JP2005056813A - Self-light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a self-light-emitting device with improved light take-out efficiency capable of emitting white light in a wide range, and to provide a manufacturing method of the same. <P>SOLUTION: The self-light-emitting device (organic EL device) comprises a transparent conductor 22 arranged on the surface of a substrate, a light-emitting part 25 formed by laminating a plurality of layers containing an EL material, a metal electrode 24 arranged at a position facing the transparent conductor 22, and a light conversion part 23 adjacent to the light-emitting part 25 and the metal electrode 24. Since a part of the light emitted from the light-emitting part 25 getting to the light conversion part 23 is emitted with its color converted at the light conversion part, the self-light-emitting device emitting light having a color of the light of the light-emitting part 25 to which the converted color is mixed, is provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a self-luminous device called an organic LED, an organic EL, an inorganic EL, or the like.

  A conventional self-light emitting device using an organic LED or the like is based on crystallization of a luminescent material by Joule heat at the time of light emission of the organic LED (it becomes an insulator due to crystallization from an amorphous state to a glass state and does not emit light). Due to the influence, it was very difficult to increase the area.

  In addition, since organic LEDs and the like are formed by laminating materials having a refractive index difference on a glass substrate, the light emitted from the light emitting part such as organic LEDs is radiated to the side by its influence, that is, the fiber effect. As a result, the efficiency of extracting light in the desired direction was poor.

  Therefore, in order to solve this problem of deterioration in efficiency, a technique for processing the entire surface of the glass substrate into a concavo-convex shape has been proposed (see, for example, Patent Document 1).

Moreover, in order to obtain visible light with such an EL element, an EL element in which an organic EL material and a fluorescent material portion are placed in parallel is disclosed in Japanese Patent Laid-Open No. 3-152897 (Patent Document 2).
JP 2002-043054 A Japanese Patent Laid-Open No. 3-152897

  However, in the case of Patent Document 1, there is a problem that the efficiency of extracting light is not increased as expected because of the structure in which light is diffusely reflected at a position far from the light emitting unit such as an organic LED to the surface of the glass substrate. Further, even in the case of Patent Document 2, the efficiency cannot be improved because light cannot be extracted efficiently.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide a self-luminous device that can improve the efficiency of extracting light and can emit light in a wide area.

  The self-luminous device of the invention of claim 1 includes a translucent substrate; a transparent conductor formed on the translucent substrate; a layer formed on the transparent conductor and containing an electroluminescent material. A light-emitting part including: a metal electrode formed on the light-emitting part so that at least a part faces the transparent conductor, and the light-emitting part reflects the emitted light; and is formed adjacent to the metal electrode and the light-emitting part And a light conversion unit.

  In the present invention and each of the following inventions, the definitions and technical meanings of terms are as follows unless otherwise specified.

  The electroluminescent material (hereinafter referred to as EL material) of the light emitting part may be organic or inorganic. Further, not only a low molecular material but also a high molecular material may be used. The metal electrode may be any metal that can reflect light, and accepts metals and alloys such as aluminum, silver, gold, and platinum. In addition, a large amount of light may be incident on the light conversion unit by providing an uneven surface on the metal electrode, or may be transmitted from the translucent substrate.

  The light conversion part has a function of converting the light color of the light emitted from the light emitting part, and an insulator such as a resist containing a fluorescent dye is preferable. The material can be formed by including a light conversion material in a resist film of a simple transparent material such as acrylic or epoxy resin or a white light-transmitting material.

  The invention according to claim 2 is the self-light-emitting device according to claim 1, wherein the light-emitting portion emits blue light, and the color conversion portion converts blue light into green and red.

  As the light emitting portion emitting blue light, there is a distyrylarylene derivative (DPVBi) or the like as an EL material. Moreover, there are fluorescent dyes such as rhodamine Bbase, DCM, and Nile red that convert blue light emission into red. Moreover, there exist coumarin 6 fluorescent dye, quinacridone, etc. as what converts blue light emission into green.

  A third aspect of the invention is the self-light-emitting device according to the first aspect, wherein the light-emitting portion emits blue light, and the color conversion portion converts blue light from yellow to orange.

  There are rubrene fluorescent dyes (converted to yellow), DCM derivative fluorescent dyes (converted to orange), and the like that convert blue light emission from yellow to orange, and these may be used in combination.

  According to a fourth aspect of the present invention, in the self-luminous device according to the first to third aspects, the color converter is formed by mixing at least two types of color converters having different colors to be converted.

  Since the light conversion unit is formed by mixing at least two types of light conversion bodies that convert light, the colored light converted by the light conversion unit is mixed, and light emission close to white can be obtained uniformly.

  The combination of the light emission color of the light emission part and the color converted by the color conversion part is not limited to the above, and the EL material of the light emission part may be 1,4 bis (4-methylstyryl) benzene (PMSB or the like). When blue-green light emission is used, substantially white light emission can be obtained from the self-light-emitting device by using a phosphor such as pyridine 1 that converts the light conversion portion from blue-green to red. It is also possible to obtain an arbitrary emission color by a combination of colors.

  A fifth aspect of the present invention is the self-luminous device according to the first to fourth aspects, characterized in that the light conversion part contains light diffusing particles.

  Form a protective layer (resist film) with a simple transparent material such as acrylic or epoxy resin or white translucent material on the light conversion part, or inorganic material such as alumina, ceria, titania, zirconia or polyethylene, polystyrene, etc. You may use what contained the transparent fine particle which consists of organic materials in the transparent material or the translucent material.

  According to the first aspect of the present invention, since the light conversion part is formed in the part adjacent to the light emitting part and the metal electrode, the light from the light emitting part is emitted from the light emitting part by refraction generated at the boundary surface of the transparent conductor. Light is radiated to the light conversion unit, and the amount of light radiated in a desired direction (front direction) is increased by reflection by the metal electrode having a reflection effect, and the light is converted by the light conversion unit. Because the light color is converted, the light color that was difficult to obtain with only the EL material can be obtained by mixing the light color obtained from the light emitting part with another light color converted by the light converting part. Can do. Furthermore, the light extraction efficiency can be improved.

  According to the second aspect of the present invention, since the light conversion unit that converts the light color of the light emitting unit into blue and the light conversion unit converts blue into green and red is provided, it is suitable for obtaining a white light-emitting device. Further, by changing the output of the light emitting unit, various light-colored self-light emitting devices can be obtained.

  According to the third aspect of the present invention, since the light conversion unit for converting the light color of the light emitting unit to blue and the light conversion unit converting blue to yellow or orange is provided, it is suitable for obtaining a white light-emitting device.

  According to the invention of claim 4, the converted colored light is mixed, and light emission close to white can be obtained uniformly.

  According to the invention of claim 5, the light emitted from the light emitting part is radiated to the light converting part by the refraction generated at the boundary surface of the transparent conductor, and is contained in the light converting part. Diffused by light diffusing particles. For this reason, the light extraction efficiency can be improved by diffusing the light from the light emitting portion.

  A first embodiment of the present invention will be described in detail with reference to the drawings. 1 is a diagram showing a configuration of an organic EL device according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of the organic EL device of FIG. 1, and FIG. 3 is an enlarged view of a main part of the organic EL device of FIG. .

  As shown in FIGS. 1 to 3, this organic EL device has, for example, a glass substrate 21 as a translucent substrate for emitting light in a matrix, and transparency formed in a line on the glass substrate 21. A light emitting portion 25 formed by laminating a plurality of layers including an anode 22 as a conductor and a layer containing an electroluminescent material (hereinafter referred to as EL material) which is an organic light emitting material on a glass substrate 21; A dish-like shape that seals the light emitting portion 25 via a cathode 24 as a metal electrode formed in a line so as to cross the anode 22 and a sealing adhesive 28 applied on the glass substrate 21. A sealing glass substrate 27 and a desiccant 26 attached to the inner surface of the sealing glass substrate 27 are provided.

  As shown in FIG. 3, an anode 22 (ITO film) is formed in a line shape on the glass substrate 21. The thickness of the glass substrate 21 is about 1.5 mm, for example. The thickness of the anode 22 (ITO film) is, for example, about 2.0 μm. A light emitting unit 25 is formed on the anode 22 (ITO film). The light emitting section 25 is formed by laminating a hole transport layer 32, a light emitting layer 33, and an electron injection layer 34 in this order. For the hole transport layer 32, for example, α-NPD, Bis [N- (1-naphthyl) -N-phenyl] benzidine or the like is used. The thickness of the hole transport layer 32 is, for example, about 0.04 μm. A distyrylarylene derivative: (DPVBi: 4,4′-bis (2,2′diphenylvinyl) -1,1′-biphenyl) is used for the light emitting layer 33. The thickness of the light emitting layer 33 is, for example, 0.02 μm. Lithium fluoride (LiF) is used for the electron injection layer 34. The thickness of the electron injection layer 34 is, for example, about 0.0007 μm, and the cathode 24 is linear in the direction intersecting the anode 22. The cathode 24 is a metal electrode made of a material that can reflect light, such as aluminum, silver, gold, or platinum, and has a thickness of about 1.0 μm, for example.

  The light conversion unit 23 is arranged in parallel with the light emitting unit 25 and in contact with the cathode 24. The light conversion unit 23 can convert a resist made of a main material such as acrylic or epoxy polyimide containing a rhodamine Bbase fluorescent dye capable of converting a blue light color into a red color, and can convert a blue light color into a green color. A resist containing coumarin 6 fluorescent dye is disposed as a G color conversion unit 23G so as to be provided along with the light emitting unit.

  FIG. 1 shows an organic EL light source in which a plurality of light emitting portions 25 are formed in a substantially square shape. When viewed from above, the light conversion unit 23 is formed around the plurality of light emitting units 25 so that the regions of the R color conversion unit 23R and the G color conversion unit 23G are equal.

  A sealing glass substrate 27 is disposed on the light conversion unit 23 and the light emitting unit 25 on the cathode 24 with a space therebetween. The sealing glass substrate 27 and the lowermost glass substrate 21 form a sealing structure that seals the light emitting portion 25 and prevents the intrusion of air, moisture, and the like.

  Since the sealing glass substrate 27 does not need to transmit light, a material such as metal may be used in addition to glass. The inner surface of the sealing glass substrate 27 is recessed in a dish shape to provide a space. A desiccant 26 for removing oxygen and water is attached to this space.

  As described above, according to the organic EL device of this embodiment, the light emitting unit 25 is formed on the glass substrate 21, and the light conversion unit 23 is arranged on the glass substrate 21 so as to be juxtaposed to the light emitting unit and adjacent to the metal electrode 24. Therefore, the light emitted from the light emitting portion 25 is radiated to the light converting portion 23 due to refraction generated at the boundary surface of the anode 22, and the light is reflected in the desired direction (front surface) by the reflection of the cathode 24 having a reflection effect. The amount of light irradiated in the direction increases, and the light is converted into red or green, so that a white organic EL device with improved light extraction efficiency can be provided.

  Thereby, when converted into a ratio improvement rate which is a percentage when the conventional front illumination intensity is 1, when applied on the light conversion portion 23 with respect to the conventional one (ratio improvement rate: 100%) The ratio improvement rate can be increased to about 120% to 140%. It is also possible to change the light color of the entire organic EL device by changing the input power to each light emitting unit 25.

  In addition, as shown in FIG. 4, the light diffusion portion 30 can be formed on the boundary surface between the light conversion portion 23 and the glass substrate 21. The light diffusing portion 30 can form a frost by masking the area where the light diffusing portion 23 is formed on the surface of the glass substrate 21 and then applying a sandblast treatment, a chemical treatment or a diffusion film to the glass substrate. By forming in this way, the light of the light emitting unit 25 and the light converted by the light converting unit 23 are diffused to each other by the diffusing unit 30 to obtain a white color in which light is easy to mix and color unevenness of light is suppressed. it can.

  Furthermore, as shown in FIG. 5, the diffusion part 30 can be provided on the surface of the glass substrate 21 opposite to the side on which the light emitting part is formed. This can be made by forming frost on the entire surface of one side of the glass substrate 21 or forming a diffusion film on the entire surface of one side of the glass substrate 21. By forming in this way, the light of the light emitting unit 25 and the light converted by the light converting unit 23 are diffused to each other by the diffusing unit 30 to obtain a white color in which the light is easy to mix and the color unevenness of the light is suppressed. Can do. Furthermore, there is an advantage that the formation of the light diffusion portion 30 can be simplified.

  Further, as shown in FIG. 6, in the case of an organic EL device in which a plurality of light emitting portions 25 are formed in a substantially rectangular shape, the regions of the R color converting portion 23R and the G color converting portion 23G are equal in the middle portion of the light emitting portion. In this manner, the light conversion unit 23 may be formed.

  Further, in the case of an organic EL device in which a plurality of light emitting portions 25 are formed in a substantially rectangular shape as shown in FIG. 7, the periphery of the light emitting portion is divided into an R color converting portion 23R so as to be divided into a cross at the center of the plurality of light emitting portions 25. You may form the light conversion part 23 so that the area | region of G color conversion part 23G may become equal. When configured for this purpose, each light emission color is formed in light, so that the light color of the entire organic EL device can be made closer to white.

  Further, the light emitting section 25 and the light converting sections (23R, 23G) also allow the size, shape, etc., to be arbitrarily changed according to each light color and light emission intensity.

  Further, as shown in FIG. 8, a plurality of light emitting portions 25 may be formed in a substantially square shape, the G color converting portion 23G may be formed around the light emitting portion 25, and the R color converting portion 23R may be further formed therearound. The R color conversion unit 23R arranged outside converts not only the blue light emitted from the light emitting unit 25 into red, but also converts the light converted from blue to green by the G color light emitting unit 23G into red. Therefore, the amount of extracted light is increased and the light emission efficiency is improved. By forming the light having the long wavelength of the converted light color on the outside in this way, it is possible to provide an organic EL device in which the light utilization rate is increased and the light emission efficiency is improved.

  Next, a second embodiment of the present invention will be described with reference to the drawings. The same parts as those in FIGS. 1 to 5 are denoted by the same reference numerals, and description thereof is omitted.

  FIG. 9 shows a second embodiment of the present invention. As in FIG. 1, the light emitting part 25 is formed in a substantially square shape, but the light diffusion part 23M is a phosphor used for the R color light diffusion part. And a phosphor mixed with the phosphor used in the G color light diffusion portion. By forming in this way, light is mixed and white can be obtained. In addition, the light color of the organic EL device can be arbitrarily changed by adjusting the amount of the phosphor that converts to R color and the phosphor that converts to G color.

  Next, a third embodiment of the present invention will be described with reference to the drawings. The same parts as those in FIGS. 1 to 5 are denoted by the same reference numerals, and description thereof is omitted.

  FIG. 10 is a plan view showing the configuration of the organic EL device, and FIG. The light-emitting layer of the light-emitting portion 25 formed in a substantially square shape uses a distyrylarylene derivative: (DPVBi) and has a blue emission color as in the first embodiment. Around the light emitting portion, a Y color light converting portion 23Y for converting blue light color into yellow is formed. The Y color conversion unit 23Y is composed of a resist material containing a rubrene fluorescent dye. If comprised in this way, the blue light radiated | emitted from the light emission part will be radiated | emitted or reflected to the light conversion part 23 similarly to 1st Embodiment, and the color mixture of blue and yellow is carried out by converting the light into yellow. Thus, white light emission can be obtained. The light converting portion 23 is made of a resist material containing light diffusing particles 29 made of alumina. The light diffusing particles are particles having a particle diameter of 5 nm to 50 nm. The light diffusing particles diffuse the light from the light emitting portion and the light whose color has been converted by the light converting portion 23 and are better mixed to easily obtain white light.

  In the organic EL device of FIG. 12, the light emitting portion 25 formed in a substantially line shape also has a blue light emission color. An O color light conversion unit 23O that converts blue light color into orange is formed around the light emitting unit. The O color conversion portion 23O is made of a resist material containing a DCM derivative fluorescent dye and light diffusing particles 29 made of alumina. The light diffusing particles are particles having a particle diameter of 5 nm to 50 nm. If comprised in this way, the blue light radiated | emitted from the light emission part will be radiated | emitted or reflected to the light conversion part 23 similarly to 1st Embodiment, and the color mixture of blue and orange is carried out by converting the light into orange. Thus, white light emission can be obtained. Furthermore, the light diffusing particles 29 included in the light conversion unit 23 can efficiently radiate the light emitted to the light conversion unit 23 to the front surface of the organic EL device. Therefore, it is possible to extract light more efficiently.

  In FIG. 13, in the organic EL device, the light emitting section 25 formed in a substantially line shape also has a blue emission color. Around the periphery of the light-emitting portion, the Y-light conversion portion 23Y is made of a resist material containing a rubrene fluorescent dye that converts blue light color to yellow, and DCM derivative fluorescence that converts blue light color to orange. If configured in this way, the color light conversion unit 23O composed of a resist containing a dye is formed, and the blue light emitted from the light emitting unit is emitted to the light conversion unit 23 as in the first embodiment. Alternatively, by reflecting and converting the light into yellow and orange, white light emission can be obtained by mixing blue, yellow and orange.

The top view which shows the structure of the organic electroluminescent apparatus of 1st embodiment of this invention. Sectional drawing of the organic electroluminescent apparatus of FIG. Sectional drawing which expanded the principal part of the organic electroluminescent apparatus of FIG. The principal part expanded sectional view of another example. Similarly the principal part expanded sectional view of another example. The top view which shows the other example of the organic electroluminescent apparatus of 1st embodiment of this invention. The top view which similarly shows the other example of the organic electroluminescent apparatus of 1st embodiment. The top view which similarly shows the other example of the organic electroluminescent apparatus of 1st embodiment. The top view which shows the structure of the organic electroluminescent apparatus of 2nd embodiment of this invention. The top view which shows the structure of the organic electroluminescent apparatus of 3rd embodiment of this invention. Sectional drawing which expanded the principal part of the organic electroluminescent apparatus of FIG. The top view which shows the other example of the organic electroluminescent apparatus of 3rd embodiment similarly. The top view which shows the other example of the organic electroluminescent apparatus of 3rd embodiment similarly.

Explanation of symbols

DESCRIPTION OF SYMBOLS 21 ... Glass substrate, 21a ... Diffuse reflection surface, 22 ... Anode, 23 ... Light conversion part, 24 ... Cathode, 25 ... Light emission part, 26 ... Desiccant, 27 ... Glass substrate for sealing, 28 ... Adhesive for sealing, DESCRIPTION OF SYMBOLS 30 ... Light-diffusion part 32 ... Hole transport layer, 33 ... Light emitting layer, 34 ... Electron injection layer.

Claims (5)

A translucent substrate;
A transparent conductor formed on a translucent substrate;
A light emitting part formed on a transparent conductor and including a layer containing an electroluminescent material;
A metal electrode which is formed on the light emitting part so that at least a part thereof faces the transparent conductor and can reflect the light emitted by the light emitting part;
A light conversion portion formed adjacent to the metal electrode and the light emitting portion;
A self-luminous device characterized by comprising: The light-emitting device according to claim 1, wherein the light-emitting unit emits blue light, and the color conversion unit converts blue light into green and red. The self-light-emitting device according to claim 1, wherein the light-emitting section emits blue light, and the color conversion section converts blue light from yellow to orange. 4. The self-light-emitting device according to claim 1, wherein the color conversion unit is formed by mixing at least two kinds of color converters having different colors to be converted. 4. The self-luminous device according to claim 1, wherein the light conversion part contains light diffusing particles.

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