JP2009146741A - Planar emission type lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a planar emission type lighting system having improved light emitting efficiency and higher presentation illumination. <P>SOLUTION: The planar emission type lighting system comprises a planar light source 100, and a point-like light source 200 arranged adjacent to the light emitting face of the planar light source 100. The optical axis of the point-like light source 200 is arranged to cross the light emitting face of the planar light source 100. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a planar light-emitting illumination system, and more particularly to a planar light-emitting illumination system that can be used for a liquid crystal backlight, a lighting fixture, or the like by combining a point light source and a planar light source.

In recent years, electroluminescent elements such as organic electroluminescence (EL) elements have been proposed as planar light-emitting illumination devices, and light-emitting diodes (LEDs) have been proposed as point light source illumination devices. An electroluminescent element emits light when a voltage is applied to a fluorescent material, and can be classified into an organic electroluminescent element and an inorganic electroluminescent element depending on the fluorescent material used. In particular, the organic electroluminescence element can easily emit light on a plane, can emit light with a high luminance of about 100 to 100,000 cd / m ² at a low voltage of about 10 V such as a battery, and the combination of materials constituting the fluorescent substance. Since it can emit a large number of colors, it attracts attention as a flat light emitter.

  There are two methods for obtaining white light emission using an organic electroluminescence element: a method obtained by synthesizing light emission each having three wavelengths of RGB (red, green, and blue), two wavelengths of blue and yellow, and blue-green and orange. There is a method of obtaining using a wavelength having a complementary color relationship such as two wavelengths. In the case of three wavelengths of RGB (red, green, and blue), for example, in an organic electroluminescence element, the luminous efficiency and life of red are lower than blue and yellow. For this reason, color deviation is likely to occur due to different deterioration rates of RGB (red, green, blue) three wavelengths, and it is difficult to easily obtain white. On the other hand, in the case of two wavelengths using complementary colors, the light emission efficiency can be increased, but for use in a liquid crystal backlight or the like that requires a full color, a white color with little red component and excellent chromaticity balance is obtained. Is difficult.

Thus, a lighting fixture using only a planar light emitting element cannot realize an illumination environment adjusted to the luminance and color temperature according to the characteristics of the light source, resulting in uniform and simple effect lighting.
On the other hand, in the case of a point light source such as an LED, spot illumination is possible, but it is the same that it is simple effect illumination.

  In addition, although an illumination system that combines a planar light emitting element and a point light source has been proposed, it is usual to individually adjust the planar light emitting element or the point light source to prepare an illumination environment. Homogeneous and simple production lighting. Also, the setting of the irradiation direction only depends on the individual setting direction.

  Therefore, the applicant of the present application has intended to provide a flat light emitter that can achieve a white color with good luminous efficiency and excellent chromaticity balance, and as shown in FIG. The LED 5 is disposed on the end face of the translucent substrate of the organic electroluminescent element in which the layer 2, the light emitting layer 3, and the cathode 4 are formed, and light is irradiated into the translucent substrate. A planar light emitting device has been proposed (Patent Document 1).

JP 2003-92002 A

  In the planar light emitting device of Patent Document 1, the light emitted from the LED element enters the translucent substrate and is guided while being totally reflected in the translucent substrate, and a part of the translucent substrate. Therefore, the emission wavelength of light emitted from the planar light emitting device can be adjusted using the light emitted from the LED element and the light emitted from the layer having a light emitting function.

According to this planar light emitting device, the color balance can be adjusted. However, there is an increasing demand for further improvement of the light emission efficiency and realization of various and highly sophisticated lighting.
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 illumination system capable of improving the light emission efficiency and enhancing the production lighting.

Therefore, the planar light-emitting illumination system of the present invention includes a planar light source and a point light source disposed in the vicinity of the light emitting surface of the planar light source, and the optical axis of the point light source is the planar light source. It is arranged to intersect with the light emitting surface of the light source.
With this configuration, the light from the point light source can be used for illumination without passing through components such as the substrate of the planar light source, so that there is little attenuation and high-efficiency and high-quality lighting can be realized. Can do. Also, by combining the light from the planar light source and the light from the point light source, it is possible to realize various and complicated lighting effects with respect to directions and emission colors.

In the planar light-emitting illumination system, the optical axis of the point light source may be greater than a critical angle so that light from the point light source can be reflected by the light emitting surface of the surface light source. The one arranged to intersect the light emitting surface of the planar light source is included.
With this configuration, since the light from the point light source is reflected by the light emitting surface of the planar light source, the light and the irradiation light from the planar light source itself combine to produce a high luminance / high color temperature and a low luminance / low color. It is possible to perform complicated production lighting in which temperatures are mixed.

Further, the present invention is the above planar light-emitting illumination system, wherein the optical axis of the point light source is arranged so that direct light from the point light source intersects light from the light emitting surface of the planar light source. Including
With this configuration, the light from the point light source is emitted without hitting the light emitting surface of the planar light source, and is combined with the light from the planar light source, so that higher efficiency can be achieved.

In the planar light-emitting illumination system according to the present invention, an upright part is provided on at least one side of a frame that supports the planar light source, and the point light source is attached to the upright part. including.
With this configuration, since the point light source is attached to the upright portion formed on the frame of the surface light source, it is possible to provide a planar light emitting illumination system that is small and has good design.

According to the present invention, in the planar light-emitting illumination system, the point light source includes a plurality of light emitting diodes (LEDs) arranged in a line so as to be parallel to a light emitting surface of the planar light source. Including things.
With this configuration, high-luminance light emission with low power consumption can be obtained. Further, although there is a variation in the amount of light of the LED itself, this variation in the amount of light can be reduced by combining with the light from the planar light source, and soft light can be obtained.

Further, the present invention includes the above planar light emitting illumination system, wherein the planar light source is an organic electroluminescence element.
According to this configuration, the structure of the organic electroluminescence element as a planar light source is adjusted, in the case of a back emission type organic electroluminescence element that emits light from the substrate side, in the case of the top emission type organic electroluminescence element that emits light from the surface side The desired photosynthesis can be realized by adjusting the physical properties of the substrate constituent material or the translucent electrode and the protective film according to each.

  Here, the planar light source refers to a surface light emitting element such as an organic electroluminescence element and an assembly formed by arranging a plurality of the same in the same plane, the entire surface constituting a light emitting surface, and The entire surface excluding the non-light emitting region such as a part of the joint portion constitutes the light emitting surface.

As described above, according to the present invention, since a planar light source and a point light source are combined, each luminance and color temperature is utilized, and a high luminance and high color temperature, and a low luminance and low color are used. By mixing the temperatures, it is possible to perform sophisticated lighting.
In addition, since the optical axis of the point light source and the light emitting surface of the surface light source such as the organic electroluminescence element intersect, the light from the point light source is irradiated to the surface light source or the vicinity thereof, By combining the light and the irradiation light from the planar light source itself, it is possible to perform complicated production lighting in which high luminance / high color temperature and low luminance / low color temperature are mixed.
Furthermore, if the light from the point light source irradiates the light exit surface of the surface light source, the reflected light from the light emitting surface and the light emitted from the surface light source itself interfere and are combined, making it more complicated. It is possible to perform direct lighting.

Hereinafter, embodiments of the present invention will be described in detail.
(Embodiment 1)
The planar light-emitting illumination system according to Embodiment 1 of the present invention, as shown in a schematic diagram of FIG. 1, is a planar configuration composed of an organic electroluminescence element and a frame body 102 that supports the organic electroluminescence element. A point light source unit 200 is disposed on a light source 100 and an upright portion 103 provided on at least one side of a frame 102 of the planar light source 100. The point light source unit 200 includes ten light emitting diodes (LEDs) 201a to 201i arranged in a line on the upright portion 103, and is reflected by the light emitting surface of the planar light source. As can be seen, the point light source is arranged so that the optical axis of the point light source intersects the light emitting surface of the planar light source 100. The angle θ1 of the optical axis of the LED with respect to the light emitting surface is arranged to be larger than the critical angle θ. In this way, the light L1 emitted from the layer having a light emitting function and the light L2 of the LED as a highly directional point light source are mixed on the light emitting surface of the planar light source, so that the emission spectrum is broadened. , To achieve advanced stage lighting.

  The planar light source includes an organic electroluminescence element 101 that constitutes a light emitting unit, and a frame 102 that supports the periphery of the organic electroluminescence element 101, and a thin illumination that incorporates a power supply circuit in the frame. Device.

As shown in FIG. 2, an enlarged cross-sectional view of the main part of the organic electroluminescence element 101 includes an anode 2 made of a transparent conductive film, a layer 3 having a light emitting function, and a cathode 4 in this order on the back surface of the translucent substrate 1. A laminate is formed. As the translucent substrate 1, a translucent glass plate such as soda lime glass or non-alkali glass, a translucent plastic plate, or the like can be used. The light-transmitting substrate 1 may be light-transmitting and may be colorless or transparent, slightly colored, or ground glass.
Further, the light L2 ′ from a part of the LED is arranged so that the optical axis is incident at an incident angle θ2 which is equal to or less than the critical angle, and is reflected by the anode or the cathode of the organic electroluminescence element. Also good.

  In addition to the so-called light emitting layer, the layer 3 having a light emitting function is a multilayer film in which a hole transport layer is stacked on the anode 2 side and an electron injection layer is stacked on the cathode 4 side. When a negative voltage is applied to the electrons, electrons injected through the electron injection layer and holes injected through the hole transport layer are combined in the light emitting layer to emit light. Thus, the light L1 emitted from the layer 3 having a light emitting function is transmitted through the anode 2 made of a transparent conductive film and the translucent substrate 1 and extracted from the surface side of the translucent substrate 1. An arrow L1 in FIG. 2 schematically shows the traveling direction of light emitted from the layer 3 having a light emitting function. The organic electroluminescence element 101 can emit light with high luminance at a low voltage of about 10 V such as a battery.

The anode 2 is an electrode for injecting holes into the layer having a light emitting function, and an electrode material made of a metal, an alloy, a conductive compound, or a mixture thereof having a high work function is preferably used. Is preferably 4 eV or more. Examples of the material of the anode 2 include Au (gold) metal, CuI (copper iodide), ITO (indium tin oxide: indium tin oxide), SnO ₂ (tin oxide), ZnO (zinc oxide), and the like. The translucent conductive material can be used. The anode 2 is formed, for example, by depositing and patterning these electrode materials on the surface of the translucent substrate 1 by a method such as a vacuum deposition method or a sputtering method. In order to transmit the light emitted from the layer 3 having a light emitting function to the outside through the anode 2, the light transmittance of the anode 2 is preferably set to 70% or more. Furthermore, the sheet resistance of the anode 2 is preferably several hundred Ω / □ or less, particularly preferably 100 Ω / □ or less. Here, the film thickness of the anode 2 varies depending on the material in order to control the light transmittance, sheet resistance, and other characteristics of the anode 2 as described above, but is set to a range of 500 nm or less, preferably 10 to 200 nm. Is desirable.

The cathode 4 is an electrode for injecting electrons into the layer 3 having a light emitting function, and it is preferable to use an electrode material made of a metal, an alloy, a conductive compound, or a mixture thereof having a low work function. The function is preferably 5 eV or less. Examples of the electrode material of the cathode 4 include sodium, sodium-potassium alloy, lithium, magnesium, aluminum, magnesium-silver mixture, magnesium-indium mixture, aluminum-lithium alloy, Al / Al ₂ O ₃ mixture, Al / LiF mixture and the like. Similarly to the anode, the cathode 4 can be obtained by, for example, patterning these electrode materials after film formation by a method such as vacuum deposition or sputtering. In order to irradiate the anode 2 with the light emitted from the layer 3 having a light emitting function, the light transmittance of the cathode 4 is preferably 10% or less. Here, the film thickness of the cathode 4 varies depending on the material, but is usually 500 nm or less, preferably in the range of 100 to 200 nm in order to control characteristics such as light transmittance of the cathode 4.

  Here, of the layer 3 having a light emitting function, a light emitting material or a doping material used for a light emitting layer sandwiched between an electron transport layer and a hole transport layer is anthracene, naphthalene, pyrene, tetracene, coronene, perylene, phthaloperylene, naphthaloperylene, Diphenylbutadiene, tetraphenylbutadiene, coumarin, oxadiazole, bisbenzoxazoline, bisstyryl, cyclopentadiene, quinoline metal complex, tris (8-hydroxyquinolinato) aluminum complex, tris (4-methyl-8-quinolinato) aluminum Complexes, tris (5-phenyl-8-quinolinato) aluminum complexes, aminoquinoline metal complexes, benzoquinoline metal complexes, tri- (p-terphenyl-4-yl) amine, 1-aryl-2,5-di (2 -Thienyl) pi Examples thereof include, but are not limited to, a roll derivative, pyran, quinacridone, rubrene, a distilbenzene derivative, a distilarylene derivative, and various fluorescent dyes.

  The layer 3 having the light emitting function has a hole transport layer laminated between the light emitting layer and the anode 2, that is, on the anode side, and the material constituting the hole transport layer has the ability to transport holes. A compound that has a hole injection effect from the anode 2, an excellent hole injection effect for the light emitting layer, prevents movement of electrons to the hole transport layer, and has an excellent thin film forming ability. Can be mentioned. Specifically, phthalocyanine derivatives, naphthalocyanine derivatives, porphyrin derivatives, N, N′-bis (3-methylphenyl)-(1,1′-biphenyl) -4,4′-diamine (TPD) and 4,4 Aromatic diamine compounds such as' -bis [N- (naphthyl) -N-phenyl-amino] biphenyl (α-NPD), oxazole, oxadiazole, triazole, imidazole, imidazolone, stilbene derivative, pyrazoline derivative, tetrahydroimidazole, Polyarylalkanes, butadiene, 4,4 ′, 4 ″ -tris (N- (3-methylphenyl) N-phenylamino) triphenylamine (m-MTDATA), and polyvinylcarbazole, polysilane, polyethylene dioxide thiophene (PEDOT) ) And other conductive polymers Molecular material and the like.

  The layer 3 having a light emitting function has an electron injection layer laminated between the light emitting layer and the cathode 4, that is, on the cathode 4 side, and the material constituting the electron injection layer is an ability to transport electrons. Has an electron injection effect from the cathode 4 and has an excellent electron injection effect for the layer 3 having a light emitting function, and further prevents movement of holes to the electron injection layer, and a thin film forming ability Can be mentioned. Specifically, fluorene, bathophenanthroline, bathocuproine, anthraquinodimethane, diphenoquinone, oxazole, oxadiazole, triazole, imidazole, anthraquinodimethane, etc. and their compounds, metal complex compounds or nitrogen-containing five-membered ring derivatives is there. Furthermore, the polymer material used for a polymer organic electroluminescent element can also be used. For example, polyparaphenylene and derivatives thereof, fluorene and derivatives thereof, and the like. The electron injection layer can be formed, for example, by co-evaporating bathophenanthroline and Cs (cesium) at a molar ratio of 1: 1.

  In this planar light emitting illumination system, the planar light source 100 composed of the organic electroluminescence element is provided with a point light source 200 composed of a line-shaped LED element attached to the frame 103. Is. The light L2 emitted from the LED elements 201a to 201i is reflected and emitted by the diffusion layer 7 formed on the back surface of the translucent substrate 1 of the organic electroluminescence element constituting the planar light source 100, and translucent. The light enters the substrate 1 and part of the light is totally reflected by the anode 2 and then emitted. Further, the emitted light L1 from the organic electroluminescence element and the emitted light L2 from the point light source 200 (LEDs 201a to 201i) are reflected on the light emitting surface of the planar light source 100 and the diffusion layer 7 constituting the light scattering portion. The light is emitted as scattered light L3 to the surface side due to the scattering phenomenon due to. Further, the light L2 ′ from a part of the LED is arranged so that the optical axis is incident at an incident angle θ2 which is less than the critical angle, and is reflected by the anode or the cathode of the organic electroluminescence element. It may be.

  Thus, in the planar light emitting illumination system according to the present embodiment, a part of the light L2 emitted from the LEDs 200a to 201i is scattered light L3 generated by the scattering phenomenon, and the light emitted from the layer 3 having a light emitting function. By mixing with L1, high-level effect lighting is possible.

  Formation of the diffusion layer that constitutes the light scattering portion 7 can be obtained by performing a sand blasting process on the surface side of the translucent substrate 1 to form minute irregularities, or disposing a diffusion bead layer. . The light scattering portion 7 is formed on the surface side of the translucent substrate 1 as long as the light L2 emitted from the LEDs 201a to 201i is emitted to the surface side of the translucent substrate 1 due to a scattering phenomenon. Not limited to this, the inside of the translucent substrate 1 may be used.

  In the planar light emitting illumination system of the present embodiment, in order to adjust the emission spectrum to be emitted, it is included in the low-intensity wavelength or the light L1 among the emission wavelengths of the light L1 emitted from the layer 3 having a light emitting function It is desirable to reinforce the wavelength that is not emitted by the emitted light L2 from the LED element. Therefore, it is desirable to appropriately select LEDs 201a to 201i having specific emission wavelengths.

  The planar light-emitting illumination system formed in this way is capable of high-efficiency and high-quality lighting by selecting an appropriate combination, such as using an electroluminescent element that emits blue and yellow and a red LED. .

In the above embodiment, a so-called back emission type organic electroluminescence element in which light is emitted from the substrate side of the organic electroluminescence element constituting the planar light source has been described. In this structure, in general, the cathode is a metal. Since it is composed of a layer, that is, a mirror-like layer, the reflected light can be effectively utilized by having a reflection surface effect. Further, since the light passes through the light-transmitting substrate, the anode, the layer having a light emitting function, and the cathode and the multilayer, although there is attenuation, softer light can be emitted by multiple reflection.
In addition, according to the so-called top emission type organic electroluminescence device in which light is emitted from the side facing the substrate, the diffusion effect can be increased by adjusting the material of the protective film covering the cathode or the upper layer. It is also possible to realize production lighting.

(Embodiment 2)
Embodiment 2 of the present invention will be described below.
The planar light-emitting illumination system of Embodiment 1 is configured such that light from a point light source is reflected by the light emitting surface of the organic electroluminescence element 100 as a planar light source. In this embodiment, FIG. And as shown in FIG. 4, the point light source 200 comprised by LED201a-201i is the light emission surface of the said planar light source, without the light L2 from the said point light source injecting into the light emission surface of the said planar light source. Further, it is arranged so as to intersect with the light L1 from the planar light source on the front side.

  With this configuration, the light from the point light source is emitted without hitting the light emitting surface of the planar light source, and is combined with the light from the planar light source, so that higher efficiency can be achieved. Since each element is formed in the same manner as in the first embodiment, description thereof is omitted here.

  As described above, according to the present embodiment, light from a point light source can be used for illumination without passing through a component such as a substrate of a planar light source, so that attenuation is small and high efficiency. In addition, advanced production lighting can be realized.

  In the above embodiment, the point light sources are all in the same direction, but it goes without saying that the emission direction may be different for each LED.

  Furthermore, the point light source 200 composed of the line light source is not integrated with the planar light source 100, but is configured to be detachable, and the point light source 200 is switched to change the direction of the point light source. It is also possible to change.

  As described above, according to the present invention, since it is possible to realize high-level effect lighting, it can be applied in a wide range from home lighting to theaters and showrooms.

1 is an external view showing a surface light emitting illumination system according to Embodiment 1 of the present invention. The principal part cross-sectional enlarged view of the planar light emission type illumination system of Embodiment 1 of this invention. External view showing a planar light-emitting illumination system according to a second embodiment of the present invention. Sectional enlarged view of the main part of the planar light-emitting illumination system according to Embodiment 2 of the present invention. The figure which shows the planar light emission type illumination system of a prior art example

Explanation of symbols

100 planar light source 200 point light source

Claims (6)

A planar light source;
Arranged close to the light emitting surface of the planar light source,
A planar light-emitting illumination system comprising: a point light source in which an optical axis of the point light source intersects a light emitting surface of the planar light source. The planar light-emitting illumination system according to claim 1,
The optical axis of the point light source is arranged to intersect the light emitting surface of the planar light source at an angle larger than a critical angle so that light from the point light source can be reflected by the light emitting surface of the planar light source. Planar light-emitting lighting system. The planar light-emitting illumination system according to claim 1,
An optical axis of the point light source is a planar light emitting illumination system arranged such that direct light from the point light source intersects light from a light emitting surface of the planar light source. A planar light-emitting illumination system according to any one of claims 1 to 3,
An upright portion is provided on at least one side of the frame that supports the planar light source,
The point light source is a planar light-emitting illumination system attached to the upright portion. The planar light-emitting illumination system according to claim 4,
The point light source is a planar light emitting illumination system including a plurality of light emitting diodes (LEDs) arranged in a line so as to be parallel to the light emitting surface of the planar light source. A planar light-emitting illumination system according to any one of claims 1 to 5,
The planar light source is a planar light-emitting illumination system that is an organic electroluminescence element.

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