JP2016085924A - Light emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light emitting device in which both soft light and sharp light are mixed in a well balanced manner.SOLUTION: A light emitting device 10 includes a surface light source 100, point light sources 200 and a diffusion plate 300. The surface light source 100 radiates light from a first surface. The diffusion plate 300 faces the first surface of the surface light source 100. The point light source 200 radiates light toward a lateral surface of the diffusion plate 300. The surface light source 100 has, for example, an organic EL element, and the point light source 200, for example, has an LED. The diffusion plate 300 has a rectangular shape. Then, the plurality of point light sources 200 are, for example, arranged along two sides facing with each other out of the diffusion plate 300.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light emitting device.

  In recent years, organic EL elements have been used as light sources for lighting devices. When the organic EL element is used, the light source of the lighting device can be a surface light source.

  Patent Document 1 describes a lighting device having a plurality of organic electroluminescence (EL) light emitting devices and a plurality of light emitting diodes (LEDs). In this lighting device, the plurality of organic EL light emitting devices and the plurality of LEDs are arranged on the same surface of the substrate. And LED is located between organic electroluminescent light-emitting devices.

JP 2012-151101 A

  When a surface light source such as an organic electroluminescence (EL) element is used as the light source of the illumination device, the light spectrum becomes wide, and the impression of illumination becomes soft. However, depending on the use of the lighting device, a component having a sharp wavelength having an impression opposite to that of soft light, for example, a narrow wavelength of light spectrum, is also required. Such sharp light can be obtained by using a point light source such as a light emitting diode (LED). That is, depending on the use of the lighting device, it is desirable that both soft light and sharp light are mixed in a well-balanced manner.

  An example of a problem to be solved by the present invention is to provide a light emitting device in which both soft light and sharp light are mixed in a well-balanced manner.

The invention according to claim 1 is a surface light source;
A diffuser plate facing the surface light source, and the light of the surface light source is incident on the first surface;
A point light source that emits light toward a second surface different from the first surface of the diffusion plate;
It is a light-emitting device provided with.

It is a top view which shows the structure of the light-emitting device which concerns on embodiment. It is AA sectional drawing of FIG. It is a top view which shows the structure of the light-emitting device which concerns on a modification. It is AA sectional drawing of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

  FIG. 1 is a plan view showing a configuration of a light emitting device 10 according to the embodiment. 2 is a cross-sectional view taken along the line AA in FIG. The light emitting device 10 according to the embodiment includes a surface light source 100, a point light source 200, and a diffusion plate 300. The surface light source 100 emits light from the first surface. The diffuser plate 300 faces the first surface of the surface light source 100. The point light source 200 emits light toward a surface different from the first surface of the diffusion plate 300 (a side surface in the example shown in the figure). This will be described in detail.

  The surface light source 100 includes a substrate 110 and a light emitting unit 120. The light emitting unit 120 is formed on the surface of the substrate 110 opposite to the first surface (light emitting surface) described above.

The substrate 110 is a light-transmitting substrate such as a glass substrate or a resin substrate. The substrate 110 may have flexibility. In the case of flexibility, the thickness of the substrate 110 is, for example, not less than 10 μm and not more than 1000 μm. The substrate 110 is, for example, a polygon such as a rectangle or a circle. When the substrate 110 is a resin substrate, the substrate 110 is formed using, for example, PEN (polyethylene naphthalate), PES (polyethersulfone), PET (polyethylene terephthalate), or polyimide. In the case where the substrate 110 is a resin substrate, an inorganic barrier film such as SiN _x or SiON is formed on at least one surface (preferably both surfaces) of the substrate 110 in order to prevent moisture from passing through the substrate 110. It is preferable.

  The light emitting unit 120 includes, for example, an organic EL element as a light emitting element. This organic EL element has a configuration in which a first electrode, an organic layer, and a second electrode are laminated in this order.

  The first electrode is a transparent electrode having optical transparency. The material of the transparent electrode is a material containing a metal, for example, a metal oxide such as ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), IWZO (Indium Tungsten Zinc Oxide), or ZnO (Zinc Oxide). The thickness of the first electrode is, for example, not less than 10 nm and not more than 500 nm. The first electrode is formed using, for example, a sputtering method or a vapor deposition method. The first electrode may be a carbon nanotube or a conductive organic material such as PEDOT / PSS.

  The organic layer has, for example, a configuration in which a hole injection layer, a light emitting layer, and an electron injection layer are stacked in this order. A hole transport layer may be formed between the hole injection layer and the light emitting layer. In addition, an electron transport layer may be formed between the light emitting layer and the electron injection layer. The organic layer may be formed by a vapor deposition method. In addition, at least one of the organic layers, for example, a layer in contact with the first electrode may be formed by a coating method such as an inkjet method, a printing method, or a spray method. In this case, the remaining layers of the organic layer are formed by vapor deposition. Further, all layers of the organic layer may be formed using a coating method.

  The second electrode is made of, for example, a metal selected from the first group consisting of Al, Au, Ag, Pt, Mg, Sn, Zn, and In, or an alloy of a metal selected from the first group. Contains a metal layer. In this case, the second electrode has a light shielding property. The thickness of the second electrode is, for example, not less than 10 nm and not more than 500 nm. However, the second electrode may be formed using the material exemplified as the material of the first electrode. The second electrode is formed using, for example, a sputtering method or a vapor deposition method.

  In the example shown in the figure, the light emitting unit 120 is formed on almost the entire surface of the substrate 110 excluding the edge, for example. The light emitting unit 120 may be constituted by one organic EL element or may be constituted by a plurality of organic EL elements. In the latter case, the plurality of organic EL elements are linear, for example, and extend in parallel to each other.

  Further, the light emitting unit 120 may include a plurality of types of organic EL elements having different spectral distributions (for example, an organic EL element that emits red light, an organic EL element that emits green light, and an organic EL element that emits blue light). Good. In this case, if at least the anodes of the plurality of types of organic EL elements are made independent of each other, the emission intensity of the plurality of types of organic EL elements can be controlled independently of each other, so that the emission color of the surface light source 100 is variable.

  The point light source 200 has, for example, a light emitting diode (LED), and the spectrum of the emission color is steep with respect to the surface light source 100. It is preferable that the peak wavelength of the emission spectrum of the point light source 200 overlaps the wavelength having a low intensity in the emission spectrum of the surface light source 100. For example, when the color temperature of the surface light source 100 is 2700K, the color temperature of the point light source 200 is around 5000K. The point light source 200 includes, for example, an LED bare chip that emits blue light, and YAG-based phosphor particles that convert blue light into, for example, yellow light. Since the blue light emitted from the LED bare chip and the yellow light generated by the wavelength conversion by the YAG phosphor particles are mixed, the light emitted from the point light source 200 becomes white light. In the LED bare chip, an LED light emitting layer made of a gallium nitride compound semiconductor or the like is formed on the surface of a substrate such as sapphire, and an LED electrode is provided on the surface of the LED light emitting layer.

  In the example shown in the figure, the diffusion plate 300 is rectangular. The plurality of point light sources 200 are arranged along each of the two sides facing each other in the diffusion plate 300, but are not arranged in the region along the remaining two sides. However, the point light source 200 may be disposed along the entire circumference of the diffusion plate 300.

  The diffuser plate 300 is configured such that light can enter from the surface (first surface) and the side surface (second surface) facing the surface light source 100. The diffuser plate 300 can emit light from a surface opposite to the surface facing the surface light source 100. The diffusion plate 300 diffuses the light incident on the inside. In order to do this, for example, if the diffusion plate 300 is formed by dispersing particles (diffusing agent) having a refractive index different from that of the base material in a transparent base material (for example, a transparent resin such as acrylic resin). Good. However, the diffusion plate 300 may have other configurations.

  As mentioned above, according to this embodiment, the light-emitting device 10 has the surface light source 100 and the point light source 200 as a light source. Light from the surface light source 100 enters the inside of the diffusion plate 300 from one surface (first surface) of the diffusion plate 300 and is diffused by the diffusion plate 300, and then the surface of the diffusion plate 300 opposite to the surface light source 100. Radiated from. On the other hand, light from the point light source 200 is incident on the inside of the diffusion plate 300 from a side surface (second surface) different from the first surface of the diffusion plate 300 and diffused by the diffusion plate 300, and then the surface of the diffusion plate 300. The light is emitted from the surface opposite to the light source 100 (third surface). Accordingly, the light emitted from the diffusion plate 300 is in a state where both soft light from the surface light source 100 and sharp light from the point light source 200 are mixed in a well-balanced manner. Further, when the surface light source 100 and the point light source 200 are arranged on the same surface side of the diffusion plate 300, the light from the surface light source 100 and the light from the point light source 200 are not sufficiently mixed and uneven. Compared to this case, in the present embodiment, since the light from the point light source 200 can be sufficiently diffused by the diffusion plate 300, the glare caused by the point light source 200 can be reduced. Further, the area of the surface light source 100 can be increased.

  FIG. 3 is a plan view illustrating a configuration of the light emitting device 10 according to the modification, and FIG. 4 is a cross-sectional view taken along line AA of FIG. FIG. 3 corresponds to FIG. 1 of the embodiment, and FIG. 4 corresponds to FIG. 2 of the embodiment. The light emitting device 10 according to this modification has the same configuration as the light emitting device 10 according to the embodiment except for the configuration of the diffusion plate 300.

  In this modification, the diffusion plate 300 has a configuration in which a plurality of diffusion portions 320 are provided on a transparent base member 310. The base member 310 is made of a transparent resin such as an acrylic resin, and transmits light at least in the thickness direction. The diffusion part 320 is formed at least on the opposite side of the light emission surface of the base member 310 by processing or printing the base member 310.

  Examples of the processing method performed on the base member 310 include a method using an ultrasonic welder, laser processing, and printing. In the method using an ultrasonic welding machine, an uneven roller is pressed against an acrylic resin base member 310 and at the same time, an ultrasonic wave is applied to the roller. In this way, the diffusion part 320 is formed in a dot shape on the surface of the base member 310. In the laser processing, a portion of the acrylic resin base member 310 to be the diffusion portion 320 is irradiated with laser. In printing, silk printing is performed on a portion of the surface of the base member 310 made of acrylic resin to be the diffusion portion 320. Although an example in which the surface of the base member 310 is processed has been described here, the diffusing portion 320 may be formed by dispersing the diffusing member in the base member 310.

  The diffusing portions 320 are two-dimensionally spaced from each other on the base member 310. And the surface light source 100 has overlapped with each of the area | region in which the diffusion part 320 is not provided among the diffusion parts 320 and the base member 310 among the diffusion plates 300. FIG. The width | variety of the spreading | diffusion part 320 is 0.2 mm or more and 10 mm or less, for example. Moreover, the space | interval s of the spreading | diffusion part 320 is 0.2 mm or more and 10 mm or less, for example.

  Also according to this modification, as in the embodiment, the light emitted from the diffusion plate 300 is in a state where both soft light and sharp light are mixed in a well-balanced manner. Moreover, compared with the case where the surface light source 100 and the point light source 200 are arrange | positioned on the same surface side of the diffusion plate 300, the glare feeling resulting from the point light source 200 can be reduced. Further, the area of the surface light source 100 can be increased. Further, the surface light source 100 also overlaps an area of the base member 310 where the diffusing portion 320 is not provided. Therefore, the amount of light emitted from the diffusion plate 300 out of the light emitted from the surface light source 100 is increased as compared with the embodiment.

  As mentioned above, although embodiment and the Example were described with reference to drawings, these are illustrations of this invention and can also employ | adopt various structures other than the above.

DESCRIPTION OF SYMBOLS 10 Light-emitting device 100 Surface light source 200 Point light source 300 Diffusion plate 310 Base member 320 Diffusion part

Claims (4)

A surface light source;
A diffuser plate facing the surface light source, and the light of the surface light source is incident on the first surface;
A point light source that emits light toward a second surface different from the first surface of the diffusion plate;
A light emitting device comprising: The light-emitting device according to claim 1.
The diffusion plate is
A base member that transmits light in the thickness direction of the diffusion plate;
A plurality of diffusing portions provided on the base member and diffusing light separated from each other;
A light emitting device comprising: The light-emitting device according to claim 2.
The surface light source is a light-emitting device that overlaps each of the diffusion plate and a region where the diffusion unit is not provided in the diffusion plate. In the light-emitting device as described in any one of Claims 1-3,
The surface light source has an organic EL element,
The point light source is a light emitting device having a light emitting diode.

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