferably, the surface emitting unit is in close contact with a portion of the transmissive member facing the light emitting region, and includes an adhesive member that transmits light emitted from the surface luminescent panel and bonds the transmissive member and the plurality of surface luminescent panels. Further prepare.

  Preferably, the surface emitting panel has a transparent substrate that is in contact with the adhesive member and transmits light emitted from the light emitting region. The absolute value of the difference between the refractive index of the adhesive member and the refractive index of the transparent substrate is smaller than 0.1. The absolute value of the difference between the refractive index of the adhesive member and the refractive index of the transmission member is smaller than 0.1.

  Preferably, the light scattering portion includes a first region and a second region that is separated from the light emitting region by a distance from the first region in the plane. The reflectance of the first region is configured to be lower than the reflectance of the second region.

  Preferably, for each of the plurality of surface emitting panels, an optical axis extending in a normal direction of the light emitting surface when a light distribution curve in a plane perpendicular to the light emitting surface of the light emitted from the surface emitting panel is drawn. Is a portion where the light distribution curve satisfies the condition of L> cos θ, where L is the luminance in the direction where the angle formed with the optical axis in the plane is θ, and L is the luminance on the front side along the plane. Have at least.

Preferably, the transmission member has a film shape or a sheet shape.
Preferably, white ink in which particles having a diameter of 100 nm to 2000 nm are dispersed is used for printing the light scattering portion .

  ADVANTAGE OF THE INVENTION According to this invention, the brightness | luminance of the front direction of the part applicable to a non-light-emitting part and its peripheral part can be improved.

  The above and other objects, features, aspects and advantages of the present invention will become apparent from the following detailed description of the present invention taken in conjunction with the accompanying drawings.

It is a top view which shows the surface emitting unit according to Embodiment 1. It is a schematic cross section along the II-II line of the surface emitting unit shown in FIG. It is a perspective view which shows the surface emitting panel, transmissive member, and light-scattering part which are used for the surface emitting unit according to Embodiment 1. It is a figure showing a mode that the light-scattering part is printed on the surface of a transmissive member. It is a figure which shows the modification of the printing pattern of a light-scattering part. It is a figure which shows the modification of the printing pattern of a light-scattering part. It is a figure which shows the modification of the printing pattern of a light-scattering part. It is a figure which shows the simulation result which followed the two-dimensional ray tracing of the light inject | emitted from a transmissive member. It is a figure which shows the simulation result which followed the two-dimensional ray tracing of the light inject | emitted from a transmissive member. It is a figure which shows the simulation result which followed the two-dimensional ray tracing of the light inject | emitted from a transmissive member. It is a figure which shows the simulation result which followed the two-dimensional ray tracing of the light inject | emitted from a transmissive member. It is a schematic cross section of the surface emitting unit according to the second embodiment. 6 is a schematic cross-sectional view of a surface emitting unit according to a third embodiment. FIG. It is sectional drawing which shows the organic EL element with which the surface emitting panel was equipped. It is a figure which shows the vertical in-plane light distribution according to the 1st structural example and 2nd structural example of the organic EL element with which the surface emitting panel shown in FIG. 1 was equipped. It is a figure which shows the outline | summary of the light distribution measuring method in a vertical surface. It is a table | surface which shows the example of conditions of the concrete film | membrane structure which implement | achieves the organic EL element according to the 1st structural example and the 2nd structural example.

  Hereinafter, the present embodiment will be described with reference to the drawings. In the following description, the same parts and components are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated. Each embodiment described below and / or each modification may be selectively combined.

[Embodiment 1]
With reference to FIGS. 1-3, surface emitting unit 100 according to the first embodiment will be described. FIG. 1 is a plan view showing the surface light emitting unit 100. In FIG. 1, a state in which a transmission member 16 described later is removed from the surface light emitting unit 100 is shown. FIG. 2 is a schematic cross-sectional view taken along the line II-II of the surface emitting unit 100 shown in FIG. FIG. 3 is a perspective view showing the surface light emitting panels 10A and 10B, the transmissive member 16, and the light scattering unit 20 used in the surface light emitting unit 100. FIG.

<Surface emitting unit 100>
As shown in FIGS. 1 to 3, the surface light emitting unit 100 has a flat, substantially rectangular parallelepiped outer shape as a whole. The surface light emitting unit 100 includes surface light emitting panels 10 </ b> A to 10 </ b> D, a transmissive member 16, and a light scattering unit 20. Hereinafter, the surface light emitting panels 10A to 10D may be collectively referred to as the surface light emitting panel 10.

  Each of the surface light emitting panels 10A to 10D is arranged so that the light emitting surfaces thereof are arranged in a planar shape, and emits light toward the front side (see arrow AR shown in FIGS. 2 and 3). The surface light emitting panel 10A has a light emitting surface 13A. Similarly, the surface light emitting panel 10B has a light emitting surface 13B, the surface light emitting panel 10C has a light emitting surface 13C, and the surface light emitting panel 10D has a light emitting surface 13D.

  The light emitting surface 13A includes a light emitting region 14A that emits light and a non-light emitting region 15A that is located on the outer periphery of the light emitting region 14A and does not emit light. Similarly, the light emitting surface 13B includes a light emitting region 14B that emits light and a non-light emitting region 15B that is located on the outer periphery of the light emitting region 14B and does not emit light. Similarly, the light emitting surface 13C includes a light emitting region 14C that emits light and a non-light emitting region 15C that is located on the outer periphery of the light emitting region 14C and does not emit light. The light emitting surface 13D includes a light emitting region 14D that emits light and a non-light emitting region 15D that is located on the outer periphery of the light emitting region 14D and does not emit light.

  Hereinafter, the light emitting surfaces 13 </ b> A to 13 </ b> D may be collectively referred to as the light emitting surface 13. Similarly, the light emitting areas 14 </ b> A to 14 </ b> D may be collectively referred to as the light emitting area 14. Similarly, the non-light emitting areas 15 </ b> A to 15 </ b> D may be collectively referred to as the non-light emitting area 15.

  The transmissive member 16 is disposed to face the light emitting surfaces 13A to 13D of the surface light emitting panels 10A to 10D, and reflects and propagates part of the light emitted from the surface light emitting panels 10A to 10D (in FIG. 2). (See the arrow extending from the surface light emitting panel 10B).

  The light scattering portion 20 is in close contact with a portion of the light incident surface of the transmissive member 16 (contact surface between the surface light emitting panel 10 and the transmissive member 16) facing the non-light emitting regions 15A to 15D of the surface light emitting panels 10A to 10D. Yes. The light scattering unit 20 scatters the light propagated by the transmission member 16 toward the front side (see the arrow extending from the light scattering unit 20 in FIG. 2).

  As described above, by providing the light scattering portion 20 in the portion facing the non-light emitting region 15 of the surface light emitting panel 10, it is possible to scatter a part of the light emitted from the surface light emitting panel 10 by the light scattering portion 20. become. As a result, the non-light emitting region 15 and the surrounding region can appear to emit light, and the luminance in the front direction of the non-light emitting region 15 and the surrounding region can be improved.

<Outline of surface emitting panel 10>
With reference to FIGS. 1-3 again, the outline | summary of the surface emitting panel 10 is demonstrated. Each of the surface light emitting panels 10A to 10D has a flat plate shape extending along the surface direction. The surface emitting panels 10A to 10D are arranged so that the light emitting surfaces 13A to 13D are arranged in a plane. The surface light emitting panels 10A to 10D are configured by a laminate of transparent substrates 11A to 11D, light emitters 12A to 12D including organic EL elements, and sealing members 17A to 17D. The transparent substrates 11A to 11D are located on the transmission member 16 side. Hereinafter, the transparent substrates 11 </ b> A to 11 </ b> D may be collectively referred to as the transparent substrate 11. Similarly, the sealing members 17A to 17D may be collectively referred to as the sealing member 17.

  The surface emitting panels 10A to 10D are arranged in an array. The surface light emitting panels 10A to 10D are arranged with a space therebetween, and a gap 30 is formed between adjacent surface light emitting panels. A total of four gaps 30 are formed between adjacent surface emitting panels among the surface emitting panels 10A to 10D.

  By providing the gap 30, it is possible to increase the area of the light source with a smaller number of panels than when the surface emitting panels 10A to 10D are arranged in contact with each other. More desirably, the gap 30 may be filled with a flexible sealing member. By providing a flexible sealing member, stress applied to the light-emitting panel can be relieved and moisture and ultraviolet light can be prevented from entering, and the life of the light-emitting panel can be extended. Furthermore, it is possible to prevent deterioration of the reflectance of the light scattering portion over time by preventing deterioration of the light scattering portion in contact with the light emitting panel. When there is no need to increase the area of the light source, the surface emitting panels 10A to 10D may be arranged in contact with each other without providing the gap 30.

  The surface light emitting panels 10A to 10D have the light emitting surfaces 13A to 13D as described above. The light emitting surfaces 13A to 13D are configured by the outer surfaces of the transparent substrates 11A to 11D located on the side opposite to the side on which the light emitters 12A to 12D are located. The light generated by the light emitters 12A to 12D is radiated toward the transmitting member 16 side (front side) through the light emitting surfaces 13A to 13D by passing through the transparent substrates 11A to 11D (FIGS. 2 and 2). (See arrow AR shown in FIG. 3).

  The light emitters 12A to 12D are sealed between the transparent substrates 11A to 11D and the sealing members 17A to 17D in order to prevent intrusion of moisture and the like that degrade them. The sealing members 17A to 17D are bonded to the transparent substrates 11A to 11D at the outer peripheral portions thereof.

  As described above, the surface light emitting panels 10A to 10D are arranged so that the light emitting surfaces 13A to 13D are arranged in a planar shape. Surface emitting panels 10A to 10D according to the present embodiment are arranged so that light emitting surfaces 13A to 13D are positioned on the same plane.

  The light emitting surfaces 13A to 13D include light emitting regions 14A to 14D that emit light and non-light emitting regions 15A to 15D that are located on the outer periphery of the light emitting regions 14A to 14D. The light emitting regions 14A to 14D have a rectangular shape. The non-light emitting regions 15A to 15D have a rectangular annular shape. The non-light emitting regions 15A to 15D are formed by providing sealing members 17A to 17D for sealing the organic EL elements included in the light emitters 12A to 12D and parts for connecting wiring to the organic EL elements. The

  In the surface emitting unit 100, a portion including the gap 30 formed between adjacent surface emitting panels and the non-light emitting area of the surface emitting panel located adjacent to the gap 30 constitutes the non-light emitting unit 40. Yes. The non-light emitting part 40 is a part that causes a dark part when no measures are taken, and a total of four non-light emitting parts 40 are formed between adjacent surface emitting panels. When the gap 30 is not formed, the non-light emitting area of the adjacent surface light emitting panel corresponds to the non-light emitting portion 40.

<Outline of the transparent member 16>
With reference to FIG. 2 and FIG. 3 again, the outline of the transmissive member 16 will be described. The transmissive member 16 is disposed so as to face the light emitting surfaces 13A to 13D of the surface light emitting panels 10A to 10D, and is located on the front side as viewed from the transparent substrates 11A to 11D. The transmissive member 16 according to the present embodiment is provided on the surface light emitting panels 10 </ b> A to 10 </ b> D so as to straddle the gap 30. The transmissive member 16 is fixed to the transparent substrates 11A to 11D (light emitting surfaces 13A to 13D) using a transparent adhesive member of an optical system.

  In the present embodiment, the transmissive member 16 and the transparent substrates 11A to 11D are formed as separate members. The light emitters 12A to 12D function as a light emitting unit, and the transmissive member 16 and the transparent substrates 11A to 11D function as a light guide unit that guides light emitted from the light emitters 12A to 12D.

  The light emitted from the light emitters 12 </ b> A to 12 </ b> D passes through the transparent substrates 11 </ b> A to 11 </ b> D and is emitted from the light emitting surfaces 13 </ b> A to 13 </ b> D, and then enters the transmission member 16. The incident light passes through the inside of the transmissive member 16 and is emitted as it is, or is reflected and propagated inside the transmissive member 16 and emitted.

<Outline of light scattering unit 20>
The light scattering unit 20 is scattered and reflected without transmitting a part of the light emitted from the light emitting surfaces 13A to 13D of the surface light emitting panels 10A to 10D and propagated inside the transmissive member 16. The light scattering portion 20 is a cross-shaped member (see FIG. 1) having a total of four rod-like portions extending from the central portion of the surface light emitting unit 100 corresponding to the four non-light emitting portions 40 (see FIG. 1). ).

  Each of the light scattering portions 20 extending in a bar shape is disposed along the outer edge of the light emitting surface of the adjacent surface light emitting panel so as to overlap the non-light emitting region when viewed from the front (light emitting surface) side. More specifically, the light scattering portion 20 is provided on the light emitting surface of the surface light emitting panel so as to straddle and extend along the outer edges of the light emitting surfaces of adjacent surface light emitting panels.

  With reference to FIG. 2 and FIG. 3, the light-scattering part 20 is demonstrated in detail. Since the four portions extending in the rod shape of the light scattering portion 20 all have the same shape, in the following, among the surface light emitting panels 10A to 10D described above, the surface light emitting panel 10A and the surface light emitting panel 10B The description will be given focusing only on the part between.

  As shown in FIGS. 2 and 3, the light scattering unit 20 is positioned on the light emitting surface 13A of the surface light emitting panel 10A and the light emitting surface 13B of the surface light emitting panel 10B so as to face the non-light emitting unit 40. . Typically, the light scattering portion 20 is formed on the surface of the transmissive member 16 that contacts the surface light emitting panel 10.

  More specifically, the light scattering unit 20 includes a non-light emitting region 15A located on the outer edge of the surface emitting panel 10B side of the light emitting surface 13A of the surface emitting panel 10A, and the surface emitting panel 10A side of the light emitting surface 13B of the surface emitting panel 10B. (That is, the light scattering portion 20 overlaps with the non-light emitting regions 15A and 15B of these portions when viewed from the front side) and the non-light emitting regions 15A. , 15B so as to extend along the surface light emitting panel 10A and the surface light emitting panel 10B.

(Print pattern of light scattering portion 20)
With reference to FIGS. 4-7, the printing pattern of the light-scattering part 20 is demonstrated. FIG. 4 is a diagram illustrating a state in which the light scattering unit 20 is printed on the surface of the transmissive member 16. 5-7 is a figure which shows the modification of the printing pattern of the light-scattering part 20. As shown in FIG.

  The light scattering unit 20 is composed of, for example, an organic solvent-based white ink in which scattering particles are dispersed. In this case, the white ink emitted from the inkjet head 301 is inkjet-printed on the surface of the transmissive member 16 on the scattering reflection surface by the light scattering unit 20. Since a printing pattern can be formed by a general-purpose method such as inkjet printing, any printing machine can be used, and the productivity of the surface light emitting unit 100 is improved.

  Moreover, the light-scattering part 20 is printed according to the position of the non-light-emitting area | region 15A-15D of surface emitting panel 10A-10D. Thereby, when the transmissive member 16 is combined with the surface light emitting panels 10A to 10D, the light scattering portion 20 can be brought into close contact with the positions of the non-light emitting regions 15A to 15D of the surface light emitting panels 10A to 10D. Become.

  In addition, the light-scattering part 20 can be printed with various pattern shapes according to the shape of the surface emitting panels 10A to 10D or the shape of the non-light emitting regions 15A to 15D. For example, as shown in FIG. 4, the light scattering portion 20 may be formed of a lattice-like scattering / reflection pattern. Further, as shown in FIG. 5, the light scattering portion 20 </ b> A may be formed of a hexagonal scattering reflection pattern. Furthermore, as shown in FIG. 6, the light scattering portion 20 </ b> B may be formed of a triangular scattering reflection pattern. As shown in FIG. 7, when the surface light emitting panel 10 is arranged in a T shape, the light scattering portion 20C is formed in a T shape in accordance with the shape of the surface light emitting panels 10A to 10D. May be.

<Simulation results>
With reference to FIG. 8 and FIG. 9, advantages of the surface light emitting unit 100 having the light scattering portion 20 facing the non-light emitting region 15 will be described. FIG. 8 and FIG. 9 are diagrams showing simulation results obtained by two-dimensional ray tracing of light emitted from the transmissive member 16.

  The horizontal axis “position” of the graphs shown in FIGS. 8 and 9 corresponds to the light emitting regions 14A and 14B and the non-light emitting region 15 in FIG. That is, the center (position = 0.0) of the horizontal axis of the graph corresponds to the center of the non-light emitting region 15 shown in FIG. The vertical axis “intensity” of the graph represents the intensity of light contained in ± 10 ° (the direction of the arrow AR shown in FIG. 2 is 0 °) immediately after emission from the transmission member 16 (hereinafter, “light intensity”). Say).

  As a simulation condition, the angular distribution of the light emission intensity in the surface light emitting panels 10A and 10B was a lumbar champ which will be described later. The thickness of the transmissive member 16 was 1 mm. Further, 95% of the light incident on the light scattering portion 20 is uniformly scattered and reflected by the light scattering portion 20.

  FIG. 8 shows a simulation result 210A in the case where the surface light emitting unit 100 does not have the light scattering unit 20, and a simulation result 220A in the case where the surface light emitting unit 100 has the light scattering unit 20 (width 2 mm). As shown in FIG. 8, the light intensity in the non-light emitting region 15 (position: −1.0 to +1.0) is higher when the light scattering portion 20 is provided than when the light scattering portion 20 is not provided. You can see that

  FIG. 9 shows a simulation result 210B when the surface light emitting unit 100 does not have the light scattering unit 20, and a simulation result 220B when the width of the light scattering unit 20 is 1 mm. As shown in FIG. 9, the light intensity in the non-light emitting region 15 (position: −0.5 to +0.5) is higher when the light scattering portion 20 is provided than when the light scattering portion 20 is not provided. You can see that As described above, the surface light emitting unit 100 includes the light scattering portion 20 facing the non-light emitting region 15, so that the luminance of the non-light emitting region 15 can be improved, and further, luminance unevenness can be reduced. .

  In addition, the reflectance of the light-scattering part 20 is not limited to 95% mentioned above. For example, the reflectance of the light scattering unit 20 may be larger than 95% or smaller than 95%.

(Modification of light scattering unit 20)
Hereinafter, modifications of the light scattering unit 20 will be described. The light scattering unit 20 according to this modification scatters and reflects the incident light in a plurality of modes without uniformly scattering and reflecting the incident light.

  The amount of light incident on the light scattering unit 20 decreases as the distance from the light emitting regions 14A and 14B increases. In order to further improve the luminance in the non-light emitting region 15, it is preferable that the light scattering unit 20 change the reflectance according to the amount of light incident on the light scattering unit 20.

  In order to realize this, the light scattering unit 20 according to the present modification has a first distance (that is, the edge region of the light scattering unit 20) and the distance from the light emitting regions 14A and 14B within the plane thereof. The second region (that is, the central region of the light scattering portion 20) that is farther than the region is included, and the reflectance of the edge region is configured to be lower than the reflectance of the central region.

  Referring to FIG. 10, the edge region corresponds to, for example, “position” of −1.0 to −0.5 and +0.5 to +1.0 shown in FIG. The central region corresponds to, for example, “position” shown in FIG. 10 from −0.5 to +0.5.

  With reference to FIG. 10 and FIG. 11, the advantage that the light-scattering part 20 has two scattering reflection patterns is demonstrated. FIG. 10 and FIG. 11 are diagrams showing simulation results obtained by two-dimensional ray tracing of light emitted from the transmissive member 16. As a simulation condition according to FIG. 10, the width of the light scattering portion 20 was set to 2.0 mm. Other simulation conditions are the same as described in FIGS. 8 and 9 and will not be described.

  FIG. 10 shows a simulation result 220A when the light scattering unit 20 has a uniform scattering reflection pattern and a simulation result 230A when the light scattering unit 20 has two scattering reflection patterns. As shown in FIG. 10, the light scattering portion 20 having two scattering reflection patterns has a non-light emitting region 15 (in particular, position: −0. It can be seen that the light intensity at 5 to +0.5) is high.

  FIG. 11 shows a simulation result 220B in the case where the light scattering portion 20 has a uniform scattering reflection pattern when the width of the light scattering portion 20 is 1.0 mm, and two light scattering portions 20 are scattered. A simulation result 230B in the case of having a reflection pattern is shown. As shown in FIG. 11, the light scattering portion 20 having two scattering reflection patterns has a non-light-emitting region 15 (position: −0.5˜) compared to the light scattering portion 20 having a uniform scattering reflection pattern. It can be seen that the light intensity at +0.5) is high.

  As described above, the luminance of the non-light emitting region 15 can be further improved by changing the reflectance of the light scattering portion 20 in accordance with the amount of light incident on the light scattering portion 20.

  In addition, although the example which the light-scattering part 20 has two area | regions of a center area | region and an edge area | region was demonstrated above, the number of the areas which the light-scattering part 20 has is not limited to two. For example, the light scattering unit 20 may have three or more regions, and may be configured so that the reflectance increases as the distance from the light emitting regions 14A and 14B increases. Further, the light scattering portion 20 is not necessarily divided into regions. For example, the light scattering unit 20 may be configured to increase the reflectance of the light scattering unit 20 according to the distance from the light emitting regions 14A and 14B.

[Embodiment 2]
Hereinafter, surface emitting unit 100A according to the second embodiment will be described. 100 A of surface emitting units according to this Embodiment differ from the surface emitting unit 100 according to Embodiment 1 by the point which further has an adhesion member. Since other points are the same as those of surface light emitting unit 100 according to the first embodiment, description thereof will not be repeated.

<Adhesive member 50>
The adhesive members 50A and 50B will be described with reference to FIG. FIG. 12 is a schematic cross-sectional view taken along the line II-II of the surface emitting unit 100A shown in FIG. The surface light emitting unit 100A includes surface light emitting panels 10A to 10D, a transmissive member 16, a light scattering unit 20, and adhesive members 50A to 50D. Hereinafter, the adhesive members 50 </ b> A to 50 </ b> D may be collectively referred to as the adhesive member 50. Moreover, below, it demonstrates paying attention only to the part between surface emitting panel 10A and surface emitting panel 10B among surface emitting panels 10A-10D mentioned above.

  The adhesive member 50 is provided in order to bond the surface light emitting panel 10 and the transmissive member 16 more reliably. The adhesive member 50A is provided in close contact with a portion of the transmissive member 16 that faces the light emitting region 14A. Similarly, the adhesive member 50B is provided in close contact with a portion of the transmissive member 16 that faces the light emitting region 14B.

  The adhesive member 50 </ b> A is in contact with the transparent substrate 11 </ b> A of the surface light emitting panel 10. Similarly, the adhesive member 50 </ b> B contacts the transparent substrate 11 </ b> B of the surface light emitting panel 10. Thereby, the adhesive member 50 adheres the transmissive member 16 to the surface light emitting panel 10. Further, the adhesive member 50 is optically transparent, and transmits light emitted from the transmission member 16 and the surface light emitting panel 10 to the front side (see arrow AR shown in FIG. 12).

  In particular, as desirable properties of the adhesive member 50, when the refractive index of the transmissive member 16 is n1, the refractive indexes of the transparent substrates 11A and 11B are n2, and the refractive index of the adhesive member 50 is n3, the following formula (1) And it is desirable to satisfy Formula (2).

| N1-n3 | <0.1 (1)
| N2-n3 | <0.1 (2)
When the transparent substrates 11A and 11B are made of resin, the refractive index n2 of the transparent substrates 11A and 11B is about 1.5, for example. In this case, when the refractive index n3 of the adhesive member 50 takes a value satisfying the formula (2) (that is, 1.4 <n3 <1.6), total reflection when entering the adhesive member 50 from the surface emitting panel 10 is achieved. Can be suppressed to about 70 degrees. That is, more light can be transmitted to the front side, and the effect of reducing luminance unevenness becomes more remarkable.

[Embodiment 3]
Hereinafter, surface emitting unit 100B according to Embodiment 3 will be described. Surface light emitting unit 100B according to the present embodiment is different from surface light emitting unit 100 according to the first embodiment in that a sealing member for collectively sealing a plurality of surface light emitting panels 10 is provided on the back surface of the light emitting surface. Since other points are the same as those of surface light emitting unit 100 according to the first embodiment, description thereof will not be repeated.

  FIG. 13 illustrates a more practical configuration of the surface light emitting unit. FIG. 13 is a schematic cross-sectional view of the surface emitting unit 100B.

  The surface light emitting unit 100 </ b> B includes the surface light emitting panel 10, the transmissive member 16, the light scattering unit 20, and the back surface sealing member 70. The back surface sealing member 70 is bonded to the back surface of the light emitting surface of the plurality of surface light emitting panels 10. Further, the edge portion of the back surface sealing member 70 is bonded to the edge portion of the transmission member 16. The plurality of surface light emitting panels 10 are vacuum-laminated on the transmissive member 16 and the back surface sealing member 70. Thereby, the penetration | invasion of a water | moisture content and an ultraviolet-ray can be prevented inside the surface emitting unit 100B, and durability of the surface emitting unit 100B increases. Further, the adhesive member 50 can prevent bubbles or peeling between the transmissive member 16 and the surface light emitting panel 10. Thereby, even when the surface light emitting unit 100A is bent, luminance unevenness caused by bubbles and peeling can be prevented. Moreover, although not shown in FIG. 13, the electrode for electric power feeding is taken out as needed. By adopting such a configuration, a surface-emitting light source that emits light in a flexible and uniform manner can be realized.

[Others]
Although the outline | summary of the surface emitting panel 10, the transmissive member 16, the light-scattering part 20, and the adhesion member 50 was demonstrated above, in order to deepen an understanding about these, these details are further demonstrated. Needless to say, the items described below are applicable to each of the above embodiments.

<Details of the surface emitting panel 10>
Details of the surface-emitting panel 10 will be described with reference to FIG. FIG. 14 is a cross-sectional view showing an organic EL element provided in the surface light emitting panel 10. Hereinafter, the surface light emitting panel 10A will be described, but the same can be said for the surface light emitting panels 10B to 10D.

  As described above, for example, a surface light-emitting panel composed of organic EL elements is used as the surface light-emitting panel 10A. FIG. 14 schematically shows a typical configuration (so-called bottom emission) of a surface light emitting panel 10 </ b> A composed of organic EL elements.

  As described above, the surface light emitting panel 10A is configured by a laminated body of the transparent substrate 11A, the light emitting body 12A including the organic EL element, and the sealing member 17A (see FIG. 2). The surface light emitting panel 10A includes a light emitter 12A that is in contact with the transparent substrate 11A (anode). The light emitter 12A includes a transparent electrode 110, a light emitting layer 120, and a reflective electrode 130 (cathode). The light emitting layer 120 includes a hole injection layer (HIL) 121, a hole transport layer (HTL) 122, a photon generation layer (EML) 123, and an electron transport layer (ETL). : Electron Transfer Layer (EIL) 124 and an electron injection layer (EIL) 125.

  The configuration of the surface light emitting panel 10A is not limited to the above. For example, the surface light emitting panel 10A may be configured by an anode / photon generation layer 123 / electron transport layer 124 / cathode. In addition, the surface light emitting panel 10A may include an anode / hole transport layer 122 / photon generation layer 123 / electron transport layer 124 / cathode. In addition, the surface light emitting panel 10A may include an anode / hole transport layer 122 / photon generation layer 123 / hole blocking layer / electron transport layer 124 / cathode. In addition, the surface light emitting panel 10A may be configured by an anode / hole transport layer 122 / photon generation layer 123 / hole blocking layer / electron transport layer 124 / cathode buffer layer / cathode. In addition, the surface light emitting panel 10A may include an anode / anode buffer layer / hole transport layer 122 / light emitting layer unit / hole blocking layer / electron transport layer 124 / cathode buffer layer / cathode.

  It is desirable to use a flexible resin substrate having plasticity for the transparent substrate 11A and the sealing member 17A. In the above description, the bottom emission is described as an example of the configuration of the surface light emitting panel 10A. However, a top emission configuration in which light is emitted toward the sealing side may be used.

(Vertical in-plane light distribution)
FIG. 15 is a diagram showing a vertical in-plane light distribution according to the first configuration example and the second configuration example of the organic EL element provided in the surface light emitting panel shown in FIG. FIG. 16 is a diagram showing an outline of a light distribution measurement method in the vertical plane. FIG. 17 is a table showing an example of specific film configuration conditions for realizing the organic EL element according to the first configuration example and the second configuration example. With reference to FIGS. 15-17, the 1st structural example and 2nd structural example of the organic EL element with which the surface emitting panel 10 of the surface emitting unit 100 was equipped are demonstrated in detail.

  In order to more effectively reduce the luminance unevenness, the luminance L at an arbitrary angle θ in the vertical in-plane light distribution curve when the light from the surface light emitting panel 10 has a luminance in the front direction of 1 is as follows: It is desirable to satisfy Expression (3).

L> cos θ (3)
As shown in FIG. 15, the organic EL elements according to the first configuration example and the second configuration example draw a light distribution curve in a plane perpendicular to the light emitting surface of the light emitted from the surface light emitting panel 10. The luminance on the front side along the optical axis extending in the normal direction of the light emitting surface (that is, the luminance at θ = 0 ° shown in the figure) is 1, and is formed between the optical axis in the plane. If the luminance in the direction in which the angle is θ (that is, the luminance in the range of −90 ° <θ <90 ° and θ ≠ 0 °) is L, the light distribution curves are all in the condition of L> cos θ. The part which satisfies is included.

  That is, the organic EL element according to the first configuration example satisfies the condition of L> cos θ in the range of −70 ° ≦ θ ≦ 70 ° (where θ ≠ 0 °), and the organic EL device according to the second configuration example. As for the EL element, the organic EL element according to the second configuration example generally satisfies the condition of L> cos θ in the range of −80 ° <θ ≦ −50 ° and 50 ° ≦ θ <80 °.

  In FIG. 15, a Lambertian distribution that is a vertical in-plane light distribution of a normal light source (the Lambertian distribution satisfies the condition of L = cos θ = 1 in a range of −90 ° <θ <90 °. ) For comparison. Further, as a method for calculating the light distribution shape shown in FIG. 15, a finite difference time domain method (FDTD method) and a light tracking method are used. In the calculation of the light distribution shape, for example, a virtual detector is provided in the transparent substrate of the light emitting panel, and the light distribution in the vertical plane observed in the transparent substrate is obtained.

  A more specific light distribution measurement method will be described with reference to FIG. Experimentally, a light shielding mask (not shown) having an opening on the light emitting surface is provided between the transparent substrate 11A and the light emitter 12A. A hemispherical lens 750 that is sufficiently larger than the opening and has the same refractive index as the transparent substrate 11A is optically provided on the opening of the light shielding mask. The light emitted from the hemispherical lens 750 through the opening of the light shielding mask is measured, and the light distribution is obtained. The light shielding mask may be provided on the light emission surface of the transparent substrate 11A. The light distribution may be measured in a state where the hemispherical lens 750 is provided on the light emitter 12A without the transparent substrate 11A.

  With reference to FIG. 17, a more specific design example of the surface light emitting panel 10 using the organic EL element will be described. The table shown in FIG. 17 shows a specific film configuration of the surface emitting panel 10.

  Below, the film | membrane structure of the surface emitting panel 10 is transparent substrate 11A (resin substrate) / transparent electrode (ITO) 110 / hole injection layer (HTL) 121 / photon generation layer (EML) 123 / electron transport layer (ETL). A bottom emission type surface emitting panel composed of 124 / reflecting electrode (Ag) 130 will be described as an example.

  As shown in FIG. 17, when the thickness of the resin substrate / ITO / HTL / EML / ETL / Ag is 0.7 mm / 150 nm / 50 nm / 20 nm / 20 nm or less / 150 nm, respectively, and the external light extraction efficiency In general, a Lambertian distribution is obtained when a light extraction sheet is provided to increase the brightness.

  When the thickness of the electron transport layer (ETL) is 50 nm and no light extraction sheet is provided, the vertical in-plane light distribution in the first configuration example is obtained. Further, if the thickness of the electron transport layer (ETL) is 300 nm, the vertical in-plane light distribution in the second configuration example can be obtained.

  In FIG. 17, the peak value of the emission wavelength emitted from the organic EL element when the film configuration is adopted is also shown as a reference.

  The vertical in-plane light distribution of the organic EL elements according to the first and second configuration examples is different from the Lambertian distribution of a normal light source in the angle dependency of light emitted from the light emitting surface. In particular, it means that the amount of light emitted in the oblique direction on the front side is larger than the amount of light emitted in the front direction.

  Therefore, by using a surface light emitting panel including an organic EL element having such a vertical in-plane light distribution, it is possible to transmit light more than when using a surface light emitting panel including an organic EL element having a Lambertian distribution. Since the amount of light that is totally reflected and propagated inside the member 16 increases, the amount of light that is scattered and reflected by the light scattering portion 20 provided facing the non-light emitting portion 40 and emitted to the front side is increased. The amount also increases.

  That is, the surface light emitting unit 100 can guide more light out of the light emitted from the organic EL element to the light emitting surface of the transmissive member 16 corresponding to the non-light emitting portion and the surrounding portion. Therefore, the luminance in the front direction of the portion is improved, and the luminance non-uniformity is reduced, and the non-light emitting portion becomes less noticeable.

  Accordingly, the surface light emitting unit 100 can be a surface light emitting unit in which the luminance in the front direction of the non-light emitting portion 40 and the portion corresponding to the non-light emitting portion 40 is improved as compared with the conventional case, and further, the luminance is not reduced. It is possible to obtain a surface light emitting unit in which the uniformity is reduced and the non-light emitting portion is not noticeable.

<Details of the transmissive member 16>
Hereinafter, desirable materials used for the above-described transmission member 16 will be described in more detail. In order to realize uniform surface light emission and highly efficient surface light emission, it is desirable that the transmittance of the transmission member 16 is high. Specifically, a sample having a total light transmittance of 80% or more in the visible light wavelength region measured by a method in accordance with JIS K 7361-1: 1997 (a test method for the total light transmittance of a plastic-transparent material) is transmitted. It is preferably used as the member 16. Moreover, as the transmissive member 16, a material excellent in flexibility is preferably used.

  The transmission member 16 is preferably in the form of a film or a sheet. As the transmissive member 16, for example, a resin substrate, a resin film, and the like are preferably exemplified, but a transparent resin film is preferably used from the viewpoint of productivity and performance such as lightness and flexibility. The transparent resin film is a film having a total light transmittance of 50% or more measured in a visible light wavelength region measured by a method in accordance with JIS K 7361-1: 1997 (a test method for total light transmittance of plastic-transparent material). Say. There is no restriction | limiting in particular in the transparent resin film which can be used preferably, About the material, a shape, a structure, thickness, etc., it can select suitably from well-known things.

  Examples of such transparent resin films include polyester resin films such as polyethylene terephthalate (PET), polyethylene naphthalate, and modified polyester, polyethylene (PE) resin films, polypropylene (PP) resin films, polystyrene resin films, and cyclic olefin resins. Polyolefin resin films such as polyvinyl chloride, vinyl resin films such as polyvinyl chloride and polyvinylidene chloride, polyether ether ketone (PEEK) resin films, polysulfone (PSF) resin films, polyether sulfone (PES) resin films, polycarbonate ( PC) resin film, polyamide resin film, polyimide resin film, acrylic resin film, triacetyl cellulose (TAC) resin film, etc. Can.

  If it is a resin film whose total light transmittance mentioned above is 80% or more, it will be more preferably used as the transmissive member 16. As the transmitting member 16, a biaxially stretched polyethylene terephthalate film, a biaxially stretched polyethylene naphthalate film, a polyethersulfone film, or a polycarbonate film is preferable from the viewpoints of transparency, heat resistance, ease of handling, strength, and cost. A biaxially stretched polyethylene terephthalate film or a biaxially stretched polyethylene naphthalate film is more preferred.

  The transmissive member 16 can be subjected to a surface treatment or an easy-adhesion layer in order to ensure the wettability and adhesion of the ink pattern as the scattering reflection member. Examples of the surface treatment include surface activation treatment such as corona discharge treatment, flame treatment, ultraviolet treatment, high frequency treatment, glow discharge treatment, active plasma treatment, and laser treatment. Examples of the easy-adhesion layer include polyester, polyamide, polyurethane, vinyl copolymer, butadiene copolymer, acrylic copolymer, vinylidene copolymer, and epoxy copolymer. it can. The easy adhesion layer may be a single layer, but may be composed of two or more layers in order to improve adhesion.

Further, an inorganic film, an organic film, or a hybrid film of an inorganic substance and an organic substance may be formed on the front or back surface of the film-like base material. The base material on which such a film is formed is JIS K. Barrier property of water vapor permeability (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) measured by a method based on 7129-1992 is 1 × 10 ⁻³ g / (m ² · 24 h) or less The film is preferably a film. Furthermore, the oxygen permeability measured by a method according to JIS K 7126-1987 is 1 × 10 ⁻³ ml / m ² · 24 h · atm or less, and the water vapor permeability (25 ± 0. 5 ° C. and relative humidity (90 ± 2)% RH) is preferably a high barrier film having 1 × 10 ⁻³ g / (m ² · 24 h) or less.

  As a material for forming a barrier film formed on the front or back surface of a film-like base material in order to obtain a high barrier film, it is a material having a function of suppressing intrusion of elements that cause deterioration of elements such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like can be used. Furthermore, in order to improve the brittleness of the barrier film, it is more preferable to have a laminated structure of these inorganic layers and layers made of organic materials. Although there is no restriction | limiting in particular about the lamination | stacking order of an inorganic layer and an organic layer, It is preferable to laminate | stack both alternately several times.

<Details of the light scattering unit 20>
Hereinafter, the above-described light scattering unit 20 will be described in more detail. The white ink as a material for forming the scattering reflection pattern in the light scattering portion 20 desirably has a high reflectance at the emission wavelength of the surface emitting panel 10 as viewed from the inside of the transmission member 16. In the following, the case where the emission wavelength of the surface light emitting panel 10 is visible light will be described. Therefore, the effect of the present invention is exhibited.

  Examples of the white ink material that has high reflectance with visible light include organic solvent-based inks in which TiO2 particles having a diameter of 100 to 2000 nm are dispersed. In order to achieve desirable uniform scattering in the visible light range, it is desirable to include scattering particles having the above-mentioned particle size. The white ink for realizing the scattered reflection is not limited to the above material, and an existing white ink material can be used.

  The method for forming the scattering reflection pattern is not limited to inkjet coating, and may be any method such as offset printing, flexographic printing, gravure printing, screen printing, thermal melt printing using a thermal transfer ribbon, and thermal sublimation printing. . In particular, offset printing enables printing with a clear pattern. Further, since the plate does not touch the transparent member directly and wears little, it is suitable for mass printing.

  Further, since the light scattering portion 20 printed by the above method is extremely thin, it can be brought into close contact without interposing bubbles between the surface light emitting panel 10 and the transmission member 16, and when the surface light emitting panel 10 is bent. Strength and luminance uniformity can be maintained.

<Details of adhesive member 50>
Hereinafter, the adhesive member 50 described above will be described in more detail. The pressure-sensitive adhesive member 50 is desirably a transparent pressure-sensitive adhesive film, a transparent gel, a transparent optical adhesive, or the like, because the surface emitting unit 100A has flexibility. In particular, when a transparent optical adhesive is used as the pressure-sensitive adhesive member 50, optical loss due to total reflection occurring between the surface light emitting panel 10 and the transmissive member 16 can be reduced, and the effect of uniforming the brightness is further enhanced.

  Examples of the transparent adhesive film include a highly transparent adhesive transfer tape and OCA tape (Optical Clear Adhesive Tape) manufactured by 3M. Examples of the transparent gel include urethane gel. Examples of the transparent optical adhesive include NOA68, NOA65, or NOA63 manufactured by Norland.

  As described above, by using the transparent and flexible adhesive member, the adhesion between the transmissive member 16 and the surface light emitting panel 10 can be improved, and the total reflection at the interface can be suppressed. Can be further reduced.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  10, 10A-10D surface light emitting panel, 11, 11A-11D transparent substrate, 12, 12A-12D light emitter, 13, 13A-13D light emitting surface, 14, 14A-14D light emitting region, 15, 15A-15D non-light emitting region, 16 transmissive member, 17, 17A-17D sealing member, 20 light scattering portion, 30 gap, 40 non-light emitting portion, 50, 50A adhesive member, 70 back surface sealing member, 100, 100A, 100B surface light emitting unit, 110 transparent electrode , 120 light emitting layer, 122 hole transport layer, 123 photon generation layer, 124 electron transport layer, 130 reflective electrode, 210A, 210B, 220A, 220B, 230A, 230B simulation result, 301 inkjet head, 750 hemispherical lens.

Claims (7)

A plurality of surface emitting panels arranged so that each light emitting surface is arranged in a plane, and radiates light toward the front side,
A transmissive member that is disposed opposite to the light emitting surface of the plurality of adjacent surface light emitting panels and reflects and propagates light emitted from the surface light emitting panel;
A light scattering portion that scatters the light propagated by the transmission member toward the front side;
Each light emitting surface of the plurality of surface emitting panels has a light emitting region that emits light, and a non-light emitting region that is located on the outer periphery of the light emitting region and does not emit light,
The light scattering portion is adapted to the shape of the surface light emitting panel so as to extend along the outer edge of the light emitting surface of the surface light emitting panel at a portion facing the non-light emitting region on the light incident surface of the transmitting member. A surface light emitting unit printed on the light emitting surface in a pattern shape .   An adhesive member that is in close contact with a portion of the transmissive member that faces the light emitting region, transmits light emitted from the surface light emitting panel, and bonds the transmissive member and the plurality of surface light emitting panels; The surface emitting unit according to claim 1. The surface-emitting panel has a transparent substrate that is in contact with the adhesive member and transmits light emitted from the light-emitting region,
The absolute value of the difference between the refractive index of the adhesive member and the refractive index of the transparent substrate is less than 0.1,
The surface emitting unit according to claim 2, wherein an absolute value of a difference between a refractive index of the adhesive member and a refractive index of the transmission member is smaller than 0.1. The light scattering portion has a first region and a second region that is separated from the light emitting region by a distance from the first region in the plane thereof,
The surface emitting unit according to any one of claims 1 to 3, wherein the reflectance of the first region is configured to be lower than the reflectance of the second region.   An optical axis extending in the normal direction of the light emitting surface when a light distribution curve in a plane perpendicular to the light emitting surface of light emitted from the surface light emitting panel is drawn for each of the plurality of surface light emitting panels. And the luminance in the direction in which the angle formed with the optical axis in the plane is θ is L, the light distribution curve satisfies the condition L> cos θ. The surface emitting unit of any one of Claims 1-4 which has a part to satisfy | fill at least.   The surface emitting unit according to claim 1, wherein the transmission member is in a film shape or a sheet shape. The printing of the light scattering portion, the white ink is used containing dispersed particles having a diameter of 100 nm to 2000 nm, a surface-emitting unit according to any one of claims 1-6.

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