JP2004206964A - El luminescent device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an EL luminescent device allowing a desired display pattern to be made simply by a user, and repeatedly and easily usable at a low cost. <P>SOLUTION: This EL luminescent device 10 is provided with: a magnetic layer 20 formed by evenly arranging micro-capsules 33 containing cross-sectionally elongate particles 31 having conductivity and made of a ferromagnetic material so as to be floated. Since the electrical property in the thickness direction can be locally changed by applying an external magnetic field to change the attitudes of the particles 31, a luminescent part 24 is made to emit light when the magnetic field is applied by bringing, for instance, a tip magnetic pole 52 of a pen-shaped magnet 50 close to the screen 16 of the luminescent device 10. Since any of the luminescent parts 24 can be extinguished when magnetic fields in directions nearly parallel with a transparent electrode 13 and a rear electrode 21 are sequentially applied by using a plate-like magnet having one surface and the other surface thereof magnetized into an S pole and an N pole, respectively, the device can repeatedly be used. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an EL light emitting device having an EL light emitting layer, and more particularly to a technique that allows a user to freely draw a display pattern.
[0002]
[Prior art]
2. Related Art An EL light emitting device that emits light from an EL light emitting layer by applying an AC voltage to a transparent electrode and a back electrode sandwiching the EL light emitting layer made of an electroluminescent material in a thickness direction thereof is known. For example, Patent Document 1 previously filed by the present applicant is that. Such sheet-shaped thin light-emitting devices are used for various purposes as a backlight of a light-emitting display panel, a backlight of a light-emitting decorative plate, and the like.
[0003]
By the way, the EL light emitting device as described above emits a display pattern defined by a light transmitting portion of a mask superimposed on the entire front surface, and the user creates a display pattern shape according to his / her preference. Or having difficulty changing it. Further, it is difficult to create a mask for a complicated pattern, a thin pattern, or a pattern including blur, and the degree of freedom of expression is limited.
[0004]
On the other hand, an insulator layer and a light-emitting layer are sequentially laminated on the comb-shaped drive electrode, and a transparent conductive material is formed on the light-emitting layer by coating or printing to form a display electrode, and a display according to a user's preference is performed. It has been proposed that patterns can be created. For example, the EL light emitting device described in Patent Document 2 is the EL light emitting device.
[0005]
[Patent Document 1]
Registered Utility Model No. 3034483 [Patent Document 2]
Japanese Patent Application Laid-Open No. 8-153592
[Problems to be solved by the invention]
However, when the EL light emitting device described above is used repeatedly, the light emitting layer is covered with a protective film, and the display electrode is formed and removed on the film to enable reuse. A transparent conductive material and a protective film are required, and the entire device is laminated with a sealing film except for the terminals, so reprocessing is also required, resulting in high costs and long working times. there were.
[0007]
SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an EL light emitting device in which a desired display pattern can be easily created on the user side and can be used repeatedly at low cost and easily. Is to provide.
[0008]
[Means for Solving the Problems]
The gist of the present invention to achieve this object is to apply an AC voltage to a transparent electrode and a back electrode sandwiching the EL light emitting layer in its thickness direction, thereby causing the EL light emitting layer to emit light. The device, wherein a magnetic layer whose electrical properties in a thickness direction is locally changed by applying a magnetic field to selectively emit light from among the EL light emitting layers includes the EL light emitting layer and the back electrode. It has been laminated between.
[0009]
【The invention's effect】
With this configuration, since the electrical properties in the thickness direction of a part of the magnetic material layer are locally changed by the application of the local magnetic field, the light is selectively emitted locally using, for example, a pen-shaped magnet. By applying a magnetic field, the electric property of the portion affected by the magnetic field changes so as to satisfy the light emission or quenching of the EL light emitting layer, and a part of the EL light emitting layer corresponding to the portion emits or quenches. As a result, a display pattern is created. As a result, an EL light-emitting device in which a desired display pattern can be easily created by a user's operation is obtained.
[0010]
Further, since the electrical properties in the thickness direction of the magnetic layer can be changed depending on the direction of the applied magnetic field, a uniform magnetic field is applied to the magnetic layer so as to bring the light emitting layer into an initial state. By changing the property so as to satisfy the quenching or light emission of the EL light emitting layer, the created display pattern can be erased, so that an EL light emitting device which can be used repeatedly at low cost and easily can be obtained.
[0011]
Other aspects of the invention
Here, preferably, the magnetic material layer is made of a ferromagnetic material having conductivity and includes microcapsules containing therein particles having a longitudinal cross section whose attitude is changed according to the direction of an external magnetic field. . For example, if the particles are allowed to move inside the microcapsule, the longitudinal orientation of the particles is changed so as to be parallel to the magnetic field according to the direction of the magnetic field (magnetic flux). Since the particle is a conductor, the distance between the electrodes in the direction perpendicular to the transparent electrode and the back electrode substantially changes, so that the particle is applied by applying a local magnetic field using, for example, a pen-shaped magnet. If the longitudinal orientation of the electrode is changed substantially perpendicularly to the transparent electrode and the back electrode, the distance between the electrodes in that part is substantially shortened, and in a state where an AC voltage is applied to the transparent electrode and the back electrode. In this case, the electric field applied to the EL light emitting layer corresponding to that portion is made stronger than in the other portions. By doing so, a predetermined or more AC electric field is strongly applied to a portion of the EL light emitting layer corresponding to a portion to which a local magnetic field is applied by the pen-shaped magnet, and a desired portion is selectively applied. Emit light.
[0012]
Further, in order to erase the light emitting portion, for example, an S pole on one surface of the magnet and an S pole on the other surface so that all of the particles in the longitudinal direction can be changed substantially parallel to the transparent electrode and the back surface electrode. A substantially parallel magnetic field may be applied to the transparent electrode and the back surface electrode by using a plate-like magnet having the N pole magnetized, and thus, it can be used repeatedly.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
[0014]
FIG. 1 is a front view showing a thin EL light emitting device 10 according to one embodiment of the present invention. In the EL light-emitting device 10, for example, a desired display pattern 11 drawn by a user is displayed on the display surface 16 by light emission.
[0015]
FIG. 2 is an enlarged perspective view showing a part of an end portion of the EL light emitting device 10, and FIG. 3 is a cross-sectional view of a main part for explaining a laminated structure of the EL light emitting device 10. 2 and 3, the EL light-emitting device 10 has a back electrode 21 in which an insulating film 22 is formed on one surface, that is, an outer surface or a back surface, and a magnetic layer that is laminated in close contact with the inner surface or the front surface of the back electrode 21. A body layer 20, an insulating sheet 15 laminated in close contact with the surface side of the magnetic layer 20, and an EL (electroluminescence) light emitting layer 14 laminated in close contact with the surface side of the insulating sheet 15. The transparent electrode 13 has a laminated structure in which the transparent electrode 13 is sequentially laminated on one surface, that is, the transparent resin sheet 12 formed on the back surface side, in close contact with the front surface side of the EL light emitting layer 14.
[0016]
The back electrode 21 is a flexible sheet having conductivity, for example, a sheet formed by bonding carbon particles with a resin or the like, a sheet formed of a metal deposition film such as an ITO film, copper, aluminum, or the like. And an insulating film 22, which is a resin resist film, is formed on the entire back surface.
[0017]
The magnetic layer 20 has a dry film thickness of 100 μm by screen printing or the like so that a large number of microcapsules 33 are uniformly arranged using a resin material 30 having an insulating property that functions as a binder, for example, an aqueous binder. To 200 μm. The microcapsules 33 contain the particles 31 and the solvent 32 therein. The wall material of the microcapsules 33 is preferably formed of, for example, a resin such as polyurethane, polyurea, acrylic, polyamide, epoxy, or natural resin. As a microencapsulation method, a core material, that is, the above-described particle 31 is dispersed. An in situ polymerization method in which a monomer or a polymerization catalyst is supplied to either the internal phase or the external phase of an emulsion (emulsion) in which the solvent 32 is dispersed, and the surface of the core material is covered with a polymer; An interfacial polymerization method in which a monomer is supplied from both an inner phase and an outer phase of an emulsion in which a polymer is dispersed, a phase separation method in which a polymer solution in which the core substance is dispersed is separated into a polymer rich phase and a dilute phase to form a wall film, and the like. It is preferably used.
[0018]
The particles 31 are made of a conductive ferromagnetic material and have a longitudinal cross section, for example, an aspect ratio is large so that encapsulation can be easily performed in the microencapsulation method, and a particle diameter of 1 μm to 50 μm. Flat rectangular particles, which are dispersed in the solvent 32 and whose longitudinal direction is changed to be parallel to the direction of the external magnetic field when an external magnetic field is applied. The particles 31 are, for example, powders of iron, nickel, cobalt or alloys thereof, stainless steel, samarium-cobalt alloy, etc., made into flakes by an atomizer, a hammer mill or the like. The coercive force, which is one of the above, is preferably set to 80,000 A / m or less so that the response speed at which the attitude of the particles 31 can be changed with respect to the external magnetic field cannot be reduced. Further, since the particles 31 are required to have an affinity for the solvent 32, a silane coupling treatment or an ester treatment is performed.
[0019]
The solvent 32 may be an electric material such as di-2-ethylhexyl sebacate (DOS), di-2-ethylhexyl decandionate (DODN), diisodecyl phthalate (DIDP), dimethyl silicone oil, phenyl xylyl ethane (PXE), diisopropyl naphthalene isomer, or the like. It is a solvent with high electrical insulation and a high boiling point. The viscosity of the solvent 32 is easily emulsified in the microencapsulation method to enable encapsulation of several tens μm to several hundred μm, and the posture of the particles 31 is changed according to the direction of an external magnetic field. In addition, the viscosity is low, for example, from several mPa · S to several tens mPa · S.
[0020]
In addition, the magnetic layer 20 applies an external magnetic field, so that the particles 31 that move in the microcapsules 33 are affected by the magnetic field, and change their longitudinal orientation in accordance with the direction of the magnetic field. The electrical properties of the magnetic layer 20 in the thickness direction, that is, since the particles 31 are conductors, the distance between the electrodes in the direction perpendicular to the transparent electrode 13 and the back electrode 21 is changed by the dimension change of the particles 31 in the direction of the vertical. Can be substantially or effectively changed.
[0021]
The insulating sheet 15 contains a white pigment such as titanium oxide, and has an effect of reflecting the light of the EL light emitting layer 14 to make it clearer. The EL light-emitting layer 14 is formed by bonding a large number of organic or inorganic EL light-emitting particles such as phosphor or phosphor particles covered with an insulating material with a resin or the like. By applying the above-described AC voltage or AC electric field, light is emitted in a predetermined color, for example, blue-green. The transparent electrode 13 is a transparent conductive thin film such as ITO, and is formed on one surface of the transparent resin sheet 12, for example, a flexible PET resin film.
[0022]
The transparent electrode 13 is laminated with the EL light-emitting layer 14 so as to expose a part of the edge, and the back electrode 21 is exposed by exposing a part of the edge, for example, by screen printing. An insulating film 22 is formed. Each exposed portion serves as a pair of electrode terminals for applying a voltage to the EL light emitting device 10, that is, for applying a voltage to each of the transparent electrode 13 and the back electrode 21.
[0023]
In the EL light-emitting device 10 configured as described above, two methods for creating the desired display pattern 11 will be described below. FIG. 4 is a partial cross-sectional view illustrating a main part of an example when light is locally emitted by applying a magnetic field, which is the first method. In FIG. 4, in a state where the entire display surface 16 is quenched (darkened), that is, in a state where the particles 31 are all substantially parallel to the transparent electrode 13 and the back surface electrode 21, the external magnetic field is For example, when the tip magnetic pole of the pen-shaped magnet 50 which is a permanent magnet provided with a magnetic pole is brought close to the display surface 16 of the EL light emitting device 10, the local magnetic pole becomes substantially perpendicular to the transparent electrode 13 and the back surface electrode 21. When a magnetic field is applied to the light emitting portion 24, the particles 31 in the microcapsules 33 of the magnetic layer 20 are oriented substantially perpendicular to the transparent electrode 13 and the back electrode 21, that is, in the direction of the magnetic flux, and the posture in the longitudinal direction is adjusted. Therefore, the size of the particles 31 in the vertical direction due to the change in the posture is increased in the vertical direction with respect to the transparent electrode 13 and the back surface electrode 21. The distance between the electrodes is substantially reduced. At this time, an AC voltage of, for example, about 300 V is applied to the pair of electrode terminals, that is, to the transparent electrode 13 and the back electrode 21 sandwiching the EL light emitting layer 14. In the state, the electric field applied to the EL light emitting layer 14 corresponding to the light emitting portion 24 is made stronger than the other portions. By doing so, a predetermined or more AC electric field is strongly applied to the light emitting portion 24 of the EL light emitting layer 14 to which the local magnetic field is applied by the pen-shaped magnet 50, and the light emitting portion 24 is A desired display pattern 11 is created by light emission.
[0024]
FIG. 5 is a partial cross-sectional view illustrating a main part of an example when the light is locally extinguished by applying a magnetic field, which is the second method. In FIG. 5, in a state where the entire display surface 16 is illuminated (brightened), that is, in a state where all the particles 31 are substantially perpendicular to the transparent electrode 13 and the back surface electrode 21, the external magnetic field is For example, when the tip magnetic pole of a pen-shaped magnet 50 that is a permanent magnet provided with a magnetic pole is brought close to the display surface 16 of the EL light-emitting device 10, the local magnetic pole becomes substantially parallel to the transparent electrode 13 and the back electrode 21. When a magnetic field is applied to the extinction portion 26, the particles 31 in the microcapsules 33 of the magnetic layer 20 are oriented in a direction substantially parallel to the transparent electrode 13 and the back surface electrode 21, that is, in the direction of the magnetic flux, and the posture in the longitudinal direction is adjusted. The vertical direction of the transparent electrode 13 and the back surface electrode 21 is reduced by the amount of the vertical dimension reduction of the particle 31 due to the change in the posture. The distance between the electrodes becomes substantially longer. At this time, for example, an AC voltage of about 300 V is applied to the pair of electrode terminals, that is, to the transparent electrode 13 and the back electrode 21 sandwiching the EL light emitting layer 14. In the state, the electric field applied to the EL light emitting layer 14 corresponding to the extinction portion 26 is weakened as compared with the other portions. In this way, the quenching portion 26 of the EL light emitting layer 14 to which a local magnetic field is applied by the pen-shaped magnet 50 is locally quenched, and a desired display pattern 11 is created.
[0025]
Next, a method of erasing the created display pattern 11 and setting it to an initial state will be described below. According to the first method, in order to make the entire display surface 16 of the EL light emitting device 10 quenched, the posture of the particles 31 is substantially parallel to the transparent electrode 13 and the back surface electrode 21. For example, using a plate-like magnet in which the S pole is magnetized on one surface and the N pole is magnetized on the other surface, the magnet is separated from the surface of the EL light emitting device 10 by several mm. By sequentially moving one surface of the plate-shaped magnet in the left and right directions while gradually moving it in one direction perpendicular to the left and right direction, a magnetic field in a direction substantially parallel to the transparent electrode 13 and the back surface electrode 21 is sequentially applied. By doing so, the light emitting portion 24 is extinguished and the entire display surface 16 is extinguished.
[0026]
Further, in the second method, in order to make the entire display surface 16 of the EL light emitting device 10 emit light, the postures of the particles 31 are all set with respect to the transparent electrode 13 and the back surface electrode 21. It may be changed substantially perpendicularly, for example, by using a planar magnet in which both the S pole and the N pole are magnetized on one surface of the magnet, that is, on the same surface side, to make close contact with the surface of the EL light emitting device 10 and In this method, the light-extinguishing portion 26 is extinguished and the entire display surface 16 emits light by sequentially applying a magnetic field in a direction substantially perpendicular to the transparent electrode 13 and the back surface electrode 21 by moving in one direction.
[0027]
As described above, according to the present embodiment, in order to selectively emit or extinguish the EL light emitting layer 14, the magnetic material whose electric property in the thickness direction is locally changed by applying a magnetic field is used. Since the layer 20 is laminated between the EL light emitting layer 14 and the back surface electrode 21, by applying a magnetic field locally using, for example, a pen-shaped magnet 50 to selectively emit or extinguish the light, the influence of the magnetic field can be reduced. The electrical properties of the part that has received the light change to satisfy the light emission or quenching of the EL light emitting layer 14, and a part of the EL light emitting layer 14 corresponding to that part emits or quench, resulting in the display pattern 11 Since it is created, the EL display device 10 in which the desired display pattern 11 can be easily created by the user's operation is obtained. Further, by applying a uniform magnetic field to the magnetic material layer 20 to bring the EL light emitting layer 14 into an initial state and changing its electric property so as to satisfy the quenching or light emission of the EL light emitting layer 14, a display created by the method will be described. Since the pattern 11 can be erased, the EL light emitting device 10 that can be used repeatedly at low cost and easily can be obtained.
[0028]
Further, according to this embodiment, the magnetic layer 20 is made of a ferromagnetic material having conductivity, and contains therein microcapsules 31 each having a longitudinal cross section whose attitude can be changed according to the direction of an external magnetic field. For example, if the particles 31 are allowed to move inside the microcapsules 33, the posture of the particles 31 in the longitudinal direction changes so as to be parallel to the direction of the external magnetic field by applying an external magnetic field. Since the electrical properties of the magnetic layer 20, that is, the particles 31 are conductors, the distance between the electrodes in the direction perpendicular to the transparent electrode 13 and the back electrode 21 is substantially changed. By applying a local magnetic field using the magnet 50, the longitudinal orientation of the particles 31 changes substantially perpendicularly to the transparent electrode 31 and the back surface electrode 21. If this is done, the distance between the electrodes in that portion is substantially reduced, and when an AC voltage is applied to the transparent electrode 13 and the back surface electrode 21, the electric field applied to the EL light-emitting layer 14 corresponding to that portion becomes different. In the EL light emitting layer 14, an AC electric field of a predetermined value or more is strongly applied to a portion of the EL light emitting layer 14 corresponding to a portion to which a local magnetic field is applied by the pen-shaped magnet 50. Part emits light selectively. In order to erase the light-emitting portion, for example, an S-pole and a magnet are provided on one surface of the magnet so that all the longitudinal orientations of the particles 31 can be changed substantially parallel to the transparent electrode 13 and the back surface electrode 21. A magnetic field in a direction substantially parallel to the transparent electrode 13 and the back electrode 21 may be sequentially applied to the transparent electrode 13 and the back surface electrode 21 by using a plate-like magnet having the N pole magnetized on the other surface. Since it can be used repeatedly without fixing, a desired display pattern can be created again.
[0029]
As mentioned above, although one Example of this invention was described using drawing, this invention is applied also to another aspect.
[0030]
For example, in the above-described embodiment, the EL light emitting device 10 is rectangular and its edge is straight, but the EL light emitting device 10 may be circular or elliptical and its edge may be curved.
[0031]
Further, in the EL light emitting device 10 of the above-described embodiment, the insulating sheet 15 may not be white, and a color may be selected in consideration of, for example, the contrast with the light emission color of the EL light emitting layer 14 as a background color. , And may not necessarily be provided.
[0032]
In the above-described embodiment, the EL light emitting device 10 is configured to be flexible as a whole. However, for example, the insulating film 22 formed by screen printing on the back electrode 21 is formed of a thick resin plate. The transparent electrode 13 may be formed of a thick transparent resin plate or a transparent glass plate instead of a flexible PET resin film, the insulating sheet 15 may be formed of a thick plate, or the magnetic layer 20 may be formed. For example, the resin material 30 to be formed may have a thick shape, and may have a plate shape having strength (hardness) as a whole.
[0033]
In addition, the insulating film 22 of the above-described embodiment may be a rubber or resin insulating sheet or the like, since a part of the edge of the back electrode 21 may be exposed as an electrode terminal and the other part may be insulated. Is also good.
[0034]
Further, the magnetic material layer 20 of the above-described embodiment is formed into a sheet by screen printing using an aqueous binder for the resin material 30, but the resin material 30 may be a solvent-based binder, an emulsion binder, or a rubber material. Any material may be used as long as it is a material that functions as a binder and has an insulating property so that it is formed into a sheet so that a large number of microcapsules 33 are uniformly arranged, and may be roll coating, knife edge method, stencil method, or the like. To form a sheet.
[0035]
Further, in the above-described embodiment, several to several tens of the particles 31 are dispersed in the solvent 32 and, when an external magnetic field is applied, the particles 31 are dispersed in the longitudinal direction so as to be parallel to the direction of the external magnetic field. The posture may be changed so as to be united in a row in two or three rows in an integrated state, so that the microcapsules 33 have a size close to the inner diameter.
[0036]
In the above-described embodiment, the particles 31 need not be flat rectangular particles such as flakes, disk-shaped flats, cylinders, prisms, etc. as long as the particles 31 are longitudinal in cross section.
[0037]
Further, in FIGS. 3 and 4 of the above-described embodiment, the microcapsules 33 included in the magnetic layer 20 are illustrated as one layer for easy understanding, but may be a multilayer.
[0038]
In addition, in the above-described embodiment, in order to make the entire display surface 16 of the EL light-emitting device 10 quenched, a plate-shaped magnet having an S pole on one surface and an N pole on the other surface is magnetized. Although the magnet is used, the light emitting portion 24 is extinguished and displayed by gradually moving in one direction perpendicular to the horizontal direction while scanning left and right while approaching the vicinity of the surface of the EL light emitting device 10 using a degausser. The entire surface 16 may be extinguished.
[0039]
In the above-described embodiment, the solvent such as di-2-ethylhexyl sebacate (DOS) shown as the solvent 32 is merely an example, and the specific gravity is 0.8 to 1 in addition to the conditions shown as the viscosity of the solvent 32 and the like. 0.4 and a solubility in water of 1% or less can be suitably used as the solvent 32.
[0040]
The above is merely an example of the present invention, and the present invention can be variously modified without departing from the gist thereof.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a front view of an EL light emitting device according to an embodiment of the present invention.
FIG. 2 is an enlarged perspective view showing a part of an end portion of the EL light emitting device of FIG. 1;
FIG. 3 is a partial cross-sectional view illustrating a main part of the EL light emitting device of FIG.
FIG. 4 is a partial cross-sectional view illustrating a main part when the EL light emitting device of FIG. 1 emits light locally by applying a magnetic field.
FIG. 5 is a partial cross-sectional view illustrating a main part when the EL light emitting device of FIG. 1 is locally extinguished by application of a magnetic field.
[Explanation of symbols]
10: EL light emitting device 13: transparent electrode 14: EL light emitting layer 20: magnetic layer 21: back electrode 31: particle 33: microcapsule

Claims (2)

An EL light emitting device of a type in which the EL light emitting layer emits light by applying an AC voltage to a transparent electrode and a back electrode sandwiching the EL light emitting layer in its thickness direction,
A magnetic layer of which electric property in the thickness direction is locally changed by applying a magnetic field to selectively emit light among the EL light emitting layers is laminated between the EL light emitting layer and the back surface electrode. An EL light-emitting device. 2. The EL light emitting device according to claim 1, wherein the magnetic layer is made of a ferromagnetic material having conductivity and includes microcapsules containing therein particles having a longitudinal cross section whose attitude is changed according to an external magnetic field.

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