KR101216550B1 - Synthesizing process of phospher and manufacturin method of phospher thick film with the same - Google Patents

Abstract

The present invention relates to a method for producing a phosphor and a method for producing a phosphor thick film using the same, the method for producing a phosphor used for field emission display (FED), comprising: (a) Y (NO ₃ ) ₃ · 6H as a starting material; Dissolving 2O, Eu (NO ₃ ) ₃ .5H ₂ O and Li (NO ₃ ) with excess citric acid and distilled water to form a solution, (b) adding an aqueous ammonia solution to the solution dissolved in step (a) By primary heating, secondary heating in a gel state to combust, and then primary grinding to produce a precursor, (c) primary precursor heat treatment of the precursor in step (b), followed by secondary grinding to form a powder And (d) subjecting the powder in step (c) to secondary heat treatment at a predetermined temperature for a predetermined time to synthesize a phosphor.
By using the above-described method for producing a phosphor and a method for preparing a thick film of a fluorescent substance using the same, the present invention synthesizes the phosphor by the sol-gel method and has excellent crystallinity and luminescence characteristics at a low temperature compared to the solid phase method, which is a general synthesis method. Phosphors can be synthesized.

Description

Method for manufacturing phosphor and method for manufacturing phosphor thick film using same {SYNTHESIZING PROCESS OF PHOSPHER AND MANUFACTURIN METHOD OF PHOSPHER THICK FILM WITH THE SAME}

The present invention relates to a method for manufacturing a phosphor and a method for fabricating a phosphor thick film using the same, and more particularly, field emission display in an oxide-based phosphor by using a sol-gel method, which is a fine powder synthesis method. The present invention relates to a method for synthesizing a Y ₂ O ₃ : (Li, Eu) phosphor emitting red light used for display, FED) and a method for producing a phosphor thick film using the synthesized phosphor powder.

In general, luminescence materials, or phosphors, include fluorescent lamps, X-ray screens, cathode ray tubes (CRTs), plasma display panels, and PDPs. ), An inorganic solid material having a luminescence phenomenon used in a very wide field as a display element such as FED.

The phosphor consists of an inorganic host lattice and a small amount of activator. When the energy lattice absorbs energy from a specific excitation source and transfers energy to the surrounding activator, the electrons transferred to the excited state are bottomed out. As it transitions to a state, it releases energy.

In this case, a material that emits energy in the form of light is called a phosphor, and this transition mechanism is called light emission.

FIG. 1 is a view illustrating a process in which a phosphor receives energy and emits light, and FIG. 2 is a view illustrating a light emitting mechanism of the phosphor shown in FIG. 1.

 Luminescence depends on the type of excitation source: photoluminescence, cathodoluminescence, electroluminescence, X-ray luminescence, radioluminescence, thermoluminescence, chemical Chemiluminescence and the like.

Table 1 is a table classifying the application equipment according to the excitation source of the phosphor.

Luminous energy Excitation energy Application device Cathodoluminescence
(Cathode ray emission) Cathode ray Color CRT 5-35 kV Mono CRT 20 V-1 kV FED Photoluminescence
(Light emission) X-ray Increase and decrease UV-rays For Computer Tomography (CT) 147 nm PDP 254 nm Fluorescent lamp 250-400 nm General lighting, mercury lamp Visible light Luminous paints, fluorescent pigments Electroluminescence
(Electroluminescence) Electric field EL display

Phosphors are largely composed of an activator, an inorganic lattice, and a sensitizer, each of which plays a different role.

 The activator acts as a luminescence center and refers to ions that actually emit light, and is mainly composed of rare earth elements.

Rare earth elements exhibit luminescent properties with good color purity due to inner transitions of unfilled 4f-electrons and external electrons in the crystal field of the host by shielding effects. The advantage was less sensitivity. These rare earth elements in mainly ^{3 +} Ce, Pr ^{+ 3,} Eu ^{+ 3,} Tb ^{+ 3,} Ho ^{+ 3,} such as Mn ^{2 +,} Bi ^{3 +,} is used.

The above-mentioned elements absorb or release energy by transition between the base level and the excitation level. At this time, the form of energy emitted is divided into a radiation transition in the form of electromagnetic waves and a non-radiation transition in the form of heat.

The seed lattice serves to hold the activator ions in the lattice.

However, recent research on phosphors has noted that the effect of the drone grating on phosphors is very large.

That is, in order to develop a phosphor having high optical efficiency, researches on absorption by the lattice lattice and how efficiently the absorbed energy transfers to the activator are conducted rather than energy absorption by direct excitation of the activator. .

The sensitizer does not absorb or emit light by itself, but serves to increase the luminescent efficiency of the active agent.

Therefore, it was possible to increase the brightness by adding a sensitizer to the phosphor. However, the exact effect of the sensitizer addition is not known to date.

The sensitizer increases the crystallinity of the mother or improves the conductivity to act as a co-ativator in the mother, thereby increasing the energy transfer efficiency or the doping efficiency of the active agent. 'S research is in progress. This effect of the sensitizer is believed to affect the luminance, color coordinates, decay time, and luminous efficiency of the phosphor.

On the other hand, sulfide-based (Y ₂ O ₂ S, ZnS: (Ag, Cl), ZnS: (Al, Cu), etc.) phosphors have been known as inorganic phosphors, and are mainly used for cathode ray tubes (CRTs). Has been.

Since its inception in 1897 by K. F. Brown of Germany, the CRT has been the most common display, delivering information to us over the last century.

However, in recent years, as information users want to receive information faster due to the rapid development of industrial society, they overcome the inconvenience caused by the increase in weight and volume due to the large screen of the conventional CRT, and have a wide viewing angle and a thin and light Flat panel displays, such as liquid crystal displays (LCDs), PDPs, FEDs, and ELs, have shown rapid progress.

In particular, FED, a field emission display whose research and development is rapidly accelerating at home and abroad, was spotlighted as a new thin and light flat panel display while maintaining the advantages of the conventional CRT.

In order to put the FED into practical use, research has been conducted on the type of substrate, the material and manufacturing technology of the tip, the vacuum packaging technology, the driving method, and the development of the phosphor. In particular, there has been a demand for the development of phosphors suitable for the FED driving method.

That is, in order to use the existing phosphor for CRT as it is, the anode potential must be raised to tens of thousands of volts, which is difficult to drive in the FED structure in which the distance between the cathode and the screen is maintained at less than 1 mm. Therefore, there is a need for a low voltage phosphor capable of driving at a low voltage and obtaining high luminance.

In addition, sulfide-based phosphors used in conventional CRTs are easily deteriorated by electrons, degassing in the phosphors, lowering the degree of vacuum of the FED device, and problems such as emitter tip contamination occur.

Therefore, since sulfide-based phosphors used in conventional CRTs have low luminous luminance, phosphors having excellent deterioration characteristics and high luminous efficiency have been required in the FED.

In order to solve such a problem, research and development of an oxide-based phosphor has begun as an alternative to a sulfide-based phosphor.

In particular, studies have been actively conducted on the synthesis method of an oxide-based phosphor for producing a phosphor having high luminous efficiency, thermally stable to a light source, and having excellent particle size characteristics.

As a typical method of synthesizing an oxide-based phosphor, a high temperature solid-state method, a sol-gel method, a coprecipitation method, a hydrothermal reaction method, a combustion method, and the like have been known.

Among them, the high temperature solid-state method was able to synthesize phosphors having good color purity and luminance characteristics through a relatively simple process.

However, the oxide phosphors synthesized by the high temperature solid-state method have irregular materials and structural uniformity because the starting material samples require a high temperature and a long heat treatment process in order to be a perfect solid solution. There was a disadvantage such as falling, the size of the phosphor particles irregularly large.

These characteristics have made it difficult to apply to high performance screens and flat panel display devices.

Accordingly, attempts have been made to synthesize phosphors having a uniform composition and excellent crystallinity at low temperatures by mixing materials in atomic units through other methods listed above rather than the high temperature solid state method.

In addition, studies to improve the fluorescence efficiency by changing the energy transfer process between the activator and the lattice lattice by controlling the concentration of the activator or co-incorporating impurities in the crystals are being conducted.

On the other hand, there have been various methods of forming the phosphor film.

In general, when making a film for a fluorescent lamp, first, a phosphor slurry should be prepared, which includes a phosphor, a binder, a nonionic or anionic surfactant for reducing solvent and surface tension, and nonionic for preventing bubbles. Add an antifoaming agent. At this time, the thickness of the film is controlled by the viscosity of the slurry and the dose of the phosphor, that is, the specific gravity.

Since the phosphor is subjected to a high temperature firing process in order to remove the organic binder and maintain a vacuum state, the phosphor should have adhesion with glass. Thus, an adhesive is added to make the phosphor have adhesion with glass.

Two types of adhesives are used, which are divided into calcium pyrophosphate and barium calcium borate.

The application process uses a flow down process.

First, the phosphor slurry is flowed into the inside of the tube, followed by blowing in warm air to dry it. At this time, the dried tube is heat-treated at around 500 ~ 600 ℃ to decompose the organic material to form a film.

Next, there were a method of making a phosphor film for CRT, a precipitation method, a photolithography method, a printing method, an electrophoresis method.

The precipitation method is a method used in monochromatic CRT.

The material used for the precipitation method is Ba (NO ₃ ) ₂ or Ba (CH ₃ CO) ₂ as an electrolyte material, and water glass (K-silicate or Na-silicate) is used as the binder.

In the precipitation method, as the phosphor precipitates, silicates (silicate) and barium (Ba) in the surrounding water glass form a complex to form a mesh so that the phosphor does not fall.

Photolithography is suitable for forming a multi-color phosphor film and has the advantage of making a fine line width, which has been widely used in the phosphor film manufacturing process of color CRT.

Materials used in photolithography are photosensitive resins, solvents, dispersants and phosphors.

The photosensitive resin currently used in CRT is a mixture of polyvinyl alcohol (PVA, molecular weight 70,000-80,000) and ammonium dichromate ((NH ₄ ) ₂ Cr ₂ O ₇ ). Dispersants, surfactants and the like.

As the phosphor film forming method formed on the photosensitive resin, a rotation coating method was used.

In the rotary coating method, as the phosphor has a specific gravity, a thickening of the film of the phosphor occurs at the center, so that the phosphor is tilted to maintain a certain angle so that the phosphor does not stay in the center part for a long time.

In the CRT, the line width can be adjusted to some extent by the amount of light.

In other words, in order to make the line width thicker, it is possible to make the adjustment by increasing the intensity of the light quantity or by increasing the irradiation time of the light quantity.

 In the PVA-Cr photoresist, the coupling reaction between the glass and the phosphor is caused by a chemical bond between the polymer resin and the -OH group of the glass.

Typically 14% HF solution is used to make -OH groups in the glass. The 14% HF treatment etches the glass surface, creating a large number of -OH groups on the glass surface.

The printing method has a simple film forming process and can form both monochromatic and multicolored patterns. However, the printing method has been used for PDP and VFD because it can be used only for flat glass.

This printing method is not suitable for the transmissive phosphor film but suitable for the reflective phosphor film due to the film thickness and the presence of a large amount of pin holes.

In addition, the printing method is inferior in film thickness uniformity, and a large amount of pinholes exist, thus requiring two or more printing processes, and a high organic viscosity is required to maintain the viscosity of the phosphor paste. This is necessary.

In general, the composition of the paste used in the PDP process is a mixture of ethyl cellulose as an organic binder and butyl carbitol acetate (BCA) and butyl carbitol (BC) as a solvent. Or terpineol. At this time, a three roll miller is used to mix and disperse each material well with the phosphor.

However, the line width of the film capable of forming the phosphor film by the printing method is limited and there are some problems in forming a high resolution film.

Electrophoresis has the advantage of reducing the consumption of the phosphor, the process can be simple to reduce the line width. On the other hand, there must be an electrode and there is a problem in the application of a large area.

The phosphor film formed by the electrophoresis method is suitable for forming a phosphor film, which is difficult to coat the phosphor, and thus has aluminum on the back of the glass and asymmetrically curved door video phones and vaccum fluorescent displays, VFD) has been applied.

The difficulty in forming the phosphor film using the electrophoresis method is that the management of the electrolyte solution has caused some difficulty in setting the conditions. In this case, Al (NO ₃ ) ₃ , La (NO ₃ ) _3, and Mg (NO ₃ ) ₂ are used as electrolytes.

In the method of forming a phosphor film using electrophoresis, the above electrolyte material is dissolved in isopropyl alcohol (IPA) and dissolved, and then a small amount of water is added to make a slurry, or a slurry is made using pure water. After connecting the cathode of the electrode to the surface to be coated with the phosphor, and the anode is connected to a conductive electrode such as a stainless steel sheet to connect a power source while maintaining a suitable distance, for example about 1 ~ 2 cm to form a coating film. At this time, the thickness of the membrane was controlled by the amount of the electrolyte, the voltage and the distance between the electrodes.

However, in addition to the general method of forming a phosphor film as described above, a method for manufacturing a phosphor thick film by coating SiO ₂ nanoparticles on the surface of a phosphor of a fine powder synthesized by a sol-gel method and coating the coated phosphor on a glass substrate Research is needed.

The present invention is to solve the problems described above, an object of the present invention is to provide a method for producing a phosphor capable of synthesizing a phosphor having a uniform composition and excellent crystallinity and luminescence properties at low temperatures.

Another object of the present invention is to provide a method for producing a thick phosphor film that can form a uniform film using a phosphor powder coated with SiO ₂ nanoparticles.

According to a feature of the present invention for achieving the above object, the present invention is a method for producing a phosphor used for field emission display (FED), (a) starting material Y (NO ₃ ) ₃ · 6H Dissolving 2O, Eu (NO ₃ ) ₃ .5H ₂ O and Li (NO ₃ ) with excess citric acid and distilled water to form a solution, (b) adding an aqueous ammonia solution to the solution dissolved in step (a) By primary heating, secondary heating in a gel state to combust, and then primary grinding to produce a precursor, (c) primary precursor heat treatment of the precursor in step (b), followed by secondary grinding to form a powder And (d) synthesizing the phosphor by performing a second heat treatment on the powder in the step (c) at a predetermined temperature for a predetermined time.

The phosphor may be a _{Y 1 .9- x Li 0 .1 Eu} x O 3 (x = 0,02, 0.05, 0.08, or 0.12).

In the step (b), the aqueous ammonia solution is added until the pH of the solution formed in the step (a) is 4 ~ 5.

In step (b), the second heating is performed for 24 hours, and in step (c), the first heat treatment is performed for 10 hours at 650 ° C.

In the step (d), the preset temperature is any one of 750, 850, 950, 1050, and 1150 ° C, and the predetermined time is 5 hours.

According to another feature of the present invention, the present invention includes the step of coating the powder SiO ₂ nanoparticles of the phosphor and (f) preparing a phosphor thick film using the phosphor powder coated in step (e), The step (e) is a step of (e1) mixing the additives including the phosphor powder, water and silica anions as starting materials and stirring for a predetermined time, (e2) the solution stirred in the step (e1) Separating the phosphor powder and the stirring solution by centrifugation for a period of time, (e3) removing the supernatant centrifuged in the step (e2) and adding a certain amount of distilled water to the remaining solution by using a stirrer to excess SiO ₂ And (e4) precipitating and drying the phosphor powder solution washed in the step (e3), followed by drying to form the phosphor powder.

In the step (e1), the stirring operation is performed for 2 hours, in the step (e2), the centrifugation operation is performed at 2000 rpm for 10 minutes, and in the step (e3), the drying operation is performed in an 80 ° C. dry oven at 24 ° C. It is carried out for a time, the steps (e2) and (e3) is characterized in that it is carried out three times.

Step (f) comprises the steps of (f1) removing foreign substances on the surface of the glass substrate, (f2) mixing the phosphor powder coated with the SiO ₂ nanoparticles and glycerin to prepare a paste, and (f3) the agent ( a twenty-third step of spin coating the paste prepared in step f2) onto the glass substrate; (f4) drying the thick film prepared in step (f3) in a dry oven for a predetermined time; and (f5) the agent ( and annealing the thick film dried in the step f3) in an electric furnace.

The drying operation in the (f4) step is carried out for 1 hour in a dry oven at 150 ℃, the annealing operation in the (f5) step is carried out for 1 hour in an electric furnace of 700 ℃, step (f3) Step (f4) is characterized in that it is carried out three times.

As described above, the present invention synthesized the phosphor by the sol-gel method was able to synthesize a phosphor having excellent crystallinity and luminescence properties at a lower temperature than the solid phase method, which is a general synthesis method.

In addition, the present invention was able to induce the liquid phase sintering with Li, which is substituted together while synthesizing the phosphor by the sol-gel method, to spheroidize the particle size of the phosphor, and act as a co-activator to increase the luminance of the phosphor.

In addition, the present invention is SiO ₂ Thick films could be prepared using the particles coated with phosphor powder.

In particular, the present invention is spheroidized particle shape using a powder substituted with Li to SiO ₂ The particles were uniformly coated on the surface of the powder to increase the luminescence properties of the thick film. In addition, the present invention was able to increase the number of coatings to increase the filling degree of the powder on the substrate to increase the luminescence properties.

In addition, the present invention is excellent in light emission characteristics than the thin film method produced by the PLD method and can be produced very easily economically, and has an improved effect than the thin film method produced by the PLD method in view of the application of the thin film for FED.

1 is a diagram illustrating a process in which a general phosphor emits light upon receiving energy.
2 is a view showing a light emitting mechanism of the phosphor shown in FIG.
3 is a flowchart illustrating a step-by-step method of manufacturing a phosphor according to a preferred embodiment of the present invention.
Figure 4 is a diagram showing the X-ray diffraction pattern measured after the synthesis by the Sol-gel method by substituting Eu to Y ₂ O ₃ in accordance with the present invention after heat treatment at each temperature.
5A and 5B illustrate Y _{2 - x} Eu _x O ₃ And _{Y 1 .9- x Li 0 .1 Eu} x O 3 X-ray diffraction pattern measured after the sample was synthesized by the sol-gel method and heat-treated.
Figure 6a is a diagram showing the X-ray diffraction pattern of the sample after the heat treatment at 650 ℃.
FIG. 6B shows an X-ray diffraction pattern of a sample separately displaying FWHM on plane (222). FIG.
7 is a sole according to the invention the gel method Y _{1 .92} Eu _{0 .08} O ₃ synthesized in And _{Y 1 .82 Li 0 .1 Eu 0} .08 O 3 Figure showing a scanning electron micrograph according to the heat treatment temperature of the phosphor powder.
8 is a view showing a morphology change according to the heat treatment temperature of the Y ₂ O ₃ : Eu phosphor powder substituted with Li after 650 ° C. heat treatment.
9A and 9B are diagrams showing the photoluminescence spectra after the phosphor powder heat-treated at 650 ° C., step-by-step, and then excited at 254 nm.
Fig. 10 is a diagram showing emission spectra when Li is not substituted for Y ₂ O ₃ : Eu phosphor powder at the same temperature, respectively.
11 is a _{Y 1 .9- x L i0 .1 Eu} x O 3 heat-treated at 1050 ℃ Figure showing the photoluminescence spectrum of the powder.
12 is a flowchart illustrating a step-by-step method of coating SiO ₂ nanoparticles on the phosphor powder used in the method for producing a phosphor thick film according to the present invention.
13 is SiO ₂ Flow chart explaining step by step a method for producing a phosphor thick film using a nanoparticle-coated phosphor powder.
14A and 14B illustrate Y ₂ O ₃ : Eu obtained by heat treating a precursor synthesized by the sol-gel method at 650 ° C. X-ray diffraction pattern of a thick film made of powder heat-treated at various temperatures.
15 is a diagram showing an X-ray diffraction pattern according to the number of coatings of a thick film.
Figure 16 is SiO _2, before and after the nanoparticles coated with _{Y 1 .82 L i0 .1 Eu 0} .08 O 3 Figure showing the powder.
Figure 17 is a Y ₁ a heat treatment at _{1050 ℃ .82 L i0 .1 Eu 0} .08 O 3 Scanning electron micrograph according to the number of coating of thick film made using powder.
Figure 18a and 18b are Y _{1 .921} Eu _{0 .08} O ₃ powder and _{Y 1 .82 L i0 .1 Eu 0} .08 O 3 A diagram showing a photoluminescence spectrum of a thick film made by using powder after heat treatment at different temperatures.
FIG. 19 is a diagram showing a light emission spectrum of a thick film film made using a powder in which Li is not substituted and a powder in which Li is substituted.
20 is a diagram showing a light emission spectrum of a thick film with respect to a change amount of Eu.
Figure 21a is a _{Y 1 .82 L i0 .1 Eu 0} .08 O 3 A diagram showing the photoluminescence spectra of thick films made by rudox coating of powders and thick films made without rudox coating.
FIG. 21B is a diagram showing a light emission spectrum of a thick film according to the number of ludox coatings. FIG.
FIG. 22A is a diagram showing cathode emission spectra depending on the amount of Eu substituted in a Y ₂ O ₃ : (Li, Eu) thick film at an anode voltage of 1 kV. FIG.
Fig. 22B is a graph showing the cathode emission intensity at 612 nm according to the amount of Eu substituted in Y ₂ O ₃ : (Li, Eu) according to the voltage applied to the anode;
FIG. 23A is a diagram showing cathode emission spectra according to the number of coatings of a thick film without Li substitution and a Li substituted thick film in a Y ₂ O ₃ : (Li, Eu) thick film while applying an anode voltage at 1 kV. FIG.
FIG. 23B shows the cathode emission spectrum at 612 nm according to the number of coatings in Y ₂ O ₃ : (Li, Eu) according to the voltage applied to the anode; FIG.
Fig. 24 is a diagram showing the light emission spectra of a thick film made by spin coating and a thick film made by PLD.

Hereinafter, a method for manufacturing a phosphor according to a preferred embodiment of the present invention and a method for manufacturing a phosphor thick film using the same will be described in detail with reference to the accompanying drawings.

In the present embodiment, Y ₂ O ₃ : (Li, Eu) phosphor, which is a red light emitting phosphor for FED, is synthesized by the sol-gel method, which is a fine powder synthesis method, and a thick film using the synthesized phosphor powder. To prepare a comparative analysis of the fluorescence characteristics between the phosphor powder and the thick film of the phosphor.

In addition, the fluorescence characteristics of the phosphor powder and the phosphor thick film by the method of manufacturing a phosphor according to the present invention and a method of manufacturing a phosphor thick film using the same by manufacturing a thin film using a pulsed laser deposition (PLD) And so on.

Therefore, the method of manufacturing the phosphor and the method of fabricating the phosphor thick film using the same will be described sequentially.

First, a method of manufacturing a phosphor according to a preferred embodiment of the present invention will be described.

3 is a flowchart illustrating a step-by-step method of manufacturing a phosphor according to a preferred embodiment of the present invention.

Phosphor production method according to the invention Y _{2 -x- y} Li _x Eu _y O ₃ (x = 0.02, 0.05, 0.08, 0.12, y = 0, 0.1) In order to synthesize the phosphor by the sol-gel method, each raw material shown in Table 2 below is used as a starting material, and is calculated stoichiometrically. Weigh precisely using chemical balance.

Table 2 is a table of reagents used for the synthesis of phosphors.

reagent water Molecular Weight Y (NO ₃ ) ₃ · 6H ₂ O 99.90% 383.01 Eu (NO ₃ ) ₃ .5H ₂ O 99.90% 428.05 Li (NO ₃ ) 99.90% 68.94

As shown in Figure 3, the samples listed in Table 2, the molar ratio (molar ratio of citric acid / metal) is dissolved in excess citric acid (citric acid) and distilled water to make a solution (S10).

The aqueous solution of ammonia (NH ₄ OH) is added until the pH of the solution reaches 4 to 5, and then slowly heated firstly with a heater (S11). Then, the sol becomes viscous as the viscosity becomes larger.

The gel state as described above is continuously heated by a heater to burn for about 24 hours (S12).

Subsequently, the burned material is put in a mortar and first ground (grinding) for 30 minutes or more (S13).

The precursor thus obtained was subjected to primary heat treatment at 650 ° C. for 10 hours (S14), and then finely ground in a grinder as secondary grinding (S15), and then 5 hours at various temperatures of 750, 850, 950, 1050, and 1150 ° C., respectively. During the second heat treatment during Y _{2 -x- y} Li _x Eu _y O ₃ A phosphor is synthesized (S16).

The temperature increase rate in the step S16 is preferably set to 5 ° C / min.

Y _{2 -x- y} Li _x Eu _y O ₃ synthesized by the sol-gel method according to the present invention To analyze the phosphor powder characteristics, X-ray diffraction analysis, scanning electron microscopy (SEM) analysis and photoluminescence (PL) intensity analysis were performed.

X-ray diffraction (XRD) analysis was performed using an X-ray diffraction tester (Shimazu, XRD-6000 model) using Cu-Kα radiation (λ = 1.5418 Hz) with an acceleration voltage of 30 kV and a current of 30 mA. , Diffraction angle (2θ) in the range of 10 to 70 °.

Here, the scanning rate of the X-ray diffraction tester is 2 ° per minute to obtain a diffraction spectrum, the crystallinity of the phosphor powder according to the effect of substituting Li, the heat treatment temperature of the phosphor synthesized by the sol-gel method Reference is made to powder diffraction file of Joint Committee on Powder Diffraction Standards (JCPDS).

Scanning electron microscopy (SEM) analysis was carried out at 15㎸ to measure the change of surface shape and particle size of phosphor powder according to the effect of substituting Li and heat treatment temperature of phosphor synthesized by sol-gel method. It observed using SEM (Hitachi, S-4200 model).

In addition, in order to obtain a photoluminescence (PL) spectrum of the phosphor according to the present invention, it was measured at room temperature using a spectrophotometer (Shimazu, RF-5301PC model).

The phosphor synthesized according to the present invention was ground in a mortar and mounted on a holder for measurement of luminescence, and the emission spectrum was obtained by exciting the sample at a wavelength of 254 nm in the range of 550 to 650 nm.

Here, in the emission measurement, a filter (UV-39) was used to remove the second order Rayleigh scattering of the excitation wave.

4 is a diagram showing an X-ray diffraction pattern measured after synthesis of the Eu in Y ₂ O ₃ by the sol-gel method and heat treatment at each temperature according to the present invention.

As shown in FIG. 4, in the case of the synthesized Y ₂ O ₃ : Eu phosphor, the X-ray diffraction pattern was compared with the JCPDS card, and as a result, all of the synthesized samples were obtained from the cubic system of the Ia3 space group. It can be seen that it was synthesized as a single phase compound.

In addition, single phase formation was possible in the sample heat-treated at 650 ° C., and the crystallinity of the synthesized sample was improved as the temperature was increased.

In general, in the solid phase reaction, the smaller the particle size and the closer to the spherical shape, the easier the surface diffusion is because the specific surface area becomes larger.

However, in the solid phase reaction method, there is a limit in reducing the size of the particles, it is difficult to control the shape of the particles, and high temperature heat treatment is required to form a single phase.

On the other hand, in the sol-gel method, since the components are uniformly mixed in atomic units, the materials are easily diffused with each other to form a single phase at a low temperature.

In other words, in the sol-gel method, the particles had a high specific surface area and thus could easily participate in the reaction.

Figures 5a and 5b _{Y 2 - x Eu x O 3} (x = 0,02, 0.05, 0.08, 0.12) , and _{Y 1 .9- x Li 0 .1 Eu} x O 3 (x = 0,02, 0.05 , 0.08, 0.12, Li = 100% excess) X-ray diffraction pattern measured after the sample was synthesized by the sol-gel method and heat-treated again at 650 ° C and then heat-treated at 1050 ° C for 5 hours. to be.

X-ray diffraction patterns of the synthesized samples as shown in FIGS. 5A and 5B were compared with the JCPDS card. As a result, all of the synthesized samples were synthesized as a single phase compound of the cubic system of the Ia3 space group. I could see that.

At this time, substituted Li and Eu do not affect the structure of Y ₂ O ₃ and Gd ₂ O ₃ or form a secondary phase.

Figure 6a is a view showing the X-ray diffraction pattern of the samples after the heat treatment at 650 ℃ to determine the effect of substituting Li in Y ₂ O ₃ : Eu, Figure 6b is a FWHM on the (222) plane X-ray diffraction pattern of samples separately (full width at half maximum).

As shown in FIGS. 6A and 6B, a broad peak sharpens due to Li substitution at 0.35 ° while Li is substituted at 0.71 ° while Li is not substituted. And it was found.

In view of these results, Li increases the crystallinity of the synthesized Y ₂ O ₃ : Eu phosphor.

That is, lithium compounds such as LiF, Li ₂ CO ₃ are well known as co-dopants, in particular fluxes, especially in solid-solid reactions, and have been reported for the consequences of Li incorporation. There is a bar.

In the present invention, Li induces liquid-phase sintering to increase crystallinity.

Figure 7 (a), (b) is the sole according to the invention the gel method Y _{1 .92} Eu _{0 .08} O ₃ synthesized in And Y _1.82 Li _0.1 Eu _0.08 O ₃ a diagram showing a scanning electron micrograph of the heat treatment temperature of the phosphor _{powder, Y 1 .92 Eu 0 .08 O} 3 And Y _{1 .82} Li _{0 .1} is a SEM picture of the rear Eu _{0 .08} O ₃ after the heat treatment at 950 ℃ for 5 hours.

As shown in (a) of FIG. 7, the phosphor powder before Li is substituted has an irregular particle size distribution, and even when it appears to be large particles, only the fine particles appear to be agglomerated.

However, as shown in FIG. 7B, Li-substituted phosphor powder has fine particles disappearing, and the particles have a rounded shape and have a particle size of about 600 nm.

As shown in FIG. 6, Li induces liquid phase sintering to increase crystallinity and promote growth of particles. This liquid phase sintering is carried out in three stages: rearrangement, solution precipitation, and Ostwald ripening.

For example, in the case of Y ₂ O ₃ : Eu phosphor, the white precursor is obtained by 650 ° C. heat treatment after synthesis by the sol-gel method, and when heat treatment is performed at a higher temperature, Li ₂ CO ₃ -Li ₂ O in the precursor. The mixture is first melted and reacted with an eutectic liquid of Y ₂ O ₃ , Eu ₂ O ₃ .

That is, the sharp edges of the solid particles are dissolved by the liquid phase of the Li ₂ CO ₃ -Li ₂ O mixture to smooth the surface of the particles, followed by the formation of larger rounded particles.

8 is a view showing a morphology change (morphology) according to the heat treatment temperature of the Y ₂ O ₃ : Eu phosphor powder substituted Li after 650 ℃ heat treatment.

As shown in (a) to (f) of FIG. 8, as the heat treatment temperature increases, the fine particles aggregate to form one particle, and the particle size increases.

On the other hand, as shown in Figure 8 (f), it appears in the form of non-uniform debris having a particle distribution of about 3 ~ 6㎛ size at 1150 ℃.

Therefore, Y ₂ O ₃ : Eu, as shown in (e) of FIG. 8, it was found that heat treatment at 1050 ° C. had the largest particle size of about 1 μm on average, and the shape was close to a spherical shape.

  In general, the conditions for increasing the luminous efficiency of the phosphor, the optimum conditions of the chemical composition and the distribution of the particle size and conditions of the particle shape are required. In general, when the powder particles become spherical, light scattering on the surface is not only reduced, but also has a high filling density, thereby increasing the luminous efficiency.

Y ₂ O _3: Eu in the phosphor powder and the Y ₂ O ₃ the grid owner and acts as the activator is Eu ^{3 +.} In this case, Y ₂ O ₃ is an equiaxed system belonging to the Ia3 space group.

Peaks for emitting light in 612㎚ impurities in the form of a structure (Eu ^{+ 3)} whereby the excitation energy is transferred to Eu ^{3 +} the active agent absorbed by the grid owner by occupying the Y position, ⁵ D ₀ of Eu ³⁺ ions Red light is emitted by the transition from the excitation level of to the base level of ⁷ F ₂ .

9A and 9B are diagrams showing the photoluminescence spectra after the phosphor powder heat-treated at 650 ° C. is subjected to heat treatment step by step and then excited at 254 nm.

As shown in FIG. 9A, the light emission intensity increases as the temperature after heat treatment increases. However, when Li is substituted as shown in FIG. 9B, the difference in emission intensity between 1050 ° C. and 1150 ° C. is not so large.

This phenomenon is due to the worse morphology at 1150 ° C as compared to 1050 ° C, as seen in the SEM photograph of FIG. 8.

On the other hand, as shown in Figs. 9a and 9b, the light emission intensity increased as the heat treatment temperature increases. This is because the crystallinity of the phosphor increases as the heat treatment temperature increases.

FIG. 10 is a diagram showing emission spectra when Li is not substituted for Y ₂ O ₃ : Eu phosphor powder at the same temperature, respectively.

As shown in Fig. 10, the phosphor powder (b) substituted by Li increases about two times as much as the luminescence intensity at 612 nm than the phosphor powder (a) without substitution.

Li ⁺ is substituted with Eu ^{3 +} is Li ⁺ with itself as a sensitizer (sensitizer) is a luminescent center ion, but acts as a sort of common surfactants (co-activator) to increase the luminous efficiency of the active agent is Eu ^{3 +.}

In view of the shape of the particles in the SEM photograph shown in FIG. 8, Li ⁺ serves as a kind of flux to promote crystallinity of the lattice lattice that induces liquid phase sintering.

For this reason, Li ⁺ is The emission intensity of the substituted Y ₂ O ₃ : Eu is higher than that of Y ₂ O ₃ : Eu.

Y ₂ O ₃ The structure shows _two crystallographically different sites with C ₂ and S ₆ symmetry, with trace amounts of impurities such as Li ⁺ and Eu ^{3 +} ions C ₂ and S ₆ You could go in two places with symmetry. For example, the two-digit crystallographic occupancy ratio is 3: 1.

In principle, the transition between energy levels is greatly affected by the symmetry of the crystal field around the rare earth ions.

That is, Y ₂ O ₃ : Eu is the ratio of the peak intensity of ⁵ D ₀ → ⁷ F ₂ (611 to 630 nm) to the ⁵ D ₀ → ⁷ F ₁ transition (near 590 nm) at the site having S ₆ symmetry. Appear larger at sites with C ₂ symmetry.

_{Y 1 .92 Li 0 .1 Eu 0} .08 O 3 Considering the effective ion radii (Li ⁺ = 76, Eu ³⁺ = 94.7, Y ^{3 +} = 90 pm) of the ions constituting the phosphor, statistically, Li and Eu ions do not occupy both positions. . And Li having the smallest ion radius is C ₂ Since it will be occupied at the site, the luminescence property is increased due to the decrease in symmetry at this site.

A study on the reduction of symmetry around the active agent and the change of energy level by substitution of Li has been demonstrated in ZnS: Tm.

11 is a Y _{1 .9- x} L _i0 heat treatment at _{1050 ℃ .1 Eu x O 3 (} x = 0.02, 0.05, 0.08, and 0.12, Li = 100% excess) is a diagram showing a light emission spectrum of the powder .

And a, Y _{1 .9- x} L _{i0 .1} Eu _x O _3, respectively an increase in the amount of Eu in the powder x with increasing the light emission intensity as shown in Fig.

On the other hand, the difference in luminescence intensity between 8 mol% and 12 mol% of the amount of substituted Eu was not very large.

As described above, the present invention synthesizes the phosphor synthesized by the sol-gel method, and can synthesize the phosphor having excellent crystallinity at a lower temperature than the solid phase method, which is a general synthesis method.

In the case of the solid-phase method, a high synthesis temperature is required for the structural coupling of a substituted activator to the host lattice, and the shape and size of the particles proceed regardless of the shape and size of the starting material. Most of this is.

On the other hand, the present invention can be obtained by the low-temperature synthesis using a sol-gel method, a phosphor having excellent luminescence properties with a small particle size, inducing liquid phase sintering with substituted Li together to spherical particle size of the phosphor, It could act as a co-activator to increase the brightness of the phosphor.

According to the analysis results, the photoluminescence intensity of the phosphor in which Li was substituted was increased by about twice the photoluminescence intensity of the phosphor in which Li was not substituted.

Next, with reference to FIGS. 12 and 13 will be described a method for producing a thick phosphor of the phosphor using the method for producing a phosphor according to the present invention.

12 is a flowchart stepwise illustrating a method of coating the SiO ₂ nano-particles in the phosphor powder used in the production method of the phosphor thick film according to the present invention, Figure 13 is SiO ₂ It is a flowchart explaining step by step a method for producing a phosphor thick film using a nanoparticle-coated phosphor powder.

First, a method of coating SiO ₂ nanoparticles on the phosphor powder will be described with reference to FIG. 12.

As shown in FIG. 12, an additive containing 30% of SiO ₂ solids on the surface of each phosphor powder synthesized by the above sol-gel method, such as Aldrich's Ludox AM-30 (trade name), was used. To coat nano-sized SiO ₂ (≦ 30 nm) particles (S20).

Referring to the coating process of the SiO ₂ nanoparticles of step S20 in detail, 0.8 g of the prepared phosphor powder, 50 ml of water (H ₂ O), and 25 ml of Ludox were put in a beaker (S21) and stirred in a stirrer for 2 hours (S22). Using the centrifuge, the stirred solution separates the phosphor powder and the stirred solution at 2000 rpm for 10 minutes (S23).

Subsequently, after the completion of centrifugation, the supernatant is removed, and a predetermined amount of distilled water is poured into the remaining solution (S24), and the excess SiO ₂ is washed again using a stirrer for 10 minutes (S25).

Subsequently, the process proceeds to step S23, and the washed solution is put back into the centrifuge and the stirrer and centrifuged and washed three times (S26).

Precipitated phosphor powder solution is precipitated and put in a dry oven at 80 ℃ dry for one day (S27).

Subsequently, with reference to FIG. 13, SiO ₂ The fabrication method of the phosphor thick film using the phosphor powder coated with nanoparticles is described.

As shown in FIG. 13, the glass substrate is placed in a 10% free acid (HF) solution for 3 minutes at room temperature to remove foreign substances on the surface of the glass substrate (S30).

The HF-treated glass substrate is cut using a diamond cutter so as to be 20 mm × 20 mm in constant size, for example, length and width (S31).

SiO ₂ 0.15 g of the coated phosphor powder and 0.15 ml of glycerin (glycerin) are put in a mortar and mixed well to make a paste (S32).

Subsequently, the prepared paste is spin-coated on a glass substrate mounted on a spin coater (S33).

At this time, the spin speed is set to 500 rpm for 10 seconds in the first step, and 1500 rpm for 20 seconds in the second step.

After the thick film made through this process is dried for 1 hour in a dry oven at 150 ℃ (S34), and maintained for 1 hour in an electric furnace of 700 ℃ (annealing) (S35). At this time, the temperature increase rate of the electric furnace is set to 3 ° C / min.

Subsequently, the process proceeds to step S33 to repeat the spin coating, drying and annealing three times (S36) to complete the fabrication of the phosphor thick film (S37).

X-ray diffraction analysis, scanning electron microscopy analysis, photoluminescence intensity analysis and cathodoluminescence intensity analysis were performed to characterize the phosphor thick films prepared using the phosphor powder synthesized by the sol-gel method according to the present invention. Was carried out.

X-ray diffraction analysis was performed using an X-ray diffraction tester (Shimazu, XRD-6000 model) using Cu-Kα radiation (λ = 1.5418 Hz), an acceleration voltage of 30 kV, a current of 30 mA, and a diffraction angle of 10 to 70 degrees (2θ). Do it in the range.

Here, the scanning rate of the X-ray diffraction tester was obtained at a diffraction spectrum of 2 ° per minute, and the change due to the SiO ₂ coating and annealing of the thick film manufactured by spin-coating method was obtained. See powder diffraction file of Joint Committee on Powder Diffraction Standards (JCPDS).

Scanning Electron Microscopy (SEM) analysis is to measure the surface state and thickness change according to the coating state and the number of coatings according to the morphology of the phosphor powder of the thick film manufactured by spin-coating method. Observation was performed using an SEM (Hitachi, S-4200 model) at 15 Hz.

In addition, in order to obtain the photoluminescence spectrum of the thick film formed by this invention, it measured at room temperature using the spectrophotometer (Shimazu, RF-5301PC model).

The photoluminescence spectrum was obtained by exciting a sample at 254 nm in the range of 550-650 nm.

Here, a filter (UV-39) is used to remove the second order Rayleigh scattering of the excitation wave in the emission measurement.

In addition, the measurement of the cathode ray emission of a thick film was carried out by attaching a substrate to a holder capable of mounting various samples, and irradiating the surface of the film with a cathode ray generated by applying 0.5-1 kV and 10 mA / cm ² under a high vacuum of 3x10 ^-6 torr or less. Cathode emission spectra are obtained on an ISS PC1 photon counting spectrofluorometer using optical fibers having a wavelength resolution of 1 nm.

14A and 14B illustrate Y ₂ O ₃ : Eu obtained by heat treating a precursor synthesized by the sol-gel method at 650 ° C. X-ray diffraction pattern of a thick film made of a powder that was finally heat treated at various temperatures, such as 750, 850, 950, 1050, 1150 ° C. for 5 hours, respectively.

As shown in FIG. 14A, in the X-ray diffraction pattern of a thick film made of Li-substituted powder, the intensity of typical peaks of Y ₂ O ₃ : Eu was weak, indicating that the film was not formed uniformly. Could.

And as the heat treatment temperature of the powder used in the manufacture of the thick film was found that the intensity of the peak of the (222), (211), (440) plane slightly increased.

As shown in FIG. 14B, in the X-ray diffraction pattern of the thick film made of Li-substituted powder, the X-ray diffraction pattern is more pronounced than that of Li-substituted, and as the powder heat-treated at high temperature is used ( 222), (211), the intensity of the peak of the (440) plane is increased, but when using the powder heat-treated at 1150 ℃ was less than the intensity using the powder treated at 1050 ℃. This is due to the morphology properties in the powder observed under a scanning electron microscope.

On the other hand, among powders heat-treated at various temperatures, the powder heat-treated at 1150 ° C does not appear similar spherical shape, whereas the powder particles heat-treated at 1050 ° C exhibits a spherical sphere.

Therefore, when the thick film is manufactured on the glass substrate, since the morphology of the coated particles is spherical, a much more uniform film is formed, as can be seen in the X-ray diffraction pattern of the manufactured thick film, the intensity of the corresponding peaks becomes stronger.

Figure 15 is a _{Y 1 .82 L i0 .1 Eu 0} .08 O 3 heat-treated at 1050 ℃ X-ray diffraction pattern according to the number of coating of the thick film produced using the powder.

As shown in FIG. 15, there is no change in the X-ray diffraction pattern with the number of coatings.

To (a) of FIG. 16 (c) Y ₁ is heat-treated at _{1050 ℃ .82 L i0 .1 Eu 0} .08 O 3 Using the powder, Ludox (SiO _2, nano-particles (≤30 ㎚)) a view showing a state before and after coating.

As can be seen in the 16 (c), SiO ₂ nanoparticles _{Y 1 .82 L i0 .1 Eu 0} .08 O 3 It was found that the particles adhere well to the surface of the powder particles.

Figure 17 (a) to (f) is a _{Y 1 .82 L i0 .1 Eu 0} .08 O 3 heat-treated at 1050 ℃ Scanning electron micrograph according to the number of coating of thick film made using powder.

As shown in (a) to (f) of FIG. 17, as the number of coatings increases, the coated area on the surface is widened, but the coated thickness is unclear due to the fusion of the powder and the substrate. Although it is not clear, it is almost 2 to 3 μm, and the thickness of the film does not increase significantly with increasing the number of coatings.

Figure 18a and 18b are Y _{1 .921} Eu _{0 .08} O ₃ powder and _{Y 1 .82 L i0 .1 Eu 0} .08 O 3 It is a figure which shows the photoluminescence spectrum of the thick film which was made and used after heat-processing each powder at different temperature.

As shown in FIG. 18A, when Li-substituted powder is used, the light emission intensity in the thick film increases as the heat treatment temperature of the used powder increases.

On the other hand, when Li is substituted, as shown in FIG. 18B, the photoluminescence intensity of the thick film f made of the powder treated at 1150 ° C. is higher than that of the thick film d made of the powder treated at 950 ° C. Lower than the light emission intensity.

This is because the morphology of the powder treated at 1150 ° C. is agglomerated in an irregular shape instead of a pseudo-spherical shape, and thus, SiO ₂ particles are not uniformly coated during the rudox coating.

FIG. 19 is a diagram showing a light emission spectrum of a thick film made using a powder in which Li is not substituted and a powder in which Li is substituted.

As shown in FIG. 19, the photoluminescence intensity of the powder (b) substituted with Li is approximately two to three times greater than the photoluminescence intensity of the powder (a) not substituted with Li.

This is the same as that of the powder, but is further influenced by the morphological properties of the powder used. That is, while Li-substituted powder is uniform in particle size and pseudo-spherical, the Li-substituted powder is not uniform in particle size and does not grow spherical. As a result, SiO ₂ nanoparticles are not uniformly coated on the surface of the phosphor.

20 is a diagram showing a light emission spectrum of a thick film with respect to the amount of change in the amount of Eu.

As shown in FIG. 20, it can be seen that the light emission intensity increases as the amount of Eu increases.

Figure 21a is to create a thick film to see Ludox coating effect, a _{Y 1 .82 L i0 .1 Eu 0} .08 O ₃ heat-treated at 1050 ℃ FIG. 21B is a view showing the light emission spectrum of the thick film made by the redox coating and the thick film made without the rudox coating, and FIG. 21B is a view showing the light emission spectrum of the thick film by the number of times of the redox coating.

As shown in FIG. 21A, the photoluminescence intensity is increased in comparison with the case where the coating of ludox is not coated.

This is because the nano-sized SiO ₂ particles coated on the surface of the powder increase the adhesion to the glass substrate when the thick film is manufactured, thereby increasing the amount of the coated phosphor powder particles per unit area of the glass substrate.

Looking at Figure 21b, it can be seen that the light emission intensity increases as the number of coatings increases.

Next, FIG. 22A is a diagram illustrating cathode emission spectra according to the amount of Eu substituted in a Y ₂ O ₃ : (Li, Eu) thick film by applying an anode voltage at 1 kV.

In the light emission spectrum, the emission intensity was high when the amount of substituted Eu was 12 mol%, but as shown in FIG. 22A, the emission intensity was the highest when the content of Eu was 8mol%.

In this way, the result of the photoluminescence spectrum and the cathode emission spectrum is different because the distribution of the activator in the phosphor having the highest luminescence intensity varies from the particle surface to the interior depending on the amount of the activator to be substituted.

That is, it is a phenomenon which arises because a phosphor penetrating depth changes with energy to be excited.

In detail, in the light emission spectrum, the penetration depth is smaller than that of the cathode ray, and the emission intensity is high when the amount of Eu is 12 mol% because it is mainly light emission on the surface of the phosphor.

On the other hand, 8 mol% of Eu in the cathode emission spectrum has the highest luminescence intensity because 8 mol% is more uniformly substituted than 12 mol% of Eu in the phosphor structure. there was.

22B is a diagram showing the cathode emission intensity at 612 nm according to the amount of Eu substituted in Y ₂ O ₃ : (Li, Eu) according to the voltage applied to the anode.

As shown in FIG. 22B, as the voltage applied to the anode increases, the penetration depth of the cathode rays increases, so that the cathode emission intensity increases.

FIG. 23A is a diagram showing cathode emission spectra according to the number of coatings of a thick film in which Li is not substituted and a thick film in which Li is substituted in a Y ₂ O ₃ : (Li, Eu) thick film while applying an anode voltage to 1 kV.

In the photoluminescence spectrum, the luminescence intensity increased as the number of Li-substituted thick films and the number of coatings increased. However, as shown in FIG. 23A in the cathode emission spectrum and the cathode, when the number of times the Li-substituted coating was three times, the cathode ray was more than two times. The luminous intensity is low.

The Li-substituted thick film is uniformly spherical in terms of the morphology of the powder used, but the Li-substituted thick film is SiO ₂ as the phosphor particles grow unevenly and pseudo-spherical. This is because nanoparticles are not uniformly coated.

In general, when the amount of incident energy increases in the luminous efficiency of the phosphor, the luminous efficiency of the entire phosphor increases.

That is, in the photoluminescence spectrum, SiO _{2 on the} surface of the phosphor Since the particles reduce the reflection of the ultraviolet rays and increase the amount of ultraviolet light incident into the phosphor, the relative filling degree at the thick film surface is increased due to the increase in the number of coatings, and thus the reflectance of the ultraviolet light is reduced, thereby increasing the amount of ultraviolet light incident. This is relatively high and the light emission intensity is high.

On the other hand, in the cathode emission spectrum, the cathode ray is used as the excitation source, so that the penetration depth is larger than that of ultraviolet rays. And SiO _{2 on the} surface of the phosphor due to the increase in the number of coatings As the amount of particles increases relatively, this can act as an impurity.

Therefore, although the relative filling degree of the three-coated thick film and the two-coated thick film surface is similar, the cathode light emission intensity of the three-coated thick film is lower than that of the twice-coated thick film.

23B is a diagram showing the cathode emission spectrum at 612 nm according to the number of coatings in Y ₂ O ₃ : (Li, Eu) according to the voltage applied to the anode.

As shown in FIG. 23B, as the voltage applied to the anode increases, the penetration depth of the cathode rays increases, so that the cathode emission intensity increases.

FIG. 24 is a diagram showing a light emission spectrum of a thick film made by spin coating and a thick film made by PLD.

As shown in FIG. 24, the primary coated thick film (b) made by spin coating has twice the photoluminescence intensity as compared to the thick film (a) made by the PLD method, and the third coated thick film (c) is made of PLD. The photoluminescence intensity is close to three times that of the thick film (a) made by the method.

This is because the size of the powder particles used for the thick film made by the spin coating method is about 1 μm, and the size of the particles of the thick film made by the PLD method is due to the difference between the size of the coated particles of 100 nm and the roughness of the film surface. .

As described above, the manufacturing method of the phosphor according to the present invention and the manufacturing method of the phosphor thick film using the same are excellent in light emission characteristics than the thin film method produced by the PLD method and can be produced very easily economically, the application of the thin film for FED In terms of aspect, it can be said to be an improved method than the thin film method produced by the PLD method.

Through the process as described above, the present invention SiO ₂ Thick films can be prepared using the particles coated with phosphor powder.

On the other hand, the most important factor in the preparation of the membrane is the morphology of the powder used.

That is, if the morphology of the powder used is bad SiO ₂ The coating of the particles is unevenly coated on the surface of the powder. As a result, adhesion to the glass substrate is deteriorated, and a nonuniform film is formed, thereby degrading the light emission characteristics of the thick film.

Therefore, the present invention uses a powder substituted with Li to spherical the particle shape so that the SiO ₂ particles are uniformly coated on the surface of the powder, thereby increasing the luminescence properties of the thick film.

In addition, the present invention increases the number of coating to increase the filling degree of the powder on the substrate to increase the luminous properties.

The scope of the present invention is not limited to the embodiments described above, but is defined by the claims, and various changes and modifications can be made by those skilled in the art within the scope of the claims. It is self evident.

Claims (10)

delete delete delete delete delete delete (a) dissolving starting materials Y (NO ₃ ) ₃ · 6H ₂ O, Eu (NO ₃ ) ₃ · 5H ₂ O and Li (NO ₃ ) with citric acid and distilled water to form a solution,
(b) adding ammonia aqueous solution to the solution dissolved in step (a), followed by primary heating, secondary heating in a gel state to combust, and then primary grinding to form a precursor,
(c) heat treating the precursor in step (b) first and then pulverizing second to form a powder;
(d) synthesizing the phosphor by performing a second heat treatment on the powder in step (c) at a predetermined temperature for a predetermined time;
(e) coating SiO ₂ nanoparticles on the surface of the phosphor powder synthesized in step (d); and
(f) preparing a phosphor thick film using the phosphor powder coated in step (e);
Step (e) is
(e1) mixing an additive including the phosphor powder, water, and a silica anion as starting materials and stirring for a predetermined time,
(e2) centrifuging the stirred solution in step (e1) for a predetermined time to separate the phosphor powder and the stirred solution,
(e3) removing the supernatant centrifuged in step (e2) and adding an amount of distilled water to the remaining solution to wash excess SiO ₂ using a stirrer; and
(e4) A method of manufacturing a thick phosphor film, comprising the step of forming a phosphor powder by precipitating and drying the phosphor powder solution washed in the step (e3). 8. The method of claim 7,
In the step (e1), the stirring operation is performed for 2 hours,
In the step (e2), the centrifugation operation is performed at 2000 rpm for 10 minutes,
In the step (e4), the drying operation is performed for 24 hours in an 80 ° C. dry oven,
Step (e2) and step (e3) is a method of manufacturing a thick film of the phosphor, characterized in that is carried out three times. 9. The method of claim 8, wherein step (f)
(f1) removing foreign substances on the surface of the glass substrate,
(f2) preparing a paste by mixing the phosphor powder coated with the SiO ₂ nanoparticles and glycerin,
(f3) step 23 of spin coating the paste prepared in step (f2) onto the glass substrate;
(f4) drying the thick film prepared in step (f3) in a dry oven for a predetermined time; and
(f5) annealing the thick film dried in the step (f3) in an electric furnace. The method of claim 9,
In the step (f4), the drying operation is performed for 1 hour in a dry oven at 150 ℃,
In the step (f5) the annealing operation is performed for 1 hour in an electric furnace of 700 ℃,
Step (f3) to step (f4) is a method for producing a thick film of the phosphor, characterized in that it is carried out three times.

Images