JP2007299571A - Crystallization method of phosphor layer, its apparatus, and thin film phosphor for display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a crystallization method of a phosphor layer in which light is irradiated on a non-crystal layer having a component to constitute a phosphor and the phosphor layer is formed by crystallizing the non-crystal layer of the phosphor without giving a high temperature and obtain the phosphor layer of high luminance while realizing energy-saving. <P>SOLUTION: A non-crystal layer having a component to constitute the phosphor is formed by a film-forming means on the upper side of a positive electrode substrate having a transparent electrode 3 on a transparent substrate 2, and it is made a non-crystal layer 8 of the phosphor in which a low melting point component and the other component with a higher melting point than the low melting point component are mixed, then light 25 is irradiated on the non-crystal layer 8 of the phosphor and the low melting point component out of the components constituting the phosphor is selectively melted and the non-crystal layer 8 of the phosphor is crystallized. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method and an apparatus for crystallizing a thin film phosphor layer, and a thin film phosphor for a display.

  Conventionally, a field emission display (hereinafter referred to as “FED”) has a structure in which an anode substrate on which a phosphor film is formed and an anode substrate on which an electron source is arranged are bonded to each other with a small space (interval). I am doing. In general, a glass substrate is used as the substrate, and in the anode, a transparent electrode is formed on the substrate, and a phosphor is further formed on the transparent electrode. In such phosphors currently used, a powder phosphor is formed on a transparent electrode by using a screen printing method, an ink jet method, or the like. It is mixed with an organic solvent or the like to make it suitable for film formation. For this reason, the baking operation | work for vaporizing these after film-forming is needed.

  According to Patent Document 1, in order to improve the point that the luminance is lower than that of the original powder only by this firing operation, laser irradiation is performed for the purpose of removing the defect of the phosphor that is the cause and improving the luminance. . As a result, although the crystallinity is improved and the luminance is also improved, this method has a technical problem that the production efficiency is low because laser irradiation is performed in addition to the conventional heat treatment.

In Patent Document 2, as a phosphor film intended for use in an FED, a phosphor layer in which a base material is an alkaline earth metal thiogallate (M-Ga ₂ S ₄ (M = Ca Sr Ba)) is a multi-source deposition method. After film formation by the (MSD) method, heat treatment is performed by a heater.

  According to Patent Literature 3, in Patent Literature 2, the optimum temperature for obtaining high luminous efficiency by improving the crystallinity is 800 ° C. for the thermal annealing method of alkaline earth metal thiogallate, and a longer treatment time is more effective. However, since the substrate generally used for displays is a glass substrate with a heat-resistant temperature of about 600 ° C, it is difficult to perform heat treatment at the optimum temperature of 800 ° C. However, laser annealing is performed as a substitute for thermal annealing.

Patent Document 4 shows a method for improving crystallinity by irradiating a thin film phosphor (crystal film) formed by MOCVD method and sputtering method with laser. Therefore, any phosphor film formed has crystallinity. And since the crystal after film formation is not a single crystal, there are many grain boundaries between crystals, diffuse reflection occurs and the light emission efficiency is low, so laser irradiation is performed to recrystallize and remove the grain boundaries. Therefore, the luminous efficiency is improved.
JP 2002-83549 A Japanese Patent Laid-Open No. 10-261367 JP 2004-111333 A JP 11-339682 A

  However, in the invention described in Patent Document 1, since the powder phosphor, which is originally a crystal, is used after being dissolved in an organic solvent or the like, the heat treatment performed after film formation is firing for vaporizing the organic solvent or the like. The purpose is not to crystallize the phosphor. Thereafter, laser irradiation is performed to improve crystallinity. If a fluorescent film that has not been fired is irradiated with laser light, the thickener or organic solvent present in the film may bind to the phosphor. For this reason, the invention described in Patent Document 1 requires heat treatment steps for vaporization and crystallization of an organic solvent or the like, and the production efficiency is low. Accordingly, the film forming means includes a sputtering method capable of forming an amorphous layer having a component that constitutes the phosphor at a ratio that increases the luminance of the phosphor without using a thickener or an organic solvent. It is desirable to adopt means.

  In the invention described in Patent Document 2, high-temperature heat treatment is required for a long time after film formation. In addition, since the glass substrate that is currently used generally has a heat-resistant temperature of about 600 ° C. that can maintain its properties, a quartz substrate that can be used even at high temperatures is used to realize the method of Patent Document 2. There must be. For this reason, the cost becomes high and it cannot be said that it is a practical method.

  Patent Document 3 gives a phosphor manufacturing process at a low temperature as compared to Patent Document 2 and uses laser annealing as a substitute for thermal annealing. However, since the temperature of the substrate during film formation is as high as 450 to 600 ° C., the heat treatment process It is hard to say that this is completely replaced with laser irradiation. In other words, at least a part of the compound reacts during the film formation, and many high melting point compounds that are hardly involved in phosphor crystallization are formed.

  In the phosphor film formation by the MOCVD method used in the invention described in Patent Document 4, a phosphor having crystallinity is obtained. However, since the crystal after film formation is polycrystalline, irregular reflection and absorption occur at the grain boundary, and the light emission efficiency is low. For this reason, polycrystals are recrystallized by applying thermal annealing or laser light as a substitute to improve luminous efficiency. Thermal annealing is performed at a substrate temperature of 300 to 1000 ° C. for several seconds to several tens of minutes, and XeCl excimer laser is used for laser irradiation.

  However, in order to use a general glass substrate, the upper limit of the heat treatment temperature is 600 ° C., so that further substrate heating is difficult. Further, in Patent Document 4, laser irradiation is performed on a fluorescent crystal film instead of thermal annealing, and laser irradiation is performed on a crystallized fluorescent film. Therefore, it can be said that this is an effective method only for laser irradiation of the phosphor film having crystallinity. In addition, high energy can be applied locally by laser irradiation. However, if laser light is simply irradiated instead of thermal annealing, the glass substrate or the transparent electrode may be damaged by the high energy laser light. Therefore, it is considered difficult to recrystallize the fluorescent crystal film. In other words, it is meaningless to perform laser irradiation on a completely crystallized fluorescent film, and once the crystallized fluorescent film is irradiated with laser, it is heated at a high temperature. Is required.

  By the way, conventionally, heat treatment of a phosphor has been performed by a solid phase reaction. This is because it is difficult to manufacture a phosphor having a high crystallinity by melting a phosphor having a very high melting point because a conventional thermal annealing uses a furnace. In addition, even if melted, constituent elements with low melting points may evaporate due to the difference in vapor pressure, making it difficult to control the composition ratio, and defects in crystals due to lack of low melting point components are likely to occur. Therefore, it is difficult to produce a phosphor having a composition ratio excellent in intended brightness. In addition, in the conventional thermal annealing using a furnace, it takes time for heating and cooling, so it can be said that this is a method in which constituent elements are easily evaporated.

  Conventionally, a high-temperature heat treatment is indispensable for the production of a high-luminance phosphor, but sufficient heat cannot be applied due to the problem of the heat-resistant temperature of the glass substrate used in the display. That is, it is difficult to produce a phosphor with good crystallinity even if heat treatment at about 600 ° C. is performed in consideration of the heat resistant temperature of the glass substrate. As a countermeasure, laser irradiation on the phosphor film has been studied in order to improve crystallinity. Conventionally, as described in Patent Documents 1 and 3, film formation at a substrate temperature at which the quality of the glass substrate can be maintained. A phosphor film already having crystallinity has been obtained by heat treatment or heat treatment, and this phosphor film has been irradiated with laser. However, the melting point of the phosphor is very high, and higher energy is required to melt the compound once crystallized. If laser irradiation is used, it is possible to give very high energy to the phosphor film. However, since laser irradiation heats and cools in an extremely short time, it dissolves the originally existing compound in a very short time. Further, it can be said that it is difficult to obtain a phosphor with higher crystallinity.

  Accordingly, an object of the present invention is to realize a phosphor film crystallization technique that cannot be realized by the conventional manufacturing method as described above, and an amorphous layer having components constituting the phosphor. Is formed by a film forming means, and high crystallinity is obtained in the phosphor layer by light that gives a relatively low temperature, particularly by laser irradiation. That is, by irradiating a non-crystalline layer having an alkaline earth metal thiogallate phosphor with light having a wavelength at which a component having a low melting point selectively or effectively absorbs and melts the phosphor. A method and apparatus for crystallizing a thin-film phosphor layer capable of producing a target high-quality crystal through a state in which a part of the amorphous layer of the phosphor in the light irradiation portion is melted, and further, It aims at providing the thin film fluorescent substance for a display.

According to the first aspect of the present invention, an amorphous layer having a component constituting the phosphor is formed on the upper side of the anode substrate having the transparent substrate 2 and the transparent electrode 3 by the film forming means. After the non-crystalline layer 8 of the phosphor in which other components having a higher melting point than the components are mixed, the non-crystalline layer 8 of the phosphor is irradiated with light 25 to lower the low melting point of the components constituting the phosphor. The phosphor layer crystallization method is characterized by selectively melting components to crystallize the phosphor amorphous layer 8 to form the phosphor layer 1.
The invention of claim 2 is a means including a sputtering method in which the film forming means can form a non-crystalline layer 8 having a component constituting the phosphor at a ratio of increasing the luminance of the phosphor, 2. The method for crystallizing a phosphor layer according to claim 1, wherein the amorphous layer 8 of the phosphor is formed at a temperature of 300 ° C. or lower.
The invention according to claim 3 is the method for crystallizing a phosphor layer according to claim 1, wherein when the low melting point component is melted, other components having a high melting point are dispersed in the melted low melting point component. is there.
The invention of claim 4 has a component constituting the phosphor on the upper side of the anode substrate having the glass substrate 2 and the transparent electrode 3, and a low melting point component and other components having a higher melting point than the low melting point component are mixed. Film forming means for forming the phosphor amorphous layer 8 composed of an amorphous layer, and light 25 for selectively melting the low melting point component of the components constituting the phosphor of the phosphor amorphous layer 8 A phosphor layer 1 is formed by crystallizing the phosphor amorphous layer 8 by irradiating the phosphor amorphous layer 8 with the light 25 of the light irradiation device. The phosphor layer crystallization apparatus is characterized in that:
The invention of claim 5 is a thin film phosphor for display having a crystallized thin film phosphor layer 1 on the upper side of an anode substrate having a transparent substrate 2 and a transparent electrode 3,
The thin film phosphor layer 1 is formed by a film forming means as an amorphous layer having a component constituting the phosphor, and a phosphor in which a low melting point component and other components having a higher melting point than the low melting point component are mixed. The amorphous layer 8 is irradiated with light 25 to selectively melt the low melting point component of the constituents of the phosphor, and the amorphous layer 8 of the phosphor is crystallized. This is a thin film phosphor for a display.

  According to the first and fourth aspects of the invention, the non-crystalline layer (the non-crystalline layer of the phosphor) having the component constituting the target phosphor is disposed on the upper side of the anode substrate having the transparent electrode on the transparent substrate. By forming the film by a film forming means and irradiating the amorphous layer with light, it is possible to make an amorphous material into a highly crystalline phosphor. In addition, since it is sufficient for the light irradiation to be provided so as to selectively melt and solidify components having a low melting point among the components constituting the phosphor, it is amorphous, as compared with the conventional case. In addition, a high-luminance phosphor layer can be manufactured in a short time by irradiation with low-energy light, and energy saving can be achieved. According to the fifth aspect of the invention, it is possible to obtain a thin-film phosphor for a high-luminance display that is efficiently manufactured while saving energy.

  According to the second aspect of the present invention, since the amorphous layer of the phosphor is deposited at a temperature of 300 ° C. or less by the film deposition means, a part of the components constituting the phosphor is formed during the deposition of the amorphous layer. Can be satisfactorily suppressed from reacting and producing a high melting point compound. As a result, it is easy to produce a phosphor having excellent luminance by highly crystallizing the amorphous layer of the phosphor.

  According to the invention of claim 3, the low melting point component is in a molten state, and the molten component is cooled and solidified from the state in which the other components are instantaneously diffused into the molten low melting point component. Can be homogenized and a good crystal state with excellent luminance can be obtained.

  1 to 8 show an embodiment of a phosphor layer crystallization apparatus according to the present invention. First, the anode of a field emission display (field emission display) to which the phosphor layer according to the present invention can be applied will be described with reference to FIG.

  The anode includes an anode substrate having a transparent electrode 3 on a transparent substrate 2 usually made of a glass substrate, and has a thin-film phosphor layer 1 on the anode substrate, that is, on one side. The phosphor layer 1 has a structure partitioned by a black matrix 4. Such a phosphor layer 1 is irradiated with an electron beam 6 from a predetermined cathode (not shown), so that the phosphor layer 1 is appropriately excited and emits light. 2 and the transparent electrode 3 can be seen through. Reference numeral 5 denotes an antistatic layer.

  Such a phosphor layer 1 is obtained by forming an intermediate substrate 9 having an amorphous layer 8 having components constituting the phosphor shown in FIG. Laser light) is applied to the amorphous layer 8 of the phosphor. First, as shown to Fig.2 (a), what formed the transparent electrode 3 and the black matrix 4 on the transparent substrate 2 which has insulation and light transmittance is prepared. The black matrix 4 can be formed by a laser ablation method using black carbon as a material.

  Next, an amorphous layer 8, that is, an amorphous layer having a component constituting the phosphor is formed by a film forming means described later. The amorphous layer 8 is a thin film, and the components constituting the phosphor are scattered in a non-crystalline state (the phosphor crystal is not formed or the generation of the phosphor crystal is suppressed), and has a low melting point. The component and other components having a higher melting point than the low melting point component are mixed.

  The amorphous layer 8 is formed on the surface of the transparent electrode 3 as shown in FIG. 2B, with an appropriate mask 7 covering the black matrix 4 arranged as shown in FIG. If the phosphor non-crystalline layer 8 is formed, an antistatic layer 5 for preventing the phosphor layer 1 from being charged up is formed as necessary to form an intermediate substrate 9 having the phosphor non-crystalline layer 8. If the non-crystalline layer 8 of the phosphor is thinned to a thickness of about several hundreds of nanometers, the anti-static layer 5 can be omitted because the phosphor layer 1 can be prevented from being charged on the surface.

Specifically, the phosphor amorphous layer 8 can be formed by appropriately arranging a mask 7 covering the black matrix 4 and forming a film by, for example, sputtering. As shown in FIG. 3, the sputtering method, which is a film forming means, is applied by installing an intermediate substrate 9 with a mask 7 in a vacuum vessel 10 connected to a vacuum pump 11. A heater 13 is installed above the intermediate substrate 9, and an opening plate 14 having an opening and a shutter 15 are sequentially arranged below the intermediate substrate 9. Further, a sputter target SrGa ₂ S ₄ : Eu 16 having Eu as a light emission center material is disposed below the shutter 15.

The film forming conditions are as follows: the temperature of the intermediate substrate 9 is 300 ° C. or less, the degree of vacuum is 10 ⁻¹ to 10 ⁻³ Torr (about 133 × 10 ⁻¹ to 10 ⁻³ Pa), the input power is 100 to 300 W, and the atmosphere of Ar gas 12 Below, an amorphous layer 8 of SrGa ₂ S ₄ : Eu16, which is a green phosphor, was formed. The reason why the intermediate substrate 9 and the amorphous layer 8 are formed while maintaining the temperature at 300 ° C. or lower is that, when the amorphous layer 8 is formed, some of the components constituting the phosphor react and the compounding proceeds. This is to prevent this. In addition, since sulfur S has the highest deficiency among the constituent components of the phosphor, it is possible to prevent deficiency of sulfur S having a low boiling point by using H ₂ S instead of Ar. In other words, it is very effective for the production of a phosphor having a composition ratio capable of obtaining light emission with high luminance.

  When the intermediate substrate 9 having the amorphous layer 8 is produced, the light 25 emitted from the light irradiation device is irradiated to the amorphous layer 8 and the low melting point component selected from the components constituting the phosphor of the amorphous layer 8 is selected. To melt. By dissolving the low melting point component, the low melting point component and the other component are allowed to react with each other in a state where other components in the solid phase are diffused into the low melting point component in the molten state, and the amorphous layer 8 of the phosphor is allowed to cool instantaneously. The whole is highly crystallized to form a phosphor layer 1. Since the non-crystalline layer 8 in which the generation of the phosphor crystal is suppressed is formed by the film forming means, the movement is not hindered by the already formed phosphor crystal, and in the low melting point component in the molten state. The other components in the solid phase diffuse well.

  In the phosphor amorphous layer 8 after film formation, the absorption edge of light transmittance appears at about 300 nm. For this reason, by irradiating the light 25 having a wavelength of less than about 300 nm, the light 25 is absorbed by the constituent components of the amorphous layer 8, so that it is theoretically irradiated with a KrF excimer laser beam that generates a laser having a wavelength of 248 nm. Also effective.

  As a typical example of the light irradiation apparatus, a laser irradiation apparatus functioning as a laser annealing apparatus is shown in FIG. Laser light, which is light 25 generated by a laser oscillator 17 that generates an excimer laser consisting of a pulsed laser, is guided into an optical device 24, energy is automatically set by an attenuator 18, and direction is changed by a reflecting mirror 22, After shaping through the long-axis homogenizer 19a and the short-axis homogenizer 19b to make the intensity uniform, the direction is again changed by the reflecting mirror 23 and passed through the condenser lens 20, so that the long axis × short axis is, for example, 200 × 0. The laser light 21 (light 25) of 4 mm is shaped and irradiated on the amorphous layer 8 of the phosphor. An intermediate substrate 9 having an amorphous layer 8 of phosphor is placed in a laser processing chamber of a laser irradiation apparatus.

When irradiating the laser beam 21, the inside of the laser processing chamber that accommodates the amorphous layer 8 of the phosphor is temporarily replaced with Ar gas, and is further made into a sulfur atmosphere with H ₂ S or the like, and the pulsed laser beam 21 having an appropriate energy density. In order to obtain good crystallization of the phosphor, it is desirable to select the irradiation condition so that the laser beam 21 is irradiated while being relatively moved so that the laser beam is irradiated a predetermined number of times. If oxygen and hydrogen in the laser processing chamber are removed before irradiation with the laser beam 21, the phosphor amorphous layer 8 can be prevented from being oxidized.

  A plurality of anodes formed with the phosphor layer 1 crystallized by changing the energy density of the laser light 21 are prepared, and observed with an SEM (scanning electron microscope) or the like. Irradiation conditions such as an appropriate energy density are determined, and the amorphous layer 8 of the phosphor is crystallized according to the irradiation conditions.

  At this time, by selecting a wavelength at which a component having a low melting point selectively or effectively absorbs and melts among the constituent components of the amorphous layer 8, a component having a low melting point can be selectively melted. A phosphor layer 1 having high crystallinity in which a component having a low melting point and a component having a high melting point are well bonded can be obtained.

  Furthermore, according to the laser beam 21, since the pulse width is narrow, the processing is performed for a short time, and excessive evaporation of the constituent components of the phosphor accompanying the laser processing is suppressed. Therefore, the total amount of raw materials necessary for film formation can be reduced. It becomes possible to decrease.

When the phosphor layer 1 manufactured by irradiating the KrF excimer laser beam was irradiated with an electron beam, green light emission having a peak at about 530 nm was confirmed. Further, in the X-ray diffraction measurement, the peak of SrGa ₂ S ₄ which is a phosphor could not be confirmed after film formation and before laser light irradiation, but it could be confirmed in the measurement after laser light irradiation. That is, the target phosphor layer 1 having sufficient crystallinity to be a high-brightness thin film phosphor has been produced by irradiating the phosphor amorphous layer 8 with laser light. The result is shown in FIG. A broad peak centered around a diffraction angle of about 22 ° observed before and after laser light irradiation is a diffraction peak caused by quartz used for the substrate during the test. Before the laser beam irradiation, no intensity peak is observed except for the region around 22 °, and it can be said that the phosphor SrGa ₂ S ₄ is not crystallized. On the other hand, the laser beam irradiation X-ray diffraction measurement after, ▼ since appearing sharp peak SrGa ₂ S ₄ as indicated by the symbol, SrGa ₂ S ₄ has favorably a by connexion phosphor laser beam irradiation It turns out that it crystallizes.

As shown in Table 1, the melting point of SrGa ₂ S ₄ is 1230 ° C., but if Sr + 2Ga + 4S is in a single crystal mixed state, the reaction of Sr—S occurs at 200 to 400 ° C. The reaction is supposed to occur at about 950 ° C., and since the melting point of Ga ₂ S ₃ is 1255 ° C., the reaction of Sr—S and the reaction of 2Ga-3S are said to be almost completed at 1255 ° C.

Accordingly, first, the reaction that generates a compound during the formation of the thin film is suppressed as much as possible to generate the amorphous layer 8, and then the amorphous layer 8 is irradiated with light 25, and low melting point components such as Ga and S are selectively selected. It is important to obtain a high-brightness thin-film phosphor layer 1 by melting it and keeping Sr in a solid phase so that SrGa ₂ S ₄ as the phosphor layer 1 is highly crystallized. That is, when forming a phosphor thin film, it is important to suppress the Sr—S reaction, the Ga—S reaction, and the 2Ga-3S reaction, and also suppress the generation of SrGa ₂ S ₄ . For this reason, the phosphor amorphous layer 8 is formed by setting the temperature of the intermediate substrate 9 to a temperature lower than 300 ° C., preferably 200 ° C. or lower, more preferably 150 ° C. or lower.

When a phosphor thin film is formed by sputtering at a temperature of the intermediate substrate 9 of 150 ° C., a high melting point compound (SrS, Ga ₂ S ₃ , GaS, etc.) or SrGa ₂ S ₄ as conceptually shown in FIG. The compound of Sr, Ga, S is formed as an amorphous layer 8 as indicated by a circle, and the phosphor thin film is formed at an intermediate substrate temperature of 450 ° C. as in Patent Document 3. As shown in FIG. 6B, refractory compounds (SrS, Ga ₂ S ₃ , GaS, etc.) (indicated by □) and SrGa ₂ S ₄ (indicated by Δ) are crystallized. When a phosphor thin film is formed at an intermediate substrate temperature of 600 ° C., a high melting point compound (SrS, Ga ₂ S ₃ , GaS, etc.) (□ mark) is conceptually shown in FIG. in addition to the illustrated) by, shown in SrGa ₂ S ₄ (△ mark) is It is formed on the amount.

  FIG. 7 shows the result of X-ray diffraction measurement performed by forming the phosphor amorphous layer 8 on the sample with the temperature of the intermediate substrate 9 set to 300 ° C. by sputtering. As can be seen from the figure, the diffraction peak due to the quartz used for the substrate during the test is only observed with a diffraction angle of around 22 ° as the center, and no other intensity peak is observed, and the compound is compounded. Progress is not allowed in practice.

In addition, the result of having performed the X-ray-diffraction measurement of the non-crystalline layer after forming the non-crystalline layer of the phosphor with the temperature of the intermediate substrate of 450 ° C. by the multi-source deposition method is shown in FIG. As can be seen from the figure, a diffraction peak (indicated by Δ) accompanying the generation of GaS is clearly confirmed, and a diffraction peak of SrS (indicated by ■) can also be confirmed. This is probably because sulfur having a low boiling point (444.674 ° C.) is likely to evaporate, but GaS having a lower sulfur ratio is more clearly observed than Ga ₂ S ₃ .

When compounding including crystallization of the phosphor occurs at the stage of forming the phosphor thin film, it is necessary to apply a high temperature exceeding 970 to 1255 ° C. as shown in Table 1 to melt the compound. Therefore, it is desirable to suppress the generation of the compound and the crystallization of the phosphor at the stage of forming the phosphor thin film as much as possible. Then, the low melting point component (Ga, S) among the components constituting the phosphor is selectively melted by the irradiation of the light 25, thereby diffusing other components into the molten low melting point component, A distribution state having excellent uniformity can be provided, and the reaction of SrGa ₂ S ₄ , that is, the crystallization of the phosphor can occur satisfactorily. When Sr—S reaction occurs in the stage of forming the phosphor thin film, the melting point of SrS is> 2000 ° C. as shown in Table 1, so that it becomes difficult to dissolve by laser irradiation, and Sr, S Insufficiency of SrGa ₂ S ₄ is caused, and the production reaction of the phosphor at a composition ratio that can obtain high luminance such as SrGa ₂ S ₄ cannot occur to a high degree.

As shown in Table 1, the melting points are SrGa ₂ S ₄ : 1230 ° C., Ga ₂ S ₃ : 1255 ° C., SrS:> 2000 ° C., GaS: 970 ° C., Sr: 769 ° C., Ga: 29.78. ° C, S: 112.8 ° C. Moreover, a boiling point is Sr: 1384, Ga: 2403 degreeC, S: 444.674 degreeC. If the intermediate substrate 9 and thus the amorphous layer 8 are formed at a temperature of 300 ° C. or lower, the evaporation of S can be prevented.

By the way, in the above-described one embodiment, SrGa ₂ S ₄ to which Eu is added as the emission center material is used as the sputtering target of the film forming means, but mixing is performed by changing the ratio of the constituent components of the phosphor. The amorphous layer 8 that is a non-crystalline layer of a phosphor having an arbitrary composition ratio can be produced by using the molded target as a sputtering target. Further, Sr, Ga, and S are separately disposed as sputtering targets of the film forming means, and Eu is disposed at a predetermined ratio on the Sr target, and fluorescent light is disposed on the transparent electrode 3 on the transparent substrate 2. It is also possible to form an amorphous layer having components constituting the body.

In the first embodiment, SrGa ₂ S ₄ : Eu is formed as the phosphor layer 1, but the phosphor layer 1 is widely used in alkaline earth metal thiogallate (M-Ga ₂ S ₄ (M = Ca , Sr, Ba) -containing thin film as long as the film forming means and the constituent elements are formed on the upper side of the substrate as separate targets, and instead of strontium (Sr), calcium (Ca), If barium (Ba) is used, it is possible to produce a phosphor layer 1 made of calcium thiogallate phosphor or barium thiogallate phosphor, europium (Eu) added calcium thiogallate phosphor, and europium added The barium thiogallate phosphor also shows a green emission color, and CaGa ₂ S ₄ and BaGa ₂ S ₄ are also effectively composed of components having a low melting point. By irradiating light with a wavelength that absorbs and dissolves, a part of the amorphous layer of the phosphor in the light irradiation part is dissolved and combined by a liquid phase-solid phase reaction to crystallize the phosphor. It is theoretically possible.

The strontium thiogallate phosphor SrGa ₂ S ₄ : Ce using Ce (cerium) as the emission center material instead of Eu has a blue emission color. The basic three colors of blue, green, and red are obtained by adding one of alkaline earth metal thiogallate (M-Ga ₂ S ₄ (M = Ca, Sr, Ba)) and adding rare earth or transition metal as the luminescent center material. Furthermore, it is considered that the present invention is not limited to crystallization of alkaline earth metal thiogallate phosphors, but can be applied to other thin film phosphors and semiconductors. There are components that cannot avoid evaporation due to laser light irradiation, in which case, by supplying an excessive amount of evaporated components on the anode substrate in advance, fluorescence with the optimum component ratio is obtained as a composition ratio for obtaining high brightness. It is possible to crystallize the body.

  Further, instead of forming a film by sputtering, an amorphous layer 8 which is an amorphous layer of a phosphor formed by a multi-source deposition (MSD) method is obtained, and this amorphous layer 8 has an ultraviolet region. By irradiating with laser light, the phosphor layer 1 having required crystallinity can be obtained as in the first embodiment. That is, as a film forming means, the temperature of the intermediate substrate 9 and thus the amorphous layer 8 is maintained at 300 ° C. or lower, and the component constituting the phosphor is made fluorescent without using a thickener or an organic solvent. It is desirable to adopt means including a sputtering method capable of forming an amorphous layer having a ratio of increasing the luminance of the body.

  The method for crystallizing the phosphor layer 1 according to the present invention can be widely applied to a method in which an amorphous layer having components constituting the phosphor is formed on the upper side, that is, one side of the anode substrate by a film forming means. This is applicable not only to FED and organic EL (organic electroluminescence) displays, but also to structures in which the crystallized phosphor layer 1 is sandwiched between insulating layers, such as inorganic EL displays. is there.

Sectional drawing which shows the anode of a field emission display provided with the fluorescent substance layer which concerns on one embodiment of this invention. Similarly, the manufacturing process of the phosphor layer is shown in cross section, FIG. 2 (a) is an explanatory diagram showing the phosphor layer before fabrication, and FIG. 2 (b) is an explanatory diagram showing the phosphor layer after fabrication. Explanatory drawing which similarly shows a sputtering method. FIG. 4A is a front view and FIG. 4B is a right side view of the laser irradiation apparatus. Similarly graph showing the results of X-ray diffraction of SrGa ₂ S ₄ after irradiation of the film formation and after the laser beam. Similarly, it is explanatory drawing which shows the mode in the film | membrane when the thin film of a fluorescent substance is formed as temperature of various intermediate substrates, FIG.6 (a) is explanatory drawing which set the temperature of the intermediate substrate to 150 degreeC, FIG.6 (b) is FIG. FIG. 6C is an explanatory diagram in which the temperature of the intermediate substrate is 450 ° C., and FIG. 6C is an explanatory diagram in which the temperature of the intermediate substrate is 600 ° C. The diagram which similarly shows the result of the X-ray diffraction of the thin film of the fluorescent substance after film-forming. The diagram which shows the result of the X-ray diffraction of the thin film of the fluorescent substance after film-forming by making the temperature of an intermediate substrate into 450 degreeC.

Explanation of symbols

1: Phosphor layer 2: Transparent substrate 3: Transparent electrode 8: Amorphous layer of phosphor 21: Laser light 21 (light)
25: Light

Claims (5)

On the upper side of the anode substrate having the transparent substrate (2) and the transparent electrode (3), an amorphous layer having a component constituting the phosphor is formed by a film forming means, and the lower melting point component and the lower melting point component are formed. After forming the phosphor amorphous layer (8) mixed with other components having a high melting point, light (25) is irradiated to the phosphor amorphous layer (8), and among the components constituting the phosphor. A method for crystallizing a phosphor layer, wherein the low melting point component is selectively melted and the amorphous layer (8) of the phosphor is crystallized to form the phosphor layer (1). The film forming means includes means including a sputtering method capable of forming an amorphous layer (8) having a component constituting the phosphor at a ratio of increasing the luminance of the phosphor, and the phosphor non-crystal. The method for crystallizing a phosphor layer according to claim 1, wherein the layer (8) is formed at a temperature of 300 ° C or lower. 2. The phosphor layer crystallization method according to claim 1, wherein when the low melting point component is melted, other components having a high melting point are dispersed in the melted low melting point component. An amorphous substrate having a component constituting a phosphor on the upper side of an anode substrate having a glass substrate (2) and a transparent electrode (3), wherein a low melting point component and other components having a higher melting point than the low melting point component are mixed. Film forming means for forming a phosphor amorphous layer (8) composed of layers, and light for selectively melting a low-melting-point component among the components constituting the phosphor of the phosphor amorphous layer (8) ( 25), and the non-crystalline layer (8) of the phosphor is crystallized by irradiating the non-crystalline layer (8) of the phosphor with the light (25) of the light irradiating device. The phosphor layer crystallization apparatus is characterized in that the phosphor layer (1) is formed. A thin film phosphor for display having a crystallized thin film phosphor layer (1) on the upper side of an anode substrate having a transparent substrate (2) and a transparent electrode (3),
The thin film phosphor layer (1) is formed by a film forming means as an amorphous layer having components constituting the phosphor, and a low melting point component and other components having a higher melting point than the low melting point component are mixed. The amorphous layer (8) of the phosphor is irradiated with light (25) to selectively melt the low melting point component of the components constituting the phosphor, so that the amorphous layer (8) of the phosphor is formed. A thin film phosphor for a display, characterized by being formed by crystallization.

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