JP2005264119A - Liquid for applying phosphor and fluorescent lamp using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid for applying a phosphor in which discoloration of fluorescent film in a baking step of the phosphor is suppressed and uniformity of thickness of the fluorescent film in longitudinal direction of a fluorescent lamp can be ensured and to provide the fluorescent lamp having a stable luminescence property by using the liquid. <P>SOLUTION: The liquid for applying the phosphor comprises water, a phosphor, a thickener and a binder and further, at least one compound selected from ammonium chloride, ammonium carbonate, ammonium hydrogencarbonate, ammonium hydrogencarbonate aluminate, ammonium fluoride, ammonium hydrogenfluoride, hydrazinium chloride, ammonium cyanate, ammonium nitrite, ammonium sulfite and ammonium acetate and the compound is included in an amount of ≥0.05 g and ≤4 g based on 1 kg phosphor. The fluorescent lamp is obtained by applying the fluorescent film 3 formed by the liquid for applying the phosphor to the inside of a glass tube 1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a phosphor coating liquid and a fluorescent lamp using the same.

  In recent years, fluorescent lamps have been widely used as office lighting and general household lighting. As a method for forming the fluorescent film of the fluorescent lamp, a phosphor coating liquid in which a phosphor, a polymer thickener, a metal oxide and the like are dispersed in water is used for a glass tube having a longitudinal direction perpendicular to the ground. A method of pouring the phosphor on the inner surface of the glass tube by pouring it into the interior, blowing warm air from the upper or lower part of the glass tube into the interior of the glass tube to dry, and then firing at a temperature of 400 ° C. or higher is adopted. . In general, the phosphor film formed in this manner varies in emission characteristics depending on its thickness. For this reason, when forming a fluorescent film, how to ensure the uniformity of the thickness of the fluorescent film is an important point.

As such a phosphor coating solution, a solution containing water, a phosphor, a water-soluble bander, a water-soluble rare earth compound, boric acid, and colloidal alumina has been proposed (for example, see Patent Document 1). .)
Japanese Patent Application Laid-Open No. 6-49445

  However, when a fluorescent film is formed inside the glass tube using the phosphor coating solution described in Patent Document 1, the water-soluble rare earth compound may react with boric acid or the like in the baking process of the fluorescent film on the glass tube. For this reason, there is a problem that the fluorescent film is colored, and as a result, the luminous flux of the fluorescent lamp decreases. Further, in order to solve this problem, when a phosphor coating solution to which no water-soluble rare earth compound is added is used, there is a problem that the thickness uniformity of the fluorescent film in the longitudinal direction of the fluorescent lamp is lowered.

  Accordingly, the present invention provides a phosphor coating solution that suppresses coloring of the phosphor film in the phosphor baking process and can ensure uniformity of the thickness of the phosphor film in the longitudinal direction of the fluorescent lamp, and stable light emission using the same. A fluorescent lamp having characteristics is provided.

  The present invention relates to a phosphor coating solution containing water, a phosphor, a thickener, and a binder, and the phosphor coating solution further includes ammonium chloride, ammonium carbonate, ammonium bicarbonate, and albumin carbonate. And containing at least one compound selected from ammonium oxyhydrogen, ammonium fluoride, ammonium hydrogen fluoride, hydradium chloride, ammonium cyanate, ammonium nitrite, ammonium sulfite, and ammonium acetate, and the amount of the compound per kg of the phosphor The phosphor coating liquid is characterized in that it is 0.05 g or more and 4 g or less.

  The present invention also relates to a fluorescent lamp having a fluorescent film deposited on the inside of a glass tube, wherein the fluorescent film comprises water, a phosphor, a thickener, a binder, ammonium chloride, and ammonium carbonate. Phosphor coating solution containing at least one compound selected from ammonium hydrogen carbonate, ammonium hydrogen carbonate, ammonium hydrogen carbonate, ammonium fluoride, ammonium hydrogen fluoride, hydradium chloride, ammonium cyanate, ammonium nitrite, ammonium sulfite, and ammonium acetate The fluorescent lamp is characterized in that the amount of the compound is 0.05 g or more and 4 g or less per kg of the phosphor.

  The phosphor coating liquid of the present invention suppresses coloring of the phosphor film in the phosphor baking process, and can ensure uniformity of the thickness of the phosphor film in the longitudinal direction of the fluorescent lamp.

  In addition, the fluorescent lamp of the present invention suppresses coloring of the fluorescent film by forming the fluorescent film using the phosphor coating liquid, and ensures the uniformity of the thickness of the fluorescent film in the longitudinal direction of the fluorescent lamp. As a result, the light emission characteristics are stabilized.

  Embodiments of the present invention will be described below.

(Embodiment 1)
First, an embodiment of the phosphor coating solution of the present invention will be described. An example of the phosphor coating liquid of the present invention is:
Contains water, phosphor, thickener and binder, and also contains ammonium chloride, ammonium carbonate, ammonium bicarbonate, ammonium hydrogen carbonate, ammonium fluoride, ammonium hydrogen fluoride, hydradium chloride, cyanic acid At least one compound selected from ammonium, ammonium nitrite, ammonium sulfite, and ammonium acetate.

  Since the phosphor coating liquid of this embodiment does not contain a water-soluble rare earth compound and boric acid, coloring of the phosphor film in the phosphor baking step is suppressed.

  In addition, the amount of the compound contained in the phosphor coating solution needs to be 0.05 g or more and 4 g or less, more preferably 0.1 g or more and 1 g or less, per 1 kg of the phosphor. Within this range, it is possible to ensure the uniformity of the thickness of the fluorescent film in the longitudinal direction of the fluorescent lamp, although it does not contain a water-soluble rare earth compound.

  The phosphor coating liquid preferably further contains a boron compound. This is because the binding property of the phosphor is further improved. As the boron compound, boron oxide, boric acid and the like can be used, but boron oxide is most preferable. This is because boron oxide is highly soluble in water. On the other hand, since the phosphor coating liquid does not contain a water-soluble rare earth compound, the phosphor film is not colored in the phosphor baking step even if it contains a boron compound. The amount of the boron compound is preferably 0.1 g or more and 3 g or less, more preferably 1 g or more and 1.5 g or less per 1 kg of the phosphor.

  Among the above compounds, ammonium chloride is particularly preferable. This is because ammonium chloride is highly soluble in water and inexpensive. Moreover, since the aqueous solution of ammonium chloride is nearly neutral, it is difficult to react with other components of the phosphor coating solution. When ammonium chloride is used as the compound, the amount of ammonium chloride is preferably from 0.1 g to 2 g, more preferably from 0.1 g to 0.2 g, per kg of the phosphor. This is because within this range, the uniformity of the thickness of the fluorescent film in the longitudinal direction of the fluorescent lamp can be more reliably ensured.

  The water used for the phosphor coating solution is preferably ion exchange water, distilled water or the like. This is because if the water contains impurities, the light emission characteristics of the phosphor film deteriorate.

  Examples of the phosphor include europium-activated yttrium oxide phosphor, cerium terbium-activated lanthanum phosphate phosphor, europium-activated strontium halophosphate phosphor, europium-activated barium magnesium aluminate phosphor, and europium manganese-activated barium magnesium. An aluminate phosphor, a terbium-activated cerium aluminate phosphor, a terbium-activated cerium magnesium aluminate phosphor, an antimony-activated calcium halophosphate phosphor, or the like can be used alone or in combination.

  The thickener is used to improve the adhesion of the phosphor coating solution to the glass surface, and for example, polyethylene oxide, hydroxypropylcellulose, hydroxymethylpropylcellulose, carboxymethylcellulose, polyvinyl alcohol and the like are preferable. In particular, polyethylene oxide is preferred. This is because polyethylene oxide is highly combustible and can be easily removed when the phosphor is fired. The amount of the thickening agent is preferably 1 g or more and 50 g or less, more preferably 10 g or more and 20 g or less, per 1 kg of the phosphor. This is because within this range, the uniformity of the phosphor coating film becomes higher.

  The binder is used to bond phosphor particles and improve the strength of the phosphor film. For example, aluminum oxide, silicon oxide, titanium oxide, zinc oxide, etc. can be used, and among these, oxidation is particularly preferred. Aluminum is preferred. This is because aluminum oxide has a large binding force. The average particle size of the binder is preferably 0.01 to 2 μm. This is because within this range, the phosphor particles can be uniformly dispersed and the phosphor particles can be reliably bound. Further, the amount of the binder is preferably 5 g or more and 60 g or less, more preferably 20 g or more and 30 g or less, per 1 kg of the phosphor. This is because the binding force can be sufficiently exhibited within this range.

(Embodiment 2)
Next, an embodiment of the fluorescent lamp of the present invention will be described with reference to the drawings. FIG. 1 is a partially broken view showing an example of the fluorescent lamp of the present invention. In FIG. 1, both ends of a glass tube 1 are sealed by a stem 2, and a rare gas such as neon, argon, and krypton and mercury are sealed inside. On the inner surface of the glass tube 1, a fluorescent film 3 formed using the phosphor coating solution described in the first embodiment is attached. A filament electrode 5 is attached to the stem 2 by two lead wires 4. A base 7 having an electrode terminal 6 is bonded to both ends of the glass tube 1, and the electrode terminal 6 and the lead wire 4 are connected.

  The fluorescent lamp of the present embodiment has a stable emission characteristic because the fluorescent film 3 is formed using the phosphor coating liquid of the first embodiment.

  Further, a conductive film can be further deposited between the glass tube 1 and the fluorescent film 3. Thereby, the fluorescent lamp of this embodiment can be made into a rapid start type with a short start time. Note that tin oxide to which antimony is added is used as a material for the conductive film.

  In the rapid start type fluorescent lamp, a current flows in the fluorescent film to assist discharge in starting. At that time, if the thickness of the fluorescent film is not uniform, discharge will reach the glass of the glass tube, especially when a current flows in the thick part of the fluorescent film, and a hole will be formed on the surface of the glass tube, or black spots As a result, mercury oxide is formed, resulting in poor light emission. However, since the fluorescent film formed using the phosphor coating liquid of Embodiment 1 has a uniform thickness, the above-described disadvantage does not occur and it is particularly effective for a rapid start type fluorescent lamp.

  The fluorescent lamp of the present embodiment is not particularly limited with respect to its shape, size, wattage, light color, color rendering, etc. emitted by the fluorescent lamp. The shape is not limited to the straight tube of the present embodiment, but includes, for example, a round shape, a double ring shape, a twin shape, a compact shape, a U shape, a light bulb shape, and a thin tube for a liquid crystal backlight. As for the size, for example, there are 4 types to 110 types. As for the wattage, for example, there are several watts to hundreds tens of watts. Examples of the light color include daylight color, daylight white color, white color, warm white color, light bulb color, and Paruk color.

  Next, the present invention will be described more specifically based on examples, but the present invention is not limited to the following examples.

<Preparation of phosphor coating liquid>
First, the following were prepared as materials for the phosphor coating solution.
(1) Dispersion medium: distilled water
(2) Phosphor: a phosphor prepared by preparing a europium-activated yttrium oxide phosphor, a cerium terbium-activated lanthanum phosphate phosphor and a europium-activated strontium halophosphate phosphor in a weight ratio of about 40:30:30
(3) Additive compound: 0.1 g of ammonium chloride per kg of phosphor
(4) Thickener: Polyethylene oxide with a weight average molecular weight of about 1 million (15 g / kg of phosphor)
(5) Binder: 30 g of gamma alumina (aluminum oxide) per kg of phosphor
(6) Boron compound: 1 g of boron oxide per 1 kg of phosphor Next, polyethylene oxide was dissolved in distilled water using a stirrer. Thereafter, the phosphor, aluminum oxide, boron oxide and ammonium chloride were added in this order and stirred.

<Production of fluorescent lamp>
Using the phosphor coating solution, a fluorescent lamp (40 W type) having the same structure as that of FIG. 1 was produced as follows. First, the phosphor coating solution was poured from above into a glass tube installed so that the vertical direction was the longitudinal direction, and allowed to flow naturally to adhere the phosphor coating solution to the inside of the glass tube. Thereafter, the adhered phosphor coating solution was dried with hot air of about 60 ° C. for about 10 minutes. After drying, the entire glass tube was placed in a gas furnace and heated in air at a temperature of about 550 ° C. for about 3 minutes, and the phosphor film was baked and fixed on the glass tube. Subsequently, a glass with an exhaust pipe having an electrode and a capsule enclosing mercury was fused to the end of the glass pipe, and the air inside the glass pipe was evacuated by a rotary pump from the exhaust pipe. Next, argon gas was sealed and an electrode was attached to produce a fluorescent lamp.

  A fluorescent lamp was produced in the same manner as in Example 1 except that a phosphor coating solution in which the amount of ammonium chloride was 0.2 g per kg of phosphor was used.

  A fluorescent lamp was produced in the same manner as in Example 1 except that a phosphor coating solution in which the amount of ammonium chloride was 0.5 g per kg of the phosphor was used.

  A fluorescent lamp was produced in the same manner as in Example 1 except that a phosphor coating solution in which the amount of ammonium chloride was 1.0 g per kg of the phosphor was used.

  A fluorescent lamp was produced in the same manner as in Example 1 except that a phosphor coating solution in which the amount of ammonium chloride was 2.0 g per kg of the phosphor was used.

(Comparative Example 1)
A fluorescent lamp was produced in the same manner as in Example 1 except that the phosphor coating solution to which no ammonium chloride was added was used.

(Comparative Example 2)
A fluorescent lamp was produced in the same manner as in Example 1 except that a phosphor coating solution in which the amount of ammonium chloride was 0.03 g per kg of the phosphor was used.

(Comparative Example 3)
A fluorescent lamp was produced in the same manner as in Example 1 except that a phosphor coating solution in which the amount of ammonium chloride was 5.0 g per kg of phosphor was used.

<Presence or absence of coloring of fluorescent film>
About each fluorescent lamp produced in the said Examples 1-5 and Comparative Examples 1-3, it was observed visually whether the fluorescent film colored in the baking process of the said fluorescent substance. As a result, in Examples 1 to 5, coloring of the fluorescent film was not recognized. On the other hand, in Comparative Examples 1 to 3, although the fluorescent film was slightly colored, it was at a level of no problem in practice.

<Evaluation of thickness uniformity of fluorescent film>
In order to evaluate the uniformity of the thickness of the formed fluorescent film, each of the fluorescent lamps produced in Examples 1 to 5 and Comparative Examples 1 to 3 was measured at two points 150 mm in the longitudinal direction from both ends of the glass tube. After cutting, the cross section was observed with an electron microscope, and the average film thickness of the fluorescent film at each point was measured at t1 and t2. And the thickness ratio (t1 / t2 or t2 / t1) was calculated | required by making the one where the value of the measured average film thickness is larger into a denominator and the smaller one as a numerator, and the thickness uniformity of the fluorescent film was evaluated. That is, as the film thickness ratio of the fluorescent film is closer to 1, it means that the fluorescent film has a uniform and good thickness in the longitudinal direction of the fluorescent lamp. Conversely, as the film thickness ratio of the fluorescent film is smaller than 1, the thickness of the fluorescent film is non-uniform, and sufficient light emission characteristics cannot be obtained when the fluorescent film is too thick or too thin. Decreases.

  The above results are shown in FIG. FIG. 2 is a diagram showing the relationship between the amount of ammonium chloride added to the phosphor coating solution per kg of the phosphor and the film thickness ratio of the phosphor film formed using the phosphor coating solution. 2, in Examples 1 to 5 in which the addition amount of ammonium chloride is 0.1 to 2.0 g per kg of the phosphor, the film thickness ratio of the phosphor film is 0.84 to 0.86, and the fluorescent lamp It can be seen that the film thickness of the fluorescent film in the longitudinal direction is substantially uniform. In particular, in Examples 1 and 2 in which the amount of ammonium chloride added is 0.1 to 0.2 g per kg of the phosphor, the uniformity of the thickness of the fluorescent film in the longitudinal direction of the fluorescent lamp is higher. I understand.

  On the other hand, in Comparative Example 1 and Comparative Example 2 in which the amount of ammonium chloride added was less than 0.05 g, the phosphor film thickness ratio was 0.55, and Comparative Example 3 in which the amount of ammonium chloride added exceeded 4.0 g. Then, the thickness ratio of the phosphor is 0.67, and it can be seen that the thickness of the phosphor film in the longitudinal direction of the fluorescent lamp is not uniform.

<Confirmation of luminous characteristics of fluorescent lamp>
The fluorescent lamps produced in Examples 1 to 5 and Comparative Examples 1 to 3 were each turned on for 100 hours, and the total luminous flux (initial luminous flux) after 100 hours of lighting was measured. The results are shown in Table 1.

  From Table 1, it can be seen that the initial luminous flux of the fluorescent lamps of Examples 1-5 is larger than the initial luminous flux of the fluorescent lamps of Comparative Examples 1-3.

  In the above examples, europium-activated yttrium oxide phosphor, cerium terbium-activated lanthanum phosphate phosphor and europium-activated strontium halophosphate phosphor were prepared in a weight ratio of about 40:30:30. However, the effect was the same for other blending ratios.

  As described above, the present invention suppresses the coloring of the fluorescent film in the phosphor baking process, and ensures the uniformity of the thickness of the fluorescent film in the longitudinal direction of the fluorescent lamp, and the stability using the same. A fluorescent lamp having the above-mentioned light emission characteristics can be provided, and its industrial value is great.

It is a partially broken view of the fluorescent lamp of the second embodiment. It is the figure which showed the relationship between the addition amount per 1 kg of fluorescent substance of the ammonium chloride added to the fluorescent substance coating liquid, and the film thickness ratio of the fluorescent film formed using the said fluorescent substance coating liquid.

Explanation of symbols

1 Glass tube 2 Stem 3 Fluorescent film 4 Lead wire 5 Filament electrode 6 Electrode terminal 7 Base

Claims (7)

A phosphor coating solution containing water, a phosphor, a thickener, and a binder,
The phosphor coating solution is further composed of ammonium chloride, ammonium carbonate, ammonium hydrogen carbonate, ammonium hydrogen carbonate aluminate, ammonium fluoride, ammonium hydrogen fluoride, hydradium chloride, ammonium cyanate, ammonium nitrite, ammonium sulfite, and ammonium acetate. Comprising at least one selected compound,
The phosphor coating solution is characterized in that the amount of the compound is 0.05 g or more and 4 g or less per kg of the phosphor.   Furthermore, the fluorescent substance coating liquid of Claim 1 containing a boron compound.   The phosphor coating solution according to claim 1 or 2, wherein the compound is ammonium chloride, and the amount of the ammonium chloride is 0.1 g or more and 2 g or less per kg of the phosphor. A fluorescent lamp having a fluorescent film deposited on the inside of a glass tube,
The phosphor film is water, a phosphor, a thickener, a binder, ammonium chloride, ammonium carbonate, ammonium hydrogen carbonate, ammonium hydrogen carbonate, ammonium fluoride, ammonium hydrogen fluoride, hydradium chloride, Formed using a phosphor coating solution containing at least one compound selected from ammonium cyanate, ammonium nitrite, ammonium sulfite, and ammonium acetate;
The fluorescent lamp, wherein the amount of the compound is 0.05 g or more and 4 g or less per kg of the phosphor.   The fluorescent lamp according to claim 4, wherein the phosphor coating liquid further contains a boron compound.   The fluorescent lamp according to claim 4 or 5, wherein the compound is ammonium chloride, and the amount of the ammonium chloride is 0.1 g or more and 2 g or less per kg of the phosphor.   The fluorescent lamp according to claim 4, further comprising a conductive film between the glass tube and the fluorescent film.

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