JP6528513B2 - Surface emitting module - Google Patents

Description

  The present invention relates to a surface light emitting module including a surface light emitter including an electroluminescent layer that emits light when a voltage is applied, and a light transmissive base material transmitting light from the surface light emitter.

  2. Description of the Related Art In recent years, in the field of lighting, a surface emitting module equipped with a surface emitting light source represented by, for example, an organic electroluminescent element (hereinafter, referred to as an organic EL (Electro Luminescence) element) has attracted attention. The organic EL element can obtain high luminance with low power consumption, and exhibits excellent performance in response and the like.

  In addition, a surface emitting panel (so-called organic EL panel) including an organic EL element can be configured to be light in weight and flexible, and thus is advantageous in that lighting devices of various forms can be realized. Recently, as a backlight of a portable communication device represented by a tablet terminal or a mobile phone, the use of a surface emitting panel including an organic EL element has been promoted.

  As shown in FIGS. 12 and 13, for example, the tablet terminal 50 has a flat case 51 with a small thickness t, and a display unit is provided at a predetermined position on the outer surface. As the display unit, at least the main display unit 52 for displaying various images is provided on the front surface of the housing 51, and the sub display units 53 to 55 for displaying icons, specific images, etc. There are also cases where it is provided in another part of the casing 51 (around the main display portion 52 of the front surface, back surface, side surface, etc.). The thickness t of the housing 51 is, for example, 7 [mm] or less, which is thin.

  Referring to FIG. 12, in the tablet terminal 50, there is a demand to narrow the width w of the frame-like portion surrounding the main display portion 52 as much as possible. Therefore, the backlight mounted inside the tablet terminal 50 needs to be capable of obtaining sufficient brightness to a position near the outer peripheral portion of the housing 51.

  Here, the organic EL panel has a light emitting area and a non-light emitting area surrounding the periphery of the light emitting area when the organic EL panel is viewed from the light emitting surface side. It is necessary to seal the organic EL element on the substrate so that the organic EL element does not deteriorate due to contact with moisture or oxygen, and a sealing layer is formed around the organic EL element This is because the region where the electroluminescent layer does not exist is located around the light emitting region by forming.

  Therefore, in order to use a surface light emitting module having a surface light emitting panel such as an organic EL panel as a back light of a tablet terminal or the like, the increase in thickness of the tablet terminal or the like is suppressed while corresponding to the non-light emitting region It is necessary to configure the surface emitting module so that sufficient brightness can be obtained even in parts.

  As one method for solving this problem, for example, in Japanese Patent Application Laid-Open No. 2013-98103 (Patent Document 1), a diffuse reflector is provided at a predetermined position on the side surface or surface of the base corresponding to the non-emission region. Thus, there is disclosed an organic light emitting device configured to efficiently extract light confined in a substrate also from a non-light emitting region. In the organic light emitting device, the apparent size of the light emitting region is expanded by efficiently extracting light also from the non-light emitting region.

JP, 2013-98103, A

  However, even when the configuration as disclosed in Patent Document 1 is adopted, the amount of light confined within the base of the portion corresponding to the non-light emitting region is not sufficiently large in the first place, so this is efficient. Even if it is taken out, a large difference in light quantity occurs between the light emitted from the portion of the base corresponding to the light emitting area and the light emitted from the portion of the base corresponding to the non-light emitting area. Therefore, a wide dark area still remains around the light emitting area, and the apparent size of the light emitting area can not be sufficiently enlarged.

  Therefore, the present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a surface emitting module capable of significantly expanding the size of the apparent light emitting region while keeping the thickness thin. I assume.

A surface emitting module according to the present invention includes a surface light emitter including an electroluminescent layer that emits light when a voltage is applied, and a light transmissive base material transmitting light from the surface light emitter. The surface light emitter has a main surface in contact with the light transmitting base material and covered by the light transmitting base material, and the main surface is the main surface when viewed from the direction orthogonal to the main surface. A light emitting region is a region where the electroluminescent layer is located, and a non-light emitting region is a region located around the light emitting region and where the electroluminescent layer is not located. The surface emitting module according to the present invention further includes a scattering surface located on the light transmitting substrate side as viewed from the main surface and separated from the main surface, viewed from a direction orthogonal to the main surface. In this case, the scattering surface is located over a wider range than the light emitting region. In the surface emitting module according to the present invention, the brightness of the central portion of the emission region on the main surface when the L _C, the bright area brightness on the main surface is 1.25 × L _C or higher but along the outer peripheral edge of the emission region is provided in the emission region, the width of the bright portion when viewed from the direction perpendicular to the main surface in case of a W _E, the W _E is, The condition of W _E ≦ 1 mm is satisfied.

In the surface-emitting module according to the present invention, the distance from the upper Symbol major surface to the scattering surface when the D, the W _E and the D is, satisfies the condition of W _E ≦ 25 × D Is preferred.

In the surface-emitting module according to the present invention, the light emitting region may be rectangular when viewed from the direction perpendicular to the main surface, in which case, the shortest with the upper Symbol emitting region when the length of the sides and the _{W A1,} the _{W E} and the _{W A1} is preferably satisfy the condition of _{W E} ≦ 0.1 × _{W A1.}

  In the surface emitting module according to the present invention, when a light distribution curve is drawn in a plane perpendicular to the main surface of the light from the surface light emitter, the light extending in a direction orthogonal to the main surface Assuming that the luminance on the front side along the axis is 1 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 It is preferable to have at least a portion that satisfies

  The surface emitting module according to the present invention preferably further includes a reflective surface located on the opposite side to the main surface as viewed from the electroluminescent layer.

  In the surface emitting module according to the present invention, it is preferable that the reflecting surface is located over a wider range than the light emitting region when viewed from the direction orthogonal to the main surface.

  According to the present invention, it is possible to provide a surface emitting module capable of significantly enlarging the apparent size of the light emitting region while keeping the thickness small.

It is a top view of a surface emitting module in an embodiment of the invention. It is a schematic cross section of the surface emitting module shown in FIG. It is a graph which shows the specific example of the in-plane light distribution distribution of the surface emitting body comprised to the surface emitting module shown in FIG. It is the figure which showed typically the state of the light radiate | emitted from the main surface of the surface emitting module in embodiment of this invention in the case of providing the surface emitting body of Lambert light distribution. It is the schematic which shows the verification model of a 1st verification test. It is a graph which shows the test result of a 1st verification test. It is the schematic which shows the verification model of a 2nd verification test. It is a table | surface which shows the test condition and test result of a 2nd verification test. It is a graph which shows the test result of a 2nd verification test. It is a graph which shows the test result of a 2nd verification test. It is a graph which shows the test result of a 2nd verification test. It is a figure which shows the structure of the front side of a tablet terminal. It is a figure which shows the structure by the side of the back of a tablet terminal.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following, as a surface emitting module to which the present invention is applied, a backlight for a tablet terminal provided with an organic EL panel as a light source will be described as an example. In the embodiments described below, the same or common parts are denoted by the same reference numerals in the drawings, and the description thereof will not be repeated.

  FIG. 1 is a plan view of a surface emitting module according to an embodiment of the present invention, and FIG. 2 is a schematic sectional view taken along line II-II in FIG. 1 of the surface emitting module shown in FIG. FIG. 3 is a graph showing a specific example of the in-plane light distribution of the surface light emitter provided in the surface light emitting module shown in FIG. Hereinafter, the surface emitting module 1 according to the present embodiment will be described with reference to FIGS. 1 to 3.

  As shown in FIGS. 1 and 2, the surface emitting module 1 according to the present embodiment includes a light transmitting substrate 10, a surface light emitter 20, and a scattering layer 30, and the outer shape thereof is, for example, illustrated. It is formed in the shape of a flat plate or a sheet having a rectangular shape in a plan view having a predetermined thickness. The organic EL panel mainly composed of the light transmitting substrate 10 and the surface light emitter 20 is a bottom emission type in which light is extracted to the outside via the light transmitting substrate 10.

  The light transmitting substrate 10, the surface light emitter 20 and the scattering layer 30 are laminated along the thickness direction of the surface light emitting module 1. The light transmitting substrate 10 is formed of a flat plate-like or sheet-like member, and the surface light emitter 20 is formed in a layer on one main surface of the light transmitting substrate 10. In addition, the scattering layer 30 is formed in a layer on the other main surface of the light transmitting substrate 10.

  Accordingly, the surface light emitter 20 has the main surface 20a in contact with the light transmitting substrate 10 and covered by the light transmitting substrate 10, and the light is emitted from the surface light emitter 20 through the main surface 20a. The transmitted light propagates in the light transmitting substrate 10, and the light transmitted through the light transmitting substrate 10 is scattered in the scattering layer 30 and irradiated to the outside of the surface light emitting module 1.

  The light transmitting substrate 10 is located between the surface light emitter 20 and the scattering layer 30, and has the wiring portions 11 and 12 on the main surface located on the surface light emitter 20 side. On the other hand, the surface light emitter 20 has an element portion 21, an insulating portion 25 and a sealing portion 26. The element portion 21 also includes an anode 22, a cathode 23, and an organic layer (electroluminescent layer) 24.

  The wiring portions 11 and 12 are patterned in a predetermined shape, and the anode 22, the organic layer 24 and the cathode 23 are sequentially stacked on the main surface of the light transmitting substrate 10 on which the wiring portions 11 and 12 are formed. Thus, the surface light emitter 20 is formed. Among these, the anode 22 mainly defines the above-described main surface 20 a of the surface light emitter 20, and is connected to the wiring portion 11. The cathode 23 is connected to the wiring portion 12.

  The light transmitting substrate 10 is formed of an insulating member that transmits light well, and preferably, a light transmitting film substrate such as polyethylene terephthalate (PET) resin or polycarbonate (PC) resin is used. Besides, as the light transmitting film substrate, it is possible to use polyimide (PI) resin, polyethylene naphthalate (PEN) resin, polystyrene (PS) resin, polyether sulfone (PES) resin, polypropylene (PP) resin, etc. The following may be used. Note that various glass substrates may be used as the light transmitting substrate 10.

  The anode 22 is formed of, for example, a conductive film having transparency, and more specifically, an ITO (mixture of indium oxide and tin oxide) film or IZO (mixture of indium oxide and zinc oxide film) A film, a ZnO film or the like is formed on the main surface of the light transmitting substrate 10 by sputtering or the like. Other materials used for the anode 22 include polyethylenedioxythiophene (PEDOT) and metal thin films made of Ag, Al, Ca, Cu, Au or the like having a film thickness of 20 nm or less. In addition, the anode 22 may be formed of fine metal wires so as not to completely cover the organic layer 24. In such a case, the sheet resistance of the anode 22 can be effectively reduced.

  The organic layer 24 is a site that generates light when a voltage is applied, and includes at least an electroluminescent layer composed of a fluorescent compound or a phosphorescent compound. The organic layer 24 may be composed of a single-layered electroluminescent layer, or may be composed of a hole transport layer, an electroluminescent layer, a hole blocking layer, an electron transport layer, and the like sequentially stacked. . In addition, a lithium fluoride film, an inorganic metal salt film or the like may be formed at any position in the thickness direction in the electroluminescent layer.

  As the electroluminescent layer, a laminated film containing an organic material typified by, for example, Alq3 (tris (8-quinolinolato) aluminum) can be suitably used. As a material of the electroluminescent layer, an organometallic complex may be used from the viewpoint of improving the external quantum efficiency of the organic EL element, prolonging the light emission lifetime, and the like. Here, as a metal element involved in the formation of a complex, any one metal belonging to Group VIII, Group IX and Group X of the periodic table of the elements or Al, Zn is preferable, and in particular, Ir or Pt, Al, It is preferable that it is Zn.

  The organic layer 24 is provided on the anode 22 by adopting, for example, any of a vapor deposition method, a spin coating method, a casting method, an inkjet method, a printing method, and the like. In particular, the spin coating method, the ink jet method, and the printing method can be suitably used because a homogeneous film can be easily obtained and the generation of pinholes can be suppressed.

  The cathode 23 is formed of, for example, a metal film having a high reflectance, and specifically, an aluminum (Al) film or the like is formed to cover the organic layer 24 by a vacuum evaporation method or the like. The cathode 23 is composed of a laminated film of a lithium fluoride (LiF) film, an Al film and a calcium (Ca) film, a laminated film of an Al film and a LiF film, a laminated film of an Al film and a barium (Ba) film, etc. May be Further, the cathode 23 may be formed of a conductive oxide film or a metal thin film.

An insulating portion 25 is provided between the anode 22 and the cathode 23 so as not to short circuit them. The insulating portion 25 is formed, for example, by depositing a SiO ₂ film or the like using sputtering or the like, and then patterning the SiO ₂ film or the like into a predetermined shape using photolithography or the like.

The sealing portion 26 is made of an insulating resin material or a glass material. The sealing portion 26 is for protecting the organic layer 24 from moisture, oxygen and the like, and substantially the entire element portion 21 including the anode 22, the organic layer 24 and the cathode 23 is between the light transmitting substrate 10 and the sealing portion 26. It is formed to seal with. The sealing portion 26 is a resin film made of PET resin, PEN resin, PS resin, PES resin, PI resin, etc., an inorganic thin film such as SiO ₂ , Al ₂ O ₃ , SiN _x or the like, and flexible acrylic. What was formed so that gas barrier property was provided may be used by laminating a plurality of resin thin films etc. in layers.

  The wiring portions 11 and 12 are preferably simultaneously formed using the same material as the anode 22 described above. The wiring portions 11 and 12 are alternately arranged along the periphery of the light transmitting base material 10 so as to surround the organic layer 24, and a feeder (not shown) is attached to the predetermined position by, for example, soldering.

  Here, a metal film of gold, silver, copper or the like may be further stacked on the wiring portions 11 and 12. By further laminating the metal film in this manner, not only the bonding property in the above-described soldering is improved, but also the light reflected at the interface located on the scattering layer 30 side is on the non-light emitting area A2 described later. When it reaches, it is possible to reflect this by the metal film and guide it to the scattering layer 30 side again, and it is possible to improve the light extraction efficiency. The wiring portions 11 and 12 may be formed only of a metal film.

  As described above, the element portion 21 formed on the main surface of the light transmitting substrate 10 is covered by the sealing portion 26 so that the surface light emitter 20 is viewed from the direction orthogonal to the main surface 20 a thereof. A light emitting area A1 where the organic layer 24 including the electroluminescent layer is located, and a non-light emitting area A2 located around the light emitting area A1 where the organic layer 24 is not located Become.

  Among them, the light emitting area A1 is formed of a substantially rectangular area located at the center of the surface emitting module 1 when viewed from the direction orthogonal to the main surface 20a, and the non-light emitting area A2 is the main surface When it sees from the direction orthogonal to 20a, it is comprised by the frame-shaped area | region along the outer periphery of light emission area A1. In FIG. 1, the boundary line B1 between the light emitting area A1 and the non-light emitting area A2 is indicated by a broken line.

  Here, as shown in FIG. 3, the surface light emitter 20 may have a so-called Lambert light distribution, which is a general light distribution, and more preferably have an oblique light distribution described below May be

  When the Lambert light distribution draws a light distribution curve in a plane perpendicular to the main surface 20a of light from the surface light emitter 20, the luminance on the front side along the optical axis extending in the direction orthogonal to the main surface 20a (That is, the brightness at θ = 0 ° shown in the figure) is 1, and the brightness in the direction in which the angle formed with the optical axis in the plane is θ (ie, −90 ° <θ <90 If the luminance in the range of θ ≠ 0 ° is L, the light distribution curve satisfies the condition of L = cos θ.

  On the other hand, when the oblique light distribution draws a light distribution curve in a plane perpendicular to the main surface 20a of light from the surface light emitter 20, the front side along the optical axis extending in the direction orthogonal to the main surface 20a Brightness (ie, brightness at θ = 0 ° shown in the figure) is 1, and brightness in a direction in which the angle formed with the optical axis in the plane is θ (ie, −90 ° <θ Assuming that the luminance in the range of 90 ° and θ ≠ 0 ° is L, the light distribution curve has a portion satisfying the condition of L> cos θ.

  Here, the light distribution curve of the oblique light distribution exemplified in FIG. 3 substantially satisfies the condition of L> cos θ in the range of −80 ° ≦ θ ≦ −60 ° and 60 ° ≦ θ ≦ 80 °. .

  Such oblique light distribution means that the angular dependence of light emitted from the main surface 20a of the surface light emitter 20 toward the light transmitting substrate 10 is different from that of a general Lambert light distribution. In particular, it means that the amount of light emitted toward the front side in the oblique direction is larger than the amount of light emitted toward the front direction. Such oblique light distribution can be realized, for example, by adjusting the thickness of the hole transport layer contained in the organic layer 24 or the like.

  Referring to FIGS. 1 and 2, scattering layer 30 includes, for example, a binder and scattering particles to scatter light using internal scattering, and examples thereof include a spray method, a vapor deposition method, and a spin coating method. The light transmitting substrate 10 is provided by adopting any of a casting method, an inkjet method, a printing method, and the like.

As the binder, for example, a mixture of polymethyl methacrylate (PMMA) resin and TiO ₂ fine particles can be used, and as the scattering fine particles, PMMA resin fine particles, hollow silica, etc. can be used.

  The scattering layer 30 is provided to straddle the boundary line B1 between the light emitting area A1 and the non-light emitting area A2 so as to be located over a wider range than the light emitting area A1 when viewed from the direction orthogonal to the main surface 20a. It is done. More specifically, the scattering layer 30 is provided so as to cover the entire surface of the main surface of the light transmitting base material 10 opposite to the side where the surface light emitters 20 are located.

  The scattering layer 30 has a scattering surface 30 a located on the light transmitting substrate 10 side as viewed from the surface light emitter 20 and separated from the main surface of the surface light emitter 20. Here, in the case where the scattering layer 30 is provided as in the present embodiment, the scattering action is obtained at an arbitrary position in the thickness direction of the scattering layer 30, so the scattering surface is not defined in a strict sense. Here, the scattering surface 30 a is defined as the main surface of the pair of main surfaces of the scattering layer 30 opposite to the side on which the light transmitting substrate 10 is located, for convenience.

  Here, without providing the scattering layer 30 as described above, the scattering surface is configured by providing fine irregularities on the main surface of the light transmitting substrate 10 opposite to the side where the surface light emitter 20 is located. Alternatively, a layer in which fine asperities are provided on one or both main surfaces may be laminated on the light transmitting substrate 10 to be a scattering layer. In that case, these scattering surfaces scatter light using interface reflection.

Here, in the surface emitting module 1 according to the present embodiment, a bright portion E is provided in the light emitting area A1 along the outer peripheral edge of the light emitting area A1 (that is, the above-described boundary line B1). Bright portion E is the brightness of the central portion C of the light emitting region A1 on the main surface 20a when the _{L C,} means a light emitting region A1 of the partial brightness on the main surface 20a is 1.25 × _{L C} Do. That is, the luminance _{L E} of the bright portion E is represented by _{L E} ≧ 1.25 × _{L C} with the _{L C.}

The luminance L _C of the central portion C of the light emitting area A1 and the luminance L _E of the bright portion _E are both on the front side along the optical axis extending in the direction orthogonal to the main surface 20 a of the surface light emitter 20 The luminances L _C and L _E are luminances without the scattering surface 30 a.

  By this configuration, it is possible to effectively enlarge the apparent light emitting region. Hereinafter, the reason will be described with reference to FIG. FIG. 4: is the figure which showed typically the state of the light radiate | emitted from the main surface of the surface emitting module in this Embodiment in the case of having provided the surface emitting body of Lambert light distribution. In FIG. 4, only the element unit 21 is schematically illustrated by simplifying the surface light emitter 20.

As shown in FIG. 4, when the surface-emission module 1 of this embodiment, as described above, was the luminance L _C of the central portion C of the light emitting region A1 of the main surface 20a of the surface light emitter 20, the brightness at the main surface 20a is 1.25 × _{L C} or more bright portion E is provided in the light-emitting area A1 along the outer edge of the light emitting region A1 (i.e. the boundary line B1). That is, a bright portion E having a locally high luminance is provided in the light emitting area A1 of a portion adjacent to the non-light emitting area A2. In FIG. 1, a boundary line B2 between the bright part E of the light emitting area A1 and the light emitting area A1 of the part other than the light part E is indicated by a two-dot chain line.

  By this configuration, the amount of light passing through the light transmitting substrate 10 in the portion corresponding to the non-emission area A2 is significantly increased, and the scattering layer in the portion corresponding to the non-emission area A2 The light reaching the 30 scattering surfaces 30a also increases accordingly. Therefore, the amount of light extracted from the scattering surface 30a of the scattering layer 30 in the portion corresponding to the non-emission area A2 also increases, and along with this, the apparent emission area is an arrow A1 '. It will expand toward the direction shown in.

Referring now to FIG. 1, where the width W _E of the bright portion E _(, the width W _E is the width of the bright portion E in the direction perpendicular to the tangential direction of the border line B1 on the main surface 20a ) Is advantageous in the sense of enlarging the apparent light emitting area. However, from the viewpoint of smoothing the luminance distribution on the scattering surface 30a, it is preferable to further reduce the width W _E of the bright portion E.

Specifically, the width W _E of the bright portion E is a scattering surface 30a of the scattering layer 30 from the main surface 20a of the surface light emitter 20 (here, the scattering surface 30a, the surface-emitting module 1 light to the outside It is preferable to be narrowed to satisfy the condition of W _E ≦ 25 × D, using the distance D (see FIG. 2) to the surface to be irradiated (refer to FIG. 2). The width W _E of the bright portion E is more preferably satisfies the condition of W _E ≦ 10 × D, more preferably if they meet the condition of W _E ≦ 5 × D.

The width W _E of the bright portion E is, W _E ≦ 1 may be narrowed so as to satisfy the condition of [mm].

The width W _E of the bright portion E, in a case where the light-emitting region A1 when viewed from a direction perpendicular from the main surface 20a is formed in a rectangular shape, the length of the shortest side of the light-emitting region A1 has When the _length is W _A1 (see FIG. 1), it may be narrowed so as to satisfy the condition of W _E ≦ 0.1 × W _A1 .

  By satisfying these conditions, it is possible to enlarge the apparent light emission area while smoothing the luminance distribution on the scattering surface 30a. These conditions are all derived based on the results of the first and second verification tests described later.

  For example, at the time of manufacturing the organic EL panel, the above-mentioned bright part E covers only the outer peripheral edge of the light emitting area A1 to be the bright part E with a protective film for shielding ultraviolet rays, and directs the ultraviolet rays to the organic layer 24 in this state. It can be formed by uniform irradiation. In that case, the luminance ratio between the bright part E and the light emitting area A1 other than the bright part E can be controlled by the amount of ultraviolet light to be irradiated.

  Moreover, the bright part E mentioned above can also be formed by providing a semipermeable membrane so that the main surface of the transparent substrate 10 of the part corresponding to light emission area A1 other than bright part E may be covered. In that case, the luminance ratio between the bright part E and the light emitting area A1 other than the bright part E can be controlled by adjusting the transmittance of the semipermeable membrane to be formed. Further, instead of the semi-permeable film described above, the light reflecting portion and the light non-reflecting portion are located at intervals of several tens of μm so that the average luminance in the light emitting area A1 is lower than the light portion E. As a result, a lattice-like reflective film may be provided on the main surface of the light transmitting substrate 10 in a portion corresponding to the light emitting area A1 other than the light portion E.

  Furthermore, by configuring the bright portion E and the light emitting area A1 other than the bright portion E by electrically independent organic EL elements, and configuring the surface emitting module 1 so as to drive these independently. The light portion E may be formed.

  As described above, by using the surface light emitting module 1 according to the present embodiment, it is possible to significantly enlarge the apparent size of the light emitting region while keeping the thickness small.

  Hereinafter, first and second verification tests that have led to the completion of the present invention will be described. The first verification test verifies by simulation the influence of the luminance of the outer periphery of the light emitting area on the apparent size of the light emitting area, and the second verification test is obtained by applying the present invention Verification of the effect and verification for deriving the preferable condition of the size of the width of the bright portion described above are performed by simulation.

  FIG. 5 is a schematic view showing a verification model of the first verification test, and FIG. 6 is a graph showing the test results of the first verification test. First, the first verification test will be described with reference to FIGS. 5 and 6.

As shown in FIG. 5, in the first verification test, it is assumed that the surface emitting module 1X configured to have a constant luminance over the entire light emitting area A1 as a verification model without having the above-mentioned bright part E did. Here, the surface emitting module 1X as a verification model is configured in two ways, one having the Lambert light distribution shown in FIG. 3 and one having the oblique light distribution, and for each of them, the main component of the surface light emitter 20 is While keeping the distance D from the surface 20a to the scattering surface 30a of the scattering layer 30 constant, the width W _A1 of the light emitting area _A1 was variously changed.

At that time, the brightness on the scattering surface 30a of the surface emitting module 1X is simulated based on the ray tracing method, and the width W _AS of the light source region _AS (here, the width W _AS of the light source region _AS is the scattering surface 30a described above 40% or more of the luminance of the maximum brightness is the width of the areas obtained) is calculated, the difference between the width W _A1 of the width W _aS and the actual emission region A1 of the light source region half (i.e. on, _{(W aS -W A1) / 2} ) as the increment of the apparent light emitting region and it was confirmed a relationship between the increase in half-width W _A1 and the light emitting region on the said apparent light emitting region A1 described above.

As a result, as shown in FIG. 6, in any of the Lambert light distribution and the oblique light distribution, when the width W _A1 of the light emission area _A1 is small and narrowed, the apparent light emission area tends to be expanded. It was confirmed that there is. From the results, it can be seen that the portion of the light emitting area A1 that affects the apparent size of the light emitting area is exclusively the outer peripheral edge of the light emitting area A1.

Therefore, in accordance with the result, the bright portion E to be provided on the outer peripheral edge of the light emitting area A1, it is preferably more that the width W _E is narrowed, when narrowing the width W _E It can be understood that it is possible to extract more light from the scattering surface 30a of the portion corresponding to the non-light emitting area A2.

As apparent from FIG. 6, in any of the Lambert light distribution and the oblique light distribution, the increase in the apparent light emission area is increased when the width W _A1 of the light emission area _A1 is about 10 mm or more. the amount is saturated, the width W _A1 of the light emitting region A1 to apply the present invention to surface-emission module configured to 10 [mm] or more can be understood to be particularly suitable.

  FIG. 7 is a schematic view showing a verification model of the second verification test, and FIG. 8 is a table showing test conditions and test results of the second verification test. 9 to 11 are graphs showing test results of the second verification test. Next, the second verification test will be described with reference to FIGS. 7 to 11.

As shown in FIG. 7, in the second verification test, the surface emitting module 1 </ b> Y having the bright part E described above is assumed as a verification model. Here, as shown in FIG. 8, in the surface emitting module 1Y as a verification model, the light distribution of the surface light emitter 20, the width W _{E of} the bright part, and the luminance of the central part C and the bright part E of the light emitting region A1. The ratio L _E / L _C and the transmittance of the scattering layer 30 were variously changed to constitute eight as in Examples 1 to 8. For comparison, assuming that this is also applied to a verification model that differs only in that it does not have the bright portion E, the transmittance of the scattering layer 30 is changed variously, and three configurations of Comparative Examples 1 to 3 are configured. .

  In addition, as shown in FIG. 7, the surface emitting module 1Y as a verification model has a main surface located on the opposite side to the main surface 20a of the surface light emitter 20 as viewed from the organic layer 24 including the electroluminescent layer as a reflection layer The reflecting surface 40 a is formed by covering at 40. Here, the organic EL panel including the light transmitting substrate 10 and the surface light emitter 20 so that the reflecting surface 40a is positioned over a wider range than the light emitting area A1 when viewed from the direction orthogonal to the main surface 20a. It is provided over the entire surface on the back side.

In any of Examples 1 to 8 and Comparative Examples 1 to 3, the shape of the light emitting region A1 is a square having a side length of 10 mm, and the shape of the light transmitting substrate 10 is one side. Is a square with a length of 12 mm. That is, the width W _A1 of the light emitting area A1 is 10 [mm], and the width of the non-light emitting area A2 is 1 [mm].

  Moreover, in any of Examples 1 to 8 and Comparative Examples 1 to 3, the thickness of the light transmitting substrate 10 is 0.42 [mm], and the thickness of the scattering layer 30 is 0.02 [mm]. It is. Therefore, the distance D between the main surface 20 a of the surface light emitter 20 and the scattering surface 30 a of the scattering layer 30 is 0.44 [mm].

  In each of Examples 1 to 8 and Comparative Examples 1 to 3, the refractive index of the light transmitting substrate 10 is 1.4936, and the reflectance and the absorptivity of the reflective surface 40a are 70%, respectively. And 30 [%].

  On the other hand, as the scattering layer 30, three types of different transmittances (three types of transmittances of 40 [%], 75 [%], and 90 [%]) are set, and any one of them is selected. And in each of Comparative Examples 1 to 3. The scattering layer having a transmittance of 40% has an absorptivity of 5% and a reflectance of 55%. The scattering layer having a transmittance of 75% has an absorptivity of 5% and a reflectance of 20%. The scattering layer having a transmittance of 90% has an absorptivity of 5% and a reflectance of 5%. In each of the scattering layers, the haze ratio is 93 [%].

Here, in the second verification test, for each of Examples 1 to 8 and Comparative Examples 1 to 3, the luminance on the scattering surface 30a is simulated based on the ray tracing method, and the width W _AS of the light source region _AS (here in width W _aS of the light source region aS calculates the 40% or more of the luminance of the maximum brightness is the width of the areas obtained) on the scattering surface 30a described above, the width W _aS of the light source regions The half value of the difference between the actual light emitting area A1 and the width W _A1 (that is, (W _AS -W _A1 ) / 2) was obtained as an increase in the apparent light emitting area.

  In FIG. 9 (A), the luminance profile on the main surface 20a of the surface light emitter 20 in Comparative Example 1 and Examples 1 to 4 is shown in relative luminance, and in FIG. 9 (B), Comparative Example 1 is shown. And the brightness | luminance profile on the scattering surface 30a in Example 1-4 is shown by the normalization brightness | luminance which set the point whose brightness | luminance is the highest to one.

  Moreover, in FIG. 10 (A), the brightness | luminance profile on the main surface 20a of the surface light-emitting body 20 in Comparative Examples 1-3 and Example 1, 5 and 6 is shown by relative brightness, and in FIG. 10 (B). The luminance profile on the scattering surface 30a in Comparative Examples 1 to 3 and Examples 1, 5 and 6 is shown by the normalized luminance with the point having the highest luminance being 1.

  Furthermore, in FIG. 11 (A), the luminance profile on the main surface 20a of the surface light emitter 20 in Comparative Example 1 and Examples 1, 7 and 8 is shown in relative luminance, and in FIG. 11 (B) The luminance profiles on the scattering surface 30a in Example 1 and Examples 1, 7 and 8 are shown as normalized luminances where the point having the highest luminance is 1.

  In Comparative Example 1, as shown in FIG. 8, the light distribution of the surface light emitter 20 was Lambert light distribution, and the scattering layer 30 used had a transmittance of 40%. In that case, the increase in the apparent light emitting area was approximately 0.19 [mm] by light being radially diffracted according to the thickness of the light transmitting base material 10. As shown in FIGS. 9 (B), 10 (B) and 11 (B), the luminance distribution on the scattering surface 30a is also relatively smooth.

  In Comparative Example 2, as shown in FIG. 8, the light distribution of the surface light emitter 20 was a Lambert light distribution, and the scattering layer 30 used had a transmittance of 75%. In this case, the light is radially diffracted according to the thickness of the light transmitting substrate 10, whereby the apparent increase of the light emitting region is approximately 0.12 [mm]. As shown in FIG. 10B, the luminance distribution on the scattering surface 30a is also relatively smooth.

  In Comparative Example 3, as shown in FIG. 8, the light distribution of the surface light emitter 20 was Lambert light distribution, and the scattering layer 30 used had a transmittance of 90%. In that case, the increase in the apparent light emitting region was approximately 0.10 [mm] by light being radially diffracted according to the thickness of the light transmitting substrate 10. As shown in FIG. 10B, the luminance distribution on the scattering surface 30a is also relatively smooth.

  In Example 1, as shown in FIG. 8, the light distribution of the surface light emitter 20 is Lambert light distribution, the width of the bright part E is 0.1 [mm], and the above-mentioned luminance ratio is 5.00, As the scattering layer 30, one having a transmittance of 40% was used. In that case, the increase in the apparent light emission area was approximately 0.42 [mm]. As shown in FIGS. 9 (B), 10 (B) and 11 (B), the luminance distribution on the scattering surface 30a is also relatively smooth.

  In Example 2, as shown in FIG. 8, the light distribution of the surface light emitter 20 is Lambert light distribution, the width of the bright part E is 0.2 [mm], and the above-mentioned luminance ratio is 2.50, As the scattering layer 30, one having a transmittance of 40% was used. In that case, the increase in the apparent light emission area was approximately 0.37 [mm]. As shown in FIG. 9B, the brightness distribution on the scattering surface 30a is also relatively smooth.

  In Example 3, as shown in FIG. 8, the light distribution of the surface light emitter 20 is Lambert light distribution, the width of the bright part E is 0.3 [mm], and the above-mentioned luminance ratio is 1.67, As the scattering layer 30, one having a transmittance of 40% was used. In that case, the increase in the apparent light emission area was approximately 0.31 [mm]. As shown in FIG. 9B, the brightness distribution on the scattering surface 30a is also relatively smooth.

  In Example 4, as shown in FIG. 8, the light distribution of the surface light emitter 20 is Lambert light distribution, the width of the bright part E is 0.4 [mm], and the above-mentioned luminance ratio is 1.25. As the scattering layer 30, one having a transmittance of 40% was used. In that case, the increase in the apparent light emission area was approximately 0.24 [mm]. As shown in FIG. 9B, the brightness distribution on the scattering surface 30a is also relatively smooth.

  In the fifth embodiment, as shown in FIG. 8, the light distribution of the surface light emitter 20 is Lambert light distribution, the width of the bright part E is 0.1 [mm], and the above-mentioned luminance ratio is 5.00, As the scattering layer 30, one having a transmittance of 75% was used. In that case, the increase in the apparent light emitting area was approximately 0.32 [mm]. As shown in FIG. 10B, the luminance distribution on the scattering surface 30a is also relatively smooth.

  In Example 6, as shown in FIG. 8, the light distribution of the surface light emitter 20 is Lambert light distribution, the width of the bright part E is 0.1 [mm], and the above-mentioned luminance ratio is 5.00, As the scattering layer 30, one having a transmittance of 90% was used. In that case, the increase of the apparent light emission area was approximately 0.27 [mm]. As shown in FIG. 10B, the luminance distribution on the scattering surface 30a has a peak locally.

  In Example 7, as shown in FIG. 8, the light distribution of the surface light emitter 20 is Lambert light distribution, the width of the bright part E is 0.2 [mm], and the above-mentioned luminance ratio is 5.00, As the scattering layer 30, one having a transmittance of 40% was used. In that case, the increase of the apparent light emission area was approximately 0.47 [mm]. As shown in FIG. 11B, the luminance distribution on the scattering surface 30a has a peak locally.

  In Example 8, as shown in FIG. 8, the light distribution of the surface light emitter 20 is Lambert light distribution, the width of the bright part E is 0.1 [mm], and the above-mentioned luminance ratio is 5.00, As the scattering layer 30, one having a transmittance of 40% was used. In that case, the increase in the apparent light emitting area was approximately 0.74 [mm]. As shown in FIG. 11B, the luminance distribution on the scattering surface 30a is also relatively smooth.

  Here, when Comparative Example 1 and Examples 1 to 4 are compared, compared with Comparative Example 1 in which the bright part E is not provided, the apparent light emitting region is obtained in Examples 1 to 4 in which the bright part E is provided. The increase was increased, and it was confirmed that the provision of the bright portion E can further expand the apparent light emission region.

  Moreover, when Comparative Examples 1 to 3 and Examples 1, 5 and 6 are compared, even when the transmittance of the scattering surface 30a is different, as compared with Comparative Examples 1 to 3 in which the bright part E is not provided, The increase in the apparent light emission area is increased in Examples 1, 5 and 6 in which the light area E is provided, and it is confirmed that the apparent light emission area can be further expanded by providing the light area E.

Further, apparent when comparing Examples 1 and 7, as compared to the width W _E is relatively small in Example 1 of the light portion E, the width W _E is relatively large Example 7 of the light portion E increase in the light emitting region of the upper is increasing, it was confirmed that the more enlarged the light-emitting region on the apparent by increasing the width W _E of the bright portion E.

  Moreover, when Example 1 and 8 are compared, compared with Example 1 in which the surface light emitter 20 has Lambert light distribution, apparently in Example 8 in which the surface light emitter 20 has oblique light distribution. It has been confirmed that the increase in the light emission area of the light emission area is increased, and the apparent light emission area can be further expanded by making the light distribution of the surface light emitter 20 oblique light distribution.

However, the luminance ratio L _{E /} L _C is high and the scattering surface having a high transmittance Example 6 30a of the central portion C and the bright portion E of the light emitting region A1, a central portion C and the bright portion E of the light emitting region A1 In Example 7 in which the luminance ratio L _E / L _C is high and the width W _{E of the} bright part E is relatively large, the luminance distribution on the scattering surface 30 a has a peak locally as described above. became. From this, even in the case where the bright portion E is provided, the width WE of the bright portion E, the luminance ratio L _E / L _C of the central portion C of _the light emitting area A1 to the bright portion E, and the scattering surface 30a It is understood that the transmissivity is in a trade-off relationship with each other in expanding the apparent light emitting area while realizing a smooth luminance distribution, and in this sense, it is clear that the light emitting area A1 should be provided at the outer peripheral edge Part E is said that it is preferable that more that the width W _E is narrowed.

  In the embodiment of the present invention mentioned above, although the case where the present invention was applied to the surface emitting module as a back light for tablet terminals was illustrated and illustrated, the applicable range of the present invention is not limited to this, Naturally, the application of the present invention is also possible to surface emitting modules for other applications.

  Further, in the embodiment of the present invention described above, although the case where the present invention is applied to a surface emitting module provided with an organic EL panel provided with an organic electroluminescent layer is described as an example, the application of the present invention The scope is not limited to this, and the present invention can of course be applied to a surface light emitting module and the like provided with an inorganic EL panel provided with an inorganic electroluminescent layer.

  As described above, the above-described embodiment disclosed this time is illustrative in all points and not restrictive. The technical scope of the present invention is defined by the scope of the claims, and includes all the modifications within the meaning and scope equivalent to the description of the scope of the claims.

  DESCRIPTION OF SYMBOLS 1 surface emitting module, 1X, 1Y surface emitting module (verification model), 10 light transmissive base materials, 11 and 12 wiring parts, 20 surface light emitters, 20 a main surface, 21 element parts, 22 anodes, 23 cathodes, 24 organic Layer (electroluminescent layer), 25 insulating portion, 26 sealing portion, 30 scattering layer, 30a scattering surface, 40 reflecting layer, 40a reflecting surface, A1 light emitting region, A2 non-light emitting region, AS light source region (apparent light emitting region ), B1 first boundary line, B2 second boundary line, C central portion, E light portion.

Claims (6)

A surface light emitter including an electroluminescent layer that emits light when a voltage is applied;
A surface emitting module comprising: a light transmitting substrate through which light from the surface light emitter is transmitted;
The surface light emitter has a main surface in contact with the light transmitting substrate and covered by the light transmitting substrate,
When viewed from the direction orthogonal to the main surface, the main surface is a light emitting region which is a region where the electroluminescent layer is located, and a region which is located around the light emitting region and in which the electroluminescent layer is not located Including certain non-emitting areas,
The surface emitting module further includes a scattering surface located on the light transmitting substrate side as viewed from the main surface and separated from the main surface,
When viewed in a direction orthogonal to the main surface, the scattering surface is located over a wider range than the light emitting region;
The brightness of the central portion of the emission region on the main surface when the L _C, the bright area brightness on the main surface is 1.25 × L _C or higher, along the outer edge of the light-emitting region Provided in the light emitting area ,
Wherein the width of the bright portion in the case of the W _E, the W _E is satisfies the condition of W _E ≦ 1 [mm], the surface-emitting module when viewed from a direction perpendicular to said main surface. The distance from the previous SL main surface to the scattering surface in case of a D, the W _E and the D is, which satisfies the condition of W _E ≦ 25 × D, a surface-emitting module according to claim 1. The light emitting region is rectangular when viewed from the direction orthogonal to the main surface,
The length of the shortest side with the previous SL-emitting region when the _{W A1,} wherein _{W E} and the _{W A1} is, which satisfies the condition of _{W E} ≦ 0.1 × _{W A1,} according to claim 1 Surface emitting module. When the light distribution curve is drawn in a plane perpendicular to the main surface of the light from the surface light emitter, the luminance on the front side along the optical axis extending in the direction orthogonal to the main surface is 1, The light distribution curve has at least a portion satisfying the condition of L> cos θ, where L is the luminance in the direction in which the angle formed with the optical axis in the plane is θ in a plane. The surface emitting module according to any one of 3 . The surface emitting module according to any one of claims 1 to 4 , further comprising a reflective surface located on the opposite side to the main surface as viewed from the electroluminescent layer. The surface emitting module according to claim 5 , wherein the reflective surface is positioned over a wider range than the light emitting region when viewed in a direction orthogonal to the main surface.