JP2007048808A - Light emitting device, manufacturing method therefor and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device wherein, even if any defect occurs in a plurality of light emitting areas, a drop of luminance in the other light emitting elements can be prevented, and a non-light emitting area can be made difficult to be recognized, and to provide an electronic apparatus. <P>SOLUTION: The light emitting device 101 is provided with a plurality of organic functional layers 20a-20e having at least a light emitting layer 23, a substrate 10 including wirings 21 and 24 to electrically connect the organic functional layers 20a-20e in series, and a color conversion layer 15 arranged at a position apart from the organic functional layers 20a-20e. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electroluminescence type light emitting device, a method for manufacturing the light emitting device, and an electronic apparatus using the same.

  Conventionally, a light-emitting device that uses light emitted from a light-emitting element as functional light such as illumination light and display light is known. For example, there is a light-emitting device using an organic EL (electroluminescence) element as a light-emitting element. The basic structure of a light-emitting device equipped with these organic EL elements is generally a structure in which an organic EL element is disposed on a glass substrate, and light emitted from the organic EL element and transmitted through the glass substrate. Is used as illumination light or display light.

As such a light emitting device, as disclosed in Patent Document 1, a light emitting device having a plurality of light emitting elements has been proposed. Even when a defect occurs in one of the plurality of light-emitting elements, the function as a light-emitting device can be maintained by allowing other light-emitting elements to continue to emit light. For this reason, compared with the light-emitting device which consists of a single light emitting element, a long life and a high yield are realizable.
JP 2005-93074 A

  However, when a defect (short circuit) occurs in one of the plurality of light emitting elements, the current flowing through the other light emitting elements is reduced, so that the luminance of each light emitting element, and hence the illuminance of the entire lighting device, is reduced. There's a problem. Further, since the non-light emitting element is recognized as a black spot, there is a problem that the commercial value is lowered.

  The present invention has been made in view of the above-described circumstances, and even when a defect occurs in one or a plurality of light emitting regions, it is possible to prevent a decrease in luminance of other light emitting elements and the like, and to provide a non-light emitting region. It is an object of the present invention to propose a light emitting device, a method for manufacturing the light emitting device, and an electronic device that can make it difficult to recognize the light.

The light emitting device, the method for manufacturing the light emitting device, and the electronic apparatus according to the present invention employ the following means in order to solve the above problems.
According to a first aspect of the present invention, a light-emitting device includes a substrate including a plurality of organic functional layers having at least a light-emitting layer, a wiring that electrically connects the plurality of organic functional layers in series, and the plurality of organic functional layers. And a color conversion layer disposed at a spaced position.
In addition, the light emitting device includes a substrate having at least one organic functional layer having at least a light emitting layer, and a wiring electrically connecting the plurality of organic functional layers in series, the plurality of organic functional layers, And a color conversion film disposed on the facing surface on the side where the wiring is formed.
According to the present invention, even if some of the plurality of organic functional layers cannot emit light due to a short circuit, the other organic functional layers can emit light without lowering the luminance. Moreover, since an electrically complicated wiring is not required, the organic functional layer and the like can be easily formed. In addition, since the color conversion layer is included, even if some of the organic functional layers cannot emit light, even if the light emitting device is viewed, it is difficult to recognize the non-light emitting portion.

In addition, the color conversion layer is arranged on the substrate or a sealing member that covers the organic functional layer. In the so-called top emission type and bottom emission type, a plurality of organic functional layers and color conversion layers can be easily formed. Can be separated by a certain distance.
Moreover, even if the said light emitting layer consists only of a blue light emitting layer, white light can be obtained by a color conversion layer.
Moreover, the said light emitting layer can obtain white light suitable for illumination by laminating | stacking a blue light emitting layer and a red light emitting layer.
In addition, when the width of the organic functional layer is equal to or greater than the distance between the organic functional layers, it is difficult to recognize light emission unevenness.
Moreover, when the distance between the organic functional layers is equal to or less than the distance from the organic functional layer to the color conversion layer, it is difficult to recognize light emission unevenness.

According to a second aspect of the present invention, there is provided a method for manufacturing a light-emitting device, comprising: arranging a plurality of organic functional layers having at least a light-emitting layer and wirings electrically connecting the plurality of organic functional layers in series on a substrate; And a step of disposing a color conversion layer at a position spaced apart from the plurality of organic functional layers.
According to the present invention, even if some of the plurality of organic functional layers cannot emit light due to a short circuit, the other organic functional layers can emit light without lowering the luminance. Moreover, since an electrically complicated wiring is not required, the organic functional layer and the like can be easily formed. In addition, since the color conversion layer is included, even if some of the organic functional layers cannot emit light, even if the light emitting device is viewed, it is difficult to recognize the non-light emitting portion.

According to a third aspect of the invention, an electronic apparatus includes the light emitting device according to the first aspect of the invention.
According to the present invention, since the thin light emitting device capable of emitting white light without unevenness is provided, a high-quality electronic device can be obtained.

Embodiments of a light-emitting device, a method for manufacturing a light-emitting device, and an electronic device according to the present invention will be described below with reference to the drawings.
[Lighting device]
FIG. 1 is a cross-sectional view schematically showing the configuration of the illumination device according to the first embodiment. FIG. 2 is a diagram schematically showing a planar structure of the lighting device.

  The illumination device (light emitting device) 101 is mainly composed of a substrate 10, an organic EL element 20 formed on the substrate 10, and a sealing member 30 fixed on the organic EL element 20. This is a so-called bottom emission type in which light emitted from the EL element 20 is emitted from the substrate 10 side.

A plurality of organic EL elements 20 are provided on the substrate 10, and each organic EL element 20 includes organic functional layers 20 a to 20 e and wirings 21 and 24.
The organic functional layers 20a to 20e in the present embodiment are composed of the hole injection layer 22 and the light emitting layer 23, and include a hole transport layer, an electron transport layer, and an electron transport layer. May be.
Further, the wirings 21 and 24 in the present embodiment are composed of the anode 21 and the cathode 24.
That is, the organic EL element 20 includes a configuration in which an anode 21, a hole injection layer 22, a light emitting layer 23, and a cathode 24 are sequentially stacked. The adjacent organic functional layers 20 a to 20 e are connected to the anode 21. Each is electrically connected to the cathode 24. That is, the plurality of organic EL elements 20 on the substrate 10 are electrically connected in series.
As shown in FIG. 1, the anode 21 of the organic functional layer 20a and the cathode 24 of the organic EL element 20e disposed at both ends of the substrate 10 are electrically connected to the light emitting circuit 40 that drives and controls the organic functional layers 20a to 20e. It is connected to the.
In addition, the width (length) of each organic EL element 20 (organic functional layers 20a to 20e) is a, and the distance between the organic EL elements 20 is c.

The substrate 10 is a light-transmitting substrate such as transparent glass or quartz so as to transmit and emit emitted light. The thickness of the substrate 10 is t.
A light conversion phosphor film 15 is disposed on the light exit surface side of the substrate 10. The light conversion phosphor film 15 converts received light into light (fluorescence) having a longer wavelength, and includes phosphor fine particles and a matrix resin.
Examples of the fluorescent fine particles include nanocrystalline fine particles of an organic fluorescent dye having a J-association property containing a cyano group. It is also possible to use inorganic phosphor fine particles which are made of an inorganic compound such as a metal compound and absorb visible light and emit fluorescence longer than the absorbed light.
The matrix resin is a resin that disperses the phosphor fine particles, and a non-curable resin, a thermosetting resin, or a photocurable resin can be used. Specifically, oligomeric or polymeric melamine resin, phenolic resin, alkyd resin, epoxy resin, polyurethane resin, maleic resin, polyamide resin, or polymethyl methacrylate, polyacrylate, polycarbonate, polyvinyl alcohol, polyvinyl pyrrolidone, hydroxy Examples include ethyl cellulose, carboxymethyl cellulose, and the like, and copolymers having monomers forming them as constituent components.

The anode 21 is also formed of a transparent conductive material in order to transmit light emitted from the light emitting layer 23 as will be described later. It is preferable to use ITO as the transparent conductive material. Further, the surface of the ITO (anode 21) is subjected to O ₂ plasma treatment as necessary, whereby the electrode surface is cleaned and the work function is adjusted, and the lyophilic property is further improved. It is to be granted.

A hole injection layer 22 is formed and disposed on the anode 21. The hole injection layer 22 is formed from, for example, a material obtained by adding polystyrene sulfonic acid to a polythiophene derivative. That is, specifically, polyethylenedioxythiophene / polystyrene sulfonic acid or the like is preferably used as a material for forming the hole injection layer 22.
In addition, about the forming material of the positive hole injection layer 22, various things can be used without being limited to what was mentioned above. For example, a material obtained by dispersing polystyrene, polypyrrole, polyaniline, polyacetylene or a derivative thereof together with the above-described polystyrene sulfonic acid in an appropriate dispersion medium can be used.

The light emitting layer 23 is formed of a known light emitting material capable of emitting fluorescence or phosphorescence. In the present embodiment, a blue light emitting material is used.
When a polymer material is used as the light emitting material, a nonpolar solvent in which the hole injection layer 22 is insoluble is used as a solvent for liquefying the polymer material so as not to redissolve the hole injection layer 22.
In particular, when the light emitting layer forming material is applied by a spin coating method or a dip method as will be described later, toluene, xylene, or the like is preferably used as the nonpolar solvent. In addition, when applying by a droplet discharge method such as an ink jet method, dihydrobenzofuran, trimethylbenzene, tetramethylbenzene, cyclohexylbenzene, or a mixture thereof is used.

In addition, as a material for forming the light emitting layer 23, a light emitting material made of a low molecular material may be used. However, when the light emitting layer 23 is formed of a low molecular material, the organic EL element 20 is preferably formed by laminating a hole transport layer, a light emitting layer, and an electron transport layer in this order from the anode 21 side. .
The hole transport layer is formed of a hole transport material such as α-NPD or TPD, or is formed as a stacked structure of a hole injection material using a starburst amine system and the hole transport material. Is preferred.
Further, as the low molecular weight material forming the light emitting layer, for example, a system in which an electron transporting light emitting material such as Alq3 (aluminum chelate complex) is doped with a small amount of a fluorescent dye (rubrene, quinacridone, DCM, or the like) is used.
Furthermore, as the electron transport layer, for example, Alq3 or PBD is used.

The cathode 24 can be composed of a metal electrode made of magnesium, calcium, aluminum or the like.
A sealing member 30 is provided on the substrate 10 so as to cover the organic EL element 20. As this sealing member 30, for example, a plate-shaped sealing substrate having electrical insulation is used. The sealing substrate is fixed to the substrate 10 with a sealing resin while covering the organic EL element 20.
As the sealing resin, for example, a thermosetting resin or an ultraviolet curable resin is used, and in particular, an epoxy resin which is a kind of thermosetting resin is preferably used. Alternatively, only the sealing resin may be used without using the sealing substrate, and the organic EL element 20 may be covered and sealed.

As a method for manufacturing the lighting device 101, the anode 21 is formed on the substrate 10, and the organic functional layers 20 a to 20 e, that is, the hole injection layer 22 and the light emitting layer 23 are formed so as to cover a part thereof.
Further, a cathode 24 is formed so as to cover a part of the anode 21 exposed from the organic functional layers 20a to 20e adjacent to the organic functional layers 20a to 20e. Thereby, the organic functional layers 20 a to 20 e on the substrate 10 are electrically connected in series by the anode 21 and the cathode 24. That is, the plurality of organic EL elements 20 are electrically connected in series.
Next, after the sealing member 30 is disposed, the light conversion phosphor film 15 is disposed on the light exit surface side of the substrate 10.

Thus, the illuminating device 101 includes a plurality of organic EL elements 20 (organic functional layers 20a to 20e), and the organic EL elements 20 are electrically connected in series. For this reason, for example, even if the organic functional layer 20e is short-circuited due to fine dust or the like and thus cannot emit light, the other organic functional layers 20a to 20d can emit light.
In addition, although a high drive voltage is required compared with the case where the some organic EL element 20 is electrically connected in parallel, since a drive current becomes fixed, the efficient illuminating device 101 can be implement | achieved. .
Furthermore, since an electrically complicated wiring is not required, the organic EL element 20 can be easily formed.

FIG. 3 is a diagram showing an emission spectrum of light emitted from the illumination device 101.
Moreover, since the illuminating device 101 includes the light conversion phosphor film 15 disposed on the light exit surface side of the substrate 10, the illuminating device that emits white light even when the organic EL element 20 emits only blue light. 101 can be realized.
Even if the light emitted from the organic EL element 20 is blue light, a part of the blue light is color-converted to orange light by the light conversion fluorescent film 15 disposed on the light exit surface side of the substrate 10. Thereby, as shown in FIG. 3, the white light used suitably for an illuminating device can be obtained easily.
Thus, since the illuminating device 101 can be comprised only by the light emitting layer 23 which light-emits blue light, improvement of manufacturing efficiency and reduction of manufacturing cost can be aimed at. Therefore, an inexpensive illumination device 101 can be realized.

  Furthermore, since the light emitting fluorescent film 15 is provided, the light emitted from each organic EL element 20 is scattered, so that, for example, when one organic EL element 20 does not emit light, there is no light emitting portion. Will be blurred. For this reason, even when the illumination device 101 is viewed from the substrate 10 side, it is difficult to recognize the non-light emitting portion. Therefore, it is possible to suppress a decrease in the commercial value of the lighting device 101.

FIG. 4 is a cross-sectional view schematically showing the configuration of the illumination device according to the second embodiment. FIG. 5 is a diagram schematically showing a planar structure of the illumination device.
Note that components that are substantially the same as those of the lighting device 101 are given the same reference numerals, and descriptions thereof are omitted or simplified.

As shown in FIG. 4, the illumination device 102 includes a light emitting layer 23 in which a blue light emitting layer 23b and a red light emitting layer 23r are stacked. Further, as shown in FIG. 5, a plurality of organic EL elements 20 (organic functional layers 20 a to 20 l) having such a light emitting layer 23 are arranged on the substrate 10 in a lattice shape (matrix shape).
The organic functional layers 20a to 20d, 20e to 20h, and 20i to 20l are arranged in series in the same direction, and are also electrically connected in series.
The anode 21 of the organic functional layers 20a, 20e, and 20i and the cathode 24 of the organic EL elements 20d, 20h, and 20l disposed at both ends of the substrate 10 are a light emitting circuit 40 that drives and controls the organic functional layers 20a to 20l. They are electrically connected in parallel.
In addition, each width | variety (length) of each organic EL element 20 (organic functional layer 20a-20l) is set to a and b, and the distance between each organic EL element 20 is set to c and d.

FIG. 6 is a diagram illustrating an emission spectrum of light emitted from the illumination device 102.
Moreover, since the illuminating device 102 is provided with the light conversion fluorescent film 15 disposed on the light exit surface side of the substrate 10, even when the organic EL element 20 emits blue light and red light, it emits white light. The lighting device 102 can be realized.
Even if the light emitted from the organic EL element 20 is blue light and red light, a part of the blue light is color-converted into orange light by the light conversion fluorescent film 15 disposed on the light output surface side of the substrate 10. As shown in FIG. 6, it is possible to easily obtain white light suitably used for the lighting device. In particular, as shown in FIG. 6, blue light, green light, and red light can be obtained in a well-balanced manner, so that good white light can be obtained.

  Moreover, the illuminating device 102 is provided with the some organic EL element 20 similarly to the illuminating device 101, and each organic EL element 20 is electrically connected in series. For this reason, even if a certain organic EL element 20 cannot emit light, the other organic EL elements 20 can emit light.

  Further, similarly to the lighting device 101, the light-converting fluorescent film 15 is provided, so that the light emitted from each organic EL element 20 is scattered, so that one organic EL element 20 does not emit light. Even when the illumination device 102 is viewed from the substrate 10 side, it is difficult to recognize the non-light emitting portion.

Next, light emission unevenness of the illumination devices 101 and 102 will be described.
FIG. 7 is a diagram for explaining uneven light emission of the illumination devices 101 and 102.
In order to evaluate the light emission unevenness of the illumination devices 101 and 102, the following formula is used.

  Unevenness (%) = (Average brightness−Lowest brightness) / (Average brightness) × 100

  According to the above formula, when the non-light-emitting organic EL element 20 is present in the illumination devices 101 and 102, the non-light-emitting organic EL element 20 causes in-plane unevenness of the illumination devices 101 and 102 (light emission on the light-emitting surface of the substrate 10). The effect on unevenness can be evaluated.

In the illumination device 101 and the illumination device 102, the thickness of the substrate 10 is t = 1.0 mm, the length between the organic EL elements 20 is c = 0.1 mm, and one organic EL element 20 emits no light. In this case, if the width (length) a of each organic EL element 20 is changed, the result shown in FIG.
When the length a of each organic EL element 20 is 1.0 mm or less, the in-plane unevenness of the illumination devices 101 and 102 (light emission unevenness of the light exit surface of the substrate 10) is 10% or less. If the in-plane unevenness (light emission unevenness) is 10% or less, it is difficult to recognize the non-light emitting area even when the light exit surface of the substrate 10 is visually observed.

  In the lighting device 102, when the thickness of the substrate 10 is t = 1.0 mm, the length between the organic EL elements 20 is d = 0.1 mm, and all the organic EL elements 20 emit light, When the length b of the organic EL element 20 is changed, the same result as in FIG. 7A is obtained.

Next, in the illumination device 101 and the illumination device 102, when the thickness of the substrate 10 is t = 0.5 mm and the length a of each organic EL element 20 is a = 1.0 mm, the length between the organic EL elements 20 is as follows. When c is changed, the result shown in FIG. 7B is obtained.
When the length c between the organic EL elements 20 is 0.5 mm or less (that is, smaller than the thickness t of the substrate 10), the in-plane unevenness of the illumination devices 101 and 102 is 10% or less. Therefore, it is difficult to recognize the non-light emitting region even when the light exit surface of the substrate 10 is visually observed.

  In the lighting device 102, when the thickness of the substrate 10 is t = 0.5 mm and the length b of each organic EL element 20 is b = 1.0 mm, the length between the organic EL elements 20 is changed by d =. If it does, it will become the result similar to Fig.7 (a).

[Electronics]
FIG. 8 is a cross-sectional configuration diagram illustrating an example of an electronic apparatus including the illumination devices 101 and 102 according to the above-described embodiments.
The image reading apparatus (electronic device) 200 is a flat bed type image reading apparatus that reads a reflection original placed on an original table.
The image reading apparatus 200 moves while irradiating light on a transparent document table 212 for placing a document on the upper surface of a box-shaped housing, and the document placed on the document table 212, and reads reflected light from the document. A carriage 213, an image processing unit 214 that digitally converts the reflected light signal read by the carriage 213, performs processing such as correction, and converts the image data into an image data; an interface 211 capable of bidirectional communication with a host computer (not shown); A document table cover 215 for covering the document table is provided.
A white surface light source 216 is disposed on a part of the document table cover 215. By irradiating light from the surface light source 216, a transparent original such as a film placed on the original table 212 can be read by the carriage 213. As the surface light source 216, illumination devices (light emitting devices) 101 and 102 are used.

Note that the lighting devices 101 and 102 can also be used as a backlight of a liquid crystal display device.
Accordingly, examples of the electronic apparatus including the lighting devices 101 and 102 include a digital camera, a personal computer, a television, a portable television, a viewfinder type / direct monitor type video tape recorder, a PDA, a portable game machine, a pager, Examples include electronic notebooks, calculators, clocks, word processors, workstations, videophones, POS terminals, and devices with touch panels. In addition, in-vehicle displays such as in-vehicle audio devices, automobile meters, and car navigation devices can be cited.

  The technical scope of the present invention is not limited to the above-described embodiments, and includes various modifications made to the above-described embodiments without departing from the spirit of the present invention. That is, the specific materials and configurations described in the embodiments are merely examples, and can be changed as appropriate.

  In the present embodiment, a so-called bottom emission type in which light emitted from the organic EL element 20 is emitted from the substrate 10 side has been described. However, even in a so-called top emission type in which light is emitted from the sealing member 30 side. Good. In this case, the light conversion phosphor film 15 is disposed on the transparent sealing member 30.

It is sectional drawing which showed typically the structure of the illuminating device 101 which concerns on 1st embodiment. It is the figure which showed the planar structure of the illuminating device 101 typically. It is a figure which shows the emission spectrum of the light irradiated from the illuminating device 101. FIG. It is sectional drawing which showed typically the structure of the illuminating device 102 which concerns on 2nd embodiment. It is the figure which showed the planar structure of the illuminating device 102 typically. It is a figure which shows the emission spectrum of the light irradiated from the illuminating device. It is a figure for demonstrating the light emission nonuniformity of the illuminating devices 101 and 102. FIG. It is a cross-sectional block diagram which shows an example of the electronic device provided with the illuminating devices 101 and 102. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Board | substrate, 15 ... Light conversion fluorescent film (color conversion layer), 20 ... Organic EL element,
20a-20l ... organic functional layer, 21 ... anode (wiring), 23 ... light emitting layer,
23r ... red light emitting layer, 23b ... blue light emitting layer, 24 ... cathode (wiring),
30 ... Sealing member 101, 102 ... Illuminating device (light emitting device),
200: Image reading device (electronic device), 216: Surface light source (light emitting device)

Claims (9)

A substrate including a plurality of organic functional layers having at least a light emitting layer, and a wiring electrically connecting the plurality of organic functional layers in series;
A color conversion layer disposed at a position spaced apart from the plurality of organic functional layers;
A light emitting device comprising: A substrate provided on one side with a plurality of organic functional layers having at least a light emitting layer, and wiring that electrically connects the plurality of organic functional layers in series;
A light emitting device comprising: a color conversion film disposed on an opposing surface on a side where the plurality of organic functional layers and the wiring are formed.   The light emitting device according to claim 1, wherein the color conversion layer is disposed on the substrate or a sealing member that covers the organic functional layer.   The light emitting device according to any one of claims 1 to 3, wherein the light emitting layer includes only a blue light emitting layer.   The light emitting device according to any one of claims 1 to 3, wherein the light emitting layer is formed by laminating a blue light emitting layer and a red light emitting layer.   The light emitting device according to claim 1, wherein a width of the organic functional layer is equal to or greater than a distance between the organic functional layers.   The light emitting device according to claim 1, wherein a distance between the organic functional layers is equal to or less than a distance from the organic functional layer to the color conversion layer. Arranging a plurality of organic functional layers having at least a light emitting layer on the substrate, and wiring for electrically connecting the plurality of organic functional layers in series;
Disposing a color conversion layer at a position spaced from the plurality of organic functional layers;
A method for manufacturing a light-emitting device, comprising: An electronic apparatus comprising the light emitting device according to claim 1.

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