JP5326342B2 - Light emitting display device and method of manufacturing light emitting display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting display device which is excellent in safety without using an organic solvent and can prevent light-emitting characteristics from reducing and can lessen types of formation materials. <P>SOLUTION: The light-emitting display device 1 has a storage container 3 forming one electrode 10 in the inside, and a light-emitting body 5 formed in the storage container 3. Furthermore, the other electrode 11 keeps in contact with the light-emitting body 5. Furthermore, the light-emitting body 5 has an ionic liquid 6, a light-emitting material 7 dissolved into the ionic liquid 6, and a gelatinized material 8 for gelling the ionic liquid 6. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a light emitting display device including a storage container having one electrode formed on the inner surface and a light emitter filled in the storage container, and in particular, has excellent safety and reduced light emission characteristics. The present invention relates to a light emitting display device and a method for manufacturing the light emitting display device.

  In recent years, development of light-emitting display devices such as organic EL has been rapidly progressing. Since the light emitting element used in the organic EL light emitting display device is a self light emitting element, it can be made thinner and lighter than a liquid crystal light receiving element that requires a backlight. In addition, since the organic EL light-emitting element is a self-light-emitting element, it is more visible than a liquid crystal light-receiving element. For this reason, the organic EL light-emitting display device has features such as excellent visibility, high-speed display properties, low-voltage drivability, and thinning.

  2. Description of the Related Art An organic EL light emitting display device generally includes a pair of substrates each having an electrode formed on each surface facing each other, and a light emitting layer sandwiched between the pair of substrates. It contains a luminescent material. Among these, the light emitting layer has a thickness of several hundred nm. For this reason, the distance between each electrode which opposes is short, and each electrode is easy to mutually contact. Further, a direct current voltage is applied to the light emitting layer of the organic EL light emitting display device. For this reason, impurities are likely to be accumulated at the interface between the electrodes constituting the organic EL light emitting display device. This shortens the operating life of the light emitting layer used in the organic EL light emitting display device.

In order to solve such a problem, a light emitting display device using a light emitting layer made of a liquid utilizing an electrochemical reaction has been developed (for example, see Patent Documents 1 to 3 and Non-Patent Documents 1 and 2). Among these, in the light emitting display devices in Patent Documents 1 and 2 and Non-Patent Documents 1 and 2, the distance between the pair of electrodes is both several μm or more. For this reason, each electrode does not contact each other. In addition, since an AC voltage is applied to the light-emitting layers of the light-emitting display devices in Patent Documents 1 to 3 and Non-Patent Document 1, the problem of shortening the operating life of the light-emitting layers is solved.
JP 2007-139899 A JP 2006-301302 A JP 2005-302332 A `` Toshiba review vol.60, No.9, P33 (2005) '' "Journal of the Electrochemical Society, Vol.152 (8) pA1677 (2005)"

  As shown in FIG. 2, the light-emitting display device 21 in Patent Documents 1 to 2 and Non-Patent Documents 1 and 2 is sandwiched between a pair of substrates 23 in which electrodes 24 are formed on surfaces facing each other, and the pair of substrates 23. And a light emitting layer 25 in which a light emitting substance 28 is dissolved in an electrolyte composed of an organic solvent 26 and a supporting salt 27. Thus, since the flammable organic solvent 26 is used as the light emitting layer 25, there is a problem in safety in handling.

  Moreover, since the organic solvent 26 has volatility, it volatilizes relatively easily. For this reason, there is also a problem that the concentration in the light emitting layer 25 changes, the light emitting layer 25 is deteriorated, and the light emitting characteristics of the light emitting layer 25 are lowered.

  Furthermore, as described above, in the light emitting layer 25 using the organic solvent 26, it is necessary to dissolve the supporting salt 27 in the organic solvent 26 in order to cause the light emitting layer 25 to emit light sufficiently. For this reason, when using the organic solvent 26 as the light emitting layer 25, the kind of material which comprises the light emitting layer 25 increases.

  The present invention has been made in consideration of such points, and is a light-emitting display device that does not use an organic solvent, is excellent in safety, and can prevent deterioration in light-emitting characteristics. An object of the present invention is to provide a light-emitting display device and a method for manufacturing the light-emitting display device that can reduce the types of constituent materials.

  The present invention includes a storage container having one electrode formed on the inner surface, a light emitter formed in the storage container, and the other electrode in contact with the light emitter, the light emitter being an ionic liquid And a light-emitting substance dissolved in the ionic liquid and a gelling material that gels the ionic liquid.

  The present invention is the light-emitting display device, wherein one electrode formed on the inner surface of the storage container is made of any material of gold, platinum, silver, aluminum, tin, bismuth, and carbon.

  The present invention is the light-emitting display device, wherein the gelling material is composed of silica nano-sized fine particles or titanium oxide nano-sized fine particles.

  The present invention is a light-emitting display device in which a light emitter emits light when an AC voltage is applied thereto.

  The present invention is the light-emitting display device in which the ionic liquid includes any one of aliphatic, imidazolium, and pyridium materials.

  The present invention is a light-emitting display device in which the light-emitting substance includes any one of a ruthenium compound / complex, PVB (polyvinyl butyral), DPA (9,10-diphenylanthracene), and perylene.

  The present invention includes a step of preparing a storage container having one electrode formed on the inner surface, a step of dissolving a luminescent material in an ionic liquid, and a gel that gels the ionic liquid into an ionic liquid in which the luminescent material is dissolved A step of adding a luminescent material, a step of filling a ionic liquid in which a luminescent substance is dissolved and a gelled material is added into a storage container in which one electrode is formed on the inner surface, and forming a luminescent material; And a step of bringing the other electrode into contact with the light emitter filled in the storage container.

  According to the present invention, the illuminant includes an ionic liquid, a luminescent material dissolved in the ionic liquid, and a gelling material that gels the ionic liquid, and therefore uses a flammable organic solvent. A light emitter is formed without any problems. Since the ionic liquid of this luminous body is flame retardant, it is relatively safe in handling compared to the case where a flammable organic solvent is used. In addition, since the organic solvent is volatile, it is easily vaporized. However, according to the present invention, the ionic liquid of the light emitter is not vaporized because it is nonvolatile. For this reason, it can prevent that a light-emitting body deteriorates and can maintain the stable performance, without the light emission characteristic of a light-emitting body falling. Further, when an organic solvent is used when forming the light emitter, it is necessary to dissolve the supporting salt in the organic solvent. However, according to the present invention, since the light emitter contains the ionic liquid, Furthermore, it is not necessary to dissolve the supporting salt. For this reason, the kind of material which comprises a light-emitting body can be decreased.

  Further, according to the present invention, since the luminescent material is composed of an ionic liquid, a luminescent material dissolved in the ionic liquid, and a gelling material that gels the ionic liquid, the luminescent material is dissolved. The phosphor can be formed by gelling the ionic liquid and filling the gelled ionic liquid into a storage container without sealing. As a result, the upper surface of the light emitter can be exposed to the outside. Therefore, light emitted from the light emitter can be easily and reliably extracted to the outside, and stable performance can be maintained over a long period of time without deteriorating the light emission characteristics of the light emitter.

  Embodiments of the present invention will be described below with reference to the drawings. Here, FIG. 1 is a diagram showing an embodiment of a light emitting display device according to the present invention. Among these, FIG. 1 is a diagram showing a cross-sectional configuration of a light-emitting display device according to an embodiment of the present invention.

  First, the light-emitting display device 1 according to the present invention will be described with reference to FIG. Here, the light emitting display device 1 emits light when a voltage is applied, and is used as various displays.

  As shown in FIG. 1, the light emitting display device 1 includes a storage container 3 in which one electrode 10 is formed on the inner surface, and a light emitting body 5 formed in the storage container 3. Among these, the luminous body 5 includes an ionic liquid 6, a luminescent substance 7 dissolved in the ionic liquid 6, and a gelling material 8 that gels the ionic liquid 6.

  A wire (the other electrode) 11 is inserted into the light emitter 5 from above the light emitter 5. In this case, the light emitter 5 is in contact with the portion of the wire 11 inserted into the light emitter 5.

  As shown in FIG. 1, an AC power supply 13 that applies a voltage to the light emitter 5 is connected between the electrode 10 formed on the inner surface of the storage container 3 and the wire 11.

  By the way, the ionic liquid 6 is also called a molten salt, and consists only of ions that maintain a liquid state at room temperature. Unlike the liquid electrolyte in which the supporting salt is dissolved in the organic solvent, the ionic liquid 6 has characteristics such as flame retardancy and non-volatility. In the luminescent material 5 formed by dissolving the luminescent material 7 in the ionic liquid 6 and adding the gelling material 8, when the inside of the luminescent material 5 is electrochemically reacted, the voltage applied to the luminescent material 5 is kept low. It is possible to cause the redox reaction at high speed.

  In addition, the material used for the ionic liquid 6 is preferably a material having a high polarity in order to dissolve a wide variety of light-emitting substances 7 at a high concentration. For example, aliphatic, imidazolium, and pyridium materials can be used. . Of these, the 1-allyl-3-alkylimidazolium system can be particularly preferably used.

The material used for the luminescent substance 7 is not particularly limited as long as it is a material that emits electrochemiluminescence. For example, PVB (polyvinyl butyral), DPA (9,10-diphenylanthracene), perylene, RuCl ₆ , RuPF ₆ , Ru ( Ru (ruthenium) compounds and complexes such as bpy ₃ ) Cl ₂ and Ru (d ₈ -bpy ₃ ) PF ₆ can be preferably used. Moreover, there is no restriction | limiting in particular about the density | concentration of the luminescent substance 7, Although 10 wt% or less is desirable, Especially it can use suitably between 1 wt% and 5 wt%.

  Here, the gelation means a state in which the ionic liquid 6 loses fluidity, and it is preferable to use silica nano-sized fine particles or titanium oxide nano-sized fine particles as the gelled material 8. The amount of the gelling material 8 added is preferably 1 wt% to 15 wt%, and particularly preferably 3 wt% to 7 wt%.

  The material used for the storage container 3 is not limited to a transparent material, and for example, ceramic or the like can be used.

  Moreover, as a material used for the electrode 10 provided in the inner surface of each storage container 3, and the wire 11, gold (Au), platinum (Pt), silver (Ag), aluminum (Al), tin (Sn), bismuth Metal materials such as (Bi) and carbon materials can be used. In this case, since the electrode 10 is formed of a material that does not transmit the light emitted from the light emitter 5, the light emitted from the light emitter 5 by the electrode 10 is reflected inward of the storage container 3 to emit light. The brightness of the light emitted from the body 5 and extracted outside can be increased. In this case, ITO (Indium Tin Oxide) containing indium, which is a rare metal, is not used as the material for the electrode 10 and the wire 11. For this reason, the light emitted from the light emitter 5 can be extracted to the outside using a relatively inexpensive material.

  Next, a method for manufacturing the light emitting display device 1 according to the present embodiment will be described.

  First, as shown in FIG. 1, the storage container 3 having one electrode 10 formed on the inner surface is prepared. In this case, first, a storage container 3 having a desired size and thickness is prepared. Thereafter, the electrode 10 is formed over the entire inner surface of the storage container 3 by sputtering or EB vapor deposition.

  Next, the luminescent material 7 is dissolved in the ionic liquid 6. In this case, the luminescent material 7 is mixed with the ionic liquid 6 so as to have a desired concentration, and stirred at a predetermined temperature for a predetermined time. As a result, the luminescent material 7 is sufficiently dissolved in the ionic liquid 6.

  Next, a gelling material 8 that gels the ionic liquid 6 is added to the ionic liquid 6 in which the luminescent substance 7 is dissolved, and the ionic liquid 6 in which the luminescent substance 7 is dissolved is gelled by mixing for a predetermined time. The

  Next, the gelled ionic liquid 6 is filled in the storage container 3 in which one electrode 10 is formed on the inner surface to form the light emitter 5.

  Thereafter, the wire 11 is inserted into the light emitter 5 from the outside of the light emitter 5 formed in the storage container 3. In this way, the light emitting display device 1 shown in FIG. 1 is obtained.

  Next, a usage pattern of the light emitting display device 1 having such a configuration will be described.

  In the light-emitting display device 1 according to the present embodiment shown in FIG. 1, when the light emitter 5 is caused to emit light, first, an alternating current is applied to the light emitter 5 from the AC power supply 13 via the electrode 10 on the inner surface of the storage container 3 and the wire 11. A voltage is applied. In this case, for example, an electrochemical reduction reaction occurs in the vicinity of the electrode 10 in the storage container 3 serving as a cathode, and radical anions 14 are generated from the ionic liquid 6 and the luminescent material 7. On the other hand, an electrochemical oxidation reaction takes place near the portion of the wire 11 serving as the anode inserted into the light emitter 5, and radical cations 15 are generated from the ionic liquid 6 and the light emitting substance 7.

  While an AC voltage is applied to the light emitter 5, since an AC voltage is applied to the electrode 10 on the inner surface of the storage container 3 and the wire 11, the reduction reaction and the oxidation reaction are alternately repeated on the electrode 10 and the wire 11. It is. That is, the radical anion 14 generated by the reduction reaction in the vicinity of the electrode 10 moves toward the portion of the opposing wire 11 inserted into the light emitter 5. Next, the polarities of the electrode 10 and the wire 11 are reversed, and radical cations 15 are generated in the vicinity of the electrode 10 by an oxidation reaction. During this time, the radical anion 14 that has moved from the vicinity of the electrode 10 toward the portion of the opposing wire 11 inserted into the light emitter 5 returns to the electrode 10. As a result, the radical anion 14 and the radical cation 15 collide. Next, a neutral molecule in a ground state and a neutral molecule in an excited state are generated from the colliding radical anion 14 and radical cation 15. Thereafter, the neutral molecule in the excited state is deactivated, and light is emitted from the neutral molecule.

  In the same manner as the light emission mechanism in the vicinity of the electrode 10, the generated radical anion 14 and radical cation 15 collide with each other in the vicinity of the portion of the wire 11 inserted into the light emitter 5, and excited molecules Is generated and emits light. As described above, since the radical anion 14 and the radical cation 15 collide with each other in the vicinity of the electrode 10 and in the vicinity of the portion of the wire 11 inserted in the light emitter 5, light emission occurs. Even when the distance is relatively long, the light emitter 5 can emit light.

  As described above, according to the present embodiment, the light emitter 5 includes the ionic liquid 6, the luminescent material 7 dissolved in the ionic liquid 6, and the gelling material 8 that gels the ionic liquid 6. Therefore, the light emitter 5 is formed without using a flammable organic solvent. Compared to the case where a flammable organic solvent is used, according to the present embodiment, the ionic liquid 6 included in the light emitter 5 is flame retardant, and is relatively safe in handling. In addition, the organic solvent is volatile because it is volatile, but according to the present embodiment, the ionic liquid 6 included in the light emitter 5 is vaporized because it is nonvolatile. Absent. For this reason, it can prevent that the light-emitting body 5 deteriorates, and can maintain the stable performance, without the light emission characteristic of the light-emitting body 5 falling. Furthermore, according to the present embodiment, since the ionic liquid 6 is used when forming the light emitter 5, it is not necessary to dissolve the supporting salt in the ionic liquid 6. For this reason, the kind of material which comprises the light-emitting body 5 can be decreased.

  Moreover, according to this Embodiment, since the light-emitting body 5 consists of the ionic liquid 6, the luminescent substance 7 melt | dissolved in this ionic liquid 6, and the gelling material 8 which gelatinizes the ionic liquid 6. FIG. The phosphor 5 can be formed by gelling the ionic liquid 6 in which the luminescent material 7 is dissolved and filling the gelled ionic liquid 6 in the storage container 3 without sealing. As a result, the upper surface of the light emitter can be exposed to the outside. For this reason, the light emitted from the light emitter 5 can be easily and reliably extracted to the outside, and stable performance can be maintained over a long period of time without deteriorating the light emission characteristics of the light emitter 5.

  Further, according to the present embodiment, as described above, the electrode 10 and the wire 11 formed on the inner surface of the storage container 3 are formed of a material that does not transmit light emitted from the light emitter 5. For this reason, the electrode 10 can reflect the light emitted from the light emitter 5 to the inside of the storage container 3 and increase the luminance of the light emitted from the light emitter 5 and extracted to the outside. In this case, since ITO (Indium Tin Oxide) containing rare metal indium is not used as the material of the electrode 10 and the wire 11, light emitted from the light emitter 5 using a relatively inexpensive material. Can be taken out.

  In the present embodiment, an example is shown in which the electrode 10 formed on the inner surface of the storage container 3 is formed of a material that does not transmit light emitted from the light emitter 5. However, the present invention is not limited to this. As a material used for the electrode 10, ITO that is a transparent electrode may be used, and a reflection plate (not shown) may be provided on the outer surface of the storage container 3. In this case, the reflection plate can reflect the light emitted from the light emitter 5 toward the inside of the storage container 3, thereby increasing the luminance of the light emitted from the light emitter 5 and extracted to the outside.

  As an example of the present invention, the light-emitting display device 1 of FIG. 1 was manufactured by the following method.

  First, a ceramic container 3 having a depth of 7 mm and an opening diameter of 10 mm was prepared, and a gold electrode 10 was formed on the inner surface of the container 3 by sputtering so as to have a thickness of 150 nm. Next, the storage container 3 in which the electrode 10 was formed on the inner surface was washed with a neutral detergent, further subjected to ultrasonic cleaning, and then dried.

Next, 2 wt% of Ru (bpy ₃ ) Cl ₂ as the luminescent material 7 is mixed with 1-allyl-3-butylimidazolium bis (trifluoromethanesulfonyl) imide (abbreviation: ABImTFSI) which is the ionic liquid 6. Then, the mixture was stirred at 65 ° C. and 500 rpm for 3 hours to sufficiently dissolve Ru (bpy ₃ ) Cl ₂ as the luminescent material 7 to produce a luminescent solution.

  Next, 7 wt% of a gelling material (silica fine particles (Aerosil 200 manufactured by Nippon Aerosil Co., Ltd.)) 8 wt% was added to this luminescent solution and mixed for a predetermined time to gel the luminescent solution. Next, the light emitting body 5 was formed by filling the gelled luminescent solution into the storage container 3. Next, a gold wire (wire) 11 having a diameter of 2 mm was inserted into the light emitter 5 so that the distance between the tip of the gold wire 11 and the electrode 10 in the storage container 3 was 2 mm.

Thereafter, an AC voltage of 60 Hz and ± 5 V was applied to the luminous body 5 obtained in this example. As a result, light emission having a luminance of 120 cd / m ² could be obtained.

FIG. 1 is a diagram showing a cross-sectional configuration of a light emitting display device according to an embodiment of the present invention. FIG. 2 is a diagram showing a cross-sectional structure of a conventional light emitting display device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light emitting display device 3 Storage container 5 Light emitter 6 Ionic liquid 7 Luminescent substance 8 Gelling material 10 Electrode 11 Wire 13 AC power supply 14 Radical anion 15 Radical cation 21 Light emitting display device 23 Substrate 24 Electrode 25 Light emitting layer 26 Organic solvent 27 Support salt 28 Luminescent substances

Claims (6)

A storage container having one electrode formed on the inner surface;
A light emitter formed in the storage container;
The other electrode in contact with the light emitter,
The phosphor has an ionic liquid, a luminescent substance dissolved in the ionic liquid, and a gelling material that gels the ionic liquid,
The illuminant emits light when an alternating voltage is applied ,
A light emitting display device characterized in that an opening for exposing an upper surface of a light emitting body to the outside is provided in an upper portion of the storage container .   2. The light emitting display device according to claim 1, wherein the one electrode formed on the inner surface of the storage container is made of any material selected from gold, platinum, silver, aluminum, tin, bismuth, and carbon.   The light-emitting display device according to claim 1, wherein the gelling material is composed of nano-sized fine particles of silica or nano-sized fine particles of titanium oxide.   4. The light-emitting display device according to claim 1, wherein the ionic liquid includes any one of aliphatic, imidazolium, and pyridium materials.   The light-emitting substance includes any one of a ruthenium compound / complex, PVB (polyvinyl butyral), DPA (9,10-diphenylanthracene), and perylene, according to any one of claims 1 to 4. Luminescent display device. Preparing a storage container in which one electrode is formed on the inner surface;
Dissolving a luminescent material in an ionic liquid;
Adding a gelling material that gels the ionic liquid to the ionic liquid in which the luminescent material is dissolved;
In a storage container in which one electrode is formed on the inner surface, a step of filling a ionic liquid in which a luminescent substance is dissolved and a gelling material is added, and forming a light emitter that emits light by application of an alternating voltage;
A step of bringing the other electrode into contact with the luminous body filled in the storage container ,
An opening is provided at the top of the storage container,
In the step of forming a light emitter, the upper surface of the light emitter is exposed to the outside from an opening provided in an upper portion of the storage container .

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