JP2010176884A - Light emitting display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting display device of which light-emitting lifetime can be further extended even when an AC voltage is applied between each of electrodes. <P>SOLUTION: The light-emitting display device 1 includes a support 2 and a light-emitting part 5 supported by the support 2. A pair of electrodes 3, 4 are connected to the light-emitting part 5. Each of the electrodes 3, 4 contains at least carbon of 50 wt.% as a main component. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a light-emitting display device including a support, a light-emitting unit supported by the support, and a pair of electrodes connected to the light-emitting unit, and in particular, at least 50 wt. The present invention relates to a light-emitting display device containing carbon.

  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.

  An organic EL light-emitting display device generally includes a pair of substrates each having electrodes formed on opposite surfaces, and a light-emitting layer sandwiched between the pair of substrates, and a voltage is applied to the light-emitting layer. And has a thickness of several hundreds of nanometers. 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 4 and Non-Patent Documents 1 and 2).

  Among these, the light-emitting display devices in Patent Documents 1 to 3 and Non-Patent Documents 1 and 2 are composed of a pair of substrates in which electrodes are formed on surfaces facing each other, an organic solvent and a supporting salt sandwiched between the pair of substrates. A light-emitting layer in which a light-emitting substance is dissolved in an electrolyte, and an AC voltage is applied between the electrodes so that the light-emitting layer emits light. Here, as a material used for each electrode, a transparent metal oxide such as ITO (indium tin oxide) or FTO (fluorine-added tin oxide) is generally used.

JP 2008-47450 A 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)"

  However, when ITO or FTO is used as the material of each electrode, there is a problem that the light emission lifetime of the light emitting layer is shortened. That is, an alternating voltage is applied between the electrodes, and when a negative voltage is applied to the metal oxide (ITO or FTO) forming the electrode, a part of the metal oxide is reduced to form a metal (indium (In ) Or tin (Sn)) is produced, and the component change of the metal oxide forming the electrode occurs. This shortens the light emission lifetime of the light emitting layer.

  Patent Document 1 discloses an electrochemiluminescence device by alternating current drive in which a porous electrode is formed on the surface of one electrode using a material such as carbon nanotube. However, in this electrochemiluminescence device, the other electrode formed using a material such as FTO is in contact with the electrolyte layer (light-emitting layer), which makes it possible to extend the light-emitting lifetime of the light-emitting layer. There is a limit.

  On the other hand, when a DC voltage is applied between the electrodes, a metal oxide such as ITO or FTO is used for the positive electrode to which a positive voltage is applied, and a metal or the like is used for the negative electrode to which a negative voltage is applied. Thus, the problem that a part of the metal oxide is reduced can be avoided. However, since a DC voltage is applied between the electrodes, as described above, impurities are likely to accumulate at the interface between the electrodes, and it becomes difficult to increase the light emission lifetime.

  In addition, when a light emitting layer is caused to emit light by applying a DC voltage between the electrodes, in general, the thickness of the light emitting layer is made as thin as possible in order to maintain the electric field strength in the light emitting layer at a predetermined value. It is preferable. This causes a problem that the electrodes are close to each other and easily contact each other. On the other hand, when an AC voltage is applied between the electrodes to cause the light emitting layer to emit light, a portion in the vicinity of the interface between the electrode and the light emitting layer emits light. Accordingly, it is not necessary to reduce the thickness of the light emitting layer in order to maintain the electric field strength of the light emitting layer. For example, even when the thickness of the light emitting layer is 1 mm or more, light emission is performed at a relatively low voltage. The layer can emit light. For this reason, it is possible to avoid the problem that the electrodes are easily in contact with each other.

  The present invention has been made in consideration of such points, and an object of the present invention is to provide a light emitting display device capable of further extending the light emission life even when an AC voltage is applied between the electrodes. To do.

  The present invention comprises a support, a light emitting part supported by the support, and a pair of electrodes connected to the light emitting part, each electrode containing at least 50 wt% carbon as a main component. A light emitting display device.

  The present invention comprises a support, a light emitting part supported by the support, and a pair of electrodes connected to the light emitting part, each electrode containing at least 50 wt% carbon as a main component, The light emitting display device is characterized by being integrally formed by sintering a carbon paste in which carbon particles and a plasticizer are mixed.

  The present invention is the light emitting display device in which the plasticizer of each electrode is made of a polymer resin.

  The present invention is the light-emitting display device, wherein the plasticizer of each electrode is made of polyvinylidene fluoride.

  The present invention is a light-emitting display device in which one electrode is formed on a surface of a support and the other electrode is connected to a light-emitting portion supported by the support.

  In the present invention, the support is composed of a pair of substrates, the light emitting portion is composed of a light emitting layer sandwiched between the substrates, each electrode is provided inside the corresponding substrate, and the area of the planar shape of one electrode is The light emitting display device is smaller than the area of the planar shape of the other electrode.

  The present invention is characterized in that the support is made of a substrate, and each electrode is formed in a comb-teeth shape having a base portion and a comb portion connected to the base portion on the surface of the substrate, and the comb portions of each electrode enter each other. Is a light emitting display device.

  The present invention is the light-emitting display device characterized in that the carbon of each electrode includes any of glassy carbon, graphite, a mixture of graphite and amorphous carbon, and carbon nanotubes.

  According to the present invention, the pair of electrodes connected to the light emitting part contains at least 50% by weight of carbon as a main component. Since carbon contained in each electrode is electrochemically stable, the material of each electrode is not reduced even when a negative voltage is applied to each electrode. For this reason, it can prevent that the material of an electrode changes a component and can further lengthen the light emission lifetime of a light emission part.

FIG. 1 is a diagram showing a light-emitting display device according to a first embodiment of the present invention. FIG. 2A is an exploded perspective view showing a light emitting display device according to a second embodiment of the present invention. FIG.2 (b) is a figure which shows the XX sectional view in Fig.2 (a). FIG. 3A is a perspective view showing a light-emitting display device according to a third embodiment of the present invention. FIG.3 (b) is a figure which shows the YY line cross section in Fig.3 (a). FIG. 4 is a diagram showing a light-emitting display device in Example 1 of the present invention. FIG. 5 is a diagram showing the relationship between time and current density. FIG. 6 is a view of the light emitting display device according to the second embodiment of the present invention as viewed from above.

DESCRIPTION OF EXEMPLARY EMBODIMENTS First Embodiment Hereinafter, an embodiment of the invention will be described with reference to the drawings. Here, FIG. 1 is a diagram showing a light emitting display device according to a first embodiment of the light emitting display device according to 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.

  A light-emitting display device 1 shown in FIG. 1 includes a substrate (support) 2, a light-emitting body (light-emitting unit) 5 supported by the substrate 2, and a pair of electrodes 3 and 4 connected to the light-emitting body 5. I have. One electrode 3 of the pair of electrodes 3 and 4 is formed on the surface of the substrate 2, and the other electrode 4 is formed in a wire shape, and a part of the electrode 3 is inserted into and connected to the light emitter 5. An AC power source 6 that applies an AC voltage to the light emitter 5 is connected between the electrodes 3 and 4.

  Each of the electrodes 3 and 4 contains at least 50% by weight of carbon as a main component, and is integrally formed by sintering the carbon particles at 800 ° C. or higher. The carbon particles of the electrodes 3 and 4 are not limited to materials having translucency, but glassy carbon (glassy carbon, GC), graphite, a mixture of graphite and amorphous carbon (plastic-formed carbon ( PFC)), carbon nanotubes (CNT) and the like can be used.

  Of these, PFC is a mixture of micron-sized graphite crystals and organic polymer compound oligomers (binders / carbons), then formed into an arbitrary shape by extrusion or embossing, and fired at 800 ° C. or higher. It is obtained. This PFC is finally composed of 100% carbon and has a feature that it can be easily processed into various shapes. For this reason, in this Embodiment, PFC can be used suitably as a material which forms each electrode 3 and 4. FIG. A typical PFC includes a mechanical pencil core.

  Also, a pencil lead can be used instead of the PFC. The pencil core is obtained by kneading clay as a substitute for binder carbon into graphite crystals, containing at least 50% carbon, and obtained by sintering carbon particles at 800 ° C. or higher. It becomes a ceramic sintered body. Such a mixed sintered body of carbon and ceramic also has electrochemical stability and good workability. When both are compared in terms of flexibility, PFC is superior. Therefore, when PFC is used as an electrode, the electrode can be flexible.

  In addition, as a method of forming one electrode 3, a plastic paste is sintered after a carbon paste containing at least 50% by weight of carbon as a main component and mixed with carbon particles and a plasticizer is subjected to pattern printing by screen printing or the like. May be. As a result, the electrode can be formed in an arbitrary shape. In this case, the material used for the plasticizer must be electrochemically stable and not elute into the ionic liquid for a long period of time. Among the polymer resins, particularly PVDF (polyvinylidene fluoride) is used. It can be used suitably. In this case, it is preferable to use carbon nanotubes as the carbon particles.

  The luminous body 5 includes an ionic liquid, a luminescent material dissolved in the ionic liquid, and a gelling material that gels the ionic liquid, and is formed into a lump shape in an arbitrary shape on the surface of the substrate 2. It is placed. In addition, it is not restricted to this, The light-emitting body 5 consists of a luminescent liquid which consists of an ionic liquid and the luminescent substance melt | dissolved in this ionic liquid, and does not gelatinize but the surface of the board | substrate 2 by surface tension You may make it mount.

  By the way, the ionic liquid is also called a molten salt and consists only of ions that maintain a liquid state at room temperature. This ionic liquid is different from a liquid electrolyte in which a supporting salt is dissolved in an organic solvent, and has characteristics such as flame retardancy and non-volatility. In the luminescent layer 14 formed by dissolving the luminescent substance in this ionic liquid, when the inside of the luminescent layer 14 is subjected to an electrochemical reaction, the voltage applied to the luminescent layer 14 can be kept low, and the redox reaction can be performed at high speed. Can be awakened.

  Moreover, as a material used for the ionic liquid, a material having a high polarity is desirable in order to dissolve various kinds of luminescent substances at a high concentration. For example, a quaternary ammonium salt system, an imidazolium system, a pyridium system, or the like can be used. . Among these, in particular, an ionic liquid composed of an acyclic quaternary ammonium salt cation can be suitably used because it has a wide potential window and is electrochemically stable.

The material used for the luminescent material is not particularly limited as long as it is a material that emits electrochemiluminescence. For example, PVB (polyvinyl butyral), DPA (9,10-diphenylanthracene), perylene, rubrene, RuCl ₆ , RuPF ₆ , Ru Ru (ruthenium) compounds and complexes such as (bpy ₃ ) Cl ₂ , Ru (bpy ₃ ) (PF ₆ ) ₂ , Ru (d ₈ -bpy ₃ ) (PF ₆ ) ₂ can be suitably used. The concentration of the luminescent material is not particularly limited. However, if the concentration exceeds 10 wt%, the luminescent material cannot be sufficiently dissolved. Therefore, the concentration of the luminescent material is preferably at least 10 wt%. Furthermore, if the concentration of the luminescent substance is high even if it is 10 wt% or less, the transparency of the luminescent liquid itself is lowered, and light emitted to the outside from the luminescent material 5 formed in a droplet shape or a gel lump shape is reduced. In order to weaken, it is preferable that the concentration of the light-emitting substance is 1 wt% to 5 wt%.

  Here, the ionic liquid contained in the luminous body 5 has flame retardancy. This is relatively safe in handling compared to the case of using a flammable organic solvent. Furthermore, this ionic liquid is non-volatile. Thereby, compared with the case where the organic solvent which has volatility is used, an ionic liquid does not vaporize and it can prevent that the light-emitting body 5 deteriorates. For this reason, the stable performance can be maintained without deteriorating the light emission characteristics of the light emitter 5.

  Gelation means a state in which the ionic liquid loses fluidity, and it is preferable to use silica nano-sized fine particles or titanium oxide nano-sized fine particles as the gelled material. Moreover, since the softness | flexibility of a gel will be lost and the moldability will fall when the density | concentration of a gelling material exceeds 15 wt%, it is desirable that the density | concentration of a gelling material is at least 1 wt%-15 wt%. Furthermore, even if it is 15 wt% or less, if the concentration of the gelling material is high, the thixotropy is lowered and it becomes difficult to perform printing or the like, so the concentration of the gelling material is 3 wt% to 7 wt%. Is preferred. Thus, the light-emitting body 5 can be formed in a lump by gelling the ionic liquid.

  As a material used for the substrate 2, for example, transparent glass or a film can be used. When light emitted from the light emitter 5 is taken out from above or from the side of the light emitter 5, the material used for the substrate 2 is not limited to a transparent material.

  Next, the operation of the light emitting display device 1 in the present embodiment will be described.

When the light emitter 5 is caused to emit light in the light emitting display device 1 shown in FIG. 1, first, an AC voltage is applied from the AC power source 6 to the light emitter 5 through the electrodes 3 and 4. In this case, for example, an electrochemical reduction reaction occurs in the vicinity of one electrode 3 serving as a cathode, and radical anions are generated from the luminescent material. On the other hand, an electrochemical oxidation reaction occurs in the vicinity of the other electrode 4 serving as an anode, and radical cations are generated from the luminescent material. In an electronically neutral molecule, a radical anion and a radical cation are generated as a result of redox, but Ru (bpy ₃ ) ²⁺ is generated when Ru (bpy ₃ ) (PF ₆ ) ₂ is used as the light-emitting substance. In a salt such as (PF ₆ ⁻ ) ₂ , the same action and effect are exhibited by changing the valence of monovalent Ru to monovalent Ru and trivalent Ru.

  While the alternating voltage is applied to the light emitter 5, the alternating voltage is applied to the one electrode 3 and the other electrode 4, so that the reduction reaction and the oxidation reaction occur alternately in the one electrode 3 and the other electrode 4. Repeated. That is, for example, the radical anion generated by the reduction reaction in the vicinity of one electrode 3 moves toward the other electrode 4. Next, the polarities of one electrode 3 and the other electrode 4 are reversed, and radical cations are generated in the vicinity of one electrode 3 by an oxidation reaction. During this time, radical anions that have moved from the vicinity of one electrode 3 toward the other electrode 4 return to one electrode 3. As a result, the radical anion and the radical cation collide. Next, a neutral molecule in the ground state and a neutral molecule in the excited state are generated from the colliding radical anion and radical cation. Thereafter, the neutral molecule in the excited state returns to the ground state, whereby light is emitted from the neutral molecule.

  In the case of the electrode structure shown in FIG. 1, radical anions and radical cations are diffused radially. Accordingly, even when the electrode area of the one electrode 3 and the electrode area of the other electrode 4 are greatly different, the electrode is not limited to the smaller electrode (corresponding to the other electrode 4), Light is emitted from the entire surface of the electrode having the larger area (corresponding to one electrode 3).

  In the same manner as the light emission mechanism in the vicinity of the one electrode 3, the generated radical anion and radical cation collide with each other in the vicinity of the other electrode 4 to generate excited molecules and emit light.

  Here, even when the light emitter 5 shown in FIG. 1 is caused to emit light, the radical anion and the radical cation collide near the one electrode 3 and the other electrode 4 to emit light. For this reason, the light emitter 5 can emit light even when the distance between one electrode 3 and the tip of the other electrode 4 is relatively long.

  During this time, since an AC voltage is applied between the electrodes 3 and 4 as described above, a negative voltage is alternately applied to the electrodes 3 and 4. However, each electrode 3, 4 contains at least 50% by weight of carbon that is not electrochemically stably reduced. As a result, the material of the electrodes 3 and 4 can be prevented from changing the components, and the components can be kept constant.

  As described above, according to the present embodiment, the pair of electrodes 3 and 4 connected to the light emitter 5 is formed by using plastic formed carbon (PFC), and the plastic formed carbon is formed by electrochemical. It is composed of carbon that is not stably reduced. Thus, even when a negative voltage is applied to the electrodes 3 and 4, the material of the electrodes 3 and 4 is not reduced. For this reason, it can prevent that the material of the electrodes 3 and 4 changes a component, and the light emission lifetime of the light-emitting body 5 can be made still longer.

  Further, according to the present embodiment, the luminous body 5 molded in a lump shape is placed on the substrate 2 having one electrode 3 formed on the surface, and the other luminous body 5 is placed in the luminous body 5 from above the luminous body 5. The light emitter 5 can emit light by inserting the electrode 4 and applying an AC voltage to the light emitter 5 via the one electrode 3 and the other electrode 4. In this case, since the light emitter 5 is exposed to the outside, the light emitted from the light emitter 5 can be easily and reliably extracted to the outside.

  In the present embodiment, an example is shown in which the other electrode 4 is inserted into the light emitter 5 from above the light emitter 5. However, the present invention is not limited to this, and the light emitter 5 can be made to emit light by being inserted into the light emitter 5 from the side of the light emitter 5. Further, without inserting the other electrode 4 into the light emitter 5, the light emitter 5 can be caused to emit light by contacting the surface or side surface of the light emitter 5. Furthermore, the other electrode 4 is not limited to being formed in a wire shape, and an electrode 4 having various shapes can also be used.

Second Embodiment Next, the second embodiment of the present invention will be described with reference to FIG. Here, FIG. 2A is an exploded perspective view showing the light emitting display device according to the second embodiment of the present invention, and FIG. 2B is a sectional view taken along line XX in FIG. FIG.

  In the light emitting display device according to the second embodiment shown in FIGS. 2A and 2B, the support is composed of a pair of substrates, each electrode is provided inside the corresponding substrate, and the planar shape of one of the electrodes Is mainly different in that it is smaller than the area of the planar shape of the other electrode, and the other configuration is substantially the same as that of the second embodiment shown in FIG. 2A and 2B, the same parts as those of the first embodiment shown in FIG.

  In the light-emitting display device 1 shown in FIGS. 2A and 2B, the support is composed of a pair of substrates 2, and the light-emitting portion is composed of a light-emitting layer 14 formed in layers sandwiched between the substrates 2. Yes.

  Each electrode 3, 4 is provided inside the corresponding substrate 2, and the planar area of one electrode 3 is smaller than the planar area of the other electrode 4. That is, as shown in FIGS. 2A and 2B, one electrode 3 is composed of a display electrode 10 whose plane is formed in a circular shape, and the other electrode 4 is opposed to the display electrode 10. The plane is formed in a circular shape, and includes an auxiliary electrode 11 having an area smaller than that of the display electrode 10. In the light emitting display device 1 shown in FIG. 2, a plurality of such display electrodes 10 and auxiliary electrodes 11 are provided inside the corresponding substrate 2 and arranged in a matrix. Among these, each display electrode 10 is connected to the AC power source 6 in a row via the display bus line 12, and each auxiliary electrode 11 is connected to the AC power source 6 via the auxiliary bus line 13 for display. The bus lines 12 are connected in a row in a direction perpendicular to the bus lines 12. Thus, the light emitting layer 14 can selectively emit light between each display electrode 10 and the auxiliary electrode 11 corresponding thereto. The display bus line 12 and the auxiliary bus line 13 are covered with an insulating material and insulated from the light emitting layer 14.

  Each display electrode 10 and each auxiliary electrode 11 contain at least 50 wt% carbon as a main component, and are integrally formed by sintering the carbon particles at 800 ° C. or higher. The carbon particles are not limited to light-transmitting materials, and glassy carbon (glassy carbon, GC), graphite, a mixture of graphite and amorphous carbon, carbon nanotubes (CNT), or the like may be used. it can. Among these, it is preferable to use a mixture of graphite and amorphous carbon, that is, plastic formed carbon (PFC).

  As a method for forming each electrode 3, 4, as described in the first embodiment, a carbon paste containing at least 50 wt% carbon as a main component and mixed with carbon particles and a plasticizer is screened. The plasticizer may be sintered after pattern printing by printing or the like.

  As shown in FIG. 2B, a pair of spacers 15 that maintain a constant distance (gap) between the pair of electrodes 3 and 4 are provided between the pair of substrates 2 so as to surround the light emitting layer 14. Yes. The distance between the pair of electrodes 3 and 4, that is, the distance between the display electrode 10 and the auxiliary electrode 11 may be 1 μm or more and 5 mm or less. The light emitting device according to the present invention is characterized in that it emits light at a low voltage even when the distance between the electrodes is large. The distance between the electrodes can be set to the order of μm or less, but it is defective due to electrode contact or foreign matter. In order to prevent the occurrence of defects due to the adhesion of the film, the thickness is preferably 500 μm or more. On the other hand, since it is difficult to obtain a sufficient light emission phenomenon when the distance between the electrodes is large, the distance between the electrodes is preferably 2 mm or less.

  Further, out of the spacers 15 provided between the pair of substrates 2, one spacer 15 is formed with an injection hole (not shown) for injecting a gelled ionic liquid. After the ionized ionic liquid is injected, a sealing material (not shown) for sealing the injection hole is provided.

  Moreover, as a material used for the board | substrate 2, it is suitable to use transparent glass or a film, for example. As a result, the light emitted from the light emitting layer 14 can be extracted on the substrate 2 side (the upper side shown in FIGS. 2A and 2B) on which the auxiliary electrode 11 is provided.

  In the light-emitting display device 1 shown in FIGS. 2A and 2B, the display electrode 10 of one electrode 3 and the other electrode 4 from the AC power supply 6 through the display bus line 12 and the auxiliary bus line 13. A voltage is applied to the auxiliary electrode 11, whereby an AC voltage is applied to the light emitting layer 14. In the meantime, the reduction reaction and the oxidation reaction are alternately repeated in the display electrode 10 and the auxiliary electrode 11, and are generated by the reduction reaction in the vicinity of the display electrode 10 by the light emission mechanism similar to that of the light emitting display device 1 shown in FIG. The radical anion and the radical cation collide with each other by the oxidation reaction to emit light. Similarly, in the vicinity of the auxiliary electrode 11, the generated radical anion and radical cation collide with each other to emit light.

  Thus, according to the present embodiment, each display electrode 10 and each auxiliary electrode 11 are formed using plastic formed carbon (PFC), and this plastic formed carbon is electrochemically formed. It contains at least 50% by weight of carbon that is not stably reduced, and the carbon particles are sintered at 800 ° C. or higher. Thus, even when a negative voltage is applied to the electrodes 3 and 4, the material of the electrodes 3 and 4 is not reduced. For this reason, it can prevent that the material of the electrodes 3 and 4 changes a component, and the light emission lifetime of the light emitting layer 14 can be lengthened further.

  Further, according to the present embodiment, the auxiliary electrode 11 out of the electrodes 3 and 4 provided inside each substrate 2 has a smaller area than the display electrode 10. Thereby, the light emitted from the light emitting layer 14 can be easily and reliably extracted to the substrate 2 side on which the auxiliary electrode 11 is provided.

  In the present embodiment, the example in which the light emitting layer 14 is integrally formed and sandwiched between a pair of substrates 2 each provided with a plurality of display electrodes 10 and auxiliary electrodes 11 inside is described. However, the present invention is not limited to this. For example, a light-transmitting partition member (not shown) extending between the pair of substrates 2 is provided between the display electrodes 10, and the light emitting layer 14 is attached to each display electrode. A light emitting layer division body (not shown) may be formed by dividing every ten. In this case, since the light-transmitting partition member is interposed between the respective light emitting layer divided bodies, it is possible to reliably prevent the light emitted by each light emitting layer divided body from being transmitted to other adjacent light emitting layer divided bodies. be able to.

Third Embodiment Next, a third embodiment of the present invention will be described with reference to FIG. Here, FIG. 3A is a perspective view showing a light emitting display device according to a third embodiment of the present invention, and FIG. 3B shows a cross section taken along line YY in FIG. FIG.

  In the light emitting display device according to the third embodiment shown in FIGS. 3A and 3B, the support is made of a substrate, and each electrode has a base portion and a comb portion connected to the base portion on the surface of the substrate. It is formed in a comb-like shape, and the comb portions of each electrode are mainly different from each other, and other configurations are substantially the same as those of the first embodiment shown in FIG. 3A and 3B, the same parts as those in the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the light-emitting display device 1 shown in FIGS. 3A and 3B, the support is made of the substrate 2, and the light-emitting body (light-emitting portion) 5 is formed in a lump shape (cuboid shape) on the substrate 2. It is mounted on.

  Each electrode 3, 4 is formed in a comb-like shape having base portions 3 a, 4 a and comb portions 3 b, 4 b connected to the base portions 3 a, 4 a on the surface of the substrate 2, and the comb portions of the electrodes 3, 4 enter each other. It is out.

  That is, one electrode 3 of the pair of electrodes 3 and 4 has a base 3a having a rectangular shape and one end connected so as to be orthogonal to the base 3a and the other end on the other electrode 4 side. It includes a plurality of comb portions 3b extending and arranged at a predetermined interval. The other electrode 4 has a rectangular base 4a and one end connected so as to be orthogonal to the base 4a and the other end of each comb of one electrode 3 toward the one electrode 3 side. It includes a plurality of comb portions 4b extending between 3b and arranged at a predetermined interval so as to face each comb portion 3b.

  The widths of the comb portions 3b of the one electrode 3 and the comb portions 4b of the other electrode 4 may be 10 μm or more and 2 mm or less, respectively, and are preferably in the range of 100 μm to 1 mm. Further, the gap between the comb portion 3b of one electrode 3 and the comb portion 4b of the other electrode 4 opposite to the comb portion may be 5 μm or more and 1 mm or less, and is particularly preferably in the range of 50 μm to 200 μm. .

  Further, at least the comb portion 3b and the comb portion 4b of the one electrode 3 and the other electrode 4 include at least 50% by weight of carbon as a main component, and are integrally formed by sintering the carbon particles at 800 ° C. or higher. . The carbon particles of the electrodes 3 and 4 are not limited to materials having translucency, but glassy carbon (glassy carbon, GC), graphite, a mixture of graphite and amorphous carbon, carbon nanotubes (CNT). Etc. can be used. Among these, it is preferable to use a mixture of graphite and amorphous carbon, that is, plastic formed carbon (PFC).

  In addition, as a method of forming each electrode 3, 4, as described in the first embodiment, a carbon paste containing at least 50 wt% carbon as a main component and mixing carbon particles and a plasticizer is used. It is preferable to sinter the plasticizer after pattern printing by screen printing or the like.

  In the light emitting display device 1 shown in FIGS. 3A and 3B, an AC voltage is applied to the light emitter 5 from the AC power source 6 through the pair of electrodes 3 and 4. During this time, the reduction reaction and the oxidation reaction are alternately repeated in one electrode 3 and the other electrode 4, and reduction is performed in the vicinity of each comb portion 3 b of one electrode 3 by the light emission mechanism similar to that of the light emitting display device 1 shown in FIG. Radical anions generated by the reaction and radical cations generated by the oxidation reaction collide with each other to emit light. Similarly, in the vicinity of each comb portion 4b of the other electrode 4, the generated radical anion and radical cation collide with each other to emit light.

  As described above, according to the present embodiment, at least the comb portion 3b and the comb portion 4b of the one electrode 3 and the other electrode 4 are formed using plastic formed carbon (PFC). Contains at least 50% by weight of carbon that is not stably reduced electrochemically, and the carbon particles are sintered at 800 ° C. or higher. Thus, even when a negative voltage is applied to the electrodes 3 and 4, the material of the electrodes 3 and 4 is not reduced. For this reason, it can prevent that the material of an electrode changes a component, and the light emission lifetime of the light-emitting body 5 can be made still longer.

  Further, according to the present embodiment, the luminous body 5 formed in a lump shape is placed on the substrate 2 on the surface of which the pair of electrodes 3 and 4 are formed in a comb-teeth shape. By applying an AC voltage via the third electrode 4 and the other electrode 4, the light emitter 5 can emit light. In this case, since the light emitter 5 is exposed to the outside, the light emitted from the light emitter 5 can be easily and reliably extracted to the outside. Stable performance can be maintained over a long period of time without deteriorating the light emission characteristics of the light emitter 5.

  In the present embodiment, an example in which the light emitter 5 is formed in a rectangular parallelepiped shape is shown. However, the present invention is not limited to this, and the light emitter 5 can be formed into a block shape in an arbitrary shape to cause the light emitter 5 to emit light. Furthermore, the luminescent liquid composed of the ionic liquid and the luminescent material may be placed on the surface of the substrate 2 by surface tension without causing the luminescent material 5 to gel.

Example 1
As an example of the present invention, the light-emitting display device 1 of FIG. 4 was manufactured by the following method.

  First, one electrode 3 formed in a cylindrical shape with a diameter of about 2.7 mm and a mechanical pencil core (the other electrode 4) with a diameter of about 0.9 mm are prepared, and the one electrode 3 is made to stand upright. It was. Here, the material used for the one electrode 3 is made of glassy carbon (GC) containing 100% by weight of carbon and carbon particles sintered at 2000 ° C. The mechanical pencil used for the other electrode 4 The core material is made of plastic formed carbon (PFC) containing 100% by weight of carbon and carbon particles sintered at 800 ° C.

Next, 1 (allyl-3-butylimidazolium bis (trifluoromethanesulfonyl) imide (abbreviation: ABImTFSI), which is an ionic liquid, is mixed with 5 wt% of Ru (bpy ₃ ) (PF ₆ ) ₂ as a luminescent substance. The mixture was mixed and stirred at 65 ° C. and 500 rpm for 3 hours to sufficiently dissolve Ru (bpy ₃ ) (PF ₆ ) ₂ as a luminescent substance to produce a luminescent solution.

  Next, 7 wt% of a gelling material (silica fine particles (Aerosil 200 manufactured by Nippon Aerosil Co., Ltd.)) was added to this luminescent solution and mixed for a predetermined time to gel the luminescent solution. Next, the gelled luminescent solution is formed into a lump to form the luminescent material 5, which is placed on the upper surface (end surface) of one of the electrodes 3, and the inside of the luminescent material 5 from above the luminescent material 5. The other electrode 4 was inserted into.

Thereafter, an AC voltage of square wave, 60 Hz, ± 3 V was applied to the luminous body 5 obtained in this example through the electrodes 3 and 4. As a result, the relationship between time and current density as shown in FIG. 5 was obtained. As shown in FIG. 5, when ITO is used as the material of the electrodes 3 and 4, after the light emission is started, the ITO is reduced and the current density immediately decreases, and the light emission luminance decreases. On the other hand, when each of the electrodes 3 and 4 is formed by GC or PFC as in the present invention, the current density does not decrease even after the light emission is started, and the light emission luminance is made almost constant. Can be maintained. For example, when the light emitter 5 is caused to emit light using the light emitting display device 1 having an initial light emission luminance of 100 cd / m ² , the luminance is halved in about 15 minutes when ITO is used for the electrodes 3 and 4. When the electrodes 3 and 4 are respectively formed of GC and PFC as in the invention, the light emission luminance does not decrease even after 10 hours or more have elapsed. As a result, the light emission life could be greatly improved.

Example 2
The light emitting display device 1 according to the present embodiment is different from the first embodiment in that the electrodes 3 and 4 are formed in a comb shape. As Example 2, the light-emitting display device 1 of FIG. 6 was manufactured by the following method.

  First, a mechanical pencil core having a diameter of about 0.9 mm is arranged in a comb-teeth shape as one electrode 3 on the glass substrate 2 to form a comb portion 3b, and each comb portion 3b is electrically connected by a conductive paste. Thus, the base 3a was formed. Similarly, as the other electrode 4, a mechanical pencil core having a diameter of about 0.9 mm is arranged in a comb-like shape to form a comb portion 4 b, and each comb portion 4 b is electrically connected by a conductive paste to form a base portion 4 a. Formed. The gap between the comb portion 3b of one electrode 3 and the comb portion 4b of the other electrode 4 opposite to the comb portion 3b is about 1 mm. The core material of the mechanical pencil used for the electrodes 3 and 4 is made of plastic-formed carbon (PFC) containing 100% by weight of carbon and carbon particles sintered at 800 ° C.

Next, 1 (allyl-3-butylimidazolium bis (trifluoromethanesulfonyl) imide (abbreviation: ABImTFSI), which is an ionic liquid, is mixed with 5 wt% of Ru (bpy ₃ ) (PF ₆ ) ₂ as a luminescent substance. The mixture was mixed and stirred at 65 ° C. and 500 rpm for 3 hours to sufficiently dissolve Ru (bpy ₃ ) (PF ₆ ) ₂ as a luminescent substance to produce a luminescent solution.

  Next, 7 wt% of a gelling material (silica fine particles (Aerosil 200 manufactured by Nippon Aerosil Co., Ltd.)) was added to this luminescent solution and mixed for a predetermined time to gel the luminescent solution. Next, the gelled luminescent solution was formed into a lump to form the luminescent material 5, and the luminescent material 5 was placed on the glass substrate 2.

Thereafter, an AC voltage of square wave, 60 Hz, ± 5 V was applied to the luminous body 5 obtained in this example. As a result, light emission having a luminance of 200 cd / m ² could be obtained.

Example 3
The light-emitting display device 1 in this embodiment is different in that each electrode 3 and 4 is formed with a pencil lead instead of a mechanical pencil lead, and other configurations are substantially the same as those in the first and second embodiments. is there. The material of the pencil core is made of a mixed sintered body of carbon and ceramic containing 50% by weight of carbon and carbon particles sintered at 1000 ° C.

  When the light emitting element similar to Example 1 and Example 2 was produced, the same result as Example 1 and Example 2 was able to be obtained.

Example 4
The light-emitting display device 1 in this embodiment is different in that each electrode 3 and 4 is formed of a carbon paste mixed with carbon fine particles and polyvinylidene fluoride instead of a mechanical pencil lead and a pencil lead. Is substantially the same as the first and second embodiments. The material of the carbon paste contains 50% by weight of carbon and is obtained by solidifying polyvinylidene fluoride at 150 ° C. after pattern printing by screen printing.

  When the light emitting element similar to Example 1 and Example 2 was produced, the same result as Example 1 and Example 2 was able to be obtained.

DESCRIPTION OF SYMBOLS 1 Light emitting display apparatus 2 Board | substrate 3 One electrode 3a Base part 3b Comb part 4 The other electrode 4a Base part 4b Comb part 5 Light emitter 6 AC power supply 10 Display electrode 11 Auxiliary electrode 12 Display bus line 13 Auxiliary bus line 14 Light emitting layer 15 Spacer

Claims (8)

A support;
A light emitting unit supported by the support;
A pair of electrodes connected to the light emitting unit,
Each electrode includes at least 50% by weight of carbon as a main component. A support;
A light emitting unit supported by the support;
A pair of electrodes connected to the light emitting unit,
Each of the electrodes includes at least 50% by weight of carbon as a main component, and is integrally formed by sintering a carbon paste in which carbon particles and a plasticizer are mixed.   The light emitting display device according to claim 2, wherein the plasticizer of each electrode is made of a polymer resin.   The light-emitting display device according to claim 3, wherein the plasticizer of each electrode is made of polyvinylidene fluoride. One electrode is formed on the surface of the support,
The light-emitting display device according to claim 1, wherein the other electrode is connected to the light-emitting portion supported by the support. The support consists of a pair of substrates,
The light emitting unit is composed of a light emitting layer sandwiched between the substrates,
Each electrode is provided inside the corresponding substrate,
The light emitting display device according to claim 1, wherein the area of the planar shape of one electrode is smaller than the area of the planar shape of the other electrode. The support consists of a substrate,
Each electrode is formed in a comb-teeth shape having a base portion and a comb portion connected to the base portion on the substrate surface,
The light-emitting display device according to claim 1, wherein comb portions of the electrodes are inserted into each other.   8. The light emitting display device according to claim 1, wherein the carbon of each electrode includes any one of glassy carbon, graphite, a mixture of graphite and amorphous carbon, and carbon nanotubes. .

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