JP4164150B2 - Method for producing optical functional thin film - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing an optical functional thin film having a phosphor dispersed in an insulator mainly composed of Si .
[0002]
[Prior art]
Examples of optical functional thin films, particularly thin films having a light emitting function, include EL, LEDs, lasers, etc. EL (electroluminescence) is attracting attention as a large area light emitter mainly composed of inorganic materials. . Applications of this include ceiling lighting, computer displays, and backlights, and research and development are still underway. As the EL, an inorganic EL element using a conventional inorganic material and a current injection type organic EL element which has been attracting attention in recent years are well known. As the former inorganic EL element, many studies have been made such as AC, DC drive-heavy insulation layer lamination type EL, AC drive double insulation layer lamination type EL, AC drive dispersion type EL, and DC drive dispersion type EL.
[0003]
Apart from these, an EL using a characteristic of porous Si has been prototyped in recent years. Hereinafter, the dispersion type EL and the porous Si type EL according to the present invention will be described.
[0004]
"AC drive distributed EL"
A general configuration of an AC drive distributed EL will be described with reference to FIG.
FIG. 1 is a schematic diagram of an AC drive distributed EL element. In the figure, 11 is a substrate, 12 is a transparent electrode, 13 is a light emitting layer, 14 is a dielectric layer (insulating layer), and 15 is a back electrode.
[0005]
The substrate 11 is made of transparent glass or plastic so that the emitted light is transmitted. A material such as In ₂ O ₃ , SnO ₂ , ZnO, or ITO is attached to the transparent electrode 12 with a thickness of several hundred nm. The light emitting layer 13 is produced by dispersing phosphor powder of II-VI group compound such as ZnS in a binder and coating it to a thickness of 50-100 μm. Here, the particle diameter of the phosphor is 5 to 30 μm, and Cu, Cl, I, Mn, or the like is added as an activator or coactivator that becomes the emission center. As the binder in the light emitting layer, an organic material such as cyanoethyl cellulose having a relatively large dielectric constant, or an inorganic material such as low-melting glass is used.
[0006]
In order to prevent dielectric breakdown, the dielectric layer 14 is provided on the light emitting layer with a thickness of several hundreds of nanometers to several tens of micrometers. As the dielectric layer, oxides such as A1 ₂ O ₃ , SiO ₂ , Y ₂ O ₃ , Ta ₂ O ₅ and BaTiO ₃ , nitrides such as Si ₃ N ₄ , AlN and BN are used. Al is generally used as the back electrode, but in addition to this, film formation with a paste agent such as Pt, Ag, Au—Pd—Ag, Ag—Pt—Pd is also possible.
[0007]
By applying an AC voltage of several hundreds V and several hundreds to several KHz between the transparent electrode and the back electrode of the EL element thus obtained, the electrons in the current induced in the phosphor in the light emitting layer between the electrodes. Is excited to emit light, and the light is emitted through the transparent electrode 12 downward in FIG. The light emission intensity at this time is 100 cd / m ² , and the light emission efficiency is about several lm / W. In recent years, attempts have been made to improve the composition of the binder of the phosphor layer and the insulating layer. For example, Japanese Patent Laid-Open No. 5-89963 reports that an EL element having a low frequency, a constant voltage and a high luminance was produced by including SiO ₂ , ZrO ₂ , B ₂ O ₃ , Li ₂ O or the like in the glass phase. Has been.
[0008]
"DC drive distributed EL"
A general configuration of the DC drive distributed EL will be described with reference to FIG.
FIG. 2 is a schematic diagram of a DC drive distributed EL element. In the figure, 21 is a substrate, 22 is a transparent electrode, 23 is a light emitting layer, and 24 is a back electrode. The substrate, the transparent electrode, and the back electrode have the same specifications as the materials and configurations described in the AC drive dispersion type EL. However, since a direct current flows in the DC drive type, an insulating layer is not provided, and the light emitting layer 23 is slightly different. The light emitting layer 23 is prepared by dispersing a fluorescent powder having electrical conductivity in some binder with a thickness of several tens of μm. As the electrically conductive phosphor, a fine powder having a particle size of sub-μm to several μm is used, and the surface of the phosphor particle is given conductivity by solution treatment or annealing treatment.
[0009]
In the DC drive dispersion type EL, a relatively large current flows at a low voltage at first, but no light emission is observed in this case. When a voltage is applied for a long time with the transparent electrode being positive and the back electrode being negative, a phenomenon called forming occurs and the resistance is increased. This is thought to be because the bonding between the electrically conductive phosphors on the transparent electrode side was cut. Then, a high electric field is generated in the thin cut portion of several μm, so that light emission can be seen. In general, a luminance of several hundred cd / m ² can be obtained at a driving voltage of several tens to 100 V, but the efficiency is about 0.2 to 0.31 m / W.
[0010]
"Porous Si EL"
Next, the porous Si type EL will be described.
First, the Si porous film will be described. When an electrochemical reaction is caused in an acidic solution using Si or a Si compound as a positive electrode, a reaction called anodization or anodization occurs. As the most known method, when a slight current is passed in a hydrofluoric acid solution using a Si wafer as a positive electrode, anodization proceeds and porous Si is generated on the surface of the Si wafer. Porous Si refers to a state in which a large number of fine holes are opened with the Si skeleton remaining. The size and shape of the holes vary from several nm to several μm depending on the type and concentration of the dopant in the Si wafer and the concentration and current value of the hydrofluoric acid in the solution when anodized. These are usually classified into three types and called microporous Si, mesoporous Si, and macroporous Si in ascending order. In general, a micro size indicates a bolus Si having a pore diameter of 2 nm or less, a meso size indicates a porous Si having a pore diameter of 2 to 50 nm, and a macro size indicates a bolus Si having a pore size of 50 nm or more. For more details, see "POROUS SILICON SCIENCE ANDTECHNOLOGY": C. Vial, J.M. It is described in, for example, the editing by Derrien SPRINGER Publishing.
[0011]
A more specific manufacturing method will be described with reference to FIGS. In the drawing, a schematic diagram of an anodizing, anodizing, and electrodeposition reactor is shown. In the figure, 41 is a Si wafer substrate, 42 is a counter electrode, 43 is an electrolytic solution of a mixed solution of hydrofluoric acid, water and ethanol, 44 is a reaction container such as a Teflon container, and 45 is a constant current source (power source). When a current of several tens of mA / cm ² is passed using the Si wafer as an anode, the above-described microporous Si is obtained when the Si wafer is a p-type having a high resistance. Mesoporous Si is obtained when the Si wafer is of low resistance p type. In the case of an n-type Si wafer, light irradiation is required, but the pore diameter tends to be larger than that of the p-type, resulting in mesoporous or macroporous Si.
[0012]
In recent years, many EL devices using porous Si have been studied, but are different from the above-described dispersion type EL in principle, so-called LEDs. For example, Koshida et al., “Appl. Phys. Lett.” Vol. 60, 347 to 349 (1992) report an EL device using porous Si. This element will be described with reference to FIG.
[0013]
FIG. 3 is a schematic view of an EL element using porous Si. In the figure, 31 is a Si substrate, 32 is a porous Si layer, 33 is a surface electrode, and 34 is a back electrode. Here, a Si wafer having a medium resistance of p-type of 10 to 20Ω is used for the Si substrate 31. First, Al is vapor-deposited on the back electrode 34 to form an ohmic junction. Thereafter, anodization is carried out in an aqueous solution in which HF (20%) and ethanol are mixed at 10 mA / cm ² for 5 to 10 minutes to produce a porous Si layer 32 having a thickness of several μm. Thereafter, the surface of the porous layer is etched with KOH or the like, dried and evacuated, and then a surface electrode 33 such as Au or ITO is formed. When a back electrode of the device thus obtained is positive and a surface electrode is negative and a voltage of 10 to 20 V is applied, a current of several hundred mA / cm ² is generated, and the EL is observed though it is weak. Is done.
[0014]
[Problems to be solved by the invention]
In the above prior art, the dispersion type EL element has low luminance, rapid deterioration of luminance, luminance cannot be obtained unless it is driven at high frequency, and when glass is used as a binder, high temperature heat treatment is required in the element manufacturing process. There were problems such as deterioration. In the case of an EL element using porous Si, there are practical problems such as very low luminance and poor efficiency.
[0015]
That is, an object of the present invention is to provide a method for easily producing a thin film having optical functionality.
[0020]
[Means for Solving the Problems]
That is, the present invention includes the steps of any part on the base plate or by positive Gokusan the substrate made of Si in an aqueous oxalic acid solution to form a porous layer is SiO _2, was formed on the porous layer A method for producing an optical functional thin film comprising a step of dispersing phosphor fine particles .
[0021]
Alternatively, there is a porous layer mainly composed of Si on the substrate, and when producing an optical functional thin film having a structure in which phosphor fine particles are dispersed in the porous layer, (1) the porous layer does not contain fluorine. (2) A method for producing the porous layer by anodizing in an aqueous solution containing fluorine, or (3) Anodizing the porous layer in an aqueous solution containing fluorine. After that, it is effective to prepare by anodizing in an aqueous solution not containing fluorine. In the above manufacturing method, it is preferable to have a step of producing a phosphor by an electrodeposition method, annealing after anodic oxidation or anodization, or after electrodeposition of the phosphor.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described in detail.
First, a bolus film of Si and Si compound used in the present invention will be described.
[0023]
When an electrochemical reaction is caused in an acidic solution using Si or a Si compound as a positive electrode, a reaction called anodization or anodization occurs. As described above, as described above, when a slight current is passed in a hydrofluoric acid solution using a Si wafer as a positive electrode, anodization proceeds and porous Si is generated on the surface of the Si wafer. Most of the porous layer immediately after fabrication leaves a Si skeleton, and the device of the present invention is inconvenient because of its low resistance. Therefore, it is necessary to appropriately oxidize the surface portion of the Si skeleton. As the oxidation method, the obtained element is gradually oxidized even if it is left as it is, but there are methods of anodizing again with an acid other than hydrofluoric acid and annealing in an atmosphere having an oxidizing action. Further, such porous Si can be produced not only on a Si single crystal substrate but also on a substrate having another composition such as a Si thin film or SiC.
[0024]
In an acidic aqueous solution containing no fluorine, a thin oxide film can often be formed on the surface of the Si wafer even if the Si wafer is anodized. Lahmann et al., “Jonal of Electrochemical Society” Vol. 143 (1996) pl313 to 1318, it is known that when the voltage is increased, fine irregularities are formed on the surface, and a low-density silicon oxide layer is formed. Although the low-density silicon oxide layer has not been investigated, the present inventors have confirmed that the micropores are in a porous shape opened in a sponge shape. Unlike the anodization in the hydrofluoric acid, this hole has a structure that falls within the range of several nm to several tens of nm almost independent of the type and concentration of the dopant, the concentration of the solution when anodizing, and the current value. Examples of acids that form such porous SiO ₂ include oxalic acid, sulfuric acid, nitric acid, hydrochloric acid, and acetic acid.
[0025]
Electrodeposition is preferable for embedding the phosphor in the pores of the porous film obtained as described above. Various methods can be used as long as the electrodeposition method is used, but the AC electrodeposition method is convenient for preventing adhesion of extra fine particles or film on the surface of the porous film. The electrodeposition method can be performed by the apparatus shown in FIG. 4 similar to the anodization or anodic oxidation. In this case, the solution is prepared according to the phosphor to be electrodeposited. A power source capable of applying an AC pulse is also used. The applied voltage depends on the properties of the porous film, but the higher the insulation, the higher the applied voltage.
[0026]
The phosphor to be embedded requires a material that can be excited by an electron beam. When the phosphor emits ultraviolet rays, an ultraviolet-excited phosphor can be used at the same time. In this case, the ultraviolet-excited phosphor does not need to be prepared by electrodeposition, and may be formed in a range where ultraviolet rays reach by coating. Even if the AC electrodeposition method is used, extra particles or films may adhere to the surface, but this may adversely affect the device characteristics, so it is preferable to remove them. Effective removal methods include reverse sputtering and chemical removal using a solution.
[0027]
As the phosphor, a material that can be electrodeposited is preferable, and ZnO: Zn is effective for this purpose. There are several reports of electrodeposition of ZnO: Zn phosphors. For example, Izaki et al., “J. Elecyrochem. Soc.” Vol. 143, L53 (1996). A nitric acid aqueous solution of Zn is prepared at a concentration of 0.01 to 0.5 mol / L, a substrate is used as the cathode, Zn is used as the anode, and the cathode is set to about −1 V with respect to the Ag / AgCl reference electrode. Then, a ZnO film is formed at a speed of about 0.0 l μm / min.
[0028]
Although the phosphor is embedded in the porous film by the above method, the present invention can be similarly applied to the case where the porous layer is formed by anodic oxidation in an aqueous solution not containing fluorine. However, the conditions for electrodeposition shift to the high voltage side.
[0029]
In order to make the light emitting layer thick, a porous Si / SiO ₂ composite structure can be produced by producing a macroporous Si layer in a hydrofluoric acid solution and then anodizing it with a solution other than hydrofluoric acid.
[0030]
Further, the light emission characteristics may be improved by annealing after the electrodeposition of the phosphor. This is considered to be caused by improvement in crystallinity and composition ratio of phosphor fine particles, shape change, and improvement in the interface with the porous portion.
[0031]
In order to evaluate the device characteristics of the optical functional thin film in which the phosphor thus obtained is embedded, an electric field may be applied by sandwiching the thin film between the transparent electrode and the back electrode. Here, particularly in the case of AC driving, the dielectric layer may be positively formed adjacent to the porous layer, but the porous SiO ₂ layer itself may serve as an insulating layer.
[0032]
The thin film thus obtained has optical functionality. In particular, the light emitting device has improved characteristics such as luminance, light emission efficiency, and life as compared with a conventional EL as a light emitting device, and its manufacturing method is simple.
Although the above description is limited to a Si wafer, a thin film such as polysilicon or amorphous silicon can be similarly produced.
[0033]
【Example】
The following examples further illustrate the present invention.
In addition, in the following Examples 1-3, Example 2 shows the Example of this invention, Example 1 and Example 3 show a reference example.
[0034]
Example 1
The optical functional thin film and the light emitting device according to the present invention will be described with reference to FIGS.
FIG. 5 is a schematic view of an AC driven dispersion type EL element using an anodized porous Si film.
[0035]
In FIG. 4, 41 is a Si wafer, 42 is a counter electrode, 43 is a mixed solution of hydrofluoric acid, water and ethanol, 44 is a Teflon container, and 45 is a constant current source. First, a solution in which hydrofluoric acid, ethanol, and water are mixed at 1: 1: 3 is prepared, and a p-type medium resistance substrate is used as an anode and platinum is used as a cathode at a current of several tens mA / cm ^{2 in} the solution. The porous Si is produced by flowing. Here, on the back surface of the Si substrate 52, an Al electrode was deposited as the back electrode 51 to form an ohmic junction. Although not shown, the back portion is shielded so that Al does not touch the solution during anodization. When the thickness of the porous layer 53 reaches several μm, the anodization is finished, the substrate is washed with distilled water, soaked in isopropyl alcohol, washed and dried, and then FE-SEM (Field Emission Electron Microscope: field emission scanning type) When observed with an electron microscope, a porous layer 53 shown in FIG. 5A was obtained.
[0036]
Next, in order to slightly oxidize the porous layer 53, anodization was performed for several seconds at 30 V in a 0.3 M sulfuric acid aqueous solution using the same apparatus as in FIG. Thereafter, it was washed with distilled water, dipped in isopropyl alcohol and then dried.
[0037]
Electrodeposition was performed in order to embed the phosphor in the pores of the porous layer 53 thus obtained. The same apparatus as in FIG. 4 can also be used for electrodeposition. In this case, the solution is an aqueous solution in which zinc nitrate is dissolved, and a power source capable of applying an AC pulse is used. The solution is an aqueous solution of zinc nitrate 0.1 mol / L, and a 15 V alternating current (50 Hz) voltage is applied for several tens of seconds while keeping the solution temperature at 50 ° C., and the inside of the porous layer as shown in FIG. Depending on the pore diameter, ZnO ultrafine particles 54 having a particle diameter of several tens to several hundreds of nanometers were electrodeposited. In this case, since ZnO may also adhere to the surface, the surface was cleaned and removed with phosphoric acid or the like for a short time, and then annealed in a reducing atmosphere for a short time.
[0038]
Next, in order to evaluate the characteristics of the porous film embedded with the obtained phosphor, an insulating layer 55 was first prepared. The insulating layer was a SiO ₂ thin film and was formed to a thickness of several hundreds of nm by sputtering. Here, the insulating layer is not necessarily made of SiO _{2 as} long as it is insulating and dielectric. A transparent electrode 56 was formed on the porous layer and the insulating layer 55 by ITO film formation.
[0039]
For comparison with this device, a light emitting layer was formed by embedding ZnO phosphor with low melting point glass on the same substrate, a SiO ₂ insulating layer was formed thereon, and an ITO transparent electrode was formed on the surface to produce an EL device. When an electric field of 300 V and 200 Hz was applied at room temperature to compare and evaluate the light emission characteristics, both devices showed similar light emission. However, when an electric field of 100 V and 100 Hz was applied, the device of the present invention had a higher emission intensity of 50% or more. That is, it can be seen that the characteristics at a low electric field and low frequency are excellent.
[0040]
Example 2
Next, another embodiment of the present invention will be described with reference to FIGS.
FIG. 6 is a schematic view of an AC driven dispersion type EL element using an anodized porous SiO ₂ film.
[0041]
First, porous SiO ₂ is produced by the apparatus shown in FIG. In this case, the aqueous solution is a 0.3M oxalic acid aqueous solution and is oxidized using the Si wafer as an anode. The Si electrode was fabricated by ohmic bonding an Al electrode of the back electrode 64 to the back surface. In this case, the voltage was set to a constant voltage of about 40 V, and processing was performed for several hours with a current value of several mA / cm ² . The current value first decreased rapidly and then fluctuated around several mA / cm ² . When the cross section of the porous layer 62 thus obtained was observed by FE-SEM, as shown in FIG. 6A, the structure in which the pores 63 were dispersed in the SiO ₂ matrix on the substrate 61, that is, the pore diameter was several nm. A porous film having fine pores opened in the form of sponge at several tens of nanometers was formed. These holes were not uniform when leaving the substrate surface, but were partially densely opened.
[0042]
Electrodeposition was performed in the same manner as in Example 1 in order to embed the phosphor in the pores of the porous film obtained as described above. However, since the insulating property of the porous layer was large, the applied voltage was set slightly higher. Electrodeposition was performed for several minutes and then washed in the order of distilled water and isopropyl alcohol. As a result of FE-SEM observation of the cross section of the obtained porous layer, as shown in FIG. A nanostructure in which 65 ZnO fine particles were embedded was obtained. The particle size of the phosphor fine particles 65 was several nm to several tens of nm reflecting the particle size of the pores.
[0043]
After the film thus obtained was annealed in a reducing atmosphere, a phosphor layer 66 capable of further ultraviolet excitation was formed on the phosphor layer by mixing the phosphor with a low melting point glass and baking it. Here, YVO ₄ : Eu ³⁺ , Y ₂ O ₃ : Eu ³⁺ , YBO ₃ : Eu ^3+, etc. were used as phosphors that can be excited by ultraviolet rays.
[0044]
Next, in order to evaluate the characteristics of the obtained optical functional thin film, a mask was applied so that unnecessary portions were not formed, and a transparent electrode 67 was formed by ITO film formation. In order to evaluate the characteristic of this element, it compared with the conventional EL element similar to Example 1. FIG. When the light emission was evaluated by applying an electric field of 400 V and 400 Hz at room temperature, the light emission intensity of the element of the present invention was 20% or more. Further, in the case of applying an electric field of 100 V and 100 Hz, the device of the present invention had a higher emission intensity of 60% or more. That is, it can be seen that the characteristics at a low electric field and low frequency are excellent.
[0045]
Example 3
Next, an embodiment having another aspect of the present invention will be described with reference to FIGS.
FIG. 7 is a schematic diagram of an AC and DC drive dispersion type EL element using a porous Si / SiO ₂ film.
[0046]
In FIG. 4, 41 is a Si wafer, 42 is a counter electrode, 43 is a mixed solution of hydrofluoric acid, water and ethanol, 44 is a Teflon container, and 45 is a current source. First, a solution in which hydrofluoric acid, ethanol, and water are mixed at 1: 1: 10 is prepared. In the solution, an n-type medium resistance substrate is used as an anode and platinum is used as a cathode at 10 to 20 mA / Porous Si is produced by applying a current of cm ² . Here, on the back surface of the Si substrate 71, an Al electrode as a back electrode 72 was deposited to prepare an ohmic junction. Although not shown, the back portion is shielded so that Al does not touch the solution during anodization. When the thickness of the porous layer reached several μm, the anodization was completed, washed with distilled water, washed by immersing in isopropyl alcohol, dried, and observed by FE-SEM. The macroporous shown in FIG. Layer 73 was obtained. The pore diameter of this macroporous was several μm.
[0047]
Next, porous SiO ₂ is produced using the same apparatus. In this case, the aqueous solution is a 0.3M oxalic acid aqueous solution and is oxidized using the Si wafer as an anode. In this case, the voltage was set to about 40 V, and the treatment was performed for several hours with a current value of several mA / cm ² . The current value first decreased rapidly and then fluctuated around several mA / cm ² .
[0048]
When the cross section of the porous layer thus obtained was observed by FE-SEM, as shown in FIG. 7B, a SiO ₂ porous layer 74 was formed from the pore 78 in the macroporous Si layer toward the inside of the substrate. This porous layer 74 was a porous film having a pore diameter of several nanometers to several tens of nanometers and fine pores opened like a sponge.
[0049]
Electrodeposition was performed in the same manner as in Example 1 in order to embed the phosphor in the pores of the porous film obtained as described above. However, the applied voltage was set slightly higher because of its high insulation. Distilled water alternating electrodeposition after applying a few minutes, and washed sequentially with isopropyl alcohol, result of a cross-section of the porous layer was FE-SEM observation, and the pores of the porous SiO ₂ as shown in FIG. 7 (c) A nanostructure in which ZnO was embedded in a part of the macroporous pore was obtained. The film thus obtained was annealed in a reducing atmosphere. The size of the phosphor fine particles was several tens of nanometers to several micrometers, reflecting the pore diameter.
[0050]
Next, in order to evaluate the characteristics of the obtained optical functional thin film, a surface electrode is formed. In this example, since macroporous Si is used, first, an electrode is formed inside the pore in the macroporous. Then, Sn was electrodeposited to form an internal electrode 76. Thereafter, a mask was applied so that unnecessary portions were not formed, and the surface transparent electrode 77 was formed by ITO film formation.
[0051]
In order to evaluate the characteristic of this element, it compared with the conventional EL element similar to Example 1. FIG. When light emission was evaluated by applying an electric field of 200 V and 200 Hz at room temperature, the light emission intensity of the element of the present invention was about 60% higher. Further, the decay rate of the emission intensity after driving for 10 hours was about 40% smaller in the device of the present invention. This shows that the device of the present invention is improved in both brightness and life.
[0052]
Further, light emission was observed even when a negative DC electric field was applied to the back electrode 72 and a positive DC electric field was applied to the surface electrode 77. That is, this element can also be applied as a DC drive EL.
[0053]
【The invention's effect】
As described above, the following effects can be obtained by using the optical functional thin film, the light emitting device, and the manufacturing method thereof of the present invention.
1) An optical functional thin film having a light emitting function can be obtained by a simple method.
2) An efficient light-emitting device can be obtained at constant voltage and low frequency.
3) A light-emitting device that can be easily combined with Si is obtained.
4) A simple method for producing an optical functional thin film or a light emitting device is provided.
[Brief description of the drawings]
FIG. 1 is a schematic view of an AC drive distributed EL element.
FIG. 2 is a schematic view of a DC drive distributed EL element.
FIG. 3 is a schematic view of an EL element using porous Si.
FIG. 4 is a schematic view of an anodizing, anodizing, and electrodeposition reactor.
FIG. 5 is a schematic view of an AC driven dispersion type EL element using an anodized porous Si film.
FIG. 6 is a schematic view of an AC driven dispersion type EL element using an anodized porous SiO ₂ film.
FIG. 7 is a schematic view of an AC and DC drive dispersion type EL element using a porous Si / SiO ₂ film.
[Explanation of symbols]
11, 21, 41 Substrate 21, 22, 56, 67, 77 Transparent electrode 13, 23 Light emitting layer 14 Dielectric layer (insulating layer)
15, 24, 34, 51, 64, 72 Back electrodes 31, 52, 61, 71 Si substrate 32 Porous Si layer 33 Surface electrode 42 Counter electrode 43 Electrolyte 44 Reaction vessel 45 Power supply 53 Porous layer 54 Phosphor 55 Insulating layer 62 Porous SiO ₂ layers 63 and 78 Pore 65 Phosphor fine particles 66 Phosphor layer 73 Macroporous layer 74 SiO ₂ porous layer 75 Phosphor dispersion layer 76 Internal electrode

Claims (7)

Process part or all over the base plate to form a porous layer is a SiO ₂ substrate made of Si by positive Gokusan of in an aqueous oxalic acid solution, dispersing the phosphor particles in the porous layer formed The manufacturing method of the optical functional thin film characterized by having a process. The method of manufacturing an optical functional thin film according to claim 1 Symbol placing the phosphor electrodeposited dispersing the phosphor particles in the porous layer. After the anode oxidation, or a method of manufacturing an optical functional thin film according to claim 2 Symbol placing comprising the step of annealing after electrodeposition of the phosphor. The said anodic oxidation WHEREIN: Al electrode is ohmic-bonded with respect to the board | substrate which consists of Si on the back surface of the board | substrate which consists of said Si, The board | substrate which consists of said Si is an anode, The anode is characterized by the above-mentioned. Manufacturing method of optical functional thin film. 5. The method for producing an optical functional thin film according to claim 4, wherein the phosphor fine particles are ZnO fine particles. 6. The method for producing an optical functional thin film according to claim 5, further comprising a step of annealing in a reducing atmosphere and a step of further providing a phosphor layer after the step of dispersing the phosphor fine particles. The step of further providing the phosphor layer includes coating and firing the phosphor layer by mixing any one of YVO ₄ : Eu ³⁺ , Y ₂ O ₃ : Eu ³⁺ , YBO ₃ : Eu ³⁺ and low melting point glass. The method for producing an optical functional thin film according to claim 6, wherein the optical functional thin film is produced by the following process.

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