JP5459658B2 - Planar light emitting device - Google Patents

Description

  The present invention relates to a planar light emitting device that has a luminance gradient on both the front and back surfaces and can emit light with a production effect.

  2. Description of the Related Art Conventionally, planar light emitting devices that emit light on one or both sides using a light emitting element such as organic EL (electroluminescence) are known (see, for example, Patent Documents 1 to 5).

  However, the above conventional planar light emitting device is intended to emit light with uniform luminance and high efficiency, and does not produce an effect by changing the luminance.

  On the other hand, a plurality of optical films made of polycarbonate resin or the like are stacked on a light guide plate made of transparent acrylic resin or the like formed in a rectangular shape, and the brightness of two fluorescent lamps arranged at both ends of the light guide plate is individually set. There is an example of a planar light-emitting device that forms a luminance gradient by controlling to (for example, see Patent Document 6).

  However, the above planar light emitting device emits light only on one side, and does not emit light with a luminance gradient on both sides.

JP 2003-195303 A JP 2004-233957 A JP 2003-100444 A JP 2006-156205 A Japanese Patent Application Laid-Open No. 06-151059 JP 2000-206487 A

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a planar light-emitting device that has a gradient in luminance on both the front and back surfaces and can provide a production effect.

The planar light-emitting device of the present invention has a pair of light-transmitting electrodes provided in the thickness direction and a layer having a light-emitting function sandwiched between the pair of light-transmitting electrodes, and the layer having the light-emitting function A planar light emitting module that emits light emitted from each of the pair of translucent electrodes to each of the module surface and the module back surface; and an arbitrary surface module provided on the module surface and the module back surface. total so is substantially constant output of the at the point module surface side and the module backside output, comprising a reflective member which reflectance is set, wherein the reflective member is a reflective index gradient It is controlled, and is characterized in that the gradient direction of luminance is reversed between the module front surface and the module back surface .

With this configuration, the sum of the luminances of both the front and back surfaces, that is, the surfaces facing each other is substantially constant, so that the luminance suppressed on one surface can be enhanced on the other surface, and efficient light emission is possible. Moreover, the planar light-emitting device which can produce production effects, such as a feeling of depth, can be provided because a brightness | luminance changes gradually. Also, by making the luminance gradients on both sides opposite to each other, the luminance suppressed on one surface can be enhanced on the other surface, so that efficient light emission is possible.

  Furthermore, the present invention provides the above planar light-emitting device, wherein the reflective member increases brightness by continuously changing the reflectance in a predetermined direction from the end surface with respect to light emitted from the planar light-emitting module. It is characterized by forming a gradient.

  With this configuration, it is possible to provide a planar light emitting device capable of producing an effect of gradually changing luminance as in a sense of depth. In addition, since the reflectance is continuously changed to form a gradient in luminance, the luminance suppressed on one surface can be enhanced on the other surface, and efficient light emission is possible.

In the planar light emitting device according to the present invention, the reflective member is a light- transmitting substrate coated with a light diffusive reflective material.

  With this configuration, it is possible to provide a planar light emitting device capable of producing an effect of gradually changing luminance as in a sense of depth.

In the planar light emitting device according to the present invention, the reflective member is a film containing a light diffusive reflective material coated on the translucent electrode.

  With this configuration, it is possible to provide a planar light emitting device capable of producing an effect of gradually changing luminance as in a sense of depth.

  In the planar light emitting device according to the present invention, the reflective member is formed by depositing a metal thin film on the translucent electrode.

  With this configuration, by depositing a metal thin film on the translucent electrode, it is possible to form a half mirror whose reflectivity changes continuously, and the effect of gradually changing the brightness as in the sense of depth. A planar light emitting device having the same can be provided.

Further, the present invention has the planar light emitting device described above, wherein the light-diffusing reflective material or thickness of the coating of the metal thin film of the reflective member is one that continuously changes is there.

This configuration, the thickness of the coating of the reflective member by continuously changing, by applying a gradient in reflectance can form a gradient in luminance, it exhibits the dramatic effect such as sense of depth Is possible.

Further, the present invention provides a planar light emitting device of the above, the concentration of the light diffusing reflecting material of the reflective member is characterized in that in which changes continuous manner.

With this configuration, by continuously changing the concentration of the light diffusive reflective material of the reflective member, it is possible to form a gradient in luminance by providing a gradient in reflectivity, and there is an effect such as a sense of depth. It becomes possible.

  In the planar light emitting device according to the present invention, the layer having the light emitting function is formed of an organic EL element.

  With this configuration, it is possible to provide a surface light-emitting device that has a gradient in luminance on both the front and back surfaces and can efficiently produce both sides of light, which can produce a production effect.

  ADVANTAGE OF THE INVENTION According to this invention, the planar light-emitting device which has a gradient in brightness | luminance on both front and back sides, and can show | play an effect can be provided.

Sectional drawing which shows schematic structure of the planar light-emitting device concerning embodiment of this invention FIG. 3 is a schematic diagram showing a luminance gradient of light emission in the planar light emitting device according to the embodiment of the present invention. (A) The perspective view which shows the installation image of the planar light-emitting device which concerns on embodiment of this invention (b) The perspective view which shows the other installation image of the planar light-emitting device which concerns on embodiment of this invention 1 is a perspective view illustrating a schematic configuration of a planar light emitting device according to a first embodiment of the present invention. In the surface light-emitting device of Example 2 of this invention, the perspective view which shows the schematic structure In the planar light-emitting device of Example 3 of this invention, the perspective view which shows the schematic structure

  Hereinafter, planar light-emitting devices according to embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a schematic configuration of a planar light emitting device according to an embodiment of the present invention.

  In FIG. 1, the planar light emitting device 1 of the present embodiment includes a planar light emitting module 10 and luminance gradient forming members 20 a and 20 b as a pair of reflective members disposed on both surfaces of the planar light emitting module 10. It is a configuration.

  The planar light emitting module 10 constitutes an organic EL element, and includes a layer 11 having a light emitting function and a pair of translucent electrodes 12a and 12b arranged so as to sandwich the layer 11 having a light emitting function. Is done. The translucent electrodes 12a and 12b are composed of an ITO (Indium Tin Oxide) thin film formed by sputtering or the like, and the layer having a light emitting function is composed of a coating film. Here, the layer having a light emitting function refers to the entire layer for exhibiting the light emitting function, such as a buffer layer, a charge injection layer, a charge transport layer, and a light emitting layer.

  The pair of translucent electrodes 12a and 12b is connected to a lighting circuit (not shown) to be an anode or a cathode, respectively, and causes the layer 11 having a light emitting function to emit light by applying a voltage between both electrodes.

  The luminance gradient forming members 20a and 20b have a function of radiating the light emitted from the planar light emitting module 10 to the outside with a luminance gradient that is horizontal and opposite to each other. Here, the horizontal direction means a direction orthogonal to the optical axis of the light emitted from the planar light emitting module 10.

  FIG. 2 is a schematic diagram showing a luminance gradient of light emitted from the planar light emitting device 1 configured as described above. In the figure, the luminances La and Lb indicated by vectors are point symmetric with respect to the center of gravity of the planar light emitting device 1, and the sum of the absolute values of the vectors is substantially constant at any position in the horizontal direction.

  Next, the installation state of the planar light emitting device 1 according to the present embodiment will be described. FIGS. 3A and 3B are diagrams illustrating an installation image of the planar light emitting device 1.

  In both figures, the planar light emitting device 1 is formed in a large-sized panel and installed in a passage or the like, and is emitted from the planar light emitting device 1 when people M1 to M3 proceed in the direction indicated by the arrows. As the brightness of the light gradually decreases, it is possible to achieve a production effect that gives the passage a sense of depth.

  The luminance gradient forming members 20a and 20b can be formed of a reflective member that diffusely reflects the light emitted from the planar light emitting module 10, and are equivalent by forming a gradient of reflectance in the horizontal direction. It is possible to form a brightness gradient.

  Below, the Example of the planar light-emitting device which actualized the brightness | luminance gradient formation members 20a and 20b is described using drawing. 4 to 6 for describing the embodiment, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is simplified or omitted.

Example 1
FIG. 4 is a perspective view showing a schematic configuration of the planar light emitting device of Example 1 of the present invention.

  In FIG. 4, the planar light-emitting device 2 of the present embodiment is composed of a planar light-emitting module 10 and a pair of diffuse reflection layers 21a and 21b arranged with the sandwiched therebetween.

  The diffuse reflection layers 21a and 21b are formed by dispersing a light diffuse reflection material, for example, a white pigment such as silica or aluminum oxide, in a light-transmitting binder such as an acrylic resin or a vinyl resin. It is formed by coating on a substrate.

  As shown in FIG. 4, the gradient of reflectance in the diffuse reflection layers 21 a and 21 b is formed by continuously changing the concentration of paint during coating from one end face to the other end face. Further, the apparent concentration may be changed by continuously changing the thickness of the coating film while keeping the coating concentration constant during coating.

  The diffuse reflection layers 21a and 21b may be formed by directly coating the both surfaces of the planar light emitting module 10 with the paint having the above composition.

  The planar light emitting device 2 of this embodiment configured as described above diffuses and reflects light uniformly radiated from both surfaces of the planar light emitting module 10 by the diffuse reflection layers 21a and 21b having gradients in reflectance. The light having a luminance gradient in different directions in the horizontal direction is emitted from both sides.

  Thereby, the planar illumination which has a production effect can be performed. In addition, since the luminance gradients are opposite to each other in the diffuse reflection layers 21a and 21b, the luminance suppressed on one surface can be enhanced on the other surface, and efficient light emission is possible.

(Example 2)
FIG. 5 is a perspective view showing a schematic configuration of the planar light emitting device of Example 2 of the present invention.

  In FIG. 5, the planar light emitting device 3 of the present embodiment is composed of a planar light emitting module 10 and a pair of diffuse reflection layers 22 a and 22 b arranged with the sandwiched therebetween.

  In the diffuse reflection layers 22a and 22b, a dot pattern for controlling the reflectance is formed on a translucent substrate using a paint having the same composition as that of the first embodiment.

  The gradient of reflectance in the diffuse reflection layers 22a and 22b is formed by continuously changing the density of dots in the dot pattern from one end face to the other end face. Further, the dot shape or size may be continuously changed. Further, the dot density and shape may be combined.

  The dot pattern to be applied onto the light-transmitting substrate can be formed by printing such as screen printing or ink jet.

  As a method other than the printing technique, a dot pattern made of a metal thin film can be formed by sputtering, vapor deposition, photolithography, or the like.

  Note that the diffuse reflection layers 22 a and 22 b may be formed by directly applying the coating material having the above-described composition or dots made of a metal thin film to both surfaces of the planar light emitting module 10.

  The planar light emitting device 3 of the present example configured as described above diffuses light uniformly radiated from both surfaces of the planar light emitting module 10 with a gradient in reflectance, as in the first example. By performing diffuse reflection by the reflection layers 22a and 22b and radiating light having luminance gradients in different directions in the horizontal direction from both surfaces, it is possible to perform planar illumination with a production effect. Moreover, the luminance gradient between the diffuse reflection layers 22a and 22b is opposite to each other, whereby the luminance suppressed on one surface can be enhanced on the other surface, and efficient light emission can be achieved.

(Example 3)
FIG. 6 is a perspective view showing a schematic configuration of a planar light emitting device according to Example 3 of the present invention.

  In FIG. 6, the planar light emitting device 4 of the present embodiment is composed of a planar light emitting module 10 and a pair of half mirrors 23 a and 23 b disposed as a reflective member interposed therebetween.

  The half mirrors 23a and 23b are formed by forming a metal thin film such as aluminum or silver on a light-transmitting substrate by vacuum vapor deposition or sputtering. By controlling the thickness of the thin film to be formed, the reflectance and transmittance can be controlled. Give a gradient.

  The planar light emitting device 4 of the present example configured as described above reflects light uniformly radiated from both surfaces of the planar light emitting module 10 in the same manner as in the first and second embodiments described above. It is possible to perform planar illumination with a production effect by diffusing and reflecting or transmitting light by the half mirrors 23a and 23b having a gradient, and emitting light having a luminance gradient in different directions in the horizontal direction from both sides.

  In addition, since the luminance gradients are opposite to each other in the half mirrors 23a and 23b, the luminance suppressed on one surface can be increased on the other surface, and efficient light emission is possible.

  As described above, according to the planar light emitting device according to the embodiment of the present invention, the planar light emitting module and the planar light emitting module are disposed on both surfaces and radiated from the planar light emitting module. A pair of reflective members (luminance gradient forming members) that diffuse and reflect light, form a luminance gradient opposite to each other in the horizontal direction, and radiate the light to the outside are provided.

  The brightness gradient forming member is formed as a diffuse reflection layer coated on a translucent substrate by controlling the concentration of a paint kneaded with a white pigment. Moreover, it forms as a diffuse reflection layer which printed the coating material of the same composition on the translucent board | substrate by controlling the dot density of a dot pattern. Further, it is formed as a half mirror deposited by controlling the thickness of the metal thin film.

  Thereby, planar light emission having a production effect can be performed, and the luminance suppressed on one surface can be enhanced on the other surface, so that efficient light emission is possible.

1, 2, 3 Planar light emitting device 10 Planar light emitting module 11 Layer having light emitting function 12a, 12b Translucent electrode 20a, 20b Luminance gradient forming member (reflective member)
21a, 21b, 22a, 22b Diffuse reflective layer (reflective member)
23a, 23b Half mirror (reflective member)

Claims (8)

A pair of translucent electrodes provided in the thickness direction; and a layer having a light emitting function sandwiched between the pair of translucent electrodes, and the light emitted from the layer having the light emitting function is A planar light emitting module that emits light to the module front surface and the module back surface on each side of the translucent electrode;
A reflective member provided on the module surface and the module back surface, the reflectivity of which is set so that the sum of the output on the module surface side and the output on the module back side at an arbitrary point of the planar module is substantially constant ; and it includes a,
The reflective member has a controlled reflectance gradient,
A planar light-emitting device configured such that luminance gradient directions are reversed on a module front surface and a module back surface . The planar light emitting device according to claim 1 ,
The reflective member is
A planar light-emitting device that forms a gradient in luminance by continuously changing reflectance in a predetermined direction from an end surface with respect to light emitted from the planar light-emitting module. The planar light emitting device according to claim 2 ,
The planar light emitting device, wherein the reflective member is a light transmissive substrate coated with a light diffusive reflective material. The planar light emitting device according to claim 2 ,
The planar light emitting device, wherein the reflective member is a film containing a light diffusive reflective material coated on the translucent electrode. The planar light emitting device according to claim 2 ,
The planar light emitting device, wherein the reflective member is formed by depositing a metal thin film on the translucent electrode. A planar light-emitting device according to any one of claims 3 to 5 ,
In which the thickness changes continuously is planar light emitting device of the light diffusing reflective material or coating of the metal thin film of the reflective member. The planar light-emitting device according to claim 3 or 4 ,
The density of the light diffusing reflecting material of the reflective member is planar light emitting device is to change continuous manner. A planar light-emitting device according to any one of claims 1 to 7,
The planar light emitting device, wherein the layer having a light emitting function is formed from an organic EL element.

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