JP4124785B2 - Light emitting element - Google Patents

Description

  The present invention relates to a light emitting element. In particular, the present invention relates to a light-emitting element that constitutes a unit pixel of a large-screen display that has a simple configuration, is easy to manufacture, and has low power consumption.

  In recent years, liquid crystal displays and plasma displays have been widely used as large flat displays, but developments are being pursued in pursuit of displays with higher image quality and higher efficiency. Examples of such display candidates include an electroluminescence display (ELD) and a field emission display (FED). Non-Patent Document 1 describes ELD in general as follows. The former is based on a structure in which an electric field is applied to a phosphor as a light emitting layer through an insulating layer, and a dispersion type and a thin film type are known. The dispersion type has a structure in which ZnS particles to which impurities such as Cu are added are dispersed in an organic binder, an insulating layer is formed thereon, and sandwiched between upper and lower electrodes. The impurities form a pn junction in the phosphor particles, and when an electric field is applied, electrons emitted by a high electric field generated at the junction surface are accelerated, and then recombined with holes to emit light. The latter has a structure in which a phosphor thin film such as Mn-doped ZnS, which is a light-emitting layer, has electrodes arranged via an insulator layer. The presence of the insulator layer makes it possible to apply a high electric field to the light emitting layer, and emitted electrons accelerated by the electric field excite the light emission center to emit light. On the other hand, the FED has a structure comprising an electron-emitting device and a phosphor facing the electron-emitting device in a vacuum container, and accelerates electrons emitted from the electron-emitting device into the vacuum to irradiate the phosphor layer to emit light. It is.

In any device, electron emission is a trigger for light emission, so a technique for emitting electrons with low voltage and high efficiency is important. As such a technique, attention is focused on electron emission by polarization inversion of a ferroelectric. For example, in Non-Patent Document 2 shown below, as shown in FIG. 20, a PZT ceramic 31 having a planar electrode 32 installed on one surface and a grid electrode 33 installed on the other surface is contained in a vacuum vessel 36. It has been proposed that electrons are emitted by facing the platinum electrode 34 via the grid electrode 35 and applying a pulse voltage between the electrodes. Reference numeral 37 denotes an exhaust port. According to the proposal, the pressure in the container is 1.33 Pa (10 ⁻² Torr), and it is described that no discharge occurs at atmospheric pressure.

  A display that uses electrons emitted by accelerating the electrons emitted from the polarization inversion of the ferroelectric substance in the vacuum chamber to emit light from the phosphor layer, or a display using this light emission, is also described in Patent Document 1 and Patent Document 2 below. However, the basic configuration is to make the phosphor layer emit light by using a configuration having an electrode having a phosphor layer instead of the platinum electrode of Non-Patent Document 2.

On the other hand, a light-emitting element using electrons emitted by polarization reversal of a ferroelectric substance in a non-vacuum is disclosed, for example, in Patent Document 3 as an electroluminescent surface light source element. This element is formed on a substrate 45 in the order of a lower electrode 42, a ferroelectric thin film 41, an upper electrode 43, a carrier multiplication layer 48, a light emitting layer 44, and a transparent electrode 46, as shown in FIG. The upper electrode has an opening 47. By reversing the applied voltage pulse between the lower electrode and the upper electrode, electrons are emitted from the upper electrode opening to the carrier multiplication layer, and further accelerated by the positive voltage applied to the transparent electrode, while multiplying the electrons. It reaches the light emitting layer and emits light. It is described that the carrier multiplication layer is made of a semiconductor having a relatively low dielectric constant and a band gap that does not absorb the emission wavelength emitted from the light emitting layer. This element can be considered as a kind of ELD. Further, Patent Document 4 discloses a configuration in which one of the insulators is made of a ferroelectric thin film in a configuration in which a light emitting layer made of a phosphor formed by sputtering is sandwiched between front and back insulating layers and a pulse electric field is applied. Has been.
JP 07-64490 A US Pat. No. 5,453,661 Japanese Patent Laid-Open No. 06-283269 Japanese Patent Laid-Open No. 08-083686 Edited by Shoichi Matsumoto, “Electronic Display”, Ohmsha, July 7, 1995, p. 113-125 Jun-ichi Asano et al., 'Field-Exited ElectronEmission from Ferroelectric Ceramic in Vacuum' Japanese Journal of Applied Physics Vol. 31Part1p.3098-3101, Sep / 1992

  In the prior art, those requiring a vacuum state have a problem that the structure is complicated and it is extremely difficult to enlarge the screen. For example, although a field emission display (FED) can be expected to have high luminous efficiency, a vacuum container that maintains a high-vacuum space for emitting electron beams is required. For this reason, the structure of the display is complicated, and it is considered difficult to realize a large screen structure. No FED has been commercialized yet.

  There is a plasma display that does not require a vacuum container. The plasma display temporarily converts discharge energy into ultraviolet light energy, and the ultraviolet light emits light by exciting the phosphor. In the process of exciting the phosphor, this ultraviolet light is often absorbed by members other than the phosphor, which makes it difficult to increase the light emission efficiency and consumes a large amount of power when a large screen display is used. is there.

  Similarly, there are ELs that do not require a vacuum vessel, but inorganic ELs have problems in light emission efficiency and color reproducibility, and organic ELs use a thin film formation process used for manufacturing liquid crystal displays and the like. There is a problem that the equipment becomes large. Further, it is difficult to increase the screen size, and no product has been commercialized yet.

The light emitting device of the present invention is a light emitting device including at least two kinds of electrical insulator layers having different dielectric constants and at least two electrodes ,
One of the electrical insulator layers is a porous light emitter layer;
Another one of the electrical insulator layers is a gas layer, a ferroelectric layer, or a dielectric layer having a relative dielectric constant of 100 or more,
The porous phosphor layer is formed of phosphor particles or phosphor particles coated with an insulating layer,
Another layer of the insulator layer is disposed above and / or below the porous light emitter layer;
The two electrodes sandwich at least one of the two types of electrical insulator layers, or are in contact with or separated from any one of the two types of electrical insulator layers. Arranged,
A DC or AC electric field is applied to the at least two electrodes, and any one of the following a to c
a. Causing a breakdown in the gas layer between the at least two electrodes;
b. Polarization is reversed by the ferroelectric layer or the dielectric layer having a relative dielectric constant of 100 or more.
c. Electrons are generated from the electron emitter by the tunnel effect and collide with the porous light emitter layer through the gas layer.
To generate primary electrons (e−), and the primary electrons (e−) collide with phosphor particles including the phosphor of the porous light emitting layer to generate a large number of secondary electrons (e−) in an avalanche manner. At the same time, ultraviolet rays are generated, and the generated secondary electrons and ultraviolet rays excite and emit phosphor particles containing the phosphor .

According to the light emission principle of the present invention , a direct current or an alternating electric field is applied to the at least two electrodes, and any one of the following means a to c:
a. Causing a breakdown in the gas layer between the at least two electrodes;
b. Polarization is reversed by the ferroelectric layer or the dielectric layer having a relative dielectric constant of 100 or more.
c. Electrons are generated from the electron emitter by the tunnel effect and collide with the porous light emitter layer through the gas layer.
To generate primary electrons (e−), and the primary electrons (e−) collide with phosphor particles including the phosphor of the porous light emitting layer to generate a large number of secondary electrons (e−) in an avalanche manner. At the same time, ultraviolet rays are generated, and the generated secondary electrons and ultraviolet rays excite phosphor particles containing the phosphor.
In the present specification, the porous light emitter layer is also simply referred to as a porous light emitter.

  Since the light emitting device of the present invention emits light by creeping discharge in the porous light emitting layer, it does not use a thin film formation process when manufacturing the light emitting device as in the prior art, and requires a vacuum system or a carrier multiplication layer. Therefore, the structure is simple, and manufacturing and processing are easy. In addition, it is possible to provide a light-emitting element with favorable light emission efficiency and relatively low power consumption when a large display is used.

  The light emitting device of the present invention includes at least a first electrode, a dielectric layer, a porous light emitting layer, and a second electrode from the back side, and a gap is provided between the porous light emitting layer and the electrode. . Thus, when an alternating electric field is applied between the first electrode and the second electrode, gas breakdown occurs in the gap, and generation of primary electrons is promoted. By these primary electrons, creeping discharge is generated in the porous light emitting layer between the electrodes, and secondary electrons and ultraviolet rays are emitted. The emitted secondary electrons and ultraviolet rays emit light by exciting the emission center of the porous light emitting layer.

  The gap can be arbitrarily set, but is preferably provided in the range of 1 μm to 300 μm. If it is less than 1 μm, it tends to be difficult to control the gap, and if it exceeds 300 μm, it tends to be difficult to cause dielectric breakdown. In general, dielectric breakdown of air in the atmosphere is 3 kV / mm, and it is necessary to apply an electric field of 300 V or more (with a gap of 100 μm). When the pressure is reduced, dielectric breakdown occurs at 300 V or lower, but when a high voltage is applied, damage is caused to various parts of the cell structure. Therefore, the range of the interval is preferable in order to apply a voltage that does not cause damage. The interval is more preferably 10 μm or more and 100 μm or less.

  The light emitting device of the present invention emits light by creeping discharge in the porous light emitting layer, and the structure is simple because the formation of the porous light emitting layer does not require a thin film formation process, vacuum system, carrier multiplication layer, etc. Easy to manufacture. Further, the luminous efficiency is good, and the power consumption when a large display is manufactured is relatively small. Furthermore, the light emitting device of the present invention may be provided with a discharge separation means between the porous light emitting layers, thereby avoiding crosstalk during light emission. Here, crosstalk refers to a phenomenon in which the light emission between pixels adjacent to a certain pixel influences each other to lower the light emission efficiency.

  The discharge separation means of the present invention is particularly preferably configured by providing partition walls and / or spaces. The partition wall separating the porous light emitting layer is preferably an electrical insulator having a thickness of 80 to 300 μm.

When the partition wall is used, it is preferably formed of an inorganic material. As the inorganic material, glass, ceramic, dielectric or the like can be used. Dielectric materials include Y ₂ O ₃ , Li ₂ O, MgO, CaO, BaO, SrO, Al ₂ O ₃ , SiO ₂ , MgTiO ₃ , CaTiO ₃ , BaTiO ₃ , SrTiO ₃ , ZrO ₂ , TiO ₂ and B ₂ O ₃ , PbTiO ₃ , PbZrO ₃ , PbZrTiO ₃ (PZT), etc.

  When the gap is used as the discharge separation means, the gap distance is preferably 80 to 300 μm.

  The gap between the porous light emitting layer and the second electrode may be partitioned in the thickness direction by ribs. This is because electrons are easily generated from the wall surfaces of the ribs due to dielectric breakdown. A preferable material of the rib can be selected from the same material as that of the partition wall. The surfaces of the ribs and partition walls are preferably as smooth as possible. When the surface is smooth, the generated electrons are easily hopped along the rib, and the luminous efficiency of the porous light emitting layer can be increased.

  The atmosphere in the light emitting element is preferably at least one selected from air, oxygen, nitrogen, and a rare gas.

  The atmosphere of the light emitting element preferably includes at least one selected from the decompressed gas.

  The porous light emitting layer preferably emits at least red (R), green (G) or blue (B).

  The porous light emitting layer is preferably formed of phosphor particles having an insulating layer on the surface.

  The porous light emitting layer is preferably formed of phosphor particles and insulating fibers.

  The porous light emitting layer is preferably formed of phosphor particles having an insulating layer on the surface and insulating fibers.

  The apparent porosity of the porous light emitting layer is preferably in the range of 10% to less than 100%. In order to hop electrons in the porous light emitting layer (aggregation of phosphor particles and voids), it is necessary that the voids between the individual phosphor particles be shorter than the mean free path of electrons. For example, electron hopping is not inhibited.

  The first or second electrode is preferably an address electrode or a display electrode.

  The second electrode is a transparent electrode, and is preferably disposed on the observation surface side.

  The light emitting device of the present invention is a light emitting device including a dielectric layer, a porous light emitting layer, a pair of electrodes, and another electrode, wherein the porous light emitting layer includes inorganic phosphor particles, and the pair of electrodes Is arranged such that an electric field is applied to at least a part of the dielectric layer, and the other electrode is disposed between the other electrode and at least one of the pair of electrodes. It arrange | positions so that an electric field may be applied to at least one part. That is, for example, a multi-terminal light-emitting element such as a three-terminal light-emitting element. With the configuration described above, when an electric field that reverses polarization is applied between a pair of electrodes, first, primary electrons are emitted from the dielectric layer by polarization inversion. Thereafter, by applying an alternating electric field between at least one of the other electrode and the pair of electrodes, the emitted primary electrons creep along the avalanche in the porous light-emitting layer to generate secondary electrons. Finally, a large amount of secondary electrons are generated to excite the emission center, and the porous luminous body layer emits light.

  The pair of electrodes may be disposed on a dielectric layer. One of the pair of electrodes may be disposed at a boundary between the dielectric layer and the porous light emitting layer, and the other may be disposed at the dielectric layer. The other electrode may be disposed on the porous light emitter layer. The pair of electrodes may be formed with a boundary between the dielectric layer and the porous light emitting layer interposed therebetween. The pair of electrodes may be formed at the boundary between the dielectric layer and the porous light emitter layer. Further, of the pair of electrodes, one electrode may be formed at the boundary between the dielectric layer and the porous light emitter layer, and the other electrode may be formed at the dielectric layer.

  The porous luminescent layer may be composed of continuous pores connected to the surface of the porous luminescent layer, a gas filled in the pores, and phosphor particles. The gas filled in the pores may be at least one gas selected from the atmosphere, oxygen, nitrogen, inert gas, and reduced pressure gas.

  The dielectric layer may be composed of a dielectric sintered body. The dielectric layer may be composed of dielectric particles and a binder. The dielectric layer may be formed of a thin film. Moreover, the said porous light-emitting body layer may be comprised by the fluorescent substance particle and the insulating layer of the said fluorescent substance particle surface. The porous luminescent layer may be composed of phosphor particles and insulating fibers. The porous luminescent layer may be composed of phosphor particles, an insulating layer on the surface of the phosphor particles, and insulating fibers.

  By applying an electric field for polarization reversal to the pair of electrodes, primary electrons are emitted from the dielectric layer, and the emitted primary electrons are creepingly discharged in the porous light emitting layer to generate secondary electrons. In addition, it is preferable that a large amount of secondary electrons generated by the creeping discharge collide with the phosphor particles and the porous luminescent layer emits light. The light emission may be performed in at least one gas atmosphere selected from air, oxygen, nitrogen, an inert gas atmosphere, and a reduced pressure gas. It is also preferable to apply an alternating electric field between the other electrode and at least one of the pair of electrodes after applying an electric field whose polarization is reversed between the pair of electrodes.

  The light-emitting device of the present invention is a light-emitting device including a porous light-emitting body, and is composed of a porous light-emitting body including insulating phosphor particles. It is configured.

  The light emitting device of the present invention is a light emitting device including an electron emitter, a porous light emitter, and a pair of electrodes, the porous light emitter includes inorganic phosphor particles, and the porous light emitter is formed of an electron emitter. The pair of electrodes are disposed adjacent to the electron emitter so as to be irradiated with the generated electrons, and the pair of electrodes are arranged so that an electric field is applied to at least a part of the porous light emitter.

  According to the above, electrons are emitted by the electron emitter, and an alternating electric field is applied between the pair of electrodes, so that the emitted electrons generate creeping discharge in the avalanche layer in the porous luminous body layer. Let As a result, the luminescent center is excited by the emitted electrons to cause the porous luminescent material to emit light. A DC electric field may be used instead of the alternating electric field.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
This will be described with reference to FIGS. In this example, the dielectric layer and the first electrode are respectively formed on one surface of the porous light emitting layer, and the other surface of the porous light emitting layer on which the dielectric layer and the first electrode are not formed A plurality of the porous light emitting layers in which the second electrode is disposed, and a discharge separation means is provided between the plurality of porous light emitting layers. In particular, this is a light emitting device in which a part of the plurality of porous light emitting layers share a dielectric layer, and the discharge separating means is formed of barrier ribs.

  FIG. 1 is a cross-sectional view of a light-emitting element in this embodiment mode, and FIGS. 2 to 6 are views for explaining a manufacturing process of the light-emitting element in this embodiment mode. In these drawings, 1 is a light emitting element, 2 is a porous light emitting layer, 3 is a phosphor particle, 4 is an insulating layer, 5 is a substrate, 6 is a first electrode (back electrode), 7 is a second electrode ( (Observation surface electrode), 8 is a translucent substrate, 9 is a gap (gas layer), 10 is a dielectric layer, and 11 is a partition.

  As shown in FIG. 2, Ag paste is baked to a thickness of 30 μm on one side of a sintered body of a dielectric 10 having a thickness of 0.3 to 1.0 mm to form the first electrode 6 in a predetermined shape. . Next, as shown in FIG. 3, the dielectric layer on which the electrode shown in FIG. 2 was formed was adhered on the substrate 5 made of glass or ceramic.

In the present embodiment was used BaTiO ₃ as a _{dielectric, SrTiO 3, CaTiO 3, MgTiO} 3, PZT (PbZrTiO 3), the same effect can be obtained by using a dielectric such as PbTiO _3. The same effect can be obtained by using a dielectric such as Al ₂ O ₃ , MgO, ZrO ₂ , but the luminous intensity is weaker than that of the dielectric having a large relative dielectric constant. This can be improved by reducing the thickness of the dielectric layer.

  Further, the dielectric layer can be formed by a molecular deposition method such as sputtering, CVD, or vapor deposition, or a thin film forming process such as sol / gel. When a sintered body is used as the dielectric layer, this can also be used as the substrate 5. The thickness of the dielectric layer varies extremely when a sintered body is used or when it is formed by a thick film process. However, in actuality, a capacitance component is necessary, and adjustment is made in relation to the dielectric constant.

  Next, as shown in FIG. 4, a plurality of porous light emitting layers 2 are formed in a predetermined shape on the dielectric layer 10 by screen printing.

  As shown in FIG. 6, the porous light emitting layer 2 is prepared by preparing phosphor particles 3 whose surface is covered with an insulating layer 4 made of a metal oxide such as MgO in the following manner.

As phosphor particles 3, inorganic particles such as BaMgAl ₁₀ O ₁₇ : Eu ²⁺ (blue), Zn ₂ SiO ₄ : Mn ²⁺ (green), YBO ₃ : Eu ³⁺ (red) with an average particle diameter of 2 to 3 μm It is possible to use compounds. The method of forming the insulating layer 4 made of MgO on the surface is the same for all phosphor particles. Specifically, the phosphor particles 3 are added to the Mg precursor complex solution and stirred for a long time, and then the phosphors are used. The particles were taken out and dried, and then heat-treated at 400 to 600 ° C. in the atmosphere, whereby a uniform coating layer of MgO, that is, the insulating layer 4 was formed on the surface of the phosphor particles 3.

  In the present embodiment, a paste prepared by kneading 45% by mass of terpineol (α-terpineol) and 5% by mass of ethyl cellulose with respect to 50% by mass of the phosphor particles having the insulating layer 4 is prepared for each phosphor. Using this, as shown in FIG. 4, the thickness of the printed porous light-emitting layer becomes 80 to 100 μm by repeatedly performing the operation of screen printing in a predetermined shape and then drying a plurality of times. It was adjusted.

  Regarding the light emission from the porous light emitting layer, as shown in FIG. 4, a porous light emitting layer is provided for each emission color so that red (R), green (G) and blue (B) light emission can be obtained. A general method is to sequentially print a predetermined pattern (for example, a stripe shape) to form a regularly arranged porous light emitting layer. However, after forming a light emitting layer capable of obtaining white light emission, In addition, a desired emission color may be obtained by performing color separation with a color filter.

As described above, the substrate 5 on which the porous light-emitting layer is printed is finally heat-treated at 400 to 600 ° C. for 2 to 5 hours in an N ₂ atmosphere, whereby a porous film having a thickness of about 50 to 80 μm is obtained. An aggregate of the light emitting layer 2 was formed.

  Moreover, although the said paste was implemented by adding an organic bander or an organic solvent to the phosphor particles, the same effect was obtained even when a paste obtained by adding an aqueous colloidal silica solution to the phosphor particles was used.

  FIG. 6 is a schematic diagram in which the cross section of the porous light emitting layer 2 in the present embodiment is enlarged. As a result of the heat treatment of the phosphor particles 3 uniformly coated with the insulating layer 4 made of MgO, each particle is shown in FIG. Are shown to form a porous light emitting layer in contact with each other.

In this embodiment, since the heat treatment temperature is set to be relatively low, the porosity of the porous light emitting layer is increased, and the apparent porosity is in the range of 10% to less than 100%. If the porosity is very large and the state becomes 100%, it is not preferable because the luminous efficiency is lowered and air discharge is generated inside the porous light emitting layer. Conversely, when the porosity is less than 10%, the occurrence of creeping discharge is hindered. Yan surface discharge is generated at the interface of the gas (in this case the gap) and the insulator solid (phosphor particles). Apparent porosity becomes smaller when creeping discharge no longer exist voids may turn hard to occur. Conversely, that a creeping discharge is less likely to occur since the apparent porosity is greater than the mean free path of electrons as described above to be larger. Incidentally, it is presumed that when the apparent porosity is in the range of 10% to less than 100%, the phosphor particles are close to a point contact state so as to be adjacent three-dimensionally.

Next, in the assembly composed of the porous light emitting layer 2, the operation of screen printing and drying the glass paste on the boundary of the porous light emitting layer is repeated a plurality of times, and then heat-treated at 600 ° C., as shown in FIG. A partition wall 11 having a thickness of about 80 to 300 μm is formed. In this embodiment, the partition wall 11 is formed after the porous light emitting layer is formed. However, the partition wall may be formed first. Moreover, the partition 11 can also be formed using the glass paste and resin containing a ceramic particle. Specifically, in the former, paste obtained by adding 50% by mass of α-terpineol to 50% by mass of mixed particles of ceramic and glass (1: 1 by weight) is screen-printed in a predetermined pattern and then dried. Is repeated, and the printed thickness is adjusted to about 100 to 350 μm, and heat treatment is performed at 400 to 600 ° C. for 2 to 5 hours in an N ₂ atmosphere to obtain a thickness of about 80 to 300 μm. The partition wall 11 can be formed. In the latter, a partition is formed using a thermosetting resin, and an epoxy resin, a phenol resin, or a cyanate resin can be mainly used, and one of these is used as a void in the porous light emitting layer. This can be done by screen printing.

  As described above, after the partition wall 11 is formed, a transparent electrode such as a glass plate formed in advance so that the second electrode 7 made of ITO (indium-tin oxide alloy) is positioned to face the porous light emitting layer. When the entire assembly of the porous light emitting layers is covered with the optical substrate 8, the light emitting element 1 in the present embodiment as shown in FIG. 1 is obtained. At that time, the translucent substrate 8 is stuck on the partition wall 11 using colloidal silica, water glass, resin, or the like so that a slight gap is generated between the porous light emitting layer 2 and the second electrode 7. The vertical width of the gap 9 between the porous light emitting layer 2 and the second electrode 7 is preferably in the range of 30 to 250 μm, particularly preferably in the range of 40 to 220 μm. If the above range is exceeded, it is necessary to apply a high voltage to the generation of primary electrons due to the dielectric breakdown of the gas, which is not preferable for reasons of economy and reliability. In addition, the interval may be narrower than the above range, but in order to cause the porous light emitting layer to emit light uniformly and evenly, an interval that does not allow the porous light emitting layer to contact the second electrode is desirable.

  In addition, it is also possible to use the translucent board | substrate with which the copper wiring was given as an alternative of the translucent board | substrate 8 which consists of ITO as a 2nd electrode. The copper wiring is formed in a fine mesh shape, and the aperture ratio (ratio to the whole portion where the wiring is not applied) is 90%, and the light transmission is compared with a translucent substrate having an ITO film. There is almost no inferiority. Also, copper is advantageous because it has a considerably lower resistance than ITO and thus greatly contributes to improvement in luminous efficiency. In addition, it is also possible to use gold, silver, platinum, or aluminum other than copper as a metal for providing fine mesh wiring. However, in the case of copper or aluminum, there is a possibility of oxidation, so that an oxidation resistance treatment is necessary.

  As described above, in this embodiment, the dielectric layer and the first electrode are respectively formed on one surface of the porous light emitting layer, and the dielectric layer and the first electrode of the porous light emitting layer are A light emitting device comprising an assembly of a plurality of the porous light emitting layers in which a second electrode is disposed on the other surface not formed, and comprising a discharge separating means between the plurality of porous light emitting layers. In particular, a partition is formed as a discharge separation means between the plurality of porous light emitting layers, and the plurality of dielectric layers are arranged such that some of the plurality of porous light emitting layers share the dielectric layer. A light-emitting element formed on some of the porous light-emitting layers can be manufactured.

In the present embodiment, the surface of the phosphor particles 3 is covered with the insulating layer 4 made of MgO. As a result, MgO has a high resistivity (10 ⁹ Ω · cm or more) and can efficiently generate creeping discharge. When the resistivity of the insulating layer is low, creeping discharge is difficult to occur, and sometimes a short circuit may occur, which is not preferable. For these reasons, it is desirable to coat with an insulating metal oxide having a high resistivity. Of course, when the resistivity of the phosphor particles to be used is high, creeping discharge is easily generated without coating with an insulating metal oxide. As the insulating layer, in addition to the above MgO, at least one selected from Y ₂ O ₃ , Li ₂ O, CaO, BaO, SrO, Al ₂ O ₃ , SiO ₂ , and ZrO ₂ can be used. The standard free energy of formation ΔG _f0 of these oxides is very small (for example, -100 kcal / mol or less at room temperature) and is a stable substance. In addition, these insulating layers have high resistivity, are easily discharged, and are difficult to reduce. Therefore, they are excellent as protective films for reducing phosphor particles and further preventing UV degradation during discharge. This is advantageous because the durability of the phosphor is increased.

  In addition to the sol / gel method, the insulating layer can be formed by a physical adsorption method using a chemical adsorption method, a CVD method, a sputtering method, a vapor deposition method, a laser method, a shear stress method, or the like. It is desirable that the insulating layer is homogeneous and uniform and does not peel off. When forming the insulating layer, the phosphor particles are immersed in a weak acid solution such as acetic acid, oxalic acid or citric acid, and impurities adhering to the surface. It is important to wash

  Furthermore, it is desirable to pre-process phosphor particles in a nitrogen atmosphere at 200 to 500 ° C. for about 1 to 5 hours before forming the insulating layer. Ordinary phosphor particles contain a large amount of adsorbed water and crystal water, and if an insulating layer is formed in such a state, it will adversely affect the life characteristics such as luminance reduction and emission spectrum shift. is there. When the phosphor particles are washed with a weakly acidic solution, the above pretreatment is performed after thoroughly washing with water.

  Moreover, what should be noted in the heat treatment step for forming the porous light emitting layer is the heat treatment temperature and atmosphere. In this embodiment, since the heat treatment was performed in a temperature range of 450 to 1200 ° C. in a nitrogen atmosphere, there was no change in the valence of rare earth atoms doped in the phosphor. However, when processing at a temperature higher than this temperature range, care must be taken because the valence of rare earth atoms may change and a solid solution composed of an insulating layer and a phosphor may be generated.

  In addition, it is necessary to pay attention to the fact that the apparent porosity of the porous light emitting layer decreases as the heat treatment temperature rises. Judging from these facts, the optimum heat treatment temperature is preferably in the range of 450 to 1200 ° C. As for the heat treatment atmosphere, a nitrogen atmosphere is preferable so as not to affect the valence of the rare earth atoms doped in the phosphor particles as described above.

  In this embodiment, the thickness of the insulating layer is about 0.1 to 2.0 μm, but is determined in consideration of the average particle diameter of the phosphor particles and the efficient generation of creeping discharge. Further, when the average particle diameter of the phosphor is on the order of submicron, it is better to coat relatively thinly. A thick insulating layer is not preferable because it causes a shift in emission spectrum, a decrease in luminance, and the like. Conversely, it is presumed that creeping discharge is slightly less likely to occur when the insulating layer becomes thinner. Therefore, the relationship between the average particle diameter of the phosphor particles and the thickness of the insulating layer is preferably in the range of 1/10 to 1/500 of the latter with respect to the former.

  Next, the light emitting action of the light emitting element 1 will be described with reference to FIGS.

As shown in FIG. 1, an alternating electric field is applied between the first electrode 6 and the second electrode 7 in order to drive the light emitting element 1. Between the electrodes 6 and 7, a dielectric layer 10, a porous light emitting layer 2, and a gap (gas layer) 9 exist in series in the thickness direction. Therefore, the applied electric field is concentrated in the gap 9 in proportion to the reciprocal of each capacitance. Accordingly, gas breakdown occurs in the gap 9 and primary electrons (e−) 24 shown in FIG. 17 are generated. The primary electrons (e−) collide with the phosphor particles 3 and the insulating layer 4 of the porous light emitting layer 2 to generate creeping discharge, and a large number of secondary electrons (e−) 25 are generated. Thereby, electrons and ultraviolet rays generated in an avalanche collide with the emission center of the phosphor, and the phosphor particles 3 are excited to emit light. In addition, the inversion of polarization is repeated in the dielectric layer by the application of an alternating electric field. As a result, electrons are generated and electric charges are injected into the porous light emitting layer, resulting in creeping discharge. Creeping discharge continuously occurs while an electric field is applied. At that time, electrons and ultraviolet rays generated in an avalanche collide with the emission center of the phosphor, and the phosphor particles 3 are excited to emit light.

  In addition, by changing the waveform of the AC electric field to be applied from a sine wave or sawtooth wave to a rectangular wave, and increasing the frequency from several tens of Hz to several thousand Hz, the emission of primary electrons, secondary electrons, and ultraviolet rays is extremely intense. Thus, the light emission luminance is improved. A burst wave is generated as the voltage of the AC electric field increases. The generation frequency of the burst wave was generated just before the peak for the sine wave and at the peak for the sawtooth wave and the rectangular wave, and the emission luminance improved as the burst wave voltage was increased. Once creeping discharge is started, ultraviolet rays and visible rays are also generated. Therefore, it is necessary to suppress the deterioration of the phosphor particles 3 due to these rays, and it is preferable to reduce the voltage after the start of light emission.

  In the present embodiment, an electric field (frequency: 1 kHz) of about 0.72 to 1.5 kV / mm is applied in the thickness direction of the porous light emitting layer to cause the phosphor particles 3 to emit light, and then about 0. By applying an alternating electric field (frequency: 1 kHz) of 5 to 1.0 kV / mm, creeping discharge was continuously performed, and the light emission of the phosphor particles 3 was continued. When the applied electric field is increased, the generation of electrons and ultraviolet rays is promoted, but when the applied electric field is small, the generation thereof is insufficient.

  In addition, the current value at the time of discharge is 0.1 mA or less, and when the light emission starts, the light emission continues even if the voltage is reduced to about 50 to 80% of the applied voltage. It was confirmed that the light emission was high in contrast, high recognizability and high reliability.

  Although driving was performed in the atmosphere in this embodiment mode, it was confirmed that light was emitted in the same manner even when the driving was performed in oxygen, nitrogen, an inert gas, or a decompressed gas.

  According to the light emitting device of the present embodiment, since light emission is caused by creeping discharge in the porous light emitting layer, there is no need to use a thin film formation process when manufacturing the light emitting device as in the prior art, and a vacuum system or carrier multiplication is performed. Since no layer is required, the structure is simple, and manufacturing and processing are easy. In addition, a light-emitting element with favorable light emission efficiency and relatively low power consumption when a large display is provided can be provided. In the present embodiment, by providing a partition as a discharge separation means at the boundary of the porous light emitting layer, crosstalk at the time of light emission can be avoided by a relatively simple method.

(Embodiment 2)
This will be described with reference to FIG. In this example, the dielectric layer and the first electrode are respectively formed on one surface of the porous light emitting layer, and the other surface of the porous light emitting layer on which the dielectric layer and the first electrode are not formed A plurality of porous light emitting layers each having a second electrode disposed thereon, and a discharge separating means is provided between the plurality of porous light emitting layers, and the discharge separating means is in particular a partition. It is an element. FIG. 7 is a cross-sectional view of the light-emitting element in this embodiment. 1 is a light-emitting element, 2 is a porous light-emitting layer, 3 is a phosphor particle, 4 is an insulating layer, 5 is a substrate, and 6 is a first electrode ( Back electrode), 7 is a second electrode (observation surface side electrode), 8 is a translucent substrate, 9 is a gap (gas layer), 10 is a dielectric layer, and 11 is a partition.

  In the first embodiment, as shown in FIG. 1, the dielectric layer 10 and the first electrode 6 formed under the porous light emitting layer are shared by the plurality of porous light emitting layers. The dielectric layer and the first electrode can be individually formed on a plurality of porous light emitting layers. The light-emitting element in this embodiment is configured as described above, and its cross-sectional structure is shown in FIG.

  The light-emitting element in this embodiment can be manufactured by a manufacturing method similar to that in Embodiment 1. Actually, Ag paste is first baked to form the first electrode 6 in accordance with the location where the porous light emitting layer is formed and arranged in a predetermined pattern, and a dielectric is formed thereon by a thick film process or the like. After forming the layer, the porous light-emitting layer may be formed by screen printing. After that, if the light-transmitting substrate 8 having the second electrode is finally formed after the partition walls are formed as in the first embodiment, the light-emitting element of the present embodiment as shown in FIG. Can be made.

  Next, the light emitting action of the light emitting element 1 will be described with reference to FIG. As shown in FIG. 7, an alternating electric field is applied between the first electrode 6 and the second electrode 7 in order to drive the light emitting element 1. Application of an alternating electric field causes a dielectric breakdown of the gas in the gap 9, and as a result, electrons are generated and electric charges are injected into the porous light emitting layer, resulting in creeping discharge. Creeping discharge continuously occurs while an electric field is applied. At that time, electrons and ultraviolet rays generated in an avalanche collide with the emission center of the phosphor, and the phosphor particles 3 are excited to emit light.

  In addition, by changing the waveform of the alternating electric field to be applied from a sine wave or sawtooth wave to a rectangular wave, and by increasing the frequency from several tens of Hz to several thousand Hz, the emission of electrons and ultraviolet rays due to creeping discharge becomes extremely intense, resulting in light emission. Brightness is improved. A burst wave is generated as the voltage of the AC electric field is increased. The frequency of the burst wave was generated just before the peak for the sine wave and at the peak for the sawtooth wave and the rectangular wave, and the emission luminance was improved as the burst wave voltage increased. Once creeping discharge is started, ultraviolet rays and visible rays are also generated. Therefore, it is necessary to suppress the deterioration of the phosphor particles 3 due to these rays, and it is preferable to reduce the voltage after the start of light emission.

  In the present embodiment, an electric field of about 0.72 to 1.5 kV / mm is applied to the thickness of the porous light emitting layer to cause the phosphor particles 3 to emit light, and then about 0.5 to 1. By applying an alternating electric field of 0 kV / mm, creeping discharge was continuously performed, and the light emission of the phosphor particles 3 was continued. When the applied electric field is increased, the generation of electrons and ultraviolet rays is promoted, but when the applied electric field is small, the generation thereof is insufficient.

  In addition, the current value at the time of discharge is 0.1 mA or less, and when the light emission starts, the light emission continues even if the voltage is reduced to about 50 to 80% of the applied voltage. It was confirmed that the light emission was high in contrast, high recognizability and high reliability.

  Although driving was performed in the atmosphere in this embodiment mode, it was confirmed that light was emitted in the same manner even when the driving was performed in oxygen, nitrogen, an inert gas, or a decompressed gas.

  According to the light emitting device of the present embodiment, since light emission is caused by creeping discharge in the porous light emitting layer, there is no need to use a thin film formation process when manufacturing the light emitting device as in the prior art, and a vacuum system or carrier multiplication is performed. Since no layer is required, the structure is simple, and manufacturing and processing are easy. In addition, a light-emitting element with favorable light emission efficiency and relatively low power consumption when a large display is provided can be provided. In the present embodiment, by providing a partition as a discharge separation means at the boundary of the porous light emitting layer, crosstalk at the time of light emission can be avoided by a relatively simple method.

(Embodiment 3)
Referring to FIG. 8, the dielectric layer and the first electrode are respectively formed on one surface of the porous light emitting layer, and the dielectric layer and the first electrode of the porous light emitting layer are not formed. It comprises an assembly of a plurality of the porous light emitting layers on which the second electrode is disposed on the other surface, and comprises a discharge separating means between the plurality of porous light emitting layers, and the discharge separating means is conductive. A light-emitting element that is a partition wall having the following structure will be described.

  FIG. 8 is a cross-sectional view of the light-emitting element in this embodiment. In the figure, 1 is the light-emitting element, 2 is the porous light-emitting layer, 3 is the phosphor particle, 4 is the insulating layer, 5 is the substrate, and 6 is the first An electrode (back electrode), 7 is a second electrode (observation surface side electrode), 8 is a translucent substrate, 9 is a gap (gas layer), 10 is a dielectric layer, and 11 is a partition.

  As described above, in the present embodiment, the conductive partition 11 effective for the extension of electrostatic shielding and creeping discharge is used as the discharge separation means. Such a conductive partition wall can be formed of various metal deposits and deposits. As an example, a method of forming using electroless nickel plating will be described.

  A specific method for manufacturing a light-emitting element is performed as follows. First, a resist film is formed by screen printing at other locations except for the portions where the partition walls are formed on the surface of the ceramic substrate 5. Thereafter, the substrate 5 is immersed in a solution composed of tin chloride and palladium chloride. Such a process is called a catalyzing / sensitizing process, and can be easily performed with a commercially available processing agent including a pre-treatment and a post-treatment.

  When the resist film is peeled off after the treatment, the palladium fine particles adhere only to the portions where the partition walls are formed. The ceramic substrate 5 thus treated is immersed in a solution (pH 4 to 6) containing nickel sulfate and sodium hypophosphite as main components, and the nickel metal is formed to a thickness of 80 to 300 μm at a temperature of about 90 ° C. By depositing, the partition wall 11 having a predetermined shape can be formed on the surface of the substrate 5. As described above, the ceramic substrate 5 on which the conductive partition 11 is formed is obtained.

  Thereafter, the first electrode 6 is formed by baking the Ag paste on the substrate 5. At this time, the first electrode 6 is formed with a slight gap so as not to contact the conductive partition 11. After the first electrode 6 is formed, the dielectric layer 10 is formed on the first electrode 6 by a thick film process or the like. Next, a paste containing phosphor particles 3 whose surface is uniformly coated with the insulating layer 4 is screen-printed and fired to form the porous light-emitting layer 2 in a predetermined pattern. When the whole assembly of the porous light emitting layers is finally covered with a glass transparent substrate 8 having an ITO film as the second electrode 7 on the surface, a light emitting device 1 as shown in FIG. 8 is obtained. At this time, a slight gap is provided so that the second electrode made of ITO and the conductive partition are not in contact with each other, so that the voltage application is not hindered when the light emitting element is driven.

  As described above, in this embodiment, the dielectric layer and the first electrode are respectively formed on one surface of the porous light emitting layer, and the dielectric layer and the first electrode of the porous light emitting layer are formed. Is formed of an assembly of a plurality of the porous light emitting layers in which the second electrode is disposed on the other surface on which the second electrode is not formed, and has a discharge separation means between the plurality of porous light emitting layers, A light emitting element in which the discharge separating means is a conductive partition is obtained.

  Next, the light emitting action of the light emitting element 1 will be described with reference to FIG. In order to drive the light emitting element 1 of FIG. 8, an alternating electric field is applied between the first electrode 6 and the second electrode 7. Application of an alternating electric field causes a dielectric breakdown of the gas in the gap 9, and as a result, electrons are generated and electric charges are injected into the porous light emitting layer, resulting in creeping discharge. Creeping discharge continuously occurs while an electric field is applied. At that time, electrons and ultraviolet rays generated in an avalanche collide with the emission center of the phosphor, and the phosphor particles 3 are excited to emit light.

  In addition, by changing the waveform of the alternating electric field to be applied from a sine wave or sawtooth wave to a rectangular wave, and by increasing the frequency from several tens of Hz to several thousand Hz, the emission of electrons and ultraviolet rays due to creeping discharge becomes extremely intense, resulting in light emission. Brightness is improved. A burst wave is generated as the voltage value of the AC electric field is increased. The frequency of the burst wave was generated just before the peak for the sine wave and at the peak for the sawtooth wave and the rectangular wave, and the emission luminance improved as the burst wave voltage was increased. Once creeping discharge is started, ultraviolet rays and visible rays are also generated. Therefore, it is necessary to suppress the deterioration of the phosphor particles 3 due to these rays, and it is preferable to reduce the voltage after the start of light emission.

  In particular, when a conductive partition is formed as in the present embodiment, creeping discharge is likely to occur, which can contribute to a reduction in driving voltage. That is, an electric field of about 0.58 to 1.2 kV / mm is applied to the thickness of the porous light emitting layer to cause the phosphor particles 3 to emit light, and then about 0.4 to 0.8 kV / mm. By applying an alternating electric field, the creeping discharge was continued and the light emission of the phosphor particles 3 was continued. When the applied electric field is increased, the generation of electrons and ultraviolet rays is promoted, but when the applied electric field is small, the generation thereof is insufficient.

  In addition, the current value at the time of discharge is 0.1 mA or less, and when the light emission starts, the light emission continues even if the voltage is reduced to about 50 to 80% of the applied voltage. It was confirmed that the light emission was high in contrast, high recognizability and high reliability.

  According to the light emitting device of the present embodiment, since light emission is caused by creeping discharge in the porous light emitting layer, there is no need to use a thin film formation process when manufacturing the light emitting device as in the prior art, and a vacuum system or carrier multiplication is performed. Since no layer is required, the structure is simple, and manufacturing and processing are easy. In addition, a light-emitting element with favorable light emission efficiency and relatively low power consumption when a large display is provided can be provided. In the present embodiment, by providing a partition as a discharge separation means at the boundary of the porous light emitting layer, crosstalk at the time of light emission can be avoided by a relatively simple method.

(Embodiment 4)
9 to 13, a dielectric layer and a first electrode are formed on one surface of the porous light emitting layer, respectively, and the dielectric layer and the first electrode of the porous light emitting layer are formed. A light emitting device comprising an assembly of a plurality of the porous light emitting layers in which the second electrode is disposed on the other surface that is not provided, and comprising a discharge separating means between the plurality of porous light emitting layers, In particular, a light-emitting element in which a plurality of porous light-emitting layers are arranged so as to share a second electrode and the discharge separation means is a gap will be described.

  FIG. 9 is a cross-sectional view of the light-emitting element in this embodiment mode, and FIGS. 10 to 13 are diagrams for explaining a manufacturing process of the light-emitting element in this embodiment mode. In these drawings, 1 is a light emitting element, 2 is a porous light emitting layer, 3 is a phosphor particle, 4 is an insulating layer, 5 is a substrate, 6 is a first electrode (back electrode), 7 is a second electrode (observation) (Surface side electrode), 8 is a translucent substrate, 9 is a gap (gas layer), 10 is a dielectric layer, 12 is a gap separating the porous light emitting layer, and 15 is a side wall.

  As shown in FIG. 10, Ag paste is baked on one surface of a glass or ceramic substrate 5 to form the first electrode 6 in a predetermined shape. Next, as shown in FIG. 11, a dielectric layer 10 is formed on the first electrode 6 by a thick film process or the like.

Next, the porous light emitting layer 2 is formed in a predetermined shape on the dielectric layer 10. At that time, as in the first embodiment, phosphor particles 3 whose surfaces were covered with an insulating layer 4 made of a metal oxide such as MgO were used. The phosphor particles 3 are inorganic such as BaMgAl ₁₀ O ₁₇ : Eu ²⁺ (blue), Zn ₂ SiO ₄ : Mn ²⁺ (green), YBO ₃ : Eu ³⁺ (red) having an average particle diameter of 2 to 3 μm. It is possible to use compounds.

  In the present embodiment, a paste is prepared for each phosphor by kneading 45% by mass of α-terpineol and 5% by mass of ethylcellulose with respect to 50% by mass of the phosphor particles having the insulating layer 4 described above. The operation of screen printing on the body layer 10 and then drying was repeated a plurality of times, so that the thickness of the printed portion was adjusted to 80 to 100 μm.

As described above, the substrate 5 on which the porous light-emitting layer is printed is heat-treated at 400 to 600 ° C. for 2 to 5 hours in an N ₂ atmosphere, whereby about 50 to 80 μm is formed on the substrate as shown in FIG. An assembly of the porous light emitting layer 2 having a thickness of 5 mm was formed.

  Next, without setting a partition wall at the boundary of the aggregate composed of the porous light emitting layer 2, leave the gap 12 of about 80 to 300 μm, and make such a void function as an alternative to the partition wall. There is a feature of this embodiment. In the present embodiment, the side wall 15 is formed so as to surround the entire assembly of the porous light-emitting layers 2, and the light transmission is performed as described later on the side wall that surrounds the assembly. Support substrate 8. The side wall 15 is formed by screen printing and drying a glass paste a plurality of times, and then baking at 600 ° C. to form a side wall 15 of about 80 to 300 μm as shown in FIG.

  The side wall 15 can also be formed using a glass paste or resin containing ceramic particles. Specifically, in the former, the paste obtained by adding 50% by mass of α-terpineol to 50% by mass of the mixed particles of ceramic and glass (1: 1 by weight) is screen-printed and then repeatedly dried. The side wall 15 having a thickness of about 80 to 300 μm is formed by adjusting the printed thickness to about 100 to 350 μm and heat-treating at 400 to 600 ° C. for 2 to 5 hours in an N 2 atmosphere. can do. In the latter, a partition is formed using a thermosetting resin, and an epoxy resin, a phenol resin, or a cyanate resin can be mainly used, and a porous light emitting layer can be selected by selecting one of these. This can be done by printing so as to surround the entire assembly.

  After the side wall 15 is formed as described above, a translucent substrate 8 such as a glass plate on which a second electrode 7 made of ITO (indium-tin oxide alloy) is formed is attached to the side wall 15. When the entire aggregate of the porous light emitting layers is covered, the light emitting element 1 in the present embodiment as shown in FIG. 9 is obtained. At that time, as shown in the figure, the second electrode 7 is formed, for example, in a stripe shape so as to face the porous light emitting layer, and is shared by the plurality of porous light emitting layers. A slight gap is provided between the porous light emitting layer 2 and the second electrode 7, and the distance between the two is preferably in the range of 30 to 250 μm, and particularly preferably in the range of 40 to 220 μm.

  As a substitute for the light-transmitting substrate 8 made of ITO as the second electrode, it is also possible to use a substrate patterned with fine mesh-like wiring made of copper, gold, silver, platinum, aluminum or the like. is there.

  As described above, the dielectric layer and the first electrode are respectively formed on one surface of the porous light emitting layer, and the dielectric layer and the first electrode of the porous light emitting layer are not formed. A light-emitting device comprising a plurality of the porous light-emitting layers having a second electrode disposed on the surface thereof, and comprising a discharge separation means between the plurality of porous light-emitting layers, A light-emitting element in which the two electrodes are arranged so as to be shared by a plurality of porous light-emitting layers and the discharge separation means is a gap can be manufactured.

  Next, the light emitting action of the light emitting element 1 will be described with reference to FIG. As shown in FIG. 9, an alternating electric field is applied between the first electrode 6 and the second electrode 7 in order to drive the light emitting element 1. Application of an alternating electric field causes a dielectric breakdown of the gas in the gap 9, and as a result, electrons are generated and electric charges are injected into the porous light emitting layer, resulting in creeping discharge. Creeping discharge continuously occurs while an electric field is applied. At that time, electrons and ultraviolet rays generated in an avalanche collide with the emission center of the phosphor, and the phosphor particles 3 are excited to emit light.

  In addition, by changing the waveform of the alternating electric field to be applied from a sine wave or sawtooth wave to a rectangular wave, and by increasing the frequency from several tens of Hz to several thousand Hz, the emission of electrons and ultraviolet rays due to creeping discharge becomes extremely intense, resulting in light emission. Brightness is improved. A burst wave is generated as the voltage value of the AC electric field is increased. The frequency of the burst wave was generated just before the peak for the sine wave and at the peak for the sawtooth wave and the rectangular wave, and the emission luminance improved as the burst wave voltage was increased. Once creeping discharge is started, ultraviolet rays and visible rays are also generated. Therefore, it is necessary to suppress the deterioration of the phosphor particles 3 due to these rays, and it is preferable to reduce the voltage after the start of light emission.

  In the present embodiment, an electric field of about 0.85 to 1.8 kV / mm is applied to the thickness of the porous light emitting layer to cause the phosphor particles 3 to emit light, and then about 0.6 to 1. By applying an alternating electric field of 2 kV / mm, creeping discharge was continuously performed, and the light emission of the phosphor particles 3 was continued. When the applied electric field is increased, the generation of electrons and ultraviolet rays is promoted, but when the applied electric field is small, the generation thereof is insufficient.

  In addition, the current value at the time of discharge is 0.1 mA or less, and when the light emission starts, the light emission continues even if the voltage is reduced to about 50 to 80% of the applied voltage. It was confirmed that the light emission was high in contrast, high recognizability and high reliability.

  Although driving was performed in the atmosphere in this embodiment mode, it was confirmed that light was emitted in the same manner even when the driving was performed in oxygen, nitrogen, an inert gas, or a decompressed gas.

  According to the light emitting device of the present embodiment, since light emission is caused by creeping discharge in the porous light emitting layer, there is no need to use a thin film formation process when manufacturing the light emitting device as in the prior art, and a vacuum system or carrier multiplication is performed. Since no layer is required, the structure is simple, and manufacturing and processing are easy. In addition, a light-emitting element with favorable light emission efficiency and relatively low power consumption when a large display is provided can be provided. In this embodiment, by providing a gap as a discharge separation means at the boundary of the porous light emitting layer, crosstalk during light emission can be avoided by a relatively simple method.

(Embodiment 5)
Referring to FIGS. 14 and 15, a dielectric layer and a first electrode are respectively formed on one surface of the porous light emitting layer, and the dielectric layer and the first electrode of the porous light emitting layer are formed. A light emitting device comprising an assembly of a plurality of the porous light emitting layers having a second electrode disposed on the other surface, and having a discharge separation means between the plurality of porous light emitting layers. In particular, the porous light emitting layer will be described.

  14 and 15 are schematic views in which the cross section of the porous light emitting layer in the present embodiment is enlarged. In these drawings, 2 is a porous light emitting layer, 3 is a phosphor particle, 4 is an insulating layer, and 18 is an insulating fiber.

  In the present embodiment, the porous light emitting layer 2 composed of the phosphor particles and the insulating fibers 18 such as ceramic and glass is formed regardless of the presence or absence of the insulating layer on the surface of the phosphor particles.

As an example of the insulating fiber 18, SiO ₂ —Al ₂ O ₃ —CaO based fiber is used, and the diameter is preferably 0.1 to 5 μm and the length is preferably 0.5 to 20 μm. By using a mixture of size fibers at a ratio of 2 parts by weight of phosphor particles and 1 part by weight of fibers, the porosity becomes relatively large, and as a result, creeping discharge easily occurs inside the porous light emitting layer. This is preferable. In the present embodiment, when forming the porous light emitting layer, a paste is prepared by kneading 45% by mass of α-terpineol and 5% by mass of ethyl cellulose with respect to 50% by mass of the mixture of phosphor particles and insulating fibers, As in the first embodiment, the paste was screen-printed in a pattern to form a porous light emitting layer. FIGS. 14 and 15 are enlarged schematic views of the cross section of the porous light emitting layer containing the insulating fiber 18 obtained as described above. FIG. 15 shows a porous light emitting layer 2 composed of phosphor particles 3 and insulating fibers 18, and FIG. 14 shows a phosphor light emitting layer 2 composed of phosphor particles 3 whose surfaces are covered with an insulating layer 4 and insulating fibers. . In addition, the first electrode, the dielectric layer, the second electrode, and the partition wall were formed by the same method as in the first embodiment, and finally the light emitting element similar to that in the first embodiment was manufactured ( Not shown).

The reason why SiO ₂ —Al ₂ O ₃ —CaO fiber is selected as the insulating fiber is that it is thermally and chemically stable and has a resistivity of 10 ⁹ Ω · cm or more, and 10% in the porous light emitting layer. This is because a large apparent porosity of not less than 100% and less than 100% can be easily obtained, and discharge is likely to occur on the surface of the fiber, resulting in occurrence of creeping discharge in the entire porous light emitting layer. Note that substantially the same results can be obtained by using insulating fibers containing SiC, ZnO, TiO ₂ , MgO, BN, or Si ₃ N ₄ series in addition to the above insulating fibers.

  Next, the light emitting action of this light emitting element is the same as that of the first embodiment. In order to drive the light emitting element, an alternating electric field is applied between the first electrode and the second electrode. Application of an alternating electric field causes a dielectric breakdown of the gas in the gap 9, and as a result, electrons are generated and electric charges are injected into the porous light emitting layer, resulting in creeping discharge. Creeping discharge continuously occurs while an electric field is applied. At that time, electrons and ultraviolet rays generated in an avalanche collide with the emission center of the phosphor, and the phosphor particles 3 are excited to emit light.

  In the present embodiment, an electric field of about 0.65 to 1.4 kV / mm is applied to the thickness of the porous light emitting layer to cause the phosphor particles 3 to emit light, and then about 0.45 to 0. By applying an alternating electric field of 90 kV / mm, creeping discharge was continuously performed, and the light emission of the phosphor particles 3 was continued. When the applied electric field is increased, the generation of electrons and ultraviolet rays is promoted, but when the applied electric field is small, the generation thereof is insufficient.

  In addition, the current value at the time of discharge is 0.1 mA or less, and when the light emission starts, the light emission continues even if the voltage is reduced to about 50 to 80% of the applied voltage. It was confirmed that the light emission was high in contrast, high recognizability and high reliability.

  Although driving was performed in the atmosphere in this embodiment mode, it was confirmed that light was emitted in the same manner even when the driving was performed in oxygen, nitrogen, an inert gas, or a decompressed gas.

  According to the light emitting device of the present embodiment, since light emission is caused by creeping discharge in the porous light emitting layer, there is no need to use a thin film formation process when manufacturing the light emitting device as in the prior art, and a vacuum system or carrier multiplication is performed. Since no layer is required, the structure is simple, and manufacturing and processing are easy. In addition, a light-emitting element with favorable light emission efficiency and relatively low power consumption when a large display is provided can be provided. In the present embodiment, by providing a partition as a discharge separation means at the boundary of the porous light emitting layer, crosstalk at the time of light emission can be avoided by a relatively simple method.

(Embodiment 6)
Referring to FIG. 16, a dielectric layer and an address electrode are respectively formed on one surface of the porous light emitting layer, and on the other surface of the porous light emitting layer where the dielectric layer and the address electrode are not formed. The operation of a light emitting device comprising an assembly of a plurality of the porous light emitting layers on which data electrodes are arranged and having a discharge separating means between the plurality of porous light emitting layers will be described.

  FIG. 16 is an exploded perspective view of the light emitting element in the present embodiment. For easy understanding, the light emitting element in the case where the discharge separating means is a gap is illustrated. In the figure, 1 is a light emitting element, 2 is a porous light emitting layer, 5 is a substrate, 8 is a translucent substrate, 10 is a dielectric layer, 12 is a gap, 21 is an address electrode, and 22 is a display electrode.

  As shown in FIG. 16, in the light emitting device 1 of the present embodiment, an address electrode 21 is formed on a substrate 5, and a plurality of porous light emitting layers 2 having a dielectric layer 10 thereon are regularly formed. An array of porous light emitting layers that are arranged and emit light of three colors of R, G, and B is formed. There are voids 12 between the porous light emitting layers, and side walls are usually provided so as to surround the entire array of porous light emitting layers 2 (not shown). The translucent substrate 8 is formed so as to face the porous light emitting layer 2 so that the display electrode 22 intersects the address electrode 21, and the translucent substrate 8 is arranged on the porous light emitting layer array. Thus, the light emitting device 1 as shown in FIG. 16 is finally formed. The address electrode and the display electrode in the present embodiment can correspond to the first electrode and the second electrode in the first to fifth embodiments described above, respectively. Also good.

  As described above, the dielectric layer and the address electrode are respectively formed on one surface of the porous light emitting layer, and the data electrode is formed on the other surface of the porous light emitting layer where the dielectric layer and the address electrode are not formed. A light-emitting element comprising a plurality of porous light-emitting layers arranged with a discharge separation means between the plurality of porous light-emitting layers, and in particular, a light-emitting element in which the discharge separation means is a gap An element is obtained.

  In the light emitting element 1 according to this embodiment configured as described above, a two-dimensional image can be displayed on the porous light emitting layer. That is, the light-emitting element 1 of the present embodiment can perform so-called simple matrix driving, and sequentially sends pulse signals to the X electrodes, and puts ON / OFF information in the Y electrodes in accordance with the timing, thereby causing the address electrodes and the display electrodes. One line is displayed by emitting light in accordance with ON / OFF of the pixels at the intersections. By sequentially switching the scanning pulse, a two-dimensional image can be displayed. Also, active driving is possible by placing a transistor in each of the pixels arranged in a matrix and turning on / off each pixel. In the present embodiment, since the void 12 is provided in the porous light emitting layer, there is almost no crosstalk of light emission. However, as described above in Embodiment 1, if a partition wall is provided between unit light emitting elements, Light emission crosstalk can be almost completely avoided.

(Embodiment 7)
FIG. 18 shows a cross section of the display device of this embodiment. This embodiment is the same as Embodiment 1 shown in FIG. 1 except that ribs 23 a and 23 b are provided between the partition walls 11. The thickness of the partition wall 11 in the horizontal direction: 150 μm, the height of 270 μm, the thickness of the ribs 23a, 23b: 50 μm, the height of 250 μm, the width of one pixel is 100 μm, the thickness of the porous light emitting layer is 230 μm, and the gap (gas layer) ) The distance 9 is 20 μm, the thickness of the dielectric layer 10 made of BaTiO ₃ is 250 μm, and the distance between the first electrode 6 and the second electrode 7 is 500 μm.

  In the present embodiment, an electric field (frequency: 1 kHz) of about 0.72 to 1.5 kV / mm is applied in the thickness direction of the porous light emitting layer to cause the phosphor particles 3 to emit light, and then about 0. By applying an alternating electric field (frequency: 1 kHz) of 4 kV / mm, creeping discharge was continuously performed to keep the phosphor particles 3 from emitting light. When the applied electric field is increased, the generation of electrons and ultraviolet rays is promoted, but when the applied electric field is small, the generation thereof is insufficient.

  In addition, the current value at the time of discharge is 0.1 mA or less, and when the light emission starts, the light emission continues even if the voltage is reduced to about 50 to 80% of the applied voltage. It was confirmed that the light emission was high in contrast, high recognizability and high reliability.

  Although driving was performed in the atmosphere in this embodiment mode, it was confirmed that light was emitted in the same manner even when the driving was performed in oxygen, nitrogen, an inert gas, or a decompressed gas.

(Embodiment 8)
FIG. 19 shows a cross section of the display device of this embodiment. This embodiment is the same as the first embodiment shown in FIG. 1 except that the partition wall 11 is formed by cutting the dielectric layer 10 made of BaTiO ₃ . The horizontal thickness of the partition wall 11 is 150 μm, the height is 270 μm, the width of one pixel is 250 μm, the thickness of the porous light emitting layer is 230 μm, the gap 9 is 20 μm, and the thickness of the dielectric layer made of BaTiO ₃ is The distance between the first electrode and the second electrode was 500 μm.

  In the present embodiment, an electric field (frequency: 1 kHz) of about 0.72 to 1.5 kV / mm is applied in the thickness direction of the porous light emitting layer to cause the phosphor particles 3 to emit light, and then about 0. By applying an alternating electric field (frequency: 1 kHz) of 4 kV / mm, creeping discharge was continuously performed to keep the phosphor particles 3 from emitting light. When the applied electric field is increased, the generation of electrons and ultraviolet rays is promoted, but when the applied electric field is small, the generation thereof is insufficient.

  In addition, the current value at the time of discharge is 0.1 mA or less, and when the light emission starts, the light emission continues even if the voltage is reduced to about 50 to 80% of the applied voltage. It was confirmed that the light emission was high in contrast, high recognizability and high reliability.

  Although driving was performed in the atmosphere in this embodiment mode, it was confirmed that light was emitted in the same manner even when the driving was performed in oxygen, nitrogen, an inert gas, or a decompressed gas.

(Comparative Example 1)
As Comparative Example 1, a silicone oil impregnation used in a dielectric breakdown test of a multilayer chip capacitor was performed. That is, when measuring the breakdown voltage in a multilayer chip capacitor, creeping discharge frequently occurs and the true breakdown voltage value cannot be measured. Therefore, a true dielectric breakdown voltage value was determined in a state in which silicone oil was impregnated in the pores of the element and no creeping discharge occurred. Using this method, the gas in the pores of the porous light emitter layer 2 of the light emitting device 1 of FIG. 1 was replaced with silicone oil. After immersion for several minutes, the silicone oil on the surface of the light-emitting element was wiped off, and an alternating electric field similar to that in Embodiment 1 was applied.

  First, it was confirmed that when the applied voltage was increased, a burst wave was generated and primary electrons were emitted from the gap. However, creeping discharge does not occur at all in the porous luminous body layer 2. Alternatively, even if creeping discharge occurs, light emission cannot be confirmed because it occurs not in the phosphor layer 2 but in the extreme surface portion. When the applied voltage was further raised, the dielectric breakdown of the porous light emitter layer 2 occurred in an instant, and the light emitting element 1 was cracked and broken.

  Of course, it was confirmed that when the light-emitting element 1 in which the silicone oil was immersed was washed with an organic solvent such as acetone and the pores were again filled with gas, the light was easily emitted and recovered. Of course, light was emitted even when the pores were evacuated.

  Further, when a conductive solution such as an acetic acid aqueous solution was impregnated in the pores, a short circuit occurred and no light was emitted.

  From the above, the greatest feature that becomes a light-emitting element in the configuration of the present invention is that the light-emitting layer 2 has continuous pores on the surface, and the pores are filled with gas or vacuum. When electrons emitted from the outside enter the light emitter layer 4, the electrons are repeatedly accelerated by creeping discharge along the pores in an avalanche manner. Then, the accelerated electrons collide with the light emission center of the phosphor particles to emit light. When the pores are filled with silicone oil or a conductive solution, it is difficult for electrons to move or a short circuit occurs, and creeping discharge does not occur, resulting in no light emission.

  In the present embodiment, the size of the pores is several hundreds μm or less. However, if the size is several mm or more, care must be taken because the device may be destroyed due to air discharge. Empirically, the packing is such that the phosphor particles 3 are in point contact. Ideally, a porous material having an apparent porosity of 10% to less than 100% is desirable.

The reason for providing the insulating layer 4 as in the above embodiment is as follows.
a. In order to increase the surface resistance of the phosphor particles 3 so that creeping discharge is likely to occur,
b. In order to protect the phosphor particles from dielectric breakdown and ultraviolet rays,
c. This is because more electrons are emitted by the secondary electron emission action such as MgO, and as a result, creeping discharge is more likely to occur.

  Moreover, although the thickness of the porous light-emitting body layer 2 is not specifically limited, it confirmed that it light-emitted in the range of 10 micrometers-3 mm. Of course, if a short circuit does not occur, light is emitted from several μm.

(Embodiment 9)
In the ninth embodiment, the case where the first electrode 6 and the second electrode 7 are formed with the dielectric layer 10 and the porous light-emitting layer 2 interposed therebetween will be described with reference to FIG. FIG. 22 is a cross-sectional view of the light-emitting element 1 in the present embodiment. 6 is a first electrode, 7 is a second electrode, 3 is a phosphor particle, 4 is an electrical insulator layer, 2 is a porous phosphor layer, and 10 is a dielectric layer. As shown in FIG. 6, the porous light emitting layer 2 is composed of phosphor particles 3 as a main component, and the surface of the phosphor particles 3 is covered with an insulator layer 4.

The phosphor particles 3 are of three types, BaMgAl ₁₀ O ₁₇ : Eu ²⁺ (blue), Zn ₂ SiO ₄ : Mn ²⁺ (green), and YBO ₃ : Eu ³⁺ (red) with an average particle diameter of 2 to 3 μm. In order to obtain the desired light emission of the inorganic compound, it is possible to use a single compound or a mixture thereof.

  In the present embodiment, the blue phosphor particles 3 are used, and the insulating layer 4 made of an insulating inorganic material made of MgO is formed on the surface thereof. Phosphor particles are added to the Mg precursor complex solution, stirred, taken out, dried, and then heat-treated at 400 to 600 ° C. in the air, so that the uniform coating layer of MgO shown in FIG. To form.

First, the manufacturing method of the light emitting element in this embodiment mode shown in FIG. 22 will be described. 50% by mass of the phosphor particle powder 3 coated with the insulating layer 4 and 50% by mass of an aqueous colloidal silica solution are mixed to form a slurry. Next, a dielectric layer 10 having a diameter of 15 mmφ and a thickness of 1 mm on which the second electrode 7 is formed (a plate-like sintered body mainly composed of BaTiO ₃ , and Ag electrode paste is baked on this back surface to a thickness of about 50 μm. Porous light emission having a thickness of about 100 μm on the dielectric layer 10 by applying the slurry on the other surface (formed with the first electrode 6) and drying it at 100 to 150 ° C. for 10 to 30 minutes with a dryer. The body layer 2 was laminated. Further, a transparent substrate (glass plate) 8 coated with a transparent second electrode (indium-tin oxide alloy (ITO), thickness: about 0.1 μm) 7 is laminated on the upper surface of the porous luminous body layer 2. did. As a result, a light emitting device 1 in which a pair of electrodes 6 and 7 were formed with the dielectric layer 10 and the porous light emitting layer 2 sandwiched therebetween was obtained.

  Next, the light emitting action of the light emitting element 1 will be described with reference to FIGS. As shown in FIG. 22, an alternating electric field is applied between the first electrode 6 and the second electrode 7 in order to drive the light emitting element 1. By applying a voltage, primary electrons (e−) 24 are emitted from the dielectric layer 10 by polarization inversion. At this time, ultraviolet rays and visible rays are generated. The primary electrons (e−) collide with the phosphor particles 3 and the insulating layer 4 of the porous light emitting layer 2 to generate creeping discharge, and a large number of secondary electrons (e−) 25 are generated. Thereby, electrons and ultraviolet rays generated in an avalanche collide with the emission center of the phosphor, and the phosphor particles 3 are excited to emit light. In addition, the inversion of polarization is repeated in the dielectric layer by the application of an alternating electric field. As a result, electrons are generated and electric charges are injected into the porous light emitting layer, resulting in creeping discharge. Creeping discharge continuously occurs while an electric field is applied. At that time, electrons and ultraviolet rays generated in an avalanche collide with the emission center of the phosphor, and the phosphor particles 3 are excited to emit light.

  In addition, by changing the waveform of the alternating electric field to be applied from a sine wave or a sawtooth wave to a rectangular wave, and by increasing the frequency from several tens of Hz to several thousand Hz, the emission of electrons and ultraviolet rays due to creeping discharge becomes very intense, Luminous brightness is improved. A burst wave is generated as the voltage of the AC electric field increases. The generation frequency of the burst wave was generated just before the peak for the sine wave and at the peak for the sawtooth wave and the rectangular wave, and the emission luminance improved as the burst wave voltage was increased. Once creeping discharge is started, ultraviolet rays and visible rays are also generated. Therefore, it is necessary to suppress the deterioration of the phosphor particles 3 due to these rays, and it is preferable to reduce the voltage after the start of light emission.

  In this embodiment, when an AC power supply is used to apply a voltage of about 0.5 to 1.0 kV / mm with respect to the thickness of the dielectric layer 10, primary electron emission (e-) 24 due to polarization inversion and creeping discharge are caused. Secondary electrons (e−) 25 were generated, and light emission was started. The current value at the time of discharge was 0.1 mA or less. Further, when light emission started, light emission continued even when the voltage was reduced to 50 to 80% of the applied voltage, and it was confirmed that the light emission had high brightness, high contrast, high recognizability, and high reliability. Further, it has become possible to produce a light emitting device having a light emission efficiency of about 2 to 5 lm / w.

  In the present embodiment, driving was performed in the atmosphere, but it was confirmed that light was emitted in the same manner even when performed in oxygen, nitrogen, an inert gas, or a reduced-pressure gas.

The light-emitting element 1 in this embodiment has a structure that is structurally close to inorganic EL (ELD), but has a completely different configuration and mechanism. First, as described in the background art regarding the structure, the phosphor used in the inorganic EL is a light emitting body made of a semiconductor as represented by ZnS: Mn ²⁺ , GaP: N, etc. The phosphor particles in may be either an insulator or a semiconductor. That is, even when using semiconductor phosphor particles having an extremely low resistance value, creeping discharge can continue to emit light without being short-circuited because it is uniformly coated with the insulating layer 4 that is an insulating inorganic substance. it can. Further, regarding the phosphor layer, the inorganic EL is a porous body having a thickness of submicron to several μm, whereas the ninth embodiment is a porous body having a thickness of several μm to several hundred μm. Further, the ninth embodiment is that the luminous body layer is porous.

  About the porous form, it is packing of the grade which the phosphor particle point-contacted from the result observed with SEM (scanning electron microscope).

Moreover, although the ultraviolet light emission powder used in the current plasma display (PDP) was used as the phosphor particles, ZnS: Ag (blue), ZnS: Cu, Au used in the cathode ray tube (CRT). , Al (green), Y ₂ O ₃ : Eu (red), similar luminescence was confirmed. The CRT phosphor has a low resistance value, so that it is difficult for creeping discharge to occur. However, when it is coated with the insulating layer 4, creeping discharge is likely to occur and light emission is likely to occur.

  In addition, the present invention is a light emitting element in which creeping discharge is generated in an avalanche with light emitted from polarization inversion of a dielectric as a base point and light is emitted. Therefore, if a system having a new function of colliding electrons in addition to polarization reversal is added to the porous light emitting layer 2, it is expected that light is easily emitted.

  In the present embodiment, colloidal silica aqueous solution was used in preparing the slurry of phosphor particles 3, but it was confirmed that the same result was obtained even when an organic solvent was used. A slurry obtained by kneading 45% by mass of α-terpineol and 5% by mass of ethyl cellulose with respect to 50% by mass of the phosphor particles is subjected to screen printing on the surface of the dielectric layer 10, and 400 to 600 ° C., 10 to 10% in the air. By performing heat treatment for 60 minutes, the porous light-emitting layer 23 having a thickness of several μm to several tens of μm can be produced. In this case, if the heat treatment temperature is raised too much, the phosphor is likely to be deteriorated, and therefore temperature management and heat treatment atmosphere management are important. It should be noted that the same result can be obtained even if the organic slurry contains the inorganic fiber 18.

Further, in the present embodiment, using BaTiO ₃ as a _{dielectric, SrTiO 3, CaTiO 3, MgTiO} 3, PZT (PbZrTiO 3), that the same effect by using a dielectric such as PbTiO ₃ is obtained confirmed. In addition, a sintered body may be used for the dielectric layer, or a dielectric layer obtained by a thin film forming process such as sputtering, CVD, vapor deposition, or sol / gel may be used.

In the present embodiment, a sintered body is used as the dielectric layer. However, light emission is possible even when a structure composed of a dielectric powder and a binder is employed. That is, a slurry obtained by kneading 40% by mass of α-terpineol and 5% by mass of ethyl cellulose on a powder obtained by mixing 15% by mass of glass powder with 40% by mass of BaTiO ₃ powder on an Al metal substrate, and drying and then air It is also possible to use a dielectric layer composed of dielectric particles and a binder by heat treatment at 400 to 600 ° C.

  In the present embodiment, blue phosphor particles are used, but it has been found that the same effect can be obtained even when red or green is used. The same effect was obtained with mixed particles of blue, red, and green.

  According to the light emitting device of the present embodiment, since light emission is caused by creeping discharge, a thin film forming process is not used for forming a phosphor layer as in the prior art, and a vacuum system and a carrier multiplication layer are not required. Is simple and easy to process.

  Moreover, although ITO was used for the electrode 7, it is also possible to use the translucent board | substrate with which the copper wiring was given as an alternative of ITO. The copper wiring is formed in a fine mesh shape, and the aperture ratio (ratio to the whole portion where the wiring is not applied) is 90%, and the light transmission is compared with a translucent substrate having an ITO film. There is almost no inferiority. Also, copper is advantageous because it has a considerably lower resistance than ITO and thus greatly contributes to improvement in luminous efficiency. In addition, it is also possible to use gold, silver, platinum, or aluminum other than copper as a metal for providing fine mesh wiring.

(Embodiment 10)
Next, the manufacturing method and the light emitting action of the tenth embodiment will be described with reference to FIG. The description of the same reference numerals as those in FIG. 22 may be omitted. A second electrode 7 was formed by printing and baking a mesh-like (about 5 to 10 mesh) Ag paste on the other surface of the dielectric 10 on which the first electrode 6 used in FIG. 22 was formed. . Thereafter, a slurry of the phosphor particle powder 3 and colloidal silica aqueous solution is applied to the upper surface of the second electrode 7 in the same manner as described above, and is dried at 100 to 150 ° C. for 10 to 30 minutes with a dryer. A porous luminous body layer 2 having a thickness of about 100 μm was laminated on the surface. As a result, the second electrode 7 was formed between the dielectric layer 10 and the porous light emitter layer 2, and the light emitting element 1 was obtained in which the first electrode 6 was formed outside the dielectric layer 10. . In the light emitting method, an AC electric field is applied between the first electrode 6 and the second electrode 7 as in the case of FIG. By applying a voltage, primary electrons (e−) 24 are emitted from the dielectric layer 10 by polarization inversion. At this time, ultraviolet rays and visible rays are generated. The primary electrons (e−) collide with the phosphor particles 3 and the insulating layer 4 of the porous light emitting layer 2 to generate creeping discharge, and a large number of secondary electrons (e−) 25 are generated. Thereby, electrons and ultraviolet rays generated in an avalanche collide with the emission center of the phosphor, and the phosphor particles 3 are excited to emit light. In addition, the inversion of polarization is repeated in the dielectric layer by the application of an alternating electric field. As a result, electrons are generated and electric charges are injected into the porous light emitting layer, resulting in creeping discharge. Creeping discharge continuously occurs while an electric field is applied. At that time, electrons and ultraviolet rays generated in an avalanche collide with the emission center of the phosphor, and the phosphor particles 3 are excited to emit light.

  Of course, in the same way as in FIG. 22, the waveform of the alternating electric field applied is changed from a sine wave or a sawtooth wave to a rectangular wave, or the frequency is increased from several tens of Hz to several thousand Hz, thereby causing more intense electron emission and creeping discharge during polarization reversal. Occurrence of light emission is improved. A burst wave is generated as the voltage value of the alternating electric field is increased. The burst wave is generated when the polarization of the dielectric layer 10 is reversed, and the generated frequency is generated immediately before the peak in the case of a sine wave and at the peak in the case of a sawtooth wave or a rectangular wave, and the emission luminance increases as the peak voltage of the burst wave increases. Improved.

  Once the creeping discharge is started, the discharge is repeated in a chain as described above, and continuously generates ultraviolet rays and visible rays. Therefore, it is necessary to suppress the deterioration of the phosphor particles 2 due to the rays. Is preferably reduced.

  In the case of FIG. 23, when a voltage of about 0.7 to 1.2 kV / mm is applied to the thickness of the dielectric layer 10, the primary electron emission (e −) 24 shown in FIG. Secondary electrons (e−) 25 were generated, and light emission was started.

  The difference in light emission between FIG. 22 and FIG. 23 is that in the former, creeping discharge is apt to occur violently in the porous light-emitting body layer 2, but in the latter, the occurrence of creeping discharge is slightly weakened and the luminance is also slightly weakened.

  Further, the reason why the mesh-like second electrode 7 is used in FIG. 23 is to make primary electrons (e −) 24 generated by polarization reversal shown in FIG. This is because, if the electrode 7 having a uniform thickness is formed, the primary electrons (e −) 24 shown in FIG.

  In the case of FIG. 23, the insulating layer 4 was not previously coated with MgO or the like, but colloidal silica used as a binder functioned as the insulating layer 4.

(Embodiment 11)
Next, a case where the pair of electrodes 6 and 7 are both formed at the boundary between the dielectric layer 10 and the porous light emitting layer 2 will be described with reference to FIG. FIG. 24 is a cross-sectional view of light-emitting element 1 in the eleventh embodiment. 6 is a first electrode, 7 is a second electrode, 3 is a phosphor particle, 2 is a porous light emitter layer, and 10 is a dielectric layer. The porous luminescent layer 2 is composed of phosphor particles 3 and ceramic fibers 18 as main components. The phosphor particles 3 are of three types, BaMgAl ₁₀ O ₁₇ : Eu ²⁺ (blue), Zn ₂ SiO ₄ : Mn ²⁺ (green), and YBO ₃ : Eu ³⁺ (red) with an average particle diameter of 2 to 3 μm. In order to obtain a desired light emission, an inorganic compound is used alone or a mixture thereof.

  Next, the manufacturing method and light emitting action of FIG. 24 will be described. First, an Ag paste is applied and baked on one surface of the dielectric sintered body 10 used in FIG. 22 to form a pair of electrodes 6 and 7. Next, a slurry obtained by kneading 45% by mass of phosphor particles, 10% by mass of inorganic fiber powder, 40% by mass of α-terpineol, and 5% by mass of ethyl cellulose was applied, dried, and then heat-treated at 400 to 600 ° C. in the atmosphere. A porous light emitting layer 2 having a thickness of about 50 μm is laminated on the dielectric layer 10. As a result, the light emitting device 1 in which the pair of electrodes 6 and 7 are both formed at the boundary between the dielectric layer 10 and the porous light emitting layer 2 is obtained.

  In the light emitting method, an AC electric field is applied between the first electrode 6 and the second electrode 7 as in the case of FIG. By applying a voltage, primary electrons (e−) 24 are emitted from the dielectric layer 10 by polarization inversion. At this time, ultraviolet rays and visible rays are generated. The primary electrons (e−) collide with the phosphor particles 3 and the ceramic fibers 18 of the porous light emitting layer 2 to generate creeping discharge, and a large number of secondary electrons (e−) 25 are generated. Thereby, electrons and ultraviolet rays generated in an avalanche collide with the emission center of the phosphor, and the phosphor particles 3 are excited to emit light. In addition, the inversion of polarization is repeated in the dielectric layer by the application of an alternating electric field. As a result, electrons are generated and electric charges are injected into the porous light emitting layer, resulting in creeping discharge. Creeping discharge continuously occurs while an electric field is applied. At that time, electrons and ultraviolet rays generated in an avalanche collide with the emission center of the phosphor, and the phosphor particles 3 are excited to emit light.

  Of course, changing the waveform of the alternating electric field applied from a sine wave or sawtooth wave to a rectangular wave, or increasing the frequency from several tens of Hz to several thousand Hz causes more intense electron emission and creeping discharge during polarization reversal, resulting in improved emission brightness. . A burst wave is generated as the voltage value of the alternating electric field is increased. The burst wave is generated when the polarization of the dielectric layer 10 is reversed, and the generated frequency is generated immediately before the peak in the case of a sine wave and at the peak in the case of a sawtooth wave or a rectangular wave, and the emission luminance increases as the peak voltage of the burst wave increases. Improved.

  Once the creeping discharge is started, the discharge is repeated in a chain as described above, and continuously generates ultraviolet rays and visible rays. Therefore, it is necessary to suppress the deterioration of the phosphor particles 3 due to the rays. Is preferably reduced.

  In this embodiment, when an AC power supply is used and a voltage of about 0.7 to 1.2 kV / mm is applied to the thickness of the dielectric, electron emission due to polarization inversion and creeping discharge occur, and then light emission starts. It was done. FIG. 24 also shows a case where a pair of electrodes are both formed at the boundary between the dielectric layer and the porous light emitter layer.

(Embodiment 12)
Referring to FIG. 25, the twelfth embodiment of the present invention, that is, the pair of electrodes 6 and 7 is disposed on the upper surface of the dielectric layer, and the porous luminous body layer 2 is laminated via the pair of electrodes. The case where the other electrode 70 is arrange | positioned on the upper surface of this porous light-emitting body layer 2 is demonstrated.

  FIG. 25 is a cross-sectional view of the light-emitting element 1 in the present embodiment. 6 and 7 are a pair of electrodes, 6 is a first electrode, 7 is a second electrode, 3 is a phosphor particle, 4 is an electrical insulator layer, 2 is a porous phosphor layer, and 10 is a dielectric. Layer and 70 are the third electrode. As shown in FIG. 6, the porous luminescent layer is composed of the phosphor particles 3 or the main component thereof. In the present embodiment, the surface of the phosphor particles 3 is covered with the insulator layer 4. We used what we did.

The phosphor particles 3 are of three types, BaMgAl ₁₀ O ₁₇ : Eu ²⁺ (blue), Zn ₂ SiO ₄ : Mn ²⁺ (green), and YBO ₃ : Eu ³⁺ (red) with an average particle diameter of 2 to 3 μm. In order to obtain a desired light emission, an inorganic compound is used alone or a mixture thereof.

  In the present embodiment, the above-described blue phosphor particles 3 are used, and an insulating inorganic insulator layer 4 made of MgO is formed on the surface thereof. Phosphor particles 11 are added to the Mg precursor complex solution, stirred for a long time, taken out, dried, and then heat-treated at 400 to 600 ° C. in the atmosphere, whereby the uniform coating layer of MgO, that is, the insulator layer 4 is fluorescent. It was formed on the surface of the body particles 3.

First, a method for manufacturing the light emitting element in the twelfth embodiment shown in FIG. 25 will be described. 50% by mass of the phosphor particles 3 coated with the insulator layer 4 and 50% by mass of an aqueous colloidal silica solution are mixed to form a slurry. Next, a dielectric layer 10 having a diameter of 15 mmφ and a thickness of 1 mm on which the first electrode 6 and the second electrode 7 are formed (a plate-like sintered body mainly composed of BaTiO ₃ , and an Ag electrode paste on the upper surface thereof) The first electrode 6 and the second electrode 7 are formed by baking to a thickness of 30 μm), and the slurry is applied via a pair of electrodes, that is, the first electrode 6 and the second electrode 7, and dried. The porous light emitting layer 2 having a thickness of about 100 μm was laminated on the dielectric layer 10 by drying at a temperature of 100 to 150 ° C. for 10 to 30 minutes. Further, a glass (not shown) coated with a transparent electrode (indium-tin oxide alloy (ITO), thickness 0.1 μm) 70 was laminated on the upper surface of the porous luminous body layer 2. Thus, a pair of electrodes 6 and 7 are formed at the boundary between the dielectric layer 10 and the porous light emitter layer 2, and the third electrode 70 is formed on the upper surface of the porous light emitter as shown in FIG. 1 was obtained. At that time, as will be described later, an inorganic fiber plate carrying a phosphor particle powder as a porous light-emitting layer may be used.

  Next, the light emitting action of the light emitting element 1 will be described. An alternating electric field is applied between the first electrode 6 and the second electrode 7. By applying a voltage, primary electrons (e−) 24 shown in FIG. At this time, ultraviolet rays and visible rays are generated. Then, by applying an alternating electric field between at least one of the other electrodes, that is, the electrode 70 and the pair of electrodes, the primary electrons (e−) 24 shown in FIG. Or collides with the insulating layer 4 to cause creeping discharge, and a large number of secondary electrons (e−) 25 shown in FIG. 17 are generated. Thereby, electrons and ultraviolet rays generated in an avalanche collide with the emission center of the phosphor, and the phosphor particles 3 are excited to emit light. In addition, the inversion of polarization is repeated in the dielectric layer by the application of an alternating electric field. As a result, electrons are generated and electric charges are injected into the porous light emitting layer, resulting in creeping discharge. Creeping discharge continuously occurs while an electric field is applied. At that time, electrons and ultraviolet rays generated in an avalanche collide with the emission center of the phosphor, and the phosphor particles 3 are excited to emit light.

  By changing the waveform of the alternating electric field to be applied from a sine wave or a sawtooth wave to a rectangular wave at this time, and by increasing the frequency from several tens of Hz to several thousand Hz, electron emission and creeping discharge during polarization inversion occur more intensely, resulting in light emission. Brightness is improved.

  A burst wave is generated as the voltage value of the alternating electric field is increased. A burst wave is generated when the dielectric layer 10 is inverted in polarization, and the generated frequency is generated just before the peak for a sine wave, and at the peak for a sawtooth wave or a rectangular wave, and the luminance is increased as the burst wave voltage is increased. did. Once the creeping discharge is started, the discharge is repeated in a chain as described above, and continuously generates ultraviolet rays and visible rays. Therefore, it is necessary to suppress the deterioration of the phosphor particles 3 due to the rays. Is preferably reduced.

  In this embodiment, an electric field of about 0.65 to 1.3 kV / mm is applied to the thickness of the dielectric layer 10 at the time of polarization reversal. After that, by applying an alternating electric field of about 0.5 to 1.0 kV / mm to the thickness of the light emitting element 1 using an AC power source, primary electron emission and creeping discharge occur, and then light emission starts. It was done. In addition, although the one where the electric field applied in the case of polarization inversion is large accelerates | stimulates generation | occurrence | production of an electron, when too small, discharge | release of an electron will become insufficient.

  Moreover, the current value at the time of discharge was 0.1 mA or less. Further, when light emission started, light emission continued even when the voltage was reduced to 50 to 80% of the applied voltage, and it was confirmed that the light emission had high brightness, high contrast, high recognizability, and high reliability. It became possible to produce a light emitting device having a light emission efficiency of 2 to 5 lm / W in terms of blue.

  In the twelfth embodiment, driving was performed in the atmosphere, but it was confirmed that light was emitted in the same manner even when performed in oxygen, nitrogen, an inert gas, or a reduced-pressure gas.

The light-emitting element 1 in Embodiment 12 has a structure that is structurally close to inorganic EL (ELD), but the configuration and mechanism are completely different. First, regarding the configuration, as already described in the background art, the phosphor used in the inorganic EL is a light emitter made of a semiconductor as represented by ZnS: Mn ²⁺ , GaP: N, etc. The phosphor particles in Form 1 may be either insulators or semiconductors. That is, even when using semiconductor phosphor particles having an extremely low resistance value, the phosphor particles 3 are uniformly covered with the insulator layer 4 made of an insulating inorganic material as described above, so that a short circuit occurs. The light can be continuously emitted by creeping discharge. In addition, the inorganic EL layer has a thickness of submicron to several μm with respect to the phosphor layer, whereas in the present embodiment, it is a porous body of several μm to several hundred μm. Further, in the present embodiment, the luminous body layer is porous.

  About the porous form, it is packing of the grade which the phosphor particle point-contacted from the result observed with SEM (scanning electron microscope).

Moreover, although the ultraviolet light emission powder used in the current plasma display (PDP) is used as the phosphor particles, ZnS: Ag (blue), ZnS: Cu, Au used in the cathode ray tube (CRT) are used. , Al (green), Y ₂ O ₃ : Eu (red), similar luminescence was confirmed. Since the phosphor for CRT has a low resistance value, it is difficult for creeping discharge to occur. Therefore, it is desirable that the surface of the phosphor is coated with the insulating layer 4 to facilitate the generation of creeping discharge and to emit light.

  The present invention is a light-emitting element that emits light by generating a large amount of secondary electrons due to creeping discharge in an avalanche using primary electrons emitted as a result of polarization reversal of a dielectric. Therefore, if a system having a new function of colliding electrons in addition to the polarization inversion is added to the porous light emitting layer 2, it is expected that the light emission is easily performed.

  In the present embodiment, colloidal silica aqueous solution was used in preparing the slurry of phosphor particles 3, but it was confirmed that the same result was obtained even when an organic solvent was used. A slurry obtained by kneading 45% by mass of α-terpineol and 5% by mass of ethyl cellulose with respect to 50% by mass of the phosphor particles is subjected to screen printing on the surface of the dielectric layer 10, and 400 to 600 ° C., 10 to 10% in the air. By performing heat treatment for 60 minutes, the porous light-emitting layer 23 having a thickness of several μm to several tens of μm can be produced. In this case, if the heat treatment temperature is raised too much, the phosphor is likely to be deteriorated, and therefore temperature management and heat treatment atmosphere management are important. It should be noted that the same result can be obtained even if the organic slurry contains the inorganic fiber 18.

Further, in the present embodiment, using BaTiO ₃ as a _{dielectric, SrTiO 3, CaTiO 3, MgTiO} 3, PZT (PbZrTiO 3), that the same effect by using a dielectric such as PbTiO ₃ is obtained confirmed. In addition, a sintered body may be used for the dielectric layer, or a dielectric layer obtained by a thin film forming process such as sputtering, CVD, vapor deposition, or sol / gel may be used.

In the present embodiment, a sintered body is used as the dielectric layer. However, light emission is possible even when a structure composed of a dielectric powder and a binder is employed. That is, a slurry obtained by kneading 40% by mass of α-terpineol and 5% by mass of ethyl cellulose on a powder obtained by mixing 15% by mass of glass powder with 40% by mass of BaTiO ₃ powder on an Al metal substrate was coated, dried and then air It is also possible to use a dielectric layer composed of dielectric particles and a binder by heat treatment at 400 to 600 ° C.

  In the present embodiment, blue phosphor particles are used, but it has been found that the same effect can be obtained even when red or green is used. The same effect was obtained with mixed particles of blue, red, and green. According to the light emitting device of the present embodiment, since light emission is caused by creeping discharge, a thin film forming process is not used for forming a phosphor layer as in the prior art, and a vacuum system and a carrier multiplication layer are not required. Is simple and easy to process.

  ITO is used for the electrode 70, but it is also possible to use a translucent substrate with copper wiring as an alternative to ITO. The copper wiring is formed in a fine mesh shape, and the aperture ratio (ratio to the whole portion where the wiring is not applied) is 90%, and the light transmission is compared with a translucent substrate having an ITO film. There is almost no inferiority. Also, copper is advantageous because it has a considerably lower resistance than ITO and thus greatly contributes to improvement in luminous efficiency. In addition, it is also possible to use gold, silver, platinum, or aluminum other than copper as a metal for providing fine mesh wiring.

(Embodiment 13)
Next, a manufacturing method and a light emitting action of the thirteenth embodiment will be described with reference to FIG. In the present embodiment, the first electrode 6 is formed on the lower surface and the second electrode 7 is formed on the upper surface with the dielectric layer 10 in between. The description of the same reference numerals as in FIG. 1 may be omitted. Using the same dielectric 10 as that used in the twelfth embodiment, the second electrode 7 is formed at the center of the upper surface and the first electrode 6 is formed on the entire lower surface by printing and baking Ag paste. Each was formed in the same manner as in Form 12. Thereafter, a slurry containing the phosphor particles 3 used in Embodiment 12 is applied to the surface of the second electrode 7 and dried at a temperature of 100 to 150 ° C. for 10 to 30 minutes with a dryer. The layer 10 was laminated with a porous luminescent layer 2 having a thickness of about 100 μm. Thereafter, as in Embodiment 12, a glass plate (not shown) in which a transparent electrode 70 (indium-tin oxide alloy (ITO), thickness 0.1 μm) is applied to the upper surface of the porous luminous body layer 2 is formed. Laminated. As a result, a pair of electrodes 6, 7 are formed on both surfaces of the dielectric layer 10, and the porous light emitting layer 2 is laminated on the upper surface of the dielectric 10 via the second electrode 7, and the porous light emission is further performed. A light emitting device 1 having a cross-sectional structure as shown in FIG. 26 in which a third electrode 70 is formed on the upper surface of the body was obtained.

  In order to drive the light emitting element 1, an AC electric field is applied between the first electrode 6 and the second electrode 7. By applying a voltage, primary electrons (e−) 24 are emitted from the dielectric layer 10 by polarization inversion. At this time, ultraviolet rays and visible rays are generated. Thereafter, by applying an alternating electric field between the third electrode 70 and at least one of the pair of electrodes, primary electrons (e−) collide with the phosphor particles 3 and the insulating layer 4 of the porous light emitting layer 2. Creeping discharge occurs, and a large number of secondary electrons (e−) 25 are generated. Thereby, electrons and ultraviolet rays generated in an avalanche collide with the emission center of the phosphor, and the phosphor particles 3 are excited to emit light. In addition, the inversion of polarization is repeated in the dielectric layer by the application of an alternating electric field. As a result, electrons are generated and electric charges are injected into the porous light emitting layer, resulting in creeping discharge. Creeping discharge continuously occurs while an electric field is applied. At that time, electrons and ultraviolet rays generated in an avalanche collide with the emission center of the phosphor, and the phosphor particles 3 are excited to emit light.

  In the thirteenth embodiment, the waveform of the alternating electric field to be applied is changed from a sine wave or a sawtooth wave to a rectangular wave as in the case of the twelfth embodiment as described above, and the frequency is increased from several tens of Hz to several thousand Hz. As a result, electron emission and creeping discharge during polarization inversion occur more violently, and the light emission luminance is improved. A burst wave is generated as the voltage value of the alternating electric field is increased. The burst wave is generated when the polarization of the dielectric layer 10 is reversed, and the generated frequency is generated immediately before the peak in the case of a sine wave and at the peak in the case of a sawtooth wave or a rectangular wave, and the emission luminance increases as the peak voltage of the burst wave increases. Improved.

  Once creeping discharge is started, the discharge is repeated in a chain and continuously generates ultraviolet light and visible light. Therefore, it is necessary to suppress deterioration of the phosphor particles 3 by light, and the voltage is reduced after the light emission starts. Is preferred.

  In the thirteenth embodiment, by applying a voltage of about 0.84 to 1.4 kV / mm to the first electrode 6 and the second electrode 7 with respect to the thickness of the dielectric layer 10, primary inversion is performed by polarization reversal. Electrons are emitted, and thereafter, either the first electrode 6 or the second electrode 7 and the electrode 70 are alternately connected to the light-emitting element 1 at a thickness of about 0.7 to 1.2 kV / mm. By applying an electric field, creeping discharge occurred and a large amount of secondary electrons were generated, and then light emission was started.

  In addition, the current value during discharge is 0.1 mA or less, and when light emission starts, light emission continues even when the voltage is reduced to 50 to 80% of the applied voltage, resulting in high brightness, high contrast, high recognizability, and high reliability. Luminescence was confirmed. It became possible to produce a light emitting device having a light emission efficiency of 2 to 5 lm / W in terms of blue.

  In the light emitting device of the thirteenth embodiment, as shown in FIG. 26, the second electrode 7 formed on the upper surface of the dielectric layer 10 is not formed on the entire surface but partially formed. This is to prevent primary electrons emitted by polarization reversal from being shielded by the electrodes themselves and to introduce them efficiently into the porous luminescent layer 2. Instead of partially forming the electrode as described above, a mesh electrode may be used as long as electrons generated by polarization reversal are smoothly emitted to the porous light emitter layer 2. Good.

  In FIG. 26, when applying the alternating voltage, the luminance is applied between the first electrode 6 and the third electrode 70 and between the second electrode 7 and the third electrode 70. Almost did not change.

(Embodiment 14)
Next, with reference to FIG. 27, the fourteenth embodiment, that is, the pair of electrodes 6 and 7 are disposed on the lower surface of the dielectric layer 10, and the porous luminous body layer 2 is laminated on the upper surface. A case where the third electrode 70 is disposed on the upper surface of the body layer 2 will be described.

  In the present embodiment, the phosphor particles whose surfaces are covered with the insulating layer 4 are used as in the twelfth embodiment. That is, the phosphor particles formed a uniform coating layer of MgO on the surface.

A method for manufacturing a light-emitting element in this embodiment will be described with reference to FIG. 50% by mass of phosphor particles 11 uniformly coated with the insulator layer 4 and 50% by mass of a colloidal silica aqueous solution are mixed to form a slurry. Next, a dielectric layer 10 having a diameter of 15 mmφ and a thickness of 1 mm on which the first electrode 6 and the second electrode 7 are formed (a plate-like sintered body mainly composed of BaTiO ₃ , and an Ag electrode paste on the lower surface thereof) The slurry is applied to the upper surface of the first electrode 6 and the second electrode 7, which are baked to a thickness of 30 μm, and is 10 to 30 at a temperature of 100 to 150 ° C. using a dryer. The porous luminescent layer 2 having a thickness of about 100 μm was laminated on the dielectric layer 10 by drying for a minute. Thereafter, a glass (not shown) coated with a transparent electrode (indium-tin oxide alloy (ITO), thickness 0.1 μm) 70 was laminated on the upper surface of the porous luminous body layer 2. As a result, a pair of electrodes 6, 7 are formed on the lower surface of the dielectric layer 10, the porous light emitter layer 2 is laminated on the upper surface of the dielectric layer 10, and further, on the upper surface of the porous light emitter layer 2 The light emitting element 1 as shown in FIG. 27 in which the third electrode 70 was formed was obtained.

  Next, the light emitting action of the light emitting element 1 will be described. An alternating electric field is applied between the first electrode 6 and the second electrode 7. By applying a voltage, primary electrons (e−) 24 are emitted from the dielectric layer 10 by polarization inversion. At this time, ultraviolet rays and visible rays are generated. After that, by applying an alternating electric field between the third electrode 70 and at least one of the pair of electrodes 6 and 7, the primary electrons (e−) are converted into the phosphor particles 3 and the insulating layer 4 of the porous light emitting layer 2. , A creeping discharge occurs, and a large number of secondary electrons (e−) 25 are generated. Thereby, electrons and ultraviolet rays generated in an avalanche collide with the emission center of the phosphor, and the phosphor particles 3 are excited to emit light. In addition, the inversion of polarization is repeated in the dielectric layer by the application of an alternating electric field. As a result, electrons are generated and electric charges are injected into the porous light emitting layer, resulting in creeping discharge. Creeping discharge continuously occurs while an electric field is applied. At that time, electrons and ultraviolet rays generated in an avalanche collide with the emission center of the phosphor, and the phosphor particles 3 are excited to emit light.

  Changing the waveform of the alternating electric field applied at this time from a sine wave or sawtooth wave to a rectangular wave, or increasing the frequency from several tens of Hz to several thousand Hz, causes more intense electron emission and creeping discharge during polarization reversal, resulting in emission brightness. Improved.

  A burst wave is generated as the voltage value of the alternating electric field is increased. A burst wave is generated when the dielectric layer 10 is inverted in polarization, and the generated frequency is generated just before the peak for a sine wave, and at the peak for a sawtooth wave or a rectangular wave, and the luminance is increased as the burst wave voltage is increased. did.

  Once the creeping discharge is started, the discharge is repeated in a chain as described above, and continuously generates ultraviolet rays and visible rays. Therefore, it is necessary to suppress the deterioration of the phosphor particles 3 due to the rays. Is preferably reduced.

  In the fourteenth embodiment, at the time of polarization reversal, an electric field of about 0.4 to 0.8 kV / mm is applied to the thickness of the dielectric layer 10, and then the thickness of the light-emitting element 1 is changed using an AC power source. On the other hand, by applying an alternating electric field of about 0.5 to 1.0 kV / mm, primary electron emission and creeping discharge were generated, and then light emission was started. Note that, when the electric field applied in the polarization inversion is larger, the generation of electrons is promoted. However, when the electric field is too small, the electron emission is insufficient.

  Moreover, the current value at the time of discharge was 0.1 mA or less. Further, when light emission started, light emission continued even when the voltage was reduced to 50 to 80% of the applied voltage, and it was confirmed that the light emission had high brightness, high contrast, high recognizability, and high reliability. It became possible to produce a light emitting device having a light emission efficiency of 2 to 5 lm / W in terms of blue.

(Embodiment 15)
A fifteenth embodiment of the present invention will be described with reference to FIG. In the present embodiment, the first electrode 6 is disposed on the lower surface of the dielectric layer 10, the porous light emitter layer 2 is laminated on the upper surface of the dielectric layer 10, and the first electrode 6 is formed on the upper surface of the porous light emitter layer 2. A second electrode 7 and a third electrode 70 are arranged.

  In the fifteenth embodiment, the phosphor particles whose surfaces are covered with the insulating layer 4 are used as in the twelfth embodiment. That is, a uniform coating layer of MgO was formed on the surface of the blue phosphor particles by the same method as in the twelfth embodiment.

Regarding the method for manufacturing a light-emitting element in the fifteenth embodiment, first, a slurry is prepared by mixing 50% by mass of phosphor particles 3 uniformly coated with the insulating layer 4 and 50% by mass of an aqueous colloidal silica solution. Next, the dielectric layer 10 having a diameter of 15 mmφ and a thickness of 1 mm on which the first electrode 6 is formed (a plate-like sintered body mainly composed of BaTiO ₃ , and Ag electrode paste is formed on the lower surface thereof to a thickness of 30 μm. The slurry is applied to the upper surface of the first electrode 6 baked) and dried in a dryer at 100 to 150 ° C. for 10 to 30 minutes, whereby the dielectric layer 10 has a thickness of about 100 μm. The phosphor layer 2 was laminated. Further, an Ag electrode paste is baked on the upper surface of the porous luminous body layer 2 so as to have a thickness of 30 μm, and the second electrode 7 is formed on a part of the surface of the porous luminous body layer 2, and then the transparent electrode A glass plate (not shown) partially coated with 70 (indium-tin oxide alloy (ITO), thickness 0.1 μm) 70 was laminated. As a result, the first electrode 7 of the pair of electrodes is formed on the lower surface of the dielectric layer 10, the porous luminous body layer 2 is laminated on the upper surface of the dielectric layer 10, and the second electrode is formed on the upper surface. The electrode 7 and the third electrode 70 were formed, and the light emitting device 1 having the cross-sectional structure of FIG. 28 was obtained.

  Next, the light emitting action of the light emitting element 1 will be described. An alternating electric field is applied between the first electrode 6 and the second electrode 7. By applying a voltage, primary electrons (e−) 24 are emitted from the dielectric layer 10 by polarization inversion. At this time, ultraviolet rays and visible rays are generated. Thereafter, by applying an alternating electric field between at least one of the other electrodes, that is, the electrode 70 and the pair of electrodes, primary electrons (e−) are applied to the phosphor particles 3 and the insulating layer 4 of the porous light emitting layer 2. Collision occurs, creeping discharge occurs, and many secondary electrons (e−) 25 are generated. Thereby, electrons and ultraviolet rays generated in an avalanche collide with the emission center of the phosphor, and the phosphor particles 3 are excited to emit light. In addition, the inversion of polarization is repeated in the dielectric layer by the application of an alternating electric field. As a result, electrons are generated and electric charges are injected into the porous light emitting layer, resulting in creeping discharge. Creeping discharge continuously occurs while an electric field is applied. At that time, electrons and ultraviolet rays generated in an avalanche collide with the emission center of the phosphor, and the phosphor particles 3 are excited to emit light.

  At this time, the waveform of the alternating electric field applied is changed from a sine wave or sawtooth wave to a rectangular wave, or the frequency is increased from several tens of Hz to several thousand Hz. improves.

  A burst wave is generated as the voltage value of the alternating electric field is increased. A burst wave is generated when the dielectric layer 10 is inverted in polarization, and the generated frequency is generated just before the peak for a sine wave, and at the peak for a sawtooth wave or a rectangular wave, and the luminance is increased as the burst wave voltage is increased. did. Once the creeping discharge is started, the discharge is repeated in a chain as described above, and continuously generates ultraviolet rays and visible rays. Therefore, it is necessary to suppress the deterioration of the phosphor particles 3 due to the rays. Is preferably reduced.

  In the present embodiment, at the time of polarization reversal, an electric field of about 0.5 to 1.0 kV / mm is applied to the thickness of the dielectric layer 10, and then the thickness of the light emitting element 1 using an AC power source. When an alternating electric field of about 0.5 to 1.0 kV / mm was applied, primary electrons were emitted and creeped to discharge, a large amount of secondary electrons were generated, and then light emission was started. Note that, when the electric field applied in the polarization inversion is larger, the generation of electrons is promoted. However, when the electric field is too small, the electron emission is insufficient.

  Moreover, the current value at the time of discharge was 0.1 mA or less. Further, when light emission started, light emission continued even when the voltage was reduced to 50 to 80% of the applied voltage, and it was confirmed that the light emission had high brightness, high contrast, high recognizability, and high reliability. It became possible to produce a light emitting device having a light emission efficiency of 2 to 5 lm / W in terms of blue.

(Embodiment 16)
A light-emitting element including an electron emitter, a porous light emitter, and a pair of electrodes in this embodiment will be described with reference to FIGS. The light-emitting element of the present embodiment is disposed adjacent to an electron emitter so that the porous light emitter includes inorganic phosphor particles and the porous light emitter is irradiated with electrons generated from the electron emitter. Are arranged so that an electric field is applied to at least a part of the porous light emitter. In particular, the electron emitter includes a cathode electrode, a gate electrode, and a Spindt-type emitter interposed between the two electrodes. By applying a gate voltage between the cathode electrode and the gate electrode, the Spindt-type emitter is obtained. A light emitting element that emits light from the emitter by irradiating the emitter with electrons emitted from the emitter will be described.

  FIG. 29 is a cross-sectional view of the light-emitting element in this embodiment. 1 is a light-emitting element having a total thickness of about 2 mm, 2 is a porous light-emitting layer having a thickness of about 30 μm, and 3 is a fluorescent light having an average particle diameter of 2 μm. Body particles, 4 is an insulating layer having a phosphor particle surface thickness of 0.5 μm, 100 is a triangular pyramidal spindt emitter having a bottom surface of 1 μm and a height of 1 μm, 6 is a first electrode having a thickness of 200 nm, 7 Is a second electrode having a thickness of 200 nm, 111 is an anode electrode having a thickness of 150 nm, 112 is a cathode electrode having a thickness of 150 nm, 113 is a gate electrode having a thickness of 200 nm, 116 is an insulating layer having a thickness of 1 μm, and 117 is a thickness. A 1.1 mm substrate 119 is an electron emitter having a thickness of 1.1 mm.

  First, a method for manufacturing a light-emitting element in this embodiment will be described with reference to the drawings. FIGS. 30A to F are views for explaining a method of manufacturing the light emitting device shown in FIG. 29. As shown in FIG. 30A, Au is vapor-deposited on the surface of the glass substrate 117 to form the cathode electrode 112. Ag, Al, or Ni may be deposited on the cathode electrode 112 instead of Au. The substrate 117 may be ceramic other than glass.

Next, to form the insulating layer 116 as shown in FIG. 30B, a glass paste is printed on the cathode electrode 112 by screen printing, dried, and baked at 580 ° C. The insulating layer 116 is formed by coating SiO ₂ on the cathode electrode by sputtering instead of screen-printing the glass paste, developing with UV exposure using a photoresist and a photomask, and then etching. Thus, it is also possible to use a so-called photolithography technique in which the SiO ₂ insulating layer 116 is selectively formed.

  Next, as shown in FIG. 30C, after Al is formed by sputtering, a gate electrode 113 made of Al is formed on the insulating layer 116 by using a photolithography technique. Note that Ni can be used as the gate electrode metal instead of Al.

Thereafter, as shown in FIG. 30E, a Spindt-type emitter is formed in a recess between the gate electrodes 113 by a two-stage vapor deposition method. Specifically, the substrate shown in FIG. 30C is inclined at an angle of about 20 ° and set in a vapor deposition apparatus, and Al ₂ O ₃ as a sacrificial material is vapor-deposited while rotating the substrate. As a result, Al ₂ O ₃ is vapor deposited so as to cover the gate electrode 113 as shown in FIG. 30D, an Al ₂ O ₃ layer 118 having a thickness of 200 nm is formed, and is not vapor deposited on the cathode electrode 112. Subsequently, when Mo is vertically deposited as an emitter, it is deposited so as to enter the recesses between the gate electrodes 113 in a self-aligned manner, and a triangular-pyramidal Mo Spindt-type emitter is formed. Thereafter, the sacrificial layer and Mo on the gate electrode 113 are lifted off, and the Mo emitter is oxidized at the time of vapor deposition. Therefore, by firing at a temperature of 550 ° C., as shown in FIG. A glass substrate in which the mold emitter 100 is formed in the recess between the gate electrodes 113 is obtained. In addition to Mo, metals such as Nb, Zr, Ni, and molybdenum steel can be used for the emitter material, and these emitters can be produced in accordance with the above-described method for producing the Mo emitter. it can.

  The porous luminous body 2 in the present embodiment is composed of phosphor particles 3 or those mainly composed of the phosphor particles 3, and in the present embodiment, the phosphor particles 3 are coated with an insulating layer 4 on the surface. used.

The phosphor particles 3 are, for example, BaMgAl ₁₀ O ₁₇ : Eu ²⁺ (blue), Zn ₂ SiO ₄ : Mn ²⁺ (green), YBO ₃ : Eu ³⁺ (red) having an average particle diameter of 2 to 3 μm. In order to obtain desired luminescence of various types of inorganic compounds, it is possible to use single or a mixture thereof.

  In the present embodiment, the blue phosphor particles 3 are used, and an insulating inorganic insulating layer 4 made of MgO is formed on the surface thereof. Specifically, the phosphor particles 3 are added to the Mg precursor complex solution, stirred for a long time, taken out, dried, and then heat-treated at 400 to 600 ° C. in the atmosphere, whereby a uniform coating layer of MgO, ie, insulation Layer 4 was formed on the surface of phosphor particles 3. 50% by mass of the phosphor particles 3 coated with the above-described insulator layer 4 and 50% by mass of an aqueous colloidal silica solution are mixed to form a slurry.

Next, a ceramic plate made of inorganic fibers (a ceramic fiber plate having a thickness of about 1 mm, Al ₂ O ₃ —CaO—SiO ₂ system and having a porosity of about 45%) is immersed in the slurry to be 100 to 150 ° C. The powder of phosphor particles is supported on the ceramic plate by drying at a temperature for 10 to 30 minutes. Thereafter, an Ag electrode paste was baked to a thickness of 30 μm on both sides to form a first electrode 6 and a second electrode 7. As shown in FIG. 30F, the ceramic fiber board thus obtained is attached to the electron emitter 119 using colloidal silica, water glass, or epoxy resin. Next, by laminating a glass (not shown) coated with a transparent anode electrode (indium-tin oxide alloy (ITO), thickness 15 μm) 111 on the upper surface of the porous luminous body 2, FIG. As shown, a light emitting device 1 is obtained in which a porous light emitter 2 is formed on an electron emitter 119 and electrodes are arranged at predetermined positions. In addition, about the electrode of the light emitting element 1, since the resistance value of transparent electrode ITO used as the anode electrode 111 is high, the 1st electrode 6 and the 2nd electrode 7 are inserted as an auxiliary electrode. Therefore, the anode electrode 111 and the second electrode 7 can be made common, and the gate electrode 113 and the first electrode 6 can be made common.

  Further, in order to prevent the trajectory of electrons emitted from the emitter from deviating greatly, Ag paste may be screen-printed on the gate electrode and a focusing electrode may be installed.

  Next, the light emitting action of the light emitting element 1 in the present embodiment will be described.

  In order to drive the light emitting element 1, first, by applying a DC electric field of 800 V and 80 V between the anode electrode 111 and the cathode electrode 112 and between the gate electrode 113 and the cathode electrode 112 in FIG. Primary electrons are emitted in the direction of the arrows in FIG. A larger applied electric field promotes the generation of electrons, but if it is too small, the electron emission becomes insufficient.

  Primary electrons are emitted as described above, and an alternating electric field is applied between the first electrode 6 and the second electrode 7. The primary electrons emitted as the charges move are multiplied by avalanche, and creeping discharge is generated inside the porous light-emitting body 2. Creeping discharges are continuously generated in a chain, charge transfer occurs around the phosphor particles, and accelerated electrons collide with the emission center to excite the porous luminous body 2 to emit light. At that time, ultraviolet rays and visible rays are also generated, and excitation light is emitted by the ultraviolet rays.

  In addition, by changing the waveform of the alternating electric field to be applied from a sine wave or a sawtooth wave to a rectangular wave, the frequency is further increased from several tens of Hz to several thousand Hz, resulting in more intense electron emission and creeping discharge. Brightness is improved.

  Once creeping discharge is started, the discharge is repeated in a chain and continuously generates ultraviolet light and visible light. Therefore, it is necessary to suppress deterioration of the phosphor particles 3 by light, and the voltage is reduced after the light emission starts. Is preferred.

  Specifically, by applying an alternating electric field of about 0.5 to 1.0 kV / mm to the thickness of the porous light emitter 1 using an AC power source, creeping discharge is generated along with the movement of charges, Subsequently, light emission was started. In addition, although the one where the electric field applied in that case is large promotes generation | occurrence | production of an electron, when too small, discharge | release of an electron will become inadequate.

In addition, the current value during discharge is 0.1 mA or less, and when light emission starts, light emission continues even when the voltage is reduced to 50 to 80% of the applied voltage, resulting in high brightness, high contrast, high recognizability, and high reliability. Luminescence was confirmed. In this way, a light emitting device having a light emission efficiency of 2.0 lm / W, a luminance of 200 cd / m ² , and a contrast of 500: 1 in terms of blue color could be manufactured.

  Although driving was performed in the atmosphere in this embodiment mode, it was confirmed that light was emitted in the same manner even when implemented in oxygen, nitrogen, an inert gas, or a reduced-pressure gas.

The light-emitting element 1 in this embodiment has a structure that is structurally close to inorganic EL (ELD), but has a completely different configuration and mechanism. First, as described in the background art regarding the structure, the phosphor used in the inorganic EL is a light emitter made of a semiconductor as represented by ZnS: Mn ²⁺ , GaP: N, etc. The phosphor particles in may be either an insulator or a semiconductor, but insulating phosphor particles are preferred. That is, even when using semiconductor phosphor particles having extremely low resistance values, as described above, the phosphor particles are continuously covered by the creeping discharge without being short-circuited by covering them uniformly with the insulating layer that is an insulating inorganic substance. This is because light can be emitted. In addition, the inorganic EL layer has a thickness of submicron to several μm with respect to the phosphor layer, whereas in the present embodiment, it is a porous body of several μm to several hundred μm. Furthermore, the feature of this embodiment is that the light emitter is porous.

  About the porous form, it is packing of the grade which the phosphor particle point-contacted from the result observed with SEM (scanning electron microscope).

Moreover, although the ultraviolet light emission powder used in the current plasma display (PDP) is used as the phosphor particles, ZnS: Ag (blue), ZnS: Cu, Au used in the cathode ray tube (CRT) are used. , Al (green), Y ₂ O ₃ : Eu (red), similar luminescence was confirmed.

  The present invention is a light emitting element in which creeping discharge is generated in an avalanche based on electrons emitted from the electron emitter 119 and light emission occurs. The novel electron emitter for irradiating electrons is a porous light emitter 2 of the present invention. It is presumed that light can be easily emitted if combined with the above.

  In the present embodiment, colloidal silica aqueous solution was used in preparing the slurry of phosphor particles 3, but it was confirmed that the same result was obtained even when an organic solvent was used. A slurry obtained by kneading 45% by mass of α-terpineol and 5% by mass of ethyl cellulose with respect to 50% by mass of the phosphor particles may be prepared, immersed in the ceramic fiber plate, and degreased by heat treatment.

  In addition, although blue phosphor particles are used in the present embodiment, it has been found that similar results can be obtained even when red or green is used. Similar results were obtained with mixed particles of blue, red, and green. In the present embodiment, an alternating electric field is applied between the first electrode 6 and the second electrode 7, but a DC electric field may be used.

  According to the light emitting device of the present embodiment, since light emission is caused by creeping discharge, the thin film forming process is hardly used for the conventional phosphor layer formation, and a vacuum system and a carrier multiplication layer are not required. Therefore, the structure is simple and processing is easy.

(Embodiment 17)
A light-emitting element including an electron emitter, a porous light emitter, and a pair of electrodes in this embodiment will be described with reference to FIGS. 31 and 32A-G. The light-emitting element of the present embodiment is disposed adjacent to an electron emitter so that the porous light emitter includes inorganic phosphor particles and the porous light emitter is irradiated with electrons generated from the electron emitter. These electrodes are installed so that an electric field is applied to at least a part of the porous light emitter. In particular, the electron emitter comprises a cathode electrode, a gate electrode, and a carbon nanotube interposed between the two electrodes, and is emitted from the carbon nanotube by applying a gate voltage between the cathode electrode and the gate electrode. A light-emitting element that irradiates a porous light emitter with emitted electrons to emit light from the porous light emitter will be described.

  FIG. 31 is a cross-sectional view of the light-emitting element in this embodiment. 1 is a light-emitting element, 2 is a porous light emitter, 3 is a phosphor particle, 4 is an insulating layer, 6 is a first electrode, and 7 is a second. , 111 is an anode electrode, 112 is a cathode electrode, 113 is a gate electrode, 116 is an insulating layer, 117 is a substrate, and 127 is a carbon nanotube.

  First, a method for manufacturing a light-emitting element in this embodiment will be described with reference to the drawings. 32A-G are views for explaining a method of manufacturing the light emitting device shown in FIG. 31. As shown in FIG. 32A, a method of forming cathode electrode 112 by vapor-depositing Au on the surface of glass substrate 117. Is performed in the same manner as in the sixteenth embodiment. Note that the substrate in the present embodiment may be ceramic other than glass. Next, the method for forming the insulating layer 116 on the cathode electrode 112 as shown in FIG. 32B and the method for forming the gate electrode 113 made of Al on the insulating layer 116 as shown in FIG. This is performed in the same manner as in the sixteenth embodiment.

Next, a paste 125 obtained by kneading 45% by mass of α-terpineol and 5% by mass of ethyl cellulose with respect to 50% by mass of the carbon nanotubes is dropped into a recess between the gate electrodes 113 by screen printing as shown in FIG. 32D. After drying, a heat treatment is performed at 400 ° C. in an N ₂ atmosphere, so that the carbon nanotubes 127 are deposited in the depressions as shown in FIG. 32E. Thereafter, when the carbon nanotube is aligned by the method of adhering the adhesive film to the surface of the carbon nanotube and then peeling off, the vertically aligned carbon nanotube, which is a preferred form as an electron emitter as shown in FIG. 32F, is obtained. Is formed.

  It is also possible to pattern the carbon nanotubes by coating a photosensitive carbon nanotube paste on the substrate on which the gate electrode is formed, and exposing and developing using a photomask. Further, a laser irradiation method can be used as a process for vertical alignment of the carbon nanotubes. Specifically, after forming a carbon nanotube film using the above-mentioned paste containing carbon nanotubes, the carbon resin is burned out by irradiating a laser to burn out the carbon nanotubes on the film surface. It is a method of exposing and raising.

Next, in the same manner as in the sixteenth embodiment, a ceramic plate made of inorganic fibers (thickness of about 1 mm, Al ₂ O ₃ —CaO—SiO ₂ type ceramic fiber plate with a porosity of about 45%) is used. A material carrying the phosphor particle powder was prepared, and Ag electrode paste was baked to a thickness of 30 μm on both sides to form the first electrode 6 and the second electrode 7. The ceramic fiber board thus obtained is attached to the electron emitter 119 using colloidal silica, water glass or epoxy resin as shown in FIG. 32G. Thereafter, by laminating glass (not shown) coated with a transparent anode electrode (indium-tin oxide alloy (ITO), thickness 15 μm) 111 on the upper surface of the porous luminous body 2, electron emission is performed. The light-emitting element 1 in the present embodiment as shown in FIG. 31 is obtained, in which the porous light-emitting body 2 is formed on the body 119 and electrodes are arranged at predetermined positions.

  Next, the light emitting action of the light emitting element 1 will be described. In order to drive the light emitting element 1, first, a DC electric field of 750 and 80 V is applied between the anode electrode 111 and the cathode electrode 112 and between the gate electrode 113 and the cathode electrode 112 in FIG. Electrons are emitted in the direction of the arrow.

  Electrons are emitted as described above, and an alternating electric field is applied between the first electrode 6 and the second electrode 7. Electrons emitted with the movement of electric charge are multiplied by avalanche, and creeping discharge is generated inside the porous light-emitting body 2. Creeping discharges are continuously generated in a chain, charge transfer occurs around the phosphor particles, and accelerated electrons collide with the emission center to excite the porous luminous body 2 to emit light. At that time, ultraviolet rays and visible rays are also generated, and excitation light is emitted by the ultraviolet rays.

  Moreover, by changing the waveform of the alternating electric field to be applied from a sine wave or a sawtooth wave to a rectangular wave, the frequency is further increased by several tens of Hz to several thousand Hz, resulting in more intense electron emission and creeping discharge. improves.

  Once the creeping discharge is started, the discharge is repeated in a chain manner as described above, and continuously generates ultraviolet rays and visible rays. Therefore, it is necessary to suppress the deterioration of the phosphor particles 3 due to the rays. It is preferable to reduce the voltage.

  Specifically, by applying an alternating electric field of about 0.5 to 1.0 kV / mm with respect to the thickness of the porous luminous body 1 using an AC power source, creeping discharge is generated along with the movement of charges, Subsequently, light emission was started. In addition, although the one where the electric field applied in that case is large promotes generation | occurrence | production of an electron, when too small, discharge | release of an electron will become inadequate.

  Further, the current value during discharge was 0.1 mA or less, and when light emission started, it was confirmed that the light emission continued even when the voltage was reduced to 50 to 80% of the applied voltage.

  Although driving was performed in the atmosphere in this embodiment mode, it was confirmed that light was emitted in the same manner even when implemented in oxygen, nitrogen, an inert gas, or a reduced-pressure gas.

  In addition, although blue phosphor particles are used in the present embodiment, it has been found that similar results can be obtained even when red or green is used. Similar results were obtained with mixed particles of blue, red, and green.

  According to the light emitting device of the present embodiment, since light emission is caused by creeping discharge, the thin film forming process is hardly used for the conventional phosphor layer formation, and a vacuum system and a carrier multiplication layer are not required. Therefore, the structure is simple and processing is easy.

(Embodiment 18)
A light-emitting element including an electron emitter, a porous light emitter, and a pair of electrodes in this embodiment will be described with reference to FIGS. 33 and 34A-C. The light-emitting element of the present embodiment is disposed adjacent to an electron emitter so that the porous light emitter includes inorganic phosphor particles and the porous light emitter is irradiated with electrons generated from the electron emitter. These electrodes are installed so that an electric field is applied to at least a part of the porous light emitter. In particular, the electron emitter is a surface conduction electron-emitting device, and a fine gap is provided in the metal oxide film, and an electric field is applied to the gap by applying a voltage to an electrode previously provided in the metal oxide film. A light-emitting element obtained by irradiating a porous light emitter with electrons generated from the gap will be described.

  FIG. 33 is a cross-sectional view of a light-emitting element in this embodiment. 1 is a light-emitting element, 2 is a porous light emitter, 3 is a phosphor particle, 4 is an insulating layer, 6 is a first electrode, and 7 is a second. , 117 is a substrate, 130 is a gap, 131 is a PdO ultrafine particle film, and 132 is a Pt electrode.

  First, a method for manufacturing a light-emitting element in this embodiment will be described with reference to the drawings. 34A to 34C are views for explaining a method of manufacturing the light emitting element in the present embodiment shown in FIG. As shown in FIG. 34A, a Pt paste is patterned on the surface of the ceramic substrate 17 by screen printing to form a Pt electrode 132 on the substrate with a small gap. Next, as shown in FIG. 34B, the Pt electrode 132 is covered with PdO ink so as to be bridged by inkjet printing, and baked to form a PdO ultrafine particle film 131 on the Pt electrode 132. Subsequently, by performing electrical treatment, cracks are generated in the PdO ultrafine particle film 31 to form a fine gap 30 of about 10 nm as shown in FIG. 34C. Since the electron emitter of this embodiment is configured in this manner, the number of steps is relatively small without using a photolithography process, which is extremely excellent in terms of economy and enlargement of the display.

Next, in the same manner as in the sixteenth embodiment described above, a ceramic plate made of inorganic fibers (a ceramic fiber plate having a thickness of about 1 mm, Al ₂ O ₃ —CaO—SiO ₂ system and a porosity of about 45%). A material carrying the phosphor particle powder is prepared, and Ag electrode paste is baked to a thickness of 30 μm on both sides to form the first electrode 6 and the second electrode 7 respectively. As shown in FIG. 33, the obtained ceramic fiber board is attached to the electron emitter 119 using colloidal silica, water glass, or epoxy resin.

  In this way, the light emitting device 1 according to the present embodiment as shown in FIG. 33 in which the porous light emitter 2 is disposed on the electron emitter 119 and the electrodes are arranged at predetermined positions is obtained.

  Next, the light emitting action of the light emitting element 1 will be described. In order to drive the light emitting element 1, first, when a DC voltage of 12 to 16 V is applied between the two pt electrodes 132 shown in FIG. 33, the tunnel effect through one of the electrodes passes through a slit of 10 nm in the direction of the arrow in the figure. Electrons are emitted and irradiated onto the porous light emitter 2.

  Electrons are emitted as described above, and an alternating electric field is applied between the first electrode 6 and the second electrode 7. Electrons emitted with the movement of electric charge are multiplied by avalanche, and creeping discharge is generated inside the porous light-emitting body 2. Creeping discharges are continuously generated in a chain, charge transfer occurs around the phosphor particles, and accelerated electrons collide with the emission center to excite the porous luminous body 2 to emit light. At that time, ultraviolet rays and visible rays are also generated, and excitation light is emitted by the ultraviolet rays.

  Moreover, by changing the waveform of the alternating electric field to be applied from a sine wave or a sawtooth wave to a rectangular wave, the frequency is further increased by several tens of Hz to several thousand Hz, resulting in more intense electron emission and creeping discharge. improves.

  Once the creeping discharge is started, the discharge is repeated in a chain manner as described above, and continuously generates ultraviolet rays and visible rays. Therefore, it is necessary to suppress the deterioration of the phosphor particles 3 due to the rays. It is preferable to reduce the voltage.

  Specifically, by applying an alternating electric field of about 0.5 to 1.0 kV / mm to the thickness of the porous light emitter 2 using an AC power source, charge transfer and creeping discharge occur, Subsequently, light emission was started. In addition, although the one where the electric field applied in that case is large promotes generation | occurrence | production of an electron, when too small, discharge | release of an electron will become inadequate.

  Further, the current value during discharge was 0.1 mA or less, and when light emission started, it was confirmed that the light emission continued even when the voltage was reduced to 50 to 80% of the applied voltage.

  Although driving was performed in the atmosphere in this embodiment mode, it was confirmed that light was emitted in the same manner even when implemented in oxygen, nitrogen, an inert gas, or a reduced-pressure gas.

Moreover, although the ultraviolet light emission powder used in the current plasma display (PDP) is used as the phosphor particles, ZnS: Ag (blue), ZnS: Cu, Au used in the cathode ray tube (CRT) are used. , Al (green), Y ₂ O ₃ : Eu (red), similar luminescence was confirmed.

  The present invention is a light-emitting element in which creeping discharge is generated in an avalanche based on electrons emitted from the electron emitter 119 and light is emitted, and a device having a novel function of irradiating electrons is added to the porous light emitter 2. It is expected to emit light easily.

  In addition, although blue phosphor particles are used in the present embodiment, it has been found that similar results can be obtained even when red or green is used. Similar results were obtained with mixed particles of blue, red, and green.

  According to the light emitting device of the present embodiment, since light emission is caused by creeping discharge, the thin film forming process is hardly used for the conventional phosphor layer formation, and a vacuum system and a carrier multiplication layer are not required. Therefore, the structure is simple and processing is easy.

Instead of using the electron emitter described in this embodiment mode, an electron can be emitted by sandwiching an insulating layer between two electrodes as a similar electron emitter and applying an electric field to both electrodes. . Specifically, when an Ir—Pt—Au alloy is used as the upper electrode, Al is used as the cathode electrode, and Al ₂ O ₃ is used as the insulating layer, the insulating layer is sandwiched between two electrodes and an electric field is applied between the electrodes. Since electrons are emitted from the electrode, a light-emitting element can be manufactured by using such an electron emitter to irradiate the porous light emitter.

(Embodiment 19)
A light-emitting element including an electron emitter, a porous light emitter, and a pair of electrodes in this embodiment will be described with reference to FIGS. 35 and 36A-D. The light-emitting element of the present embodiment is disposed adjacent to an electron emitter so that the porous light emitter includes inorganic phosphor particles and the porous light emitter is irradiated with electrons generated from the electron emitter. Are arranged so that an electric field is applied to at least a part of the porous light emitter. In particular, the electron emitter comprises a polysilicon thin film, silicon microcrystal, and an oxide film formed on the surface of the silicon microcrystal, and irradiates the porous emitter with electrons emitted by applying a voltage to the electron emitter. A light emitting element that emits light from the porous light emitter will be described.

  FIG. 35 is a cross-sectional view of the light-emitting element in this embodiment. 1 is a light-emitting element, 2 is a porous light emitter, 3 is a phosphor particle, 4 is an insulating layer, 6 is a first electrode, and 7 is a second. , 112 is a cathode electrode, 119 is an electron emitter, 141 is a metal thin film electrode, 145 is polysilicon, and 147 is silicon microcrystal. 36A to 36D are views for explaining a method of manufacturing the light emitting device shown in FIG. 35. As shown in FIG. 36A, Au is vapor-deposited on the surface of a glass substrate 143, and the cathode is formed by photolithography. The electrode 112 is formed by patterning. Subsequently, as shown in FIG. 36B, columnar polysilicon is formed by plasma CVD.

  Next, as shown in FIG. 36C, the polysilicon 145 on the cathode electrode 112 is made porous to form nanosilicon microcrystals 147. Specifically, when a substrate is immersed in a mixed solution of hydrofluoric acid and ethyl alcohol, the substrate is used as a positive electrode and Pt as a counter electrode is used as a negative electrode, and a voltage is applied between them, silicon microcrystals are formed on the cathode electrode 112. The

  Next, the substrate 143 is washed and immersed in a sulfuric acid solution. When a voltage is applied with the substrate as the positive electrode and Pt as the negative electrode, both the surfaces of the polysilicon 145 and the silicon microcrystal are oxidized. Finally, as shown in FIG. 36D, a metal thin film electrode 141 such as an Au alloy or an Ag alloy is provided by sputtering, and patterning is performed by photoetching, whereby an electron emitter 119 is obtained. As described above, the manufacturing method of the electron emitter in the present embodiment has a relatively small number of steps, and can be manufactured using a wet process, so that it is excellent in economic efficiency.

Next, in the same manner as in the eleventh embodiment, an inorganic fiber ceramic plate (thickness of about 1 mm, Al ₂ O ₃ —CaO—SiO ₂ -based ceramic fiber plate with a porosity of about 45%) is used. A material carrying the phosphor particle powder was prepared, and Ag electrode paste was baked to a thickness of 30 μm on both sides to form the first electrode 6 and the second electrode 7. As shown in FIG. 35, the ceramic fiber board thus obtained is attached to the electron emitter 119 using colloidal silica, water glass or epoxy resin.

  Through the above-described steps, the light-emitting element 1 of FIG. 35 in the present embodiment in which the porous light-emitting body 2 is disposed on the electron-emitting body 119 and the electrode is disposed at a predetermined position is obtained.

  Next, the light emitting action of the light emitting element 1 will be described. In order to drive the light emitting element 1, first, by applying a DC electric field of 15 to 20 V between the metal thin film electrode 141 and the cathode electrode 112 in FIG. 35, electrons tunnel through the silicon microcrystals from the cathode electrode, It is accelerated by the oxide film and released into the porous light emitter.

  Electrons are emitted as described above, and an alternating electric field is applied between the first electrode 6 and the second electrode 7. Electrons emitted with the movement of electric charge are multiplied by avalanche, and creeping discharge is generated inside the porous light-emitting body 2. Creeping discharges are continuously generated in a chain, charge transfer occurs around the phosphor particles, and accelerated electrons collide with the emission center to excite the porous luminous body 2 to emit light. At that time, ultraviolet rays and visible rays are also generated, and excitation light is emitted by the ultraviolet rays.

  Furthermore, by changing the waveform of the alternating electric field to be applied from a sine wave or a sawtooth wave to a rectangular wave, electron emission and creeping discharge are more severely generated by further increasing the frequency from several tens of Hz to several thousand Hz. Will improve.

  Once the creeping discharge is started, the discharge is repeated in a chain manner as described above, and continuously generates ultraviolet rays and visible rays. Therefore, it is necessary to suppress the deterioration of the phosphor particles 3 due to the rays. It is preferable to reduce the voltage.

  In the present embodiment, charge transfer and creeping discharge are generated by applying an alternating electric field of about 0.5 to 1.0 kV / mm to the thickness of the porous luminous body 2 using an AC power source. Subsequently, light emission was started. In addition, although the one where the electric field applied in that case is large accelerates | stimulates an electron generation, when too small, an electron generation will become inadequate.

  Further, the current value during discharge was 0.1 mA or less, and when light emission started, it was confirmed that the light emission continued even when the voltage was reduced to 50 to 80% of the applied voltage.

  Although driving was performed in the atmosphere in this embodiment mode, it was confirmed that light was emitted in the same manner even when implemented in oxygen, nitrogen, an inert gas, or a reduced-pressure gas.

  In addition, although blue phosphor particles are used in the present embodiment, it has been found that similar results can be obtained even when red or green is used. Similar results were obtained with mixed particles of blue, red, and green.

  According to the light emitting device of the present embodiment, since light emission is caused by creeping discharge, the thin film forming process is hardly used for the conventional phosphor layer formation, and a vacuum system and a carrier multiplication layer are not required. Therefore, the structure is simple and processing is easy.

(Embodiment 20)
With reference to FIGS. 37A to 37C, an electron emitter constituting a part of the light emitting element in this embodiment will be described. The electron emitter in the present embodiment uses a whisker emitter instead of the carbon nanotube described above.

  FIGS. 37A to 37C are diagrams for explaining a method of manufacturing an electron emitter in the present embodiment, where 112 is a cathode electrode, 113 is a gate electrode, 116 is an insulating layer, 117 is a substrate, and 155 is an organometallic complex gas. Reference numeral 157 denotes a whisker emitter. As shown in FIG. 37A, Au is vapor-deposited on the surface of a glass substrate 117 to form a cathode electrode 112, an insulating layer 116 is formed thereon, and a gate electrode 113 is formed on the insulating layer 116. This is performed in the same manner as in the nineteenth embodiment. Next, as shown in FIG. 37B, whisker emitters are formed by CVD. Specifically, a large amount of Al: Zn organometallic complex gas 155 is showered toward the cathode electrode. At this time, when the amount of gas exceeds a certain amount, the thermally oxidized Al: ZnO film grows in the vertical direction. Furthermore, when the source gas is increased, the tip of the film becomes sharp and sharpens to the level of several nanometers. For this reason, Al: ZnO whiskers are patterned and vertically aligned in a self-aligning manner. By forming the film while paying attention to the input amount of the source gas, the film formation temperature, and the film formation time, an electron emitter having an Al: ZnO whisker emitter 157 is obtained as shown in FIG. 37C.

Next, a ceramic plate made of inorganic fibers by the same method as in the eleventh embodiment (ceramic fiber plate having a thickness of about 1 mm, Al ₂ O ₃ —CaO—SiO ₂ system and a porosity of about 45%) A porous luminous body having phosphor particle powder supported thereon is prepared, and a predetermined electrode is provided and laminated on the above-mentioned electron-emitting body, whereby a light emitting element (not shown) is obtained.

  Next, the light emitting action of the light emitting element 1 will be described. In order to drive the light emitting element, first, electrons are emitted from the whisker emitter by applying a DC electric field of 850 and 80 V between the anode electrode and the cathode electrode and between the gate electrode and the cathode electrode, respectively.

  Electrons are emitted as described above, and an alternating electric field is applied between the first electrode and the second electrode. The electrons emitted as the charges move are multiplied in an avalanche manner, and creeping discharge is generated inside the porous luminous body. Creeping discharges are continuously generated in a chain, charge transfer occurs around the phosphor particles, and accelerated electrons collide with the emission center to excite the porous luminous body to emit light. At that time, ultraviolet rays and visible rays are also generated, and excitation light is emitted by the ultraviolet rays.

  In addition, by changing the waveform of the alternating electric field to be applied from a sine wave or a sawtooth wave to a rectangular wave, the frequency is further increased from several tens of Hz to several thousand Hz, resulting in more intense electron emission and creeping discharge. Will improve.

  Once the creeping discharge is started, the discharge is repeated in a chain manner as described above, and continuously generates ultraviolet rays and visible rays. Therefore, it is necessary to suppress the deterioration of the phosphor particles 3 due to the rays. It is preferable to reduce the voltage.

  Specifically, by applying an alternating electric field of about 0.5 to 1.0 kV / mm to the thickness of the porous light emitter using an AC power source, charge transfer and creeping discharge occur, Flashing started. Note that, when the electric field applied at this time is larger, the generation of electrons is promoted. Further, the current value during discharge was 0.1 mA or less, and when light emission started, it was confirmed that the light emission continued even when the voltage was reduced to 50 to 80% of the applied voltage.

  Although driving was performed in the atmosphere in this embodiment mode, it was confirmed that light was emitted in the same manner even when implemented in oxygen, nitrogen, an inert gas, or a reduced-pressure gas.

  In addition, although blue phosphor particles are used in the present embodiment, it has been found that similar results can be obtained even when red or green is used. Similar results were obtained with mixed particles of blue, red, and green.

  According to the light emitting device of the present embodiment, since light emission is caused by creeping discharge, the thin film forming process is hardly used for the conventional phosphor layer formation, and a vacuum system and a carrier multiplication layer are not required. Therefore, the structure is simple and processing is easy.

  In the above-described electron emitter, silicon carbide or a diamond thin film can be used instead of the whisker emitter. A gate voltage is applied between the cathode electrode and the gate electrode in these materials as well. Thus, electrons can be emitted therefrom and irradiated onto the porous light emitter.

(Embodiment 21)
In this embodiment, with reference to FIGS. 38 to 40, a light emitting element including an electron emitter, a porous light emitter, and a pair of electrodes, in particular, a pair installed for applying an electric field to the porous light emitter. The electrode will be described.

  38 to 40 are cross-sectional views of a porous light emitter constituting a part of the light emitting element, 2 is a porous light emitter, 3 is a phosphor particle, 4 is an insulating layer, 6 is a first electrode, and 7 Is the second electrode. The porous luminescent material shown in FIG. 38 uses the blue phosphor particles 3 and the insulating inorganic insulating layer 4 made of MgO formed on the surface thereof, as in the case of the sixteenth embodiment. . Specifically, the phosphor particles are added to the Mg precursor complex solution, stirred for a long time, taken out, dried, and then heat-treated at 400 to 600 ° C. in the air, thereby forming a uniform coating layer of MgO, that is, insulating. The layer is formed on the surface of the phosphor particles. 50% by mass of the phosphor particles 3 coated with the above-described insulator layer 4 and 50% by mass of an aqueous colloidal silica solution are mixed to form a slurry.

Next, a ceramic plate made of inorganic fibers (a ceramic fiber plate having a thickness of about 1 mm, Al ₂ O ₃ —CaO—SiO ₂ system and having a porosity of about 45%) is immersed in the slurry to be 120 to 150 ° C. The phosphor particles are supported on the ceramic plate by drying at a temperature for 10 to 30 minutes. Thereafter, as shown in FIG. 38, Ag electrode paste was baked on the upper surface to a thickness of 30 μm to form the first electrode 6 and the second electrode 7. By sticking the ceramic fiber plate thus obtained to the electron emitter using colloidal silica, water glass or epoxy resin, the light emitting device (not shown) of the present invention is obtained.

  Further, in the first embodiment described above, as shown in FIG. 38, the first electrode 6 and the second electrode 7 are formed so as to face the upper surface and the lower surface of the porous luminous body. Thus, it is also possible to form it on both upper and lower sides.

  Next, as shown in FIG. 40, the case where both the 1st electrode 6 and the 2nd electrode 7 are embedded and formed in the porous light-emitting body 2 is demonstrated. The phosphor particles 3 whose surfaces were coated with an insulating layer 4 made of MgO were mixed with 5% by mass of polyvinyl alcohol and granulated, and then molded into a plate shape at a pressure of about 50 MPa using a molding die. Next, heat treatment was performed at 450 to 1200 ° C. for 2 to 5 hours in a nitrogen atmosphere to produce a plate-like porous light emitter 2. When the apparent porosity of the porous luminescent material is less than 10%, creeping discharge occurs only on the surface of the luminescent material, resulting in low luminous efficiency. Therefore, a porous luminescent material having a porous structure with an apparent porosity of 10% or more is desirable. Also, if the pores of the illuminant are too large and the porosity is excessive, it is expected that the luminous efficiency will decrease and creeping discharge will be less likely to occur. Ideally, the apparent porosity is 10% or more. Less than 100% is preferred.

  Ag electrode paste was baked to a thickness of 30 μm on the surface of the plate-like porous light-emitting body 2 obtained as described above to form the first electrode 6 and the second electrode 7. Thereafter, the surface of the above-mentioned porous luminous body on which an electrode is formed by mixing 50 mass% of the phosphor particles 3 coated with the above-described insulating layer 4 and 50 mass% of a colloidal silica aqueous solution to form a slurry. And dried at a temperature of 120 to 150 ° C. for 10 to 30 minutes. By doing so, a porous light emitter in which both the first electrode 6 and the second electrode 7 are embedded as shown in FIG. 40 is obtained.

The method of forming the MgO insulating layer on the surface of the phosphor particles may be performed as follows. First, Mg (OC ₂ H ₅ ) ₂ powder (1 mole ratio), which is a metal alkoxide, is converted from CH ₃ COOH (10 mole ratio), H ₂ O (50 mole ratio) and C ₂ H ₅ OH (50 mole ratio). The resulting solution is mixed well with stirring at room temperature to prepare an almost transparent sol-gel solution. Further, phosphor particles such as BaMgAl ₁₀ O ₁₇ : Eu ²⁺ (blue), Zn ₂ SiO ₄ : Mn ²⁺ (green), YBO ₃ : Eu ³⁺ (red) having an average particle diameter of 2 to 3 μm ( 2 mole ratio) is added little by little to the above sol-gel solution while stirring. After this operation was continued for one day, the mixed solution was centrifuged, and the powder was taken in a ceramic vat and dried at 150 ° C. overnight.

  Next, the dried powder was calcined at 400 to 600 ° C. for 2 to 5 hours in the air, whereby a uniform insulating layer made of MgO could be formed on the surface of the phosphor particles.

  The thickness of the insulating layer was 0.1 to 2.0 μm as a result of observing the phosphor particles with a transmission electron microscope (TEM). As described above, the insulating layer may be coated by immersing phosphor particles in a metal alkoxide solution, using a metal complex solution as described above, or performing deposition, sputtering, or CVD. Is also possible.

The metal oxide used as the insulating layer is Y ₂ O ₃ , Li ₂ O, MgO, CaO, BaO, SrO, Al ₂ O ₃ , SiO ₂ , MgTiO ₃ , CaTiO ₃ , BaTiO ₃ , SrTiO ₃ , ZrO _2. , TiO ₂ , B ₂ O _{3 and the} like are known, and it is desirable to form an insulating layer using at least one of these.

  In particular, when forming an insulating layer by a vapor phase method, it is desirable to pre-process phosphor particles in a nitrogen atmosphere at 200 to 500 ° C. for about 1 to 5 hours. If the insulating layer is formed in such a state, the life characteristics such as a decrease in luminance and a shift in emission spectrum are affected, which is not preferable.

  Although the thickness of the insulating layer is about 0.1 to 2.0 μm, it is determined in consideration of the average particle size of the phosphor particles and the occurrence of creeping discharge, and the average particle size is in the submicron order. Is considered to require the formation of a very thin coating layer.

  When the thickness of the insulating layer is increased, it is not preferable from the viewpoint of shift of emission spectrum, reduction of luminance, and shielding of electrons. Further, it is expected that the continuous generation of creeping discharge becomes somewhat difficult as the insulating layer becomes thinner. Therefore, the relationship between the average particle diameter of the phosphor particles and the thickness of the insulating layer is preferably in the range of 1/10 to 1/500 of the latter with respect to the former.

  Moreover, it is preferable that the phosphor particles are each coated with an insulating layer made of a metal oxide, but actually, a few phosphor particles are coated in an aggregated state. Thus, even if the phosphor particles are coated in a slightly aggregated state, there is almost no effect on the light emission.

  When the light-emitting device of the present invention was manufactured using the porous light-emitting body thus obtained, it was confirmed that a light-emitting device with high luminance, high contrast, high recognizability, and high reliability was obtained.

It should be noted that when the phosphor particles 3 whose surface is coated with the insulating layer 4 are produced, the porous light-emitting body 2 can be produced by mixing the insulating fibers 18 in order to promote the occurrence of creeping discharge. . As the insulating fiber 18 used at that time, SiO ₂ —Al ₂ O ₃ —CaO-based electrically insulating fiber or the like is suitable. FIG. 41 shows a schematic diagram of a cross section of the porous luminous body thus obtained. Moreover, it is also possible to use a mixture of the phosphor particles 3 and the insulating fibers 18 as a simple method instead of heat treating the phosphor particles 3 coated with the insulating layer 4. FIG. 42 is a schematic view of a cross section of a porous luminescent material obtained from a mixture of phosphor particles 3 and insulating fibers 18.

(Embodiment 22)
In this embodiment, an outline of the structure of a field emission display (FED) manufactured by combining the above-described porous light emitter of the present invention and an electron emitter including a Spindt emitter will be described with reference to the drawings.

  FIG. 43 is an exploded perspective view of the main part of the field emission display in the present embodiment, and FIG. 44 is a cross-sectional view of an array of light emitting elements using Spindt-type emitters in the present embodiment. In FIG. 43, 2 is a porous light emitter, 119 is an electron emitter, 170 is a field emission display, 171 is a gate line, 172 is a cathode line, 173 is an anode substrate, and 174 is a cathode substrate. 44, 1 is a light emitting element, 2 is a porous light emitter, 3 is a phosphor particle, 4 is an insulating layer, 100 is a Spindt emitter, 111 is an anode electrode, 112 is a cathode electrode, 113 is a gate electrode, and 116 is An insulator, 117 is a substrate, and 175 is a spacer.

  As shown in FIG. 43, in the field emission display 170 in the present embodiment, an anode substrate 173 having a porous light emitter 2 is laminated on a cathode substrate 174 on which an electron emitter 119 is mounted. The cathode substrate 174 is formed with two layers of wirings of a gate line 171 and a cathode line 172 orthogonal to each other, and an electron emitter 119 is formed at the intersection. By doing so, the field emission display 170 according to the present embodiment can display a two-dimensional image on the phosphor screen without deflecting the electron beam unlike the CRT.

  As described in the sixteenth embodiment, in the electron emitter 119 using the Spindt-type emitter 100, the conical Spindt-type emitter 100 and the gate electrode for applying the electron extraction voltage formed so as to surround the conical Spindt-type emitter 100 are used. 113.

  When electrons are emitted from the emitter, a positive potential is applied to the gate and a negative potential is applied to the emitter. A strong electric field is concentrated at the tip of the conical emitter, and electrons are emitted from the emitter toward the porous light emitter 2. In the Mo Spindt type emitter, electrons are emitted at a voltage of 15 to 80V. Further, in an actual display panel, a plurality of emitters can be formed corresponding to each pixel, and the operation status of the emitters can be highly redundant. By doing so, current fluctuations peculiar to this type of element are also statistically averaged, so that stable pixel emission can be obtained. The matrix drive can be a so-called simple matrix drive. A positive data pulse is applied to the gate line 171 and a negative data voltage is applied to the emitter line 172 to simultaneously display one line. By sequentially switching the scanning pulse, a two-dimensional image can be displayed. Note that active driving is also possible by placing a transistor in each pixel arranged in a matrix and turning each pixel on and off.

  As an example, FIG. 44 shows a cross section of a light emitting device in which a plurality of Spindt emitters 100 are formed and the porous light emitter 2 is laminated so as to correspond to each emitter. At this time, as shown in the drawing, it is desirable to form a spacer 175 in the porous light-emitting body 2 in order to avoid crosstalk of light emission. In the field emission display in this embodiment mode, the electron emitter 119 using the Spindt-type emitter 100 has been described. However, the present invention is not limited to this, and the present invention is applicable as long as it has a function of emitting electrons. It is possible to produce a field emission display by combining with a porous luminescent material.

(Embodiment 23)
45A to 45C are cross-sectional views of the light-emitting element in this embodiment, in which 1 is a light-emitting element, 2 is a porous light-emitting body layer, 3 is a phosphor particle, 4 is an insulating layer, 5 is a substrate, 6 is a first electrode, 7 is a second electrode, 8 is a translucent substrate, 9 is a gas layer, 10 is a dielectric layer, and 11 is a partition.

  A method for manufacturing the light emitting device of FIG. 45A is as follows. First, Ag paste is baked to a thickness of 30 μm on one surface of a sintered body of the dielectric 10 having a thickness of 0.3 to 1.0 mm to form a first electrode 6 having a predetermined shape. Next, the side on which the first electrode is formed is adhered on the glass or ceramic substrate 5. Any of the dielectric materials already described in the first embodiment can be used.

Next, phosphor particles 3 whose surfaces are covered with an insulating layer 4 made of a metal oxide such as MgO are prepared in the same manner as in the first embodiment. The phosphor particles 3 are inorganic such as BaMgAl ₁₀ O ₁₇ : Eu ²⁺ (blue), Zn ₂ SiO ₄ : Mn ²⁺ (green), YBO ₃ : Eu ³⁺ (red) having an average particle diameter of 2 to 3 μm. It is possible to use compounds.

  In the present embodiment, phosphor particles 3 whose surfaces are coated with an insulating layer 4 made of MgO are mixed with 5% by mass of polyvinyl alcohol and granulated, and then plate-shaped at a pressure of about 50 MPa using a molding die. Molded into. The molded body thus obtained was heat-treated at 450 to 1200 ° C. for 2 to 5 hours in a nitrogen atmosphere to produce a plate-like porous light emitting body 2.

  When the apparent porosity of the porous light emitter is less than 10%, when electrons collide with the porous light emitter layer, light is emitted on the surface of the porous light emitter layer, but electrons are not injected into the light emitting layer. Since light is hardly emitted in the layer, the light emission efficiency is low. Therefore, the apparent porosity of the porous light emitter in the present embodiment has a porous structure of 10% or more so that electrons generated by the discharge are smoothly injected into the porous light emitter layer. Is desirable. In addition, when the apparent porosity of the porous light emitter becomes extremely large, the light emission efficiency is lowered, and the creeping discharge is less likely to occur inside the porous light emitter layer, so the apparent porosity is 10% to less than 100%. The range of is preferable. In particular, the range of 50 to less than 100% is preferable.

  The plate-like porous light-emitting body 2 obtained as described above is attached to the dielectric layer 10 using a glass paste. At that time, the glass paste is screen-printed at both ends of the porous light emitting layer, and the porous light emitting layer is adhered thereto. Thereafter, when heat-treated at 580 ° C., the porous light emitting layer can be adhered to the dielectric layer 10 with the gas layer interposed.

  Next, porous light emission is performed by a translucent substrate 8 such as a glass plate formed in advance so that the second electrode 7 made of ITO (indium-tin oxide alloy) is positioned to face the porous light emitter layer. When the body layer is covered, the light-emitting element 1 shown in FIG. 45A is obtained. At that time, the translucent substrate 8 is formed using glass paste, colloidal silica, water glass, resin, or the like so that a slight gap in which a gas exists is generated between the porous light emitting layer 2 and the second electrode 7. Affix by heat treatment. Thus, as shown in FIG. 45A, both ends of the porous light emitter layer are bonded with glass paste or the like functioning as the partition walls 11 with the gas layers above and below the porous light emitter layer.

  The gas layers existing on the upper and lower sides of the porous light emitter layer, which are the features of the present embodiment, that is, the gas layer interposed between the porous light emitter layer 2 and the dielectric layer 10, the porous light emitter layer, and the second layer. The thickness of the gas layer interposed between the electrodes is preferably in the range of 20 to 250 μm, and most preferably in the range of 30 to 220 μm. If it is larger than the above range, it is necessary to apply a high voltage to generate the discharge, which is not preferable for economical reasons. Also, the thickness of the gas layer can be thinner than the above range, and there is no problem if the gas layer has a mean free path or more. However, if the gas layer becomes very thin, Thickness control is somewhat difficult.

  In addition, the thickness of the gas layer which exists in the upper and lower sides of the porous light-emitting body layer in this Embodiment does not necessarily need to be the same. However, in the case where gas layers are provided at two locations above and below the light emitter layer, the thickness of each gas layer is compared to the case where the gas layer is present only at one location on one side of the light emitter layer as shown in FIG. It is preferable to set a little narrower. When the thickness of the gas layer is increased, it is necessary to apply a relatively high voltage during discharge, which is not preferable from the viewpoint of economy.

  As described above, the present embodiment is characterized in that gas layers are provided above and below the porous luminous body layer, and when an alternating electric field is applied to the first electrode and the second electrode that are a pair of electrodes, As a result of simultaneous discharge in the gas layer, electrons are emitted from above and below the porous light emitter layer and efficiently injected into the light emitter layer. That is, when the applied AC electric field is gradually increased and a voltage higher than the dielectric breakdown voltage is applied to the gas layer, discharge occurs, electrons are multiplied in the gas layer, and electrons are transferred to the porous luminous body. It collides and the luminescent center of the porous luminescent layer is excited by electrons to emit light. In this way, the gas layer acts as an electron supply source, and the generated electrons are injected from above and below the porous luminous body layer and pass through the inside of the layer like an avalanche while generating creeping discharge in the entire luminous body layer. To do. Creeping discharge is continuously generated while an electric field is applied. At that time, electrons generated in an avalanche collide with the emission center of the phosphor, and the phosphor particles 3 are excited to emit light. As a result of efficiently injecting electrons from above and below the porous light emitter layer as described above, as compared with the case where electrons are injected from one side of the light emitter layer as described in Embodiment 1, the present embodiment In the phosphor layer having a porous structure in the form, the entire layer emits light uniformly and efficiently, and as a result, the luminance is remarkably increased.

  As described above, in the present embodiment, at least a pair of electrodes for applying an electric field to the gas layer, the porous light emitter layer in contact with the gas layer, and the gas layer and the porous light emitter layer; A first electrode of a pair of electrodes for applying an electric field to a dielectric layer via a gas layer, in particular on one surface of the porous light emitter layer, wherein the porous A light-emitting element in which the second electrode of the pair of electrodes is disposed via a gas layer on the other surface of the light-emitting layer where the dielectric layer and the first electrode are not disposed can be manufactured.

  In the present embodiment, as shown in FIG. 45B, a porous light emitter layer 2, 2 is not provided between the porous light emitter layers 2, 2 and the dielectric layer 10 without providing a gap composed of the gas layer 9. There may be a gap formed by the gas layers 9 and 9 between the electrode 2 and the electrodes 6 and 7, respectively.

  In this way, by applying an electric field from the pair of electrodes 6 and 7 to the gas layers 9 and 9 and the porous light emitter layers 2 and 2 in contact therewith, the porous light emitter layers 2 and 2 emit light. it can.

  In the present embodiment, what should be particularly noted in the heat treatment step for forming the porous light-emitting layer is the heat treatment temperature and atmosphere. In this embodiment, since the heat treatment was performed in a temperature range of 450 to 1200 ° C. in a nitrogen atmosphere, there was no change in the valence of rare earth atoms doped in the phosphor. However, when processing at a temperature higher than this temperature range, care must be taken because the valence of rare earth atoms may change and a solid solution composed of an insulating layer and a phosphor may be generated. As the heat treatment atmosphere, a nitrogen atmosphere is preferable so as not to affect the valence of the rare earth atoms doped in the phosphor particles as described above.

  In this embodiment, the thickness of the insulating layer is about 0.1 to 2.0 μm, but is determined in consideration of the average particle diameter of the phosphor particles and the efficient generation of creeping discharge. Further, when the average particle diameter of the phosphor is on the order of submicron, it is better to coat relatively thinly. A thick insulating layer is not preferable because it causes a shift in emission spectrum, a decrease in luminance, and the like. Conversely, it is presumed that creeping discharge is slightly less likely to occur when the insulating layer becomes thinner. Therefore, the relationship between the average particle diameter of the phosphor particles and the thickness of the insulating layer is preferably in the range of 1/10 to 1/500 of the latter with respect to the former.

  Next, the light emitting action of the light emitting element 1 will be described.

  As shown in the figure, an alternating electric field is applied between the first electrode 6 and the second electrode 7 in order to drive the light emitting element 1. When the applied AC electric field is gradually increased and a voltage higher than the dielectric breakdown voltage is applied to the gas layer, discharge occurs, and electrons are multiplied in the gas layer, which collides with the porous light emitter. The luminescent center of the luminescent layer is excited by electrons to emit light. Thus, the gas layer acts as an electron supply source, and in the present embodiment, the generated electrons are injected from above and below the porous light emitter layer, and creeping discharge is generated throughout the porous light emitter layer. It passes through the inside of the luminescent layer so as to break down while generating. Creeping discharge is continuously generated while an electric field is applied. At that time, electrons generated in an avalanche collide with the emission center of the phosphor, and the phosphor particles 3 are excited to emit light. Thus, in the present embodiment, as a result of electrons being injected from above and below the porous light emitter layer, as compared with the case where electrons are injected only from one side of the light emitter layer as in the light emitting element described in Embodiment 1. Thus, the entire porous luminous body layer emits light uniformly and efficiently, and the brightness is remarkably increased.

  In the present embodiment, since a porous light emitter having an apparent porosity of 10% to less than 100% is used, a normal light emitter layer having no porous structure emits light on its surface. However, light is hardly emitted inside the layer, whereas the porous light emitter layer in this embodiment emits light not only on the surface of the layer but also inside the light emitter layer, so that the light emission efficiency is extremely good. become. Thus, in the case of a porous layer, electrons generated by discharge due to the porous structure are smoothly injected into the inside of the layer, and creeping discharge is generated throughout the layer to emit light, resulting in high brightness. Luminescence is obtained.

  Moreover, it is desirable that the porous luminescent material used in the present embodiment has a porous structure with an apparent porosity of 10% or more. In addition, when the apparent porosity of the luminescent material is extremely increased, the desirable apparent porosity is 10 or more for reasons such that the luminous efficiency is lowered and the creeping discharge is less likely to occur inside the porous luminescent material layer. The range is less than 100%. In particular, 50 to less than 100% is most preferable.

  Note that by changing the waveform of the AC electric field to be applied from a sine wave or sawtooth wave to a rectangular wave, and increasing the frequency from several tens of Hz to several thousand Hz, the emission of electrons due to creeping discharge becomes extremely intense, and the luminance Will improve. A burst wave is generated as the voltage of the AC electric field increases. The generation frequency of the burst wave was generated just before the peak for the sine wave and at the peak for the sawtooth wave and the rectangular wave, and the emission luminance improved as the burst wave voltage was increased. Once creeping discharge is started, ultraviolet rays and visible rays are also generated. Therefore, it is necessary to suppress the deterioration of the phosphor particles 3 due to these rays, and it is preferable to reduce the voltage after the start of light emission.

  45A and 45B in the present embodiment, an electric field of about 0.79 to 1.7 and 0.75 to 1.6 kV / mm is applied to the thickness of the porous light emitter layer, respectively. The phosphor particles 3 are caused to emit light, and thereafter, by applying an alternating electric field of about 0.55 to 1.1 and 0.52 to 1.0 kV / mm, respectively, creeping discharge is continuously performed to cause fluorescence. The luminescence of the body particles 3 was maintained. When the applied electric field is increased, the generation of electrons is promoted. However, when the applied electric field is small, the generation is suppressed. When the gas present in the gas layer is air, it is necessary to apply a voltage of at least about 0.3 kV / mm, which is a breakdown voltage thereof.

  In addition, the current value during discharge is 0.1 mA or less. When light emission starts, light emission continues even when the voltage is reduced to about 50 to 80% of the applied voltage. It was confirmed that the light was emitted with high brightness, high contrast, high recognizability, and high reliability. In the present embodiment, the driving is performed in the atmosphere, but it was confirmed that the light emission was similarly performed even when the driving was performed in a rare gas or a gas in a pressurized or negative pressure state.

  According to the light emitting element of the present embodiment, since the porous light emitting layer is formed by a thick film process or the like, there is no need to use a thin film forming process when manufacturing the light emitting element as in the prior art, and a vacuum system or carrier Since no multiplication layer is required, the structure is simple, and manufacturing and processing are easy. In addition, electrons generated by the discharge collide with the light emitting layer from both sides of the porous light emitting layer, and since the structure of the light emitting body is a porous body, the collided electrons generate creeping discharge to the inside of the light emitting layer. However, since it is injected smoothly, it is possible to obtain light with very high luminance. While a normal non-porous illuminant emits light only on its surface, the porous illuminant layer of the present embodiment is characterized by high luminance because the entire layer emits light uniformly as described above. is there. In addition, the luminous efficiency is very good as compared with the phosphor emission by ultraviolet rays performed in plasma displays. Furthermore, a light-emitting element with relatively low power consumption when used in a large display can be provided. By installing barrier ribs as discharge separation means at both ends of the porous light emitter layer, it is possible to easily avoid light emission crosstalk.

  Next, FIG. 45C is the same as that of FIG. 45A-B except that the dielectric layer 10 interposed between the porous light emitter layer 2 and the first electrode 6 is not provided.

  The method for manufacturing the light emitting device of FIG. 45C is as follows. First, an Ag paste is baked to a thickness of 30 μm on one surface of a glass or ceramic substrate 5 to form a first electrode 6 in a predetermined shape.

Next, phosphor particles 3 whose surfaces are covered with an insulating layer 4 made of a metal oxide such as MgO are prepared in the same manner as in the first embodiment. The phosphor particles 3 are inorganic such as BaMgAl ₁₀ O ₁₇ : Eu ²⁺ (blue), Zn ₂ SiO ₄ : Mn ²⁺ (green), YBO ₃ : Eu ³⁺ (red) having an average particle diameter of 2 to 3 μm. It is possible to use compounds.

  In the present embodiment, as in the third embodiment, phosphor particles 3 whose surfaces are coated with an insulating layer 4 made of MgO are mixed with 5% by mass of polyvinyl alcohol and granulated, and then a molding die is used. And formed into a plate shape at a pressure of about 50 MPa. The molded body thus obtained was heat-treated at 450 to 1200 ° C. for 2 to 5 hours in a nitrogen atmosphere to produce a plate-like porous light emitting body 2.

  Both ends of the plate-like porous luminous body 2 obtained as described above are attached to the electrode side of the substrate 5 using a glass paste. Specifically, as shown in FIG. 45C, when the glass paste is screen-printed and the porous light-emitting layer is bonded and then heat-treated at 580 ° C., the porous light-emitting layer 2 is in contact with the first electrode. It is fixed in a state where a gap consisting of a slight gas layer is provided. The thickness of the gas layer existing between the porous luminous body layer 2 and the first electrode 6 is preferably in the range of 20 to 250 μm, particularly preferably in the range of 30 to 220 μm. When the above range is exceeded, it is necessary to apply a high voltage to the occurrence of discharge, which is not preferable for economic reasons. Further, the gas layer may be thinner than the above range, as long as it exceeds the mean free path of gas.

  Next, the porous light emitter is formed by a translucent substrate 8 such as a glass plate formed in advance so that the second electrode 7 made of ITO (indium-tin oxide alloy) is positioned to face the porous light emitter layer. When the layers are covered, the light-emitting element 1 in this embodiment as shown in FIG. 45C is obtained. At that time, the translucent substrate 8 is pasted by heat treatment using colloidal silica, water glass, resin, or the like so that a slight gap formed of a gas layer is formed between the porous light-emitting layer 2 and the second electrode 7. To do. The thickness of the gap between the porous light emitter layer 2 and the second electrode 7 is not necessarily the same as the thickness of the gap between the porous light emitter layer and the first electrode described above. Just set it.

  As described above, the present embodiment is characterized in that a slight gap is provided between the first electrode and the second electrode provided on both surfaces of the porous light emitter layer. Thus, a gas layer made of a rare gas, air, oxygen, nitrogen, or a mixed gas thereof is interposed between the porous light emitter layer and the pair of electrodes. When an alternating electric field is applied to a pair of electrodes of such a light-emitting element, a discharge occurs when a voltage higher than the dielectric breakdown voltage is applied to the gas layer. At that time, electrons are multiplied in the gas layer and porous The electrons collide with the luminescent material and the luminescent center of the luminescent layer is excited by the electrons to emit light. In this way, the gas layer acts as an electron supply source, and the generated electrons collide with the light emitter layer and are injected into the inside of the layer so as to pass through an avalanche while generating creeping discharge throughout the light emitter layer. Creeping discharge is continuously generated while an electric field is applied, and electrons generated in an avalanche collide with the emission center of the phosphor, and the phosphor particles 3 are excited to emit light. As described above, in this embodiment, electrons are supplied from both sides of the porous light emitter layer and smoothly and uniformly injected to the inside of the light emitter layer. As a result, the electrons are emitted from one side of the porous light emitter as in the first embodiment. Compared with the case where is injected, the entire phosphor layer emits light uniformly and efficiently, and the luminance of emitted light is increased.

In the present embodiment, the phosphor particle 3 whose surface is covered with the insulating layer 4 made of MgO is used. However, MgO has a high resistivity (10 ⁹ Ω · cm or more), and the creeping discharge is efficiently performed. This is because it can be generated. When the resistivity of the insulating layer is low, creeping discharge is difficult to occur, and there is a possibility of short-circuiting, which is not preferable. For these reasons, it is desirable to coat with an insulating metal oxide having a high resistivity. Of course, when the resistivity of the phosphor particles to be used is high, creeping discharge is easily generated without coating with an insulating metal oxide. As the insulating layer, in addition to the above MgO, at least one selected from Y ₂ O ₃ , Li ₂ O, CaO, BaO, SrO, Al ₂ O ₃ , SiO ₂ , and ZrO ₂ can be used. The standard free energy of formation ΔG _f ⁰ of these oxides is very small (for example, −100 kcal / mol or less at room temperature) and is a stable substance. In addition, since these insulating layers have high resistivity and are difficult to reduce, they are excellent as protective films that suppress reduction and deterioration of phosphor particles due to electrons, resulting in high durability of the phosphor. Convenient.

  In addition to the sol / gel method, the insulating layer can be formed by a physical adsorption method using a chemical adsorption method, a CVD method, a sputtering method, a vapor deposition method, a laser method, a shear stress method, or the like. It is desirable that the insulating layer is homogeneous and uniform and does not peel off. When forming the insulating layer, the phosphor particles are immersed in a weak acid solution such as acetic acid, oxalic acid or citric acid, and impurities adhering to the surface. It is important to wash

  Furthermore, it is desirable to pre-process phosphor particles in a nitrogen atmosphere at 200 to 500 ° C. for about 1 to 5 hours before forming the insulating layer. Ordinary phosphor particles contain a large amount of adsorbed water and crystal water, and if an insulating layer is formed in such a state, it will adversely affect the life characteristics such as luminance reduction and emission spectrum shift. is there. When the phosphor particles are washed with a weakly acidic solution, the above pretreatment is performed after thoroughly washing with water.

  Next, the light emitting action of the light emitting element 1 will be described with reference to FIG. 45C. As shown in the figure, an alternating electric field is applied between the first electrode 6 and the second electrode 7 in order to drive the light emitting element 1. At that time, the light emitting element was inserted into a quartz tube, and a mixed gas of Ne and Xe was sealed in a slightly pressurized state. When the applied AC electric field is gradually increased and a voltage higher than the dielectric breakdown voltage is applied to the gas layer, a discharge is generated, and electrons are multiplied in the gas layer, which collides with the porous light emitter. The luminescent center of the porous luminescent layer is excited by electrons to emit light. Thus, the gas layer acts as an electron supply source, and the generated electrons are injected into the inside of the layer from both sides of the porous light emitter layer, and the light emitter emits creeping discharge throughout the porous light emitter layer. Pass through the layers like a snowslide. Creeping discharge is continuously generated while an electric field is applied. At that time, electrons generated in an avalanche collide with the emission center of the phosphor, and the phosphor particles 3 are excited to emit light. In the present embodiment, as a result of electrons being injected from both the upper and lower sides of the porous luminous body layer, as compared with the case where electrons are injected from one side as described in the first embodiment, porous light emission The entire body layer emits light uniformly and efficiently, and the brightness is remarkably increased.

  Further, in the present embodiment, since a porous light emitter having an apparent porosity of 10% to less than 100% is used, a normal phosphor layer that is not a porous light emitter emits light on its surface. The porous luminous body layer emits light not only on the surface of the layer but also inside the layer, so that the luminous efficiency is very good. This is because in the case of the porous luminescent layer, electrons enter the inside of the layer by discharge, and as a result, creeping discharge occurs in the entire layer, and high-luminance light emission is obtained.

  Note that by changing the waveform of the AC electric field to be applied from a sine wave or sawtooth wave to a rectangular wave, and increasing the frequency from several tens of Hz to several thousand Hz, the emission of electrons due to creeping discharge becomes extremely intense, and the luminance Will improve. A burst wave is generated as the voltage of the AC electric field increases. The generation frequency of the burst wave was generated just before the peak for the sine wave and at the peak for the sawtooth wave and the rectangular wave, and the emission luminance improved as the burst wave voltage was increased. Once creeping discharge is started, ultraviolet rays and visible rays are also generated. Therefore, it is necessary to suppress the deterioration of the phosphor particles 3 due to these rays, and it is preferable to reduce the voltage after the start of light emission.

  In the present embodiment, the phosphor particles 3 are caused to emit light by applying an electric field of about 0.57 to 1.2 kV / mm to the thickness of the porous light-emitting layer as in the case of the light-emitting element of the second embodiment. Then, by applying an alternating electric field of about 0.39 to 0.78 kV / mm, creeping discharge was continuously performed to keep the phosphor particles 3 from emitting light. As in the second embodiment, light emission was performed even when the voltage value was reduced to about 60 to 80% compared to the case where no rare gas was sealed. The reason is that by enclosing a rare gas, an atmosphere in which discharge is more likely to occur is obtained, and the luminance can be remarkably increased by applying pressure.

  In addition, the current value at the time of discharge is 0.1 mA or less, and when the light emission starts, the light emission continues even when the voltage is reduced to about 50 to 80% of the applied voltage. Compared with the light-emitting element of Embodiment 2, it was confirmed that the light was emitted with high luminance, high contrast, high recognizability, and high reliability.

  Incidentally, when the light emitting element having no dielectric layer according to the present embodiment emits light in the atmosphere, it is about 0.89 to about driving when compared with the case where the above rare gas is sealed in a pressurized state. A relatively electric field of 1.9 kV / mm is applied to cause phosphor particles 3 to emit light, and then an alternating electric field of about 0.62 to 1.3 kV / mm is applied to continue creeping discharge. Therefore, it was necessary to sustain the light emission of the phosphor particles 3.

  According to the light emitting element of the present embodiment, since the porous light emitting layer is formed by a thick film process or the like, there is no need to use a thin film forming process when manufacturing the light emitting element as in the prior art, and a vacuum system or carrier Since no multiplication layer is required, the structure is simple, and manufacturing and processing are easy. In addition, light emission by creeping discharge based on electrons injected into the porous light-emitting layer results in high-luminance light emission, and not only the surface emits light like normal phosphors, but porous light emission. The whole body layer emits light uniformly. In addition, the luminous efficiency is very good as compared with the phosphor emission by ultraviolet rays performed in plasma displays. Furthermore, a light-emitting element with relatively low power consumption when used in a large display can be provided. By installing barrier ribs as discharge separation means at both ends of the porous light emitter layer, it is possible to easily avoid light emission crosstalk.

  Since the light emitting device according to the present invention emits light by creeping discharge, it does not use a thin film formation process for forming a phosphor layer as in the prior art, and does not require a vacuum container or a carrier multiplication layer, so that it can be manufactured. The light emitting device of the present invention is useful as a light emitter constituting a unit pixel of a large screen display. Moreover, it is useful also as a light-emitting body applied to illumination, a light source, etc.

1 is a cross-sectional view of a light-emitting element according to Embodiment 1 of the present invention. FIG. 2 is a diagram for explaining a manufacturing process of the light-emitting element according to Embodiment 1 of the present invention. FIG. 3 is a diagram for explaining a manufacturing process of the light-emitting element according to Embodiment 1 of the present invention. FIG. 4 is a diagram for explaining a manufacturing process of the light-emitting element according to Embodiment 1 of the present invention. FIG. 5 is a diagram for explaining a manufacturing process of the light-emitting element according to Embodiment 1 of the present invention. FIG. 6 is a schematic diagram enlarging the cross section of the porous light emitting layer in Embodiment 1 of the present invention. FIG. 7 is a cross-sectional view of a light-emitting element according to Embodiment 2 of the present invention. FIG. 8 is a cross-sectional view of a light-emitting element according to Embodiment 3 of the present invention. FIG. 9 is a cross-sectional view of a light-emitting element according to Embodiment 4 of the present invention. FIG. 10 is a diagram for explaining a manufacturing process of the light-emitting element in Embodiment 4 of the present invention. FIG. 11 is a diagram for explaining a manufacturing process of the light-emitting element according to Embodiment 4 of the present invention. FIG. 12 is a diagram for explaining a manufacturing process of the light-emitting element in Embodiment 4 of the present invention. FIG. 13 is a diagram for explaining a manufacturing process of the light-emitting element in Embodiment 4 of the present invention. FIG. 14 is an enlarged schematic view of the cross section of the porous light emitting layer in the fifth embodiment of the present invention. FIG. 15 is a schematic diagram enlarging a cross section of a porous light-emitting layer in Embodiment 5 of the present invention. FIG. 16 is an exploded perspective view of a light-emitting element according to Embodiment 6 of the present invention. FIG. 17 is an explanatory diagram showing the function of light emission in the first embodiment of the present invention. FIG. 18 is a cross-sectional view of a light-emitting element in Embodiment 7 of the present invention. FIG. 19 is a cross-sectional view of a light-emitting element according to Embodiment 8 of the present invention. 20 is a cross-sectional view of a conventional light emitting element in Non-Patent Document 2. FIG. FIG. 21 is a cross-sectional view of a conventional light emitting element in Patent Document 3. FIG. 22 is a cross-sectional view of a light-emitting element according to Embodiment 9 of the present invention. FIG. 23 is a cross-sectional view of a light-emitting element according to Embodiment 10 of the present invention. FIG. 24 is a cross-sectional view of a light-emitting element according to Embodiment 11 of the present invention. FIG. 25 is a cross-sectional view of a light-emitting element in Embodiment 12 of the present invention. FIG. 26 is a cross-sectional view of a light-emitting element in Embodiment 13 of the present invention. FIG. 27 is a cross-sectional view of a light-emitting element in Embodiment 14 of the present invention. FIG. 28 is a cross-sectional view of a light-emitting element in Embodiment 15 of the present invention. FIG. 29 is a cross-sectional view of a light-emitting element in Embodiment 16 of the present invention. 30A-F are process cross-sectional views for explaining a method for manufacturing the light-emitting element shown in FIG. FIG. 31 is a cross-sectional view of a light-emitting element in Embodiment 17 of the present invention. 32A-G are process cross-sectional views for explaining a manufacturing method of the light-emitting element shown in FIG. FIG. 33 is a cross-sectional view of a light emitting element in an eighteenth embodiment of the present invention. 34A to 34C are process cross-sectional views for explaining a method for manufacturing the light-emitting element shown in FIG. FIG. 35 is a cross-sectional view of a light-emitting element in Embodiment 19 of the present invention. 36A to 36D are process cross-sectional views for explaining a method for manufacturing the light-emitting element shown in FIG. 37A-C are process cross-sectional views for explaining a method for manufacturing an electron emitter according to Embodiment 20 of the present invention. FIG. 38 is a cross-sectional view of a porous light-emitting body constituting the light-emitting element in Embodiment 21 of the present invention. FIG. 39 is a cross-sectional view of a porous light-emitting body constituting the light-emitting element in Embodiment 21 of the present invention. FIG. 40 is a cross-sectional view of a porous light emitter that constitutes a light emitting element according to a twenty-first embodiment of the present invention. FIG. 41 is a schematic cross-sectional view of a porous light emitter that constitutes a light emitting element according to Embodiment 21 of the present invention. FIG. 42 is a schematic cross-sectional view of a porous light emitter that constitutes a light emitting element according to Embodiment 21 of the present invention. FIG. 43 is an exploded perspective view of the main part of the field emission display according to Embodiment 22 of the present invention. FIG. 44 is a cross-sectional view of the light-emitting element array according to Embodiment 22 of the present invention. 45A-C are cross-sectional views of the light-emitting element array according to Embodiment 23 of the present invention.

Claims (34)

A light emitting device comprising at least two electrical insulator layers having different dielectric constants and at least two electrodes ,
One of the electrical insulator layers is a porous light emitter layer;
Another one of the electrical insulator layers is a gas layer, a ferroelectric layer, or a dielectric layer having a relative dielectric constant of 100 or more,
The porous phosphor layer is formed of phosphor particles or phosphor particles coated with an insulating layer,
Another layer of the insulator layer is disposed above and / or below the porous light emitter layer;
The two electrodes sandwich at least one of the two types of electrical insulator layers, or are in contact with or separated from any one of the two types of electrical insulator layers. Arranged,
A DC or AC electric field is applied to the at least two electrodes, and any one of the following a to c
a. Causing a breakdown in the gas layer between the at least two electrodes;
b. Polarization is reversed by the ferroelectric layer or the dielectric layer having a relative dielectric constant of 100 or more.
c. Electrons are generated from the electron emitter by the tunnel effect and collide with the porous light emitter layer through the gas layer.
To generate primary electrons (e−), and the primary electrons (e−) collide with phosphor particles including the phosphor of the porous light emitting layer to generate a large number of secondary electrons (e−) in an avalanche manner. A light emitting device characterized in that ultraviolet rays are generated at the same time, and the generated secondary electrons and ultraviolet rays excite phosphor particles containing the phosphor . The porous luminous body layer is divided into a plurality of pixels for each pixel by a discharge separation means for avoiding a crosstalk phenomenon in which the light emission between adjacent pixels affects each other and lowers the luminous efficiency .
The discharge separation means is formed by barrier ribs ,
The light emitting device according to claim 1, wherein the aggregate of pixels is a light emitting device. The ferroelectric layer or dielectric layer includes a sintered body layer, a ferroelectric material or a mixed layer of particles including a dielectric material and a binder, and a molecular deposition thin film including a ferroelectric material or a dielectric material. The light emitting device according to claim 1 , wherein the light emitting device is formed of at least one selected layer. The strong on the back of the dielectric layer or the dielectric layer, the light emitting device according to claim 1 which is disposed further back of the electrode. 3. The light emitting device according to claim 1, wherein at least one gas selected from air, nitrogen, and an inert gas is present in the porous light emitting layer . The said porous light-emitting body layer is comprised by the continuous pore connected to the said porous light-emitting body layer surface, the gas with which the said pore was filled, and fluorescent substance particle. Light emitting element. The light emitting device according to claim 1 or 2, wherein an apparent porosity of the porous light emitting layer is in a range of 10% to less than 100%. 3. The light emitting device according to claim 1, wherein the porous light emitting layer is formed of at least one particle selected from phosphor particles and phosphor particles covered with an insulating layer, and an insulating fiber. The light emitting device according to claim 1, wherein the entire light emitting device is sealed so as to be in a pressurized, normal pressure or reduced pressure atmosphere. One of said electrical insulator layer is a gas layer, the gas layer, the light emitting device according to claim 1, thickness is provided at 300μm or less the range of 1 [mu] m. The light emitting device according to claim 2 , wherein the partition is made of an inorganic material. The light emitting device according to claim 2 , wherein the discharge separation unit is formed by a gap. One of said electrical insulator layer is a gas layer, the gas layer, the light emitting device according to claim 1 which is partitioned in the thickness direction by the ribs. The porous luminous body layer is formed with an array that emits three colors of red (R), green (G), and blue (B), and is driven by driving address electrodes, matrix driving or active driving. The light emitting device according to claim 1 , wherein at least red (R), green (G), or blue (B) emits light separately. The light emitting device according to claim 1, wherein the porous light emitting layer emits at least red (R), green (G), or blue (B) separately by separating colors with a color filter. Wherein the at least two electrodes arranged across said at least one dielectric layer and a porous light-emitting body layer, by applying an AC electric field, the light emitting device according to claim 1 for emitting the porous light-emitting body layer . The light emitting device according to claim 1 , wherein the at least two electrodes are address electrodes or display electrodes. The light emitting element according to claim 1 , wherein one of the at least two electrodes is a transparent electrode and is disposed on the observation surface side. One of the electrical insulator layers is a gas layer, and the gas layer is between the porous light emitter layer and the transparent electrode on the observation surface side, and between the porous light emitter layer and the back electrode. The light emitting device according to claim 1 , wherein the light emitting device is formed on at least one selected from the group consisting of: Wherein another one of the electrical insulator layer is a ferroelectric layer, the pre-Symbol porous phosphor layer emitting device according to claim 1 which is disposed in contact with the ferroelectric layer. Wherein at least two current AC electric field applied to the electrodes, at least one of said electrodes so that said exchanges electric field is also applied to a portion of the porous light-emitting body layer adjacent to the porous light-emitting body layer The light emitting device according to claim 1 , wherein the light emitting device is disposed . 2. The light emitting device according to claim 1 , wherein one of the electrical insulator layers is a ferroelectric layer, and the at least two electrodes are formed with the ferroelectric layer and the porous light emitting layer sandwiched therebetween. One of said electrical insulator layer is a ferroelectric layer, the light emitting device of claim 1, wherein the at least two electrodes are disposed adjacent to both the ferroelectric layer. 2. The light emitting device according to claim 1 , wherein one of the electrical insulator layers is a ferroelectric layer, and both of the at least two electrodes are formed at a boundary between the ferroelectric layer and the porous light emitting layer. One of the electrical insulator layers is a ferroelectric layer, one of the at least two electrodes is formed at the boundary between the ferroelectric layer and the porous light emitter layer, and the other electrode is a ferroelectric layer. The light emitting device according to claim 1 , which is disposed adjacent to the layer. One of the electrically insulating layers is a ferroelectric layer;
The at least two electrodes include a pair of electrodes and another electrode;
The pair of electrodes are arranged such that an electric field is applied to at least a part of the ferroelectric layer,
2. The light emitting device according to claim 1 , wherein the other electrode is disposed such that an electric field is applied to at least a part of the porous light emitting layer existing between one of the pair of electrodes. . The electron emitter includes a cathode electrode, a gate electrode, and a Spindt-type emitter interposed between the two electrodes, and applying a gate voltage between the cathode electrode and the gate electrode allows the Spindt-type emitter to be applied. The light emitting device according to claim 1 , wherein the porous light emitting layer is irradiated with electrons emitted from the light to emit light. 28. The light emitting device according to claim 27 , wherein the Spindt emitter has a conical shape. 28. The light emitting device according to claim 27 , wherein the Spindt emitter is made of at least one metal selected from molybdenum, niobium, zirconium, nickel, and molybdenum steel. The electron emitter includes a cathode electrode, a gate electrode, and a carbon nanotube interposed between the two electrodes, and is emitted from the carbon nanotube by applying a gate voltage between the cathode electrode and the gate electrode. The light emitting device according to claim 1 , wherein the porous light emitting layer is irradiated with emitted electrons to emit light. The electron emitter is a surface conduction electron-emitting device, the gap formed in the metal oxide film, by applying an electric field to the electrodes deployed on the metal oxide film, the porous emitting electrons generated from said gap The light emitting device according to claim 1 , wherein the light is emitted by irradiating the body. The electron emitter is composed of a silicon microcrystal having an oxide film sandwiched between polysilicon having an oxide film, and electrons generated by applying a voltage to the silicon microcrystal having the oxide film are emitted from the porous light emission. The light emitting device according to claim 1 , wherein the body layer is irradiated with light to emit light. The electron emitter includes a cathode electrode, a gate electrode, and a whisker emitter interposed between the two electrodes, and emits from the whisker emitter by applying a gate voltage between the cathode electrode and the gate electrode. The light emitting device according to claim 1 , wherein the porous light emitting layer is irradiated with emitted electrons to emit light. The electron emitter includes a cathode electrode, a gate electrode, and a silicon carbide or diamond thin film interposed between the two electrodes. By applying a gate voltage between the cathode electrode and the gate electrode, the electrons The light emitting device according to claim 1 , wherein the porous light emitting layer is irradiated with electrons emitted from the emitter to emit light.

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