JP2011034872A - Lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting device that achieves the further size reduction while allowing adjustment of the color temperature of white light. <P>SOLUTION: The lighting device has a laminated structure in which at least a reflecting electrode 2, a light-emitting layer 22, and a transparent electrode 10 are laminated. The laminated structure is configured such that an optical-path difference-adjusting layer 21 is interposed between the reflecting electrode 2 and the light-emitting layer 22 so as to adjust an optical-path difference between light emitted from the light-emitting layer 22 toward the transparent electrode 10 and light emitted from the light-emitting layer 22 toward the reflecting electrode 2 and reflected by the reflecting electrode 2. The thickness of the optical-path difference-adjusting layer 21 is adjusted such that the color temperature of white light, outgoing after transmitting through the transparent electrode 10, becomes a desired color temperature. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a lighting device using an organic EL (Electro Luminescence) element.

  In recent years, research and development of illumination devices using organic EL elements that are surface light sources have been promoted. In the lighting field, a lineup of a plurality of types of products having different color temperatures, such as daylight color, daylight white color, and light bulb color, is common even if the brightness is the same. Similarly, a product lineup is required for a lighting device using an organic EL element. Therefore, a technique for adjusting the color temperature of white light emitted from the organic EL element has been proposed (see Patent Document 1).

  In Patent Document 1, three types of laminates of an anode, a light-emitting layer, and a cathode are prepared in red, green, and blue, and these laminates are further laminated with a glass substrate interposed therebetween. Techniques for applying individual voltages between electrodes have been disclosed. According to this, since the emitted light of each laminated body is mixed, white light can be obtained, and since the voltage is adjusted individually, it is described that the color temperature of white light can be adjusted. .

JP 2005-317296 A

However, the prior art cannot be applied to a light emitting layer that emits white light in principle, and an anode and a cathode must be provided for each of the three types of light emitting layers of red, green, and blue. For this reason, there is a problem that it is difficult to reduce the thickness of the organic EL element and hence to reduce the size of the lighting device.
Accordingly, an object of the present invention is to provide an illumination device that can adjust the color temperature of white light and can be made smaller than before.

  An illumination device according to the present invention is an illumination device including a laminated structure in which at least a reflective electrode, a light emitting layer, and a transparent electrode are laminated, and the laminated structure further includes a gap between the reflective electrode and the light emitting layer. In addition, there is an optical path difference adjusting layer that adjusts an optical path difference between the light emitted from the light emitting layer toward the transparent electrode and the light emitted from the light emitting layer toward the reflective electrode and reflected by the reflective electrode. The thickness of the optical path difference adjusting layer is adjusted so that the color temperature of the white light transmitted through the transparent electrode becomes a desired color temperature.

According to the above configuration, since the color temperature of the light transmitted through the transparent electrode is adjusted by adjusting the thickness of the optical path difference adjusting layer, it is individually provided for the three types of light emitting layers of red, green, and blue. There is no need to apply a voltage to the capacitor, and the size can be reduced as compared with the prior art.
The optical path difference adjusting layer may be composed of a plurality of layers made of different materials, and only the thickness of one of the layers may be adjusted. According to this, when manufacturing a plurality of types of products having different color temperatures, it is only necessary to change the thickness of one layer, and the manufacturing cost can be reduced.

Further, the material of the layer whose thickness is adjusted may be indium tin oxide. Since the thickness of indium tin oxide can be controlled relatively easily, it can be adjusted to a desired color temperature with high accuracy.
The light emitting layer may be composed of a plurality of layers having different emission colors, and a layer having a shorter emission color wavelength may be disposed closer to the optical path difference adjusting layer. Thereby, depending on conditions, any luminescent color can be strengthened by interference, and the light extraction efficiency can be increased.

The light emitting layer may be a single layer in which materials having different emission colors are dispersed. Thus, the light emitting layer can be formed by only one film formation.
The light emitting layer may be formed of a single layer partitioned into a plurality of regions, and each region may be formed of one material selected from a plurality of materials having different emission colors.
The light emitting layer is made of a material that emits blue light, and further includes a wavelength conversion layer that absorbs blue light and emits yellow light on the opposite side of the light emitting layer with the transparent electrode interposed therebetween. Also good. Thereby, since the thickness of the optical path difference adjusting layer can be adjusted in consideration of only blue light, the design can be facilitated.

  Further, a metal pattern may be formed inside or on the surface of the transparent electrode. Thereby, the in-plane distribution of the current density can be made uniform, and as a result, luminance unevenness can be suppressed. In addition, since the electrical conductivity is increased, a large current can be supplied, and as a result, the luminance can be increased.

It is a perspective view which shows the external appearance of the illuminating device which concerns on embodiment of this invention. It is a figure which shows the one part cross section of the illuminating device which concerns on embodiment of this invention. It is a figure for demonstrating the principle which adjusts color temperature by adjustment of the thickness of an optical path difference adjustment layer, (a) is a schematic diagram of the cross section of sample A, B, C of the organic EL element of this embodiment, (B) is a figure which shows the spectrum of the emitted light of samples A, B, and C. FIG. It is a figure which shows the simulation result of the color temperature of the emitted light when changing the thickness of an optical path difference adjustment layer, (a) shows the structure of the organic EL element used for simulation, (b) shows the simulation result. It is plotted on a graph. It is a figure which shows the simulation result of the average color rendering evaluation number when changing the thickness of an optical path difference adjustment layer. (A) is a graph plotting simulation results when only the thickness of blue is changed while the thicknesses of red and green are fixed. It is a figure which shows the one part cross section of the illuminating device which concerns on a 1st modification. It is a figure which shows the one part cross section of the illuminating device which concerns on a 2nd modification. It is a figure which shows the one part cross section of the illuminating device which concerns on a 3rd modification. It is a figure which shows the one part cross section of the illuminating device which concerns on a 4th modification, (a) is sectional drawing, (b) is a top view. It is a figure which shows the one part cross section of the illuminating device which concerns on a 5th modification. It is a figure which shows the example of a metal pattern.

A mode for carrying out the present invention will be described in detail with reference to the drawings.
(Constitution)
FIG. 1 is a perspective view showing an appearance of a lighting device according to an embodiment of the present invention.
In the illumination device 100, a light emitting unit 102 and a power supply terminal 103 are arranged on an insulating substrate 101. The light emitting unit 102 is composed of an organic EL element, and receives power supply through positive and negative power supply terminals 103.

FIG. 2 is a diagram illustrating a partial cross section of the illumination device according to the embodiment of the present invention.
The lighting device 100 has a laminated structure in which an insulating substrate 1, a reflective electrode 2, an optical path difference adjusting layer 21, a light emitting layer 22, an electron injection layer 9, a transparent electrode 10, and a sealing layer 11 are laminated in this order. Specifically, the optical path difference adjusting layer 21 includes a transparent conductive layer 3, a hole injection layer 4, and a hole transport layer 5. Specifically, the light emitting layer 22 includes a blue light emitting layer 6, a green light emitting layer 7, and a red light emitting layer 8.

Details of each layer will be described below.
<Insulating substrate>
The insulating substrate 1 corresponds to the insulating substrate 101 of FIG. 1 and functions as a support substrate for the organic EL element. The insulating substrate 1 is, for example, non-alkali glass, soda glass, non-fluorescent glass, phosphoric acid glass, boric acid glass, quartz, acrylic resin, styrene resin, polycarbonate resin, epoxy resin, polyethylene, polyester, silicone type. It is made of an insulating material such as resin or alumina.
<Reflective electrode>
The reflective electrode 2 is electrically connected to the positive power supply terminal 103 in FIG. 1 and functions as a positive electrode of the organic EL element and reflects light emitted from the light emitting layer 22 toward the reflective electrode 2. Have The reflective function may be exhibited by the constituent material of the reflective electrode 2 or may be exhibited by applying a reflective coating to the surface portion of the reflective electrode 2. The reflective electrode 2 is, for example, Ag (silver), APC (silver, palladium, copper alloy), ARA (silver, rubidium, gold alloy), MoCr (molybdenum and chromium alloy), NiCr (nickel and chromium alloy). ) Etc.

<Optical path difference adjustment layer>
The optical path difference adjusting layer 21 is emitted from the light emitting layer 22 toward the transparent electrode 10 (hereinafter referred to as “direct light”) and emitted from the light emitting layer 22 toward the reflective electrode 2 and reflected by the reflective electrode 2. The optical path difference with light (hereinafter referred to as “reflected light”) is adjusted. The thickness of the optical path difference adjusting layer 21 is adjusted so that the color temperature of the emitted light from the organic EL element becomes a desired color temperature. That is, in the case of a daylight color product, the thickness of the optical path difference adjusting layer 21 is adjusted so that the daylight color temperature is obtained. Similarly, the thickness of the optical path difference adjusting layer 21 is adjusted so that the color temperatures are the same for daytime white and light bulb colors. Details will be described later.
<< Transparent conductive layer >>
The transparent conductive layer 3 is interposed between the reflective electrode 2 and the hole injection layer 4 to improve the bonding properties thereof, and the reflective electrode 2 is naturally oxidized immediately after the reflective electrode 2 is formed in the manufacturing process. Functions as a protective layer to prevent. The transparent conductive layer 3 may be formed of a conductive material having sufficient translucency with respect to the light generated in the light emitting layer 22, for example, indium tin oxide (ITO) or indium zinc oxide (ITO). Indium Zinc Oxide: IZO) is preferred. This is because good conductivity can be obtained even if the film is formed at room temperature.
<< Hole Injection Layer >>
The hole injection layer 4 has a function of injecting holes into the light emitting layer 22. For example, an oxide of a transition metal such as tungsten oxide (WOx), molybdenum oxide (MoOx), or molybdenum tungsten oxide (MoxWyOz) is used. By forming the oxide of a transition metal, voltage-current density characteristics can be improved, and the current density can be increased to increase the emission intensity. In addition to this, a conductive polymer material such as PEDOT (mixture of polythiophene and polystyrene sulfonic acid) which is conventionally known may be used.
<< Hall transport layer >>
Specific examples of the hole transport layer include triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino substitution described in JP-A-5-163488. Chalcone derivatives, oxazole derivatives, styryl anthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, porphyrin compounds, aromatic tertiary amine compounds and styryl amine compounds, butadiene compounds, polystyrene derivatives, hydrazone derivatives, triphenylmethane derivatives, tetraphenyl A benzine derivative or the like can be used, but particularly preferably a porphyrin compound, an aromatic tertiary amine compound, and a styrylamine compound. That.

<Light emitting layer>
The light emitting layer 22 is composed of three kinds of materials of red, green, and blue. The light emitting layer 22 includes, for example, an oxinoid compound, a perylene compound, a coumarin compound, an azacoumarin compound, an oxazole compound, an oxadiazole compound, a perinone compound, a pyrrolopyrrole compound, a naphthalene compound, an anthracene compound described in JP-A-5-163488. Fluorene compound, fluoranthene compound, tetracene compound, pyrene compound, coronene compound, quinolone compound and azaquinolone compound, pyrazoline derivative and pyrazolone derivative, rhodamine compound, chrysene compound, phenanthrene compound, cyclopentadiene compound, stilbene compound, diphenylquinone compound, styryl compound, Butadiene compounds, dicyanomethylenepyran compounds, dicyanomethylenethiopyran compounds, fluorescein compounds, pyririu Compound, thiapyrylium compound, serenapyrylium compound, telluropyrylium compound, aromatic aldadiene compound, oligophenylene compound, thioxanthene compound, anthracene compound, cyanine compound, acridine compound, metal chain of 8-hydroxyquinoline compound, 2-bipyridine compound It is preferably formed of a fluorescent material such as a metal chain, a chain of a Schiff salt and a group III metal, an oxine metal chain, or a rare earth chain.
<Electron injection layer>
The electron injection layer 9 has a function of injecting electrons from the transparent electrode 10 to the light emitting layer 22, and is preferably formed of, for example, barium, phthalocyanine, lithium fluoride, or a combination thereof.
<Transparent electrode>
The transparent electrode 10 is electrically connected to the negative power supply terminal 103 in FIG. 1 and functions as a negative electrode of the organic EL element. The transparent electrode 10 only needs to be formed of a conductive material having sufficient translucency with respect to the light generated in the light emitting layer 22, for example, indium tin oxide (ITO) or indium zinc oxide (Indium). Zinc Oxide: IZO) is preferred.
<Sealing layer>
The sealing layer 11 is configured so that each layer (the reflective electrode 2, the optical path difference adjusting layer 21, the light emitting layer 22, the electron injection layer 9, and the transparent electrode 10) sandwiched between the insulating substrate 1 is exposed to moisture or air. It has a function to prevent. The sealing layer 11 is formed of, for example, silicon nitride (SiN), silicon oxynitride (SiON), resin, or the like.
(Principle and simulation)
Next, details of the optical path difference adjusting layer 21 will be described.

FIG. 3 is a diagram for explaining the principle of adjusting the color temperature by adjusting the thickness of the optical path difference adjusting layer, and FIG. It is a figure, (b) is a figure which shows the spectrum of the emitted light of the samples A, B, and C.
As shown in FIG. 3A, the thicknesses of the optical path difference adjusting layers of samples A, B, and C are ta, tb, and tc, respectively (ta <tb <tc). The organic EL element of this embodiment has a structure in which direct light and reflected light cause interference. Therefore, the spectrum of the emitted light of the organic EL is modified from the emission spectrum of the light emitting layer due to the influence of interference. If the material of the optical path difference adjusting layer is the same (that is, the refractive index is the same), the influence of interference is determined by its thickness. In Samples A, B, and C, the thickness of the optical path difference adjusting layer is different, so that the influence of interference on the emission spectrum is different. The result is shown in FIG. As shown in FIG. 3B, the peak wavelengths of the emitted light from the samples A, B, and C are λa, λb, and λc, respectively. When the peak wavelength of the spectrum of the emitted light is different, the color temperature of the emitted light is different. Therefore, the color temperature of the emitted light of the organic EL element can be adjusted by adjusting the thickness of the optical path difference adjusting layer.

FIG. 4 is a diagram showing the simulation result of the color temperature of the emitted light when the thickness of the optical path difference adjusting layer is changed, (a) shows the configuration of the organic EL element used in the simulation, and (b) The simulation results are plotted on a graph.
In the simulation, as shown in FIG. 4A, three types of light emitting layers of red, green, and blue are arranged side by side. In addition, indium tin oxide (ITO) is used for the transparent conductive layer 3. In this organic EL element, the color temperature of the emitted light was calculated when the thickness of the transparent conductive layer corresponding to the blue light emitting layer 6 was changed.

The data D ₁₁ , D ₁₂ , D ₁₃ , and D ₁₄ in FIG. 4B are obtained when the thickness of the transparent conductive layer is 60 [nm], 70 [nm], 80 [nm], and 90 [nm], respectively. The color temperature of the light. The color temperature changes within a range of about 3000 [K] to about 2500 [K]. From these, it is understood that the color temperature of the emitted light of the organic EL element can be adjusted by adjusting the thickness of the optical path difference adjusting layer. D ₁₁ , D ₁₂ , D ₁₃ , and D ₁₄ each have an average color rendering index Ra of 85.

D ₂₁ , D ₂₂ , D ₂₃ , D ₂₄ , D ₂₅ , and D ₂₆ change the thickness of the transparent conductive layer corresponding to the blue light emitting layer 6 and change the mixing ratio of red and green. This is the color temperature of the emitted light. Thus, even if the thickness of the transparent conductive layer is changed, the color temperature of the emitted light can be made the same by appropriately adjusting the blending ratio to red and green.
D ₃₁ is the color temperature of the emitted light when the thickness of the transparent conductive layer corresponding to the blue light emitting layer 6 is the same as D ₂₁ and the mixing ratio of red and green is different. Thus, the color temperature of the emitted light can be adjusted in the range from about 10,000 [K] to about 1900 [K] by adjusting the blending ratio of each color. The mixing ratios of D ₂₁ and D ₃₁ are as follows.

D21 Red: 80 [%], Green: 17 [%], Blue: 3 [%]
D31 Red: 20 [%], Green: 17 [%], Blue: 63 [%]
The mixing ratio of each color can be adjusted, for example, by changing the thickness, density, material, etc. of the light emitting layer of each color.
In the above simulation, as shown in FIG. 4 (a), three types of light emitting layers of red, green, and blue are arranged side by side, but the same tendency is obtained even in a laminated structure as shown in FIG. It is assumed that is seen.

The inventors also simulated the change in the average color rendering index Ra when the thickness of the optical path difference adjusting layer was changed.
FIG. 5 is a diagram showing a simulation result of the average color rendering index when the thickness of the optical path difference adjusting layer is changed. (A) is a graph plotting simulation results when only the thickness of blue is changed while the thicknesses of red and green are fixed. (B) plots the simulation results on a graph when the thicknesses of green and blue are fixed and only the thickness of red is changed. The structure of the organic EL element used for the simulation is that shown in FIG.

According to this, it turns out that adjustment of average color rendering evaluation number Ra can also be performed by adjusting the thickness of a transparent conductive layer. In particular, when the thickness of blue is changed, it can be seen that the change in the average color rendering index Ra is large.
From the above, it was found that the color temperature of the emitted light can be adjusted by adjusting the thickness of the optical path difference adjusting layer. It was also found that the color temperature of the emitted light can be adjusted by changing the mixing ratio of each color. Therefore, it became clear that the color temperature of the emitted light can be adjusted by adjusting the thickness of the optical path difference adjusting layer. When manufacturing a plurality of types of products such as daylight color, daylight white color, and light bulb color, the thickness of the optical path difference adjusting layer may be adjusted for each type of product, and the mixing ratio of each color may be supplementarily adjusted.

  The thickness of the optical path difference adjusting layer may be adjusted by adjusting the thickness of at least one of the transparent conductive layer, the hole injection layer, and the hole transport layer, but only by adjusting the thickness of the plurality of layers. It is easier in manufacturing to adjust the thickness. In particular, when indium tin oxide is used for the transparent conductive layer, it is preferable to adjust the film thickness of the transparent conductive layer. This is because the thickness of indium tin oxide can be controlled with a high accuracy of about 5 [nm], and can be adjusted to a desired color temperature with high accuracy. Of course, the thickness of the plurality of layers may be adjusted.

Further, for the sake of convenience, the simulation is performed with the structure of FIG. 4A, but it is assumed that the same tendency can be seen even with the laminated structure of FIG. In the laminated structure of FIG. 2, the light emitting layer 22 having a shorter emission color wavelength is disposed closer to the optical path difference adjusting layer. This is due to the following reason. Since the wavelength of light decreases in the order of red, green, and blue, the optimum distance between the light emitting layer of each color and the reflective electrode may be shortened in the order of red, green, and blue. Therefore, depending on the conditions, the shorter the wavelength of the luminescent color, the closer to the optical path difference adjusting layer, the optimal distance between the luminescent layer of any color and the reflective electrode.
(Modification)
Hereinafter, modifications of the present embodiment will be described.

FIG. 6 is a diagram illustrating a cross section of a part of the illumination device according to the first modification. In this example, the light emitting layer 22 has a single layer structure of the white light emitting layer 12. The white light emitting layer 12 can be formed by, for example, dispersing each color light emitting material. With the single layer structure, the light emitting layer can be formed by only one film formation, and the number of manufacturing steps can be reduced.
FIG. 7 is a diagram illustrating a partial cross-section of the illumination device according to the second modification. In this example, the light emitting layer 22 has a single-layer structure and is divided into a plurality of regions, and each region is formed of any one of a blue light emitting material, a green light emitting material, and a red light emitting material.

  FIG. 8 is a diagram illustrating a partial cross-section of the illumination device according to the third modification. In this example, the light emitting layer 22 has a single layer structure, and is formed only from the blue light emitting layer 6. And the wavelength conversion layer 13 which absorbs blue light and light-emits yellow light is provided in the upper surface of the transparent electrode 10, and the sealing layer 11 is formed in the upper surface. In this case, blue light is emitted from the light emitting layer 22, but is partially converted into yellow light by the wavelength conversion layer 13, and white light can be obtained by mixing with the remaining blue light. Examples of the wavelength conversion layer 13 include (1) a yellow phosphor, (2) a mixture of a green phosphor and a red phosphor, and (3) a mixture of a yellow-green phosphor and a yellow-orange phosphor. Known phosphor materials can be used for each color. In addition, a phosphorescent material may be used instead of the fluorescent material.

According to this configuration, since the thickness of the optical path difference adjusting layer can be adjusted in consideration of only blue light, the design can be facilitated.
FIGS. 9A and 9B are diagrams showing a cross section of a part of a lighting device according to a fourth modification, wherein FIG. 9A is a cross-sectional view and FIG. 9B is a top view. In this example, a metal pattern 14 is formed on the upper surface of the transparent electrode 10. For the transparent electrode 10, indium tin oxide or the like is employed with emphasis on translucency, but it cannot be said that the electrical conductivity is excellent. Therefore, the distribution of current density in the plane of the light emitting layer is highest in the vicinity of the connection point with the negative electrode power supply terminal 103 in the plane of the transparent electrode 10, and becomes lower as the distance from the distribution point increases. If the difference in distribution is extremely large, the in-plane luminance unevenness is large, and the light emitting layer is easily deteriorated. Therefore, by forming a metal pattern on the upper surface of the transparent electrode 10, the in-plane current density distribution can be made uniform, and as a result, luminance unevenness and light emitting layer deterioration can be suppressed. . In addition, since the electrical conductivity of the cathode is substantially increased, a large current can be supplied and the luminance can be increased.

FIG. 10 is a diagram illustrating a partial cross-section of the illumination device according to the fifth modification. In this example, a metal pattern 14 is formed inside the transparent electrode 10. Even if it does in this way, the effect similar to a 4th modification can be acquired.
Note that the wiring patterns in the fourth and fifth modifications may be as shown in FIGS. 11A to 11F, for example. 11 (a) is a frame shape, (b) is a combination of a frame shape and a radial shape, (c) is a combination of a frame shape and a circle, (d) is a combination of a frame shape and a plurality of circles, (e) Is a combination of a frame shape and a network shape, and (f) is a combination of a frame shape and a mesh shape.

In the embodiment, the top emission type in which light is emitted through the sealing layer is described. However, the present invention is not limited to this, and the bottom emission type in which light is emitted through the insulating substrate 1 is also applicable. Is possible. In that case, the cathode becomes a reflective electrode and the anode becomes a transparent electrode.
In the embodiment, the optical path length is adjusted by adjusting the thickness of the optical path difference adjusting layer. However, the present invention is not limited thereto, and the optical path length is adjusted by adjusting the refractive index of the optical path difference adjusting layer. It doesn't matter. The refractive index can be adjusted, for example, by changing the material of the optical path difference adjusting layer or by changing the composition ratio even if the material of the optical path difference adjusting layer is the same.

  In the embodiment, since there are three layers of a transparent conductive layer, a hole injection layer, and a hole transport layer between the light emitting layer and the reflective electrode, these are optical path difference adjusting layers. However, depending on the specifications, only one or two of these layers may exist between the light emitting layer and the reflective electrode. In that case, one or two layers existing between the light emitting layer and the reflective electrode serve as an optical path difference adjusting layer.

  The present invention can be used for general lighting and the like.

DESCRIPTION OF SYMBOLS 1 Insulating substrate 2 Reflective electrode 3 Transparent conductive layer 4 Hole injection layer 5 Hole transport layer 6 Blue light emitting layer 7 Green light emitting layer 8 Red light emitting layer 9 Electron injection layer 10 Transparent electrode 11 Sealing layer 12 White light emitting layer 13 Wavelength conversion layer 14 Metal pattern 21 Optical path difference adjusting layer 22 Light emitting layer

Claims (8)

An illumination device comprising a laminated structure in which at least a reflective electrode, a light emitting layer, and a transparent electrode are laminated,
The laminated structure further includes light emitted from the light emitting layer toward the transparent electrode and light emitted from the light emitting layer toward the reflective electrode between the reflective electrode and the light emitting layer. An optical path difference adjustment layer that adjusts the optical path difference with the light reflected by is inserted,
The thickness of the said optical path difference adjustment layer is adjusted so that the color temperature of the white light which permeate | transmits and transmits the said transparent electrode may turn into desired color temperature.   The lighting device according to claim 1, wherein the optical path difference adjusting layer includes a plurality of layers made of different materials, and only the thickness of one of the layers is adjusted.   The lighting device according to claim 2, wherein the material of the layer whose thickness is adjusted is indium tin oxide.   The lighting device according to claim 1, wherein the light emitting layer includes a plurality of layers having different emission colors, and a layer having a shorter wavelength of the emission color is arranged closer to the optical path difference adjusting layer.   The lighting device according to claim 1, wherein the light emitting layer includes a single layer in which materials having different emission colors are dispersed.   The light emitting layer is formed of a single layer divided into a plurality of regions, and each region is formed of one material selected from a plurality of materials having different emission colors. Lighting equipment. The light emitting layer is made of a material that emits blue light,
Furthermore, the illuminating device of Claim 1 provided with the wavelength conversion layer which absorbs blue light and emits yellow light on the opposite side to the said light emitting layer on both sides of the said transparent electrode.   The lighting device according to claim 1, wherein a metal pattern is formed inside or on the surface of the transparent electrode.

Images