JP2004002569A - Water-soluble phosphor slurry for fluorescent lamp, fluorescent lamp using the same, and method of manufacturing the same - Google Patents

Abstract

Kind Code: A1 Abstract: When a pH value of a water-soluble phosphor slurry is adjusted to an alkaline range (pH range of more than 7 to 10 or less) capable of suppressing deterioration of the phosphor and change of the pH value with time, binding is performed. Agglomeration of alumina particles as an agent is prevented.
A water-soluble phosphor slurry for a fluorescent lamp, comprising phosphor powder, a binder, and a water-soluble binder, and adjusted to be alkaline. Alumina particles as a binder are subjected to a surface treatment so that an isoelectric point does not exist in a pH range of 7 to 10. Such alumina particles are added to the water-soluble phosphor slurry, for example, as an alkaline alumina dispersion liquid containing a surfactant so that the dispersion state can be maintained in an alkaline region.
[Selection diagram] FIG.

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a water-soluble phosphor slurry used for manufacturing a fluorescent lamp, a fluorescent lamp using the same, and a method for manufacturing the same.
[0002]
[Prior art]
Fluorescent lamps have been widely used in general lighting, light sources for office automation equipment, pixel light sources for huge screens, and the like in recent years. In addition, three-wavelength fluorescent lamps have been remarkably popular in recent years because they satisfy high efficiency and high color rendering properties at the same time for general illumination. In such a fluorescent lamp, a mixed gas containing mercury and a rare gas is sealed as a discharge gas in a glass bulb having a fluorescent film provided on an inner wall surface, and a positive column discharge is generated in the mixed gas. It is composed.
[0003]
The fluorescent film of the fluorescent lamp as described above is prepared by preparing a phosphor slurry (phosphor coating solution) containing a phosphor powder, a binder and a binder, applying the slurry to the inner surface of a glass bulb, and then baking. Is formed. As the phosphor coating solution used for forming the phosphor film, for example, an aqueous solution system to which an aqueous solution of polyethylene oxide or the like dissolved in water is applied as a binder, that is, a water-soluble phosphor slurry is used. Further, in such a water-soluble phosphor slurry, alumina (Al ₂ O ₃ ) is generally used frequently as a binder.
[0004]
By the way, since alumina particles have the property of aggregating in an alkaline liquid, and it is difficult to disperse them well in an alkaline region, when using alumina as a binder, the alumina is converted into water. In general, the pH is adjusted to be weakly acidic (pH: about 6 to 7) at the time of dispersion, and such a weakly acidic alumina dispersion is added to the water-soluble phosphor slurry. Therefore, the pH value of the water-soluble phosphor slurry itself is adjusted to a weak acidity of about 6 to 7.
[0005]
[Problems to be solved by the invention]
However, since the phosphor powder itself is susceptible to deterioration in an acidic region, if a conventional water-soluble phosphor slurry adjusted to a weak acidity is used for a long time, a phosphor film formed using such a water-soluble phosphor slurry is used. As a result, the luminance characteristics of the fluorescent lamp may be lower than the original characteristic values. From the viewpoint of maintaining the characteristics of the phosphor powder, it is desirable to adjust the water-soluble phosphor slurry to an alkaline region (pH: about 8 to 10), but alumina particles aggregate at the stage of adjusting to such a pH value, The viscosity of the water-soluble phosphor slurry is increased, and the slurry cannot be put to practical use.
[0006]
Furthermore, in a conventional water-soluble phosphor slurry using a weakly acidic alumina dispersion as a binder component, an alkali component is gradually eluted with the deterioration of the phosphor in an acidic region, whereby the water-soluble phosphor is dispersed. There is a problem that the pH value of the body slurry changes to alkaline over time. Such a change in the pH value of the water-soluble phosphor slurry over time (transition from the acidic region to the alkali region) causes an increase in the slurry viscosity, color shift of the phosphor slurry, and the like. This leads to characteristics and the like. These cause an increase in process defects and characteristic defects of the fluorescent lamp.
[0007]
The present invention has been made in order to address such problems, even when the pH value of the water-soluble phosphor slurry is adjusted to an alkaline range that can suppress the deterioration of the phosphor and the change over time of the pH value, An object of the present invention is to provide a water-soluble phosphor slurry capable of suppressing agglomeration of alumina particles as a binder, and further provide a fluorescent lamp using such a water-soluble phosphor slurry for a fluorescent lamp and production thereof It is intended to provide a way.
[0008]
[Means for Solving the Problems]
As described in claim 1, the water-soluble phosphor slurry for a fluorescent lamp of the present invention comprises a phosphor powder, a binder, and a water-soluble binder, and a water-soluble phosphor slurry for a fluorescent lamp adjusted to be alkaline. The binder is made of alumina particles, and the alumina particles are surface-treated so that an isoelectric point does not exist in a pH range of 7 to 10.
[0009]
In the water-soluble phosphor slurry for a fluorescent lamp of the present invention, alumina particles surface-treated so that the isoelectric point does not exist in the range of pH = 7 to 10 are used as a binder. Such alumina particles do not aggregate even in an alkaline region, and can maintain a good dispersion state. Therefore, even when the water-soluble phosphor slurry is adjusted to be alkaline so as to suppress the deterioration of the characteristics of the phosphor powder and the time-dependent change of the pH value based thereon, the aggregation of the alumina particles as a binder, It is possible to prevent the slurry viscosity from increasing.
[0010]
In the water-soluble phosphor slurry for a fluorescent lamp of the present invention, the binder is surface-treated with a surfactant so that the isoelectric point does not exist in the pH range of 7 to 10, for example, as described in claim 2. Alumina particles are used. As the surfactant used in the present invention, for example, as described in claim 3, a carboxylic acid type polymer surfactant is suitable. According to such a surfactant, aggregation of alumina particles in an alkaline region can be more reliably suppressed. Further, as described in claim 4, the alumina particles as the binder are added to the water-soluble phosphor slurry as, for example, an alkaline alumina dispersion liquid that maintains a dispersed state in an alkaline region.
[0011]
The phosphor lamp of the present invention uses a glass bulb filled with a discharge gas and the water-soluble phosphor slurry for a fluorescent lamp of the present invention described above on the inner wall surface of the glass bulb. It is characterized by comprising: a formed fluorescent film; and electrodes provided at both ends of the glass bulb and maintaining a positive column discharge in the discharge gas.
[0012]
Further, according to the method for manufacturing a fluorescent lamp of the present invention, as described in claim 7, a glass bulb filled with a discharge gas, a fluorescent film formed on an inner wall surface of the glass bulb, and the discharge gas In manufacturing a fluorescent lamp including an electrode that maintains a positive column discharge therein, a water-soluble phosphor dispersion liquid containing a phosphor powder and a water-soluble binder, and alumina particles as a binder, and Mixing with an alkaline alumina dispersion liquid that maintains a dispersed state in a region to prepare an alkaline water-soluble phosphor slurry; applying the water-soluble phosphor slurry to the inner wall surface of the glass bulb; Baking to form the fluorescent film.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments for carrying out the present invention will be described.
The water-soluble phosphor slurry of the present invention is a suspension in which phosphor powder, a binder, and a water-soluble binder are dispersed or dissolved in water as essential components, and is used when forming a fluorescent film of a fluorescent lamp. It is used as a phosphor coating solution. The pH value of such a water-soluble phosphor slurry is adjusted to an alkaline range, for example, in a range from more than 7 to 10 or less.
[0014]
That is, when the pH value of the water-soluble phosphor slurry is 7 or less, the phosphor powder is likely to deteriorate and the pH value is changed with time. These are factors that lower the luminance characteristics of the fluorescent lamp and the ability to form the fluorescent film (the ability to form the fluorescent film normally). On the other hand, if the pH value of the water-soluble phosphor slurry exceeds 10, the viscosity of the water-soluble binder decreases, and the desired characteristics cannot be obtained. The pH value of the water-soluble phosphor slurry is more preferably adjusted to a range of 8 to 10, and even more preferably 9 to 10.
[0015]
In the water-soluble phosphor slurry described above, the binder that binds the phosphor particles to form a phosphor film is made of alumina particles. The alumina particles used as the binder may be any of α-Al ₂ O ₃ , γ-Al ₂ O ₃ , and δ-Al ₂ O ₃ , and the particle diameter is in a range of 10 to 400 nm. Is preferred. Such alumina particles are preferably added, for example, so as to be in a range of 1 to 5% by mass based on the phosphor powder. When the addition amount of the alumina particles is less than 1% by mass, the adhesive strength between the fluorescent film and the glass bulb becomes weak. On the other hand, when the addition amount of the alumina particles exceeds 5% by mass, the amount of the phosphor in the phosphor film is relatively reduced, which causes a decrease in luminance of the fluorescent lamp and the like.
[0016]
Alumina particles used as a binder have been subjected to a surface treatment so that there is no isoelectric point in a pH range of 7 to 10, thereby preventing agglomeration of the alumina particles in an alkaline dispersion. Such a binder component is preferably added to the water-soluble phosphor slurry as an alkaline alumina dispersion (aqueous dispersion of alumina particles) that maintains a dispersed state in an alkaline region. The pH value of the alkaline alumina dispersion is preferably adjusted to a range of more than 7 and 10 or less, and more preferably pH = 8-10.
[0017]
Here, ordinary alumina particles (untreated alumina particles) have the property of aggregating in an alkaline liquid as described above. This is because the isoelectric point of alumina exists in a weak alkaline region (for example, the isoelectric point of γ-Al ₂ O ₃ is about pH = 8), and therefore, when the pH value of the dispersion passes through the isoelectric point. Alumina particles aggregate. Once the alumina particles have aggregated, it is difficult to disperse the alumina particles again even if the pH value is increased above the isoelectric point. It was used as a component.
[0018]
On the other hand, in the present invention, alumina particles surface-treated so as not to have an isoelectric point in the range of pH = 7 to 10 are used as a binder. Therefore, the pH value of the alumina dispersion (aqueous dispersion of alumina particles) used as an additive material of the binder and the pH value of the water-soluble phosphor slurry to which such an alumina dispersion is added are specifically set in an alkaline range, specifically, 7 Even when adjusted to a range exceeding 10 and not more than 10, the aggregation of alumina particles in the liquid can be prevented.
[0019]
Thus, when the pH value of the water-soluble phosphor slurry of the present invention is adjusted to a range of more than 7 to 10 or less, alumina particles as a binder contained therein do not substantially aggregate. is there. The same applies to the alkaline alumina dispersion. Here, the state in which the alumina particles do not substantially aggregate is defined as a condition in which the degree of aggregation (evaluated with a cup viscometer) immediately after preparing the alumina dispersion liquid or the water-soluble phosphor slurry is 100, and at normal temperature for one month. Means that the cohesion degree after being placed under the conditions described above is 105 or less.
[0020]
For the surface treatment of the alumina particles described above, for example, a surfactant is used. Specifically, an appropriate amount of a surfactant (for example, 1 to 10% of a surfactant based on the solid content of alumina) is added to a dispersion prepared by dispersing alumina powder in water, and then stirred. The polarity based on the surfactant is generated on the surface of the substrate, and the isoelectric point changes. The isoelectric point of the alumina particles can be prevented from being in the range of pH 7 to 10 by adjusting the type and amount of the surfactant at this time. That is, it is possible to prevent the agglomeration of the alumina particles in such a pH range. Here, a plurality of alumina dispersion liquids whose isoelectric points were adjusted to various pH values (for example, pH = 1 to 12) were prepared, the state of aggregation and sedimentation of each alumina dispersion liquid was visually checked, and the sedimentation due to aggregation was confirmed. The amount can be confirmed by the pH value of the largest alumina dispersion.
[0021]
The surfactant used for the surface treatment of the alumina particles may be either anionic or cationic. Specific examples of the surfactant used here include fatty acid salts, alkyl sulfate salts, alkylamine salts, and quaternary ammonium salts. Among these, a carboxylic acid type polymer surfactant is particularly preferably used. According to the carboxylic acid type polymer surfactant, aggregation of alumina particles in an alkaline region can be more reliably prevented.
[0022]
In the water-soluble phosphor slurry of the present invention, the surface treatment agent such as the surfactant described above is added to the aqueous dispersion of alumina particles, and the pH of the dispersion is adjusted to an alkaline region (specifically, the pH is adjusted to 7). (In the range of more than 10 to less than 10) and adding alumina particles (binder) to the water-soluble phosphor slurry in the form of an alkaline alumina dispersion liquid capable of maintaining a dispersed state in such an alkaline region. Is preferred. That is, the above-mentioned alkaline alumina dispersion liquid is added to a water-soluble phosphor dispersion liquid containing a phosphor powder and a water-soluble binder, and the resulting mixture is sufficiently stirred and uniformly mixed to obtain an alkaline aqueous dispersion. A luminescent phosphor slurry can be prepared.
[0023]
The phosphor powder contained in the water-soluble phosphor slurry is not particularly limited, and various known phosphors conventionally used for forming a fluorescent lamp can be used. For example, a three-wavelength phosphor having a main emission peak in a blue region around 430 to 460 nm, a green region around 540 to 550 nm, and a red region around 610 to 620 nm is used. Examples of the three-wavelength light emitting phosphor include a blue-to-blue-green light-emitting phosphor such as a divalent europium-activated aluminate phosphor, a divalent europium and a manganese-activated aluminate phosphor, and a trivalent europium-loaded phosphor. A red light-emitting phosphor such as an active yttrium oxide phosphor, a trivalent europium-activated yttrium oxysulfide phosphor, and a white light-emitting phosphor appropriately mixed with a rare-earth green light-emitting phosphor are included.
[0024]
As the water-soluble binder, various conventionally known materials can be used, and examples thereof include polyethylene oxide, hydroxyalkyl cellulose, and ammonium methacrylate. The water-soluble binder powder is preferably added to the phosphor powder in the water-soluble phosphor slurry so that the solid content of the binder is in the range of 0.5 to 5% by mass. Such a water-soluble binder is used as a solution dissolved in water or the like. Incidentally, the water-soluble phosphor slurry may contain an antifoaming agent, a surfactant and the like as optional components.
[0025]
Since the water-soluble phosphor slurry for a fluorescent lamp of the above-described embodiment has been subjected to a surface treatment so that the alumina particles do not have an isoelectric point in the range of pH = 7 to 10, the alumina as the binder is used. The particles do not aggregate even in an alkaline region, and can maintain a good dispersion state. Accordingly, the pH value of the water-soluble phosphor slurry containing alumina particles as a binder is adjusted to an alkaline range (specifically, a range where the pH value is more than 7 and 10 or less) that can suppress characteristic deterioration of the phosphor powder. Even in the case of adjustment, it is possible to prevent aggregation of alumina particles as a binder and increase in slurry viscosity based on the aggregation.
[0026]
Further, such an alkaline water-soluble phosphor slurry does not cause a change in pH value with time due to deterioration of the phosphor powder, and thus can prevent a rise in slurry viscosity with time and a color shift. Therefore, the water-soluble phosphor slurry of the present invention contributes to the improvement of the luminance characteristics of the fluorescent lamp and the like, and can be stably used for producing the fluorescent film for a long period of time. Characteristic defects can be reduced. These contribute to reduction of the manufacturing cost of the fluorescent lamp.
[0027]
Next, an embodiment of a fluorescent lamp using the above-described water-soluble phosphor slurry and a method of manufacturing the same will be described.
[0028]
FIG. 1 is a partially cutaway view showing the structure of a fluorescent lamp according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a glass bulb, and a fluorescent film 3 is formed on an inner wall surface of the glass bulb 1 via, for example, a protective layer (such as an Al ₂ O ₃ film) 2. A discharge gas at a predetermined pressure, that is, a rare gas such as argon and mercury are sealed in the glass bulb 1. A pair of electrodes are attached to both ends of the glass bulb 1, and a predetermined voltage is applied to the pair of electrodes, so that the fluorescent film 3 emits light. Reference numeral 5 in FIG. 1 denotes a base having terminal pins 5a and 5b.
[0029]
Such a fluorescent lamp is manufactured, for example, as follows. First, the above-mentioned alkaline water-soluble phosphor slurry is prepared. As described above, this water-soluble phosphor slurry is prepared by adding an alkaline alumina dispersion liquid capable of maintaining a dispersed state in an alkaline region to a water-soluble phosphor dispersion liquid containing a phosphor powder and a water-soluble binder, and adding this. It is prepared by thorough stirring.
[0030]
Next, the above-mentioned water-soluble phosphor slurry (phosphor coating solution) is applied to the inner wall surface of the glass bulb 1, and the applied film is baked at a temperature of, for example, 400 to 900 ° C. for several minutes to 1 hour to emit a fluorescent light. The film 3 is formed. Thereafter, the steps of sealing the stem to the end of the glass bulb, filling the inside of the bulb with mercury and a rare gas, closing the exhaust pipe, attaching the base 5, and the like are performed in a conventional manner. Is manufactured.
[0031]
The shape of the fluorescent lamp is not limited to a straight tube shape, and can be applied to various shapes of fluorescent lamps such as a ring shape as shown in FIG. 2, a saddle shape, and a U-shape. The ring-shaped fluorescent lamp shown in FIG. 2 has a ring-shaped glass bulb 6, and a fluorescent film 3 is formed on the inner wall surface of the ring-shaped glass bulb 1 via a protective layer 2. In the drawing, reference numeral 7 denotes an electrode filament, 8 denotes a base, and 9 denotes a terminal pin.
[0032]
In the fluorescent lamp and the method of manufacturing the same according to the above-described embodiment, the water-soluble phosphor slurry adjusted to an alkaline region capable of suppressing the deterioration of the phosphor powder, that is, the water-soluble phosphor slurry of the present invention is used. Since the fluorescent film 3 is formed, the luminance characteristics and the like of the fluorescent lamp can be enhanced, and the water-soluble phosphor slurry is excellent in storage stability and the like (prevention of aggregation). The manufacturing process can be performed stably. This contributes to the reduction of the process failure and the characteristic failure of the fluorescent lamp.
[0033]
【Example】
Next, specific examples of the present invention and evaluation results thereof will be described.
[0034]
Example 1
First, alumina powder having a primary particle size of about 15 nm is dispersed in water (concentration: 10%), and a carboxylic acid-type polymer surfactant is added to the dispersion at a ratio of 5% with respect to the solid content of alumina. Was mixed. Thus, an alkaline alumina dispersion having a pH value of about 9 was prepared. When the isoelectric point of the alumina particles in the alkaline alumina dispersion was evaluated by the method described above, it was confirmed that no isoelectric point was present in the pH range of 7 to 10.
[0035]
Next, an aqueous solution of polyethylene oxide (concentration: 1.0%) was prepared as a binder solution, and a three-wavelength light emitting rare earth phosphor powder, a surfactant, and an antifoaming agent were added thereto, followed by sufficient stirring. The above-mentioned alkaline alumina dispersion liquid was added to this water-soluble phosphor dispersion liquid with stirring, and the mixture was further sufficiently mixed to prepare a water-soluble phosphor slurry having a pH value of about 9 to 10. The content of the alumina particles (binder) in the water-soluble phosphor slurry was 2.0% by mass based on the phosphor powder. The content of polyethylene oxide as a water-soluble binder was 1.0% by mass based on the phosphor powder.
[0036]
On the other hand, as a comparative example with the present invention, a pH value of about 6 was obtained in the same manner as in Example 1 except that a weakly acidic 5% by mass alumina dispersion (manufactured by Tegussa, pH value was about 6) was used. Was prepared. Here, when the pH value of the weakly acidic (pH = about 6) alumina dispersion (liquid temperature: 25 ° C.) was changed to about 8.5, aggregation of alumina particles occurred and the viscosity increased. Assuming that the initial degree of aggregation of the alumina dispersion was 100, the degree of aggregation of the alumina dispersion having a pH value of about 8.5 was 120. The cohesion degree at this time was measured by measuring the dispersion viscosity (seconds) using a cup viscometer (Iwata Viscosity Cup NK-2 (trade name) manufactured by Anest Iwata Co., Ltd.) and evaluated by comparing the dispersion viscosity. did. The dispersion viscosity of the alkaline alumina dispersion of Example 1 was equivalent to that of the weakly acidic alumina dispersion.
[0037]
The alkaline water-soluble phosphor slurry (pH value: about 9 to 10) according to Example 1 and the weakly acidic water-soluble phosphor slurry (pH value: about 6) according to Comparative Example 1 each had a liquid temperature of 25. C., and the pH value of each slurry and the viscosity of the dispersion (measured by the cup viscometer described above) were measured at each retention period. FIG. 3 shows the change over time of the pH of the alkaline water-soluble phosphor slurry according to Example 1, and FIG. 4 shows the change over time of the dispersion viscosity. FIG. 5 shows the change over time of the pH of the weakly acidic water-soluble phosphor slurry according to Comparative Example 1, and FIG. 6 shows the change over time of the dispersion viscosity.
[0038]
As is clear from FIGS. 3 to 6, the pH value of the alkaline water-soluble phosphor slurry according to Example 1 hardly changed even after being stored for 2 months, and no increase in the viscosity of the dispersion was observed. Was. This means that the alumina particles were not aggregated in the water-soluble phosphor slurry. On the other hand, the pH value of the weakly acidic water-soluble phosphor slurry according to Comparative Example 1 changed from 6.0 to 9.5 after being placed for about one month, and the dispersion viscosity was changed with the aging of the pH value. Have also risen significantly. Thus, according to the water-soluble phosphor slurry using the alkaline alumina dispersion, it can be seen that a change in the pH value and an increase in the viscosity of the dispersion accompanying the pH change can be prevented.
[0039]
Example 2
Using the alkaline water-soluble phosphor slurry of Example 1 (after one month of storage), a fluorescent lamp was manufactured as follows. First, the alkaline water-soluble phosphor slurry that had been left for one month was poured into a vertically supported straight tube-shaped glass bulb, and was applied to the inner wall surface of the glass bulb. After being dried, it was fired in a heating furnace to form a fluorescent film. After that, the process of sealing the stem to the end of the glass bulb, the process of filling the interior of the bulb with mercury and rare gas, the process of closing the exhaust pipe, and the process of attaching the base, etc., are performed according to the usual methods. A straight tube fluorescent lamp (FL22SS.EX-N / 18-H) was manufactured. On the other hand, a straight-tube fluorescent lamp (Comparative Example 2) was produced in the same manner as in the above-mentioned Example, except that the weakly acidic water-soluble phosphor slurry (after one month indwelling) according to Comparative Example 1 was used.
[0040]
The initial luminous flux of each fluorescent lamp according to Example 2 and Comparative Example 2 was measured. Assuming that the luminous flux of the fluorescent lamp according to Comparative Example 2 was 100, the luminous flux of the fluorescent lamp according to Example 2 was about 105. This means that the weak acidic acidic water-soluble phosphor slurry caused deterioration of the phosphor due to the indwelling, while the alkaline aqueous water-soluble phosphor slurry can suppress the deterioration of the characteristics of the phosphor. When a ring-shaped fluorescent lamp was similarly manufactured using a ring-shaped glass bulb, the same result as that of a straight tube-type fluorescent lamp was obtained.
[0041]
【The invention's effect】
As described above, according to the water-soluble phosphor slurry for a fluorescent lamp of the present invention, when the phosphor is adjusted to an alkaline range where deterioration of the phosphor and a change over time of the pH value can be suppressed, alumina particles as a binder are used. Aggregation can be prevented. Therefore, according to the fluorescent lamp using such a water-soluble phosphor slurry and the method for manufacturing the same, it is possible to suppress a decrease in the luminance characteristics of the fluorescent lamp and to reduce the occurrence of process defects and characteristic defects. It becomes.
[Brief description of the drawings]
FIG. 1 is a partially cutaway view showing a configuration of a straight tube fluorescent lamp according to an embodiment of the present invention.
FIG. 2 is a partially cutaway view showing a configuration of a ring-shaped fluorescent lamp according to another embodiment of the present invention.
FIG. 3 is a diagram showing a relationship between a retention period of an alkaline water-soluble phosphor slurry and a pH value according to Example 1 of the present invention.
FIG. 4 is a diagram showing the relationship between the retention period and the viscosity of the alkaline water-soluble phosphor slurry according to Example 1 of the present invention.
FIG. 5 is a diagram showing the relationship between the retention period of a weakly acidic water-soluble phosphor slurry and the pH value according to Comparative Example 1.
FIG. 6 is a graph showing the relationship between the retention period and the viscosity of a weakly acidic water-soluble phosphor slurry according to Comparative Example 1.
[Explanation of symbols]
1 ... straight tube glass bulb, 3 ... fluorescent film, 6 ... ring glass bulb

Claims (9)

Including a phosphor powder, a binder and a water-soluble binder, and in a water-soluble phosphor slurry for a fluorescent lamp adjusted to alkaline,
A water-soluble phosphor slurry for a fluorescent lamp, wherein the binder is made of alumina particles, and the alumina particles are surface-treated so that an isoelectric point does not exist in a pH range of 7 to 10. The water-soluble phosphor slurry for a fluorescent lamp according to claim 1, wherein the alumina particles are surface-treated with a surfactant. The water-soluble phosphor slurry for a fluorescent lamp according to claim 2, wherein the surfactant is a carboxylic acid type polymer surfactant. 4. The water-soluble phosphor slurry according to claim 1, wherein the alumina particles as the binder are added to the water-soluble phosphor slurry as an alkaline alumina dispersion that maintains a dispersed state in an alkaline region. 5. Water-soluble phosphor slurry for fluorescent lamps. The fluorescent lamp water according to any one of claims 1 to 4, wherein the alumina particles do not substantially aggregate in the water-soluble phosphor slurry whose pH is adjusted to a range of more than 7 and 10 or less. Soluble phosphor slurry. A glass bulb filled with a discharge gas;
A fluorescent film formed on the inner wall surface of the glass bulb using the water-soluble phosphor slurry for a fluorescent lamp according to any one of claims 1 to 5;
Electrodes provided at both ends of the glass bulb to maintain a positive column discharge in the discharge gas;
A fluorescent lamp comprising: In manufacturing a fluorescent lamp including a glass bulb filled with a discharge gas, a fluorescent film formed on the inner wall surface of the glass bulb, and an electrode for maintaining a positive column discharge in the discharge gas,
A water-soluble phosphor dispersion liquid containing a phosphor powder and a water-soluble binder, and an alkaline alumina dispersion liquid containing alumina particles as a binder and maintaining a dispersed state in an alkaline region, are mixed with each other to form an alkaline aqueous solution. Preparing a phosphor slurry;
Applying the water-soluble phosphor slurry to the inner wall surface of the glass bulb, and baking the applied film to form the phosphor film;
A method for manufacturing a fluorescent lamp, comprising: 8. The method according to claim 7, wherein the alkaline alumina dispersion contains a surfactant. 9. The fluorescent lamp according to claim 8, wherein the alumina particles in the alkaline alumina dispersion are surface-treated with the surfactant so that an isoelectric point does not exist in a pH range of 7 to 10. Method.

Images