JPH04332457A - Fluorescent lamp and binding agent used therefor - Google Patents

Abstract

PURPOSE:To improve a fluorescent film and a binding agent used for this. CONSTITUTION:A fluorescent film 2 is constituted by binding fluorescent substance particles 21 by means of plural kinds of particulate binding agents 22 and 23 having different particle diameters, and the particulate binding agents or binding agent for fluorescent lamp are mainly composed of calcium pyrophosphate patrticulates and gamma alumina particulate having smaller particle diameter than those. The large diametric particulate binding agents interpose between mutual fluorescent substance particles, and bind both together, and since the small diametric particulate binding agents interpose between the mutual large diametric particulate binding agents and between the large diametric particulate biding agents and the fluorescent substance particles or glass surfaces and bind both together, adherent strength of the fluorescent film can be improved significantly, so that neither bulb strength nor luminous efficiency is lowered. furthermore, since neither fluorescent substances nor the glass bulb is eroded, the fluorescent film can be adhered firmly, so that the particulate binding agents hardly lowering the luminous efficiency of a lamp can be obtained.

Description

[Detailed description of the invention]

[Purpose of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent lamp in which the adhesion strength of a fluorescent film is improved without reducing luminous efficiency or bulb strength.

0002

[Prior Art] Conventionally, as a means of improving the adhesion strength of a fluorescent film in a fluorescent lamp, an inorganic binder is mixed with phosphor particles and fired, thereby bonding the phosphor particles to each other and to the glass surface of the bulb. known to bind. The following three types of inorganic binders are known to be used for this purpose. (1) Particle size 1.0 like calcium pyrophosphate fine powder
A particulate binder that is made of microparticles smaller than μ and is interposed between phosphor particles or between phosphor particles and the glass surface of a bulb, and binds them together by Van der Waals force. (2) A glassy substance that softens or melts at baking temperature, such as borates, which is interposed between the phosphor particles or between the phosphor particles and the glass surface of the bulb, and is welded by baking to bond them together. Vitreous binder. (3) A mixed binder that uses a mixture of the above-mentioned particulate binder and the above-mentioned vitreous binder, and uses both the Van der Waals force of the particulate binder and the adhesive force of the vitreous binder. .

0003

Problems to be Solved by the Invention Since the above-mentioned fine particle binder has a small Van der Waals force, if the amount of binder added to the fluorescent film is small, the binding force will be insufficient and the film strength will be poor. On the other hand, if the amount of binder is increased, the binding force becomes stronger and sufficient film strength can be obtained, but on the other hand, the proportion of phosphor in the film decreases, and the amount of ultraviolet rays and visible light due to the binder increases. Another drawback is that the luminous efficiency of the lamp is reduced due to the increased absorption of .

[0004] Furthermore, the above-mentioned vitreous binder firmly welds to the phosphor particles and the glass surface, so it has a strong binding force and a strong phosphor film can be obtained. However, on the other hand, the vitreous binder has the property of mixing with the glass and corroding it, so there is a drawback that the strength of the bulb is reduced.

Furthermore, the above-mentioned method of using a particulate binder and a vitreous binder has the advantages of both types of binders, but on the other hand, the disadvantage of the vitreous binder, which is that of glass bulbs, Erosion and the resulting loss of bulb strength remain unavoidable.

Therefore, the object of the present invention is to provide a fluorescent lamp that improves the strength of the fluorescent film without reducing luminous efficiency or bulb strength, and a binder used to obtain such a fluorescent lamp. The goal is to provide the following.

[Configuration of the invention]

[0008]

[Means for Solving the Problems] The first invention solves the above-mentioned problems by configuring a fluorescent lamp in which phosphor particles are bound together using a plurality of types of fine particle binders having different particle sizes. This has been achieved.

The second invention is that the main components of the fine particle binder used in the first invention are calcium pyrophosphate fine particles and γ alumina fine particles having a smaller particle size.

[0010] The third invention is a binder for a fluorescent lamp, the main components of which are calcium pyrophosphate fine particles and γ alumina fine particles having a smaller particle size.

[0011]

[Action] When using a mixture of a large-diameter particulate binder and a small-diameter particulate binder, the large-diameter particulate binder can be used in the gaps between the large-diameter particulate binders and between the large-diameter particulate binder and the phosphor particles. Because the small-diameter particulate binder enters and intervenes, the total contact area between both types of particulate binder and the phosphor particles is much larger than when only one type of binder is used, and therefore the van der Waals Since it has a large force, it can be bonded firmly and a strong fluorescent film can be obtained.

[0012] Further, γ alumina is suitable for use as a small-diameter particulate binder because extremely fine particles can be easily obtained, and it does not damage glass or phosphors, and other benefits can be expected.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the invention will be explained below with reference to illustrated embodiments. FIG. 2 shows an example of a fluorescent lamp to which the present invention is applied, in which (1) is a straight glass bulb, (2) is a fluorescent film formed on the inner surface of this bulb (1), and (3) is a straight glass bulb. ，
(3) is a stem with both ends of the valve (1) closed; (4)
, (4)... are pairs of lead wires introduced into the valve (1) through these stems (3), (3), respectively, and (5), (5) are pairs of lead wires, respectively. (4
), (4)... filament mounted between the tips of (
6) and (6) are caps attached to both ends of the valve (1). An appropriate amount of mercury is sealed in the bulb (1) along with a starting gas such as argon.

As shown in the schematic enlarged cross-sectional view of FIG. 1, the phosphor film (2) is made by combining phosphor particles (21) with a large-diameter fine-particle binder (22) and a small-diameter fine-particle binder (23). At the valve (
1) is bound to the glass surface (11).

The phosphor particles (21) are, for example, halophosphate phosphors, and their particle size distribution is as follows.

Particle size smaller than 6μ 15-20
% 6μ or more and 16μ or less 70-75% Larger than 16μ 10% 24μ or more None The large-diameter fine particle binder (22) is, for example, calcium pyrophosphate fine particles, whose average particle size is 1-2.5μ. The blending ratio is 0.8±0.2% by weight, taking the entire fluorescent film (2) as 100.

The small diameter fine particle binder (23) is, for example, γ
Alumina fine particles whose average particle size is 0.02~0.03μ
So, the compounding ratio is 0.3± with the entire fluorescent film (2) as 100.
It is 0.2% by weight.

To form this fluorescent film (2), phosphor particles (21), a large-diameter particulate binder (22), a small-diameter particulate binder (23), and an organic solvent such as butyl acetate are added. Add an appropriate amount of nitrocellulose and roll to adjust to a suspension. Then, pour this suspension into the valve (1).
A fluorescent film (2) can be obtained by coating the inner surface, drying, and baking at a temperature of 500° C. or higher to decompose and remove the nitrocellulose.

As shown in FIG. 1, the thus obtained phosphor film (2) has two types of fine particle binders (22) having different particle sizes as described above in the gaps between the phosphor particles (21). ), (2
3), a large-diameter fine particle binder (22) is interposed in the gap between the phosphor particles (21) and binds them together by van der Waals force, and the phosphor particles (21)
) and the large-diameter particulate binder (22), and the small-diameter particulate binder (23) is interposed between the large-diameter particulate binders (22), (22) to bind them together. Connected by Waals force. Also, in the gap between the phosphor particles (21) and the glass surface (11) of the bulb (1), a large-diameter fine particle binder (22) and a small-diameter fine particle binder (23) are added, as described above.
interposes and connects the two by van der Waals force. In this case, as is clear from FIG. 1, the total contact area of both the large and small particulate binders (22) and (23) is extremely large, so the binding force is extremely strong and they are easily peeled off. Never.

[0020] Also, both fine particle binders (22), (23)
By selecting the above-mentioned calcium pyrophosphate fine particles and gamma alumina fine particles as the material, absorption of ultraviolet rays and visible light could be reduced. Particularly small particle binder (23)
(1) Gamma alumina particles with an extremely small particle size can be easily obtained, and the particle size is extremely small even compared to α alumina, so the contact area is extremely large and strong adhesion is possible. can. (2) As mentioned above, if the particle size of γ alumina is made much smaller than the wavelength of ultraviolet rays, it will be as if it does not exist optically, and the absorption of ultraviolet rays and visible light will be small, improving luminous efficiency. (3) Since γ alumina has a getter function, the valve (
1) Impurity gas inside can be absorbed and removed, resulting in longer life. (4) Since γ alumina has lattice defects in its crystal, a fluorescent film containing it has slightly improved conductivity, and as a result, the starting characteristics of the lamp are improved. It has the following advantages.

Next, this kind of fine particle binder (22), (
23) Explain that there is an appropriate amount to use. Generally speaking, as shown in Figure 3, as the amount of binder added increases, the binding strength of the fluorescent film increases, and conversely, the light output decreases, and the point where the intensity curve intersects with the output curve is This is the optimum amount. As shown by the broken line in the figure, if a binder with stronger binding force is used, the optimal amount of addition will shift to a smaller amount.
Improves light output. For this reason, it can be understood that the fluorescent lamp of the present invention has improved light output by improving the binder of the fluorescent film.

Next, an example of the present invention is shown in a rated FLR40SW/M fluorescent lamp. Calcium pyrophosphate 0
．． Various properties were investigated for those in which 8% by weight and 0.3% by weight of gamma alumina were added, and those in which a conventional calcium pyrophosphate binder and a borate binder were used in combination. The results are shown in Table 1 below.

[0023]

Note: ◎…Excellent. ×…Inferior.

○...Slightly excellent.

As is clear from Table 1, it can be seen that in the examples of the present invention, when the light output was kept the same, the fluorescent film adhesion strength was markedly improved, and the bulb strength was also markedly improved. The reason for this is that the Van der Waals force was significantly improved in the example of the present invention as a result of using two types of fine particle binders (22) and (23) with different particle sizes, and the use of a glassy binder Sufficient adhesion strength was obtained even without the use of vitreous binders, and bulb erosion, which is a drawback of vitreous binders, was eliminated.

Next, in the examples of the present invention, the blending ratio of the calcium pyrophosphate binder (22) and the γ alumina binder (23) was varied to improve the luminous flux maintenance factor and the coverage of the fluorescent film (2). Compared with strong wear. Luminous flux maintenance rate is 10 from 0 hours after startup
It was expressed as the rate of decrease in total luminous flux at 0 hours. The results are shown in Table 2 below.

[0028]

Note: ◎...Excellent.

○...Slightly excellent.

As is clear from Table 2, all of the test specimens have excellent characteristics, but test specimen No. 3 in particular has a small luminous flux reduction rate and is extremely excellent in adhesion strength of the fluorescent film.

[0032] In the above-mentioned embodiments, both types of fine particle binders are not limited to the above-mentioned examples and may be of any material.In short, if two types of fine particle binders with different particle sizes are blended, good. Further, even if there are three or more types of these fine particle binders, it is sufficient that at least two of them have different particle sizes. Further, in the present invention, the particulate binder may be used in advance, or may be separately added to the solvent when preparing the suspension as described above. In the present invention, regardless of the type and particle size of the phosphor,
Moreover, the solvent and coating means used for coating are not limited.

[0033]

Effect of the Invention The present invention relates to an improvement of a fluorescent film in a fluorescent lamp, and the first claim is a method for forming a fluorescent film by binding phosphor particles using a plurality of types of fine particle binders having different particle sizes. With this configuration, it is possible to provide a fluorescent lamp in which the intensity of the fluorescent film is high, the bulb is not corroded by the binder and the intensity does not decrease, and furthermore, the output does not decrease due to excess binder.

[0034] In addition, the second aspect of the present invention is that the fine particle binder in the first invention contains calcium pyrophosphate fine powder and γ alumina fine particles having a smaller particle size as the main ingredients, so that the inventive effect is particularly excellent. There is.

Furthermore, in the third aspect of the present invention, since the main components are calcium pyrophosphate fine particles and γ alumina fine particles having a smaller particle size, an excellent binder for fluorescent lamps can be provided.

[Brief explanation of drawings]

FIG. 1 is a schematic enlarged sectional view of the main parts showing the principle of operation of the fluorescent lamp of the present invention.

FIG. 2 is a sectional view showing the overall structure of an embodiment of the fluorescent lamp of the present invention.

FIG. 3 is a graph showing the theoretical appropriate amount of binder in the fluorescent film in the present invention.

[Explanation of symbols]

(1)...Valve (11)...Glass surface (2)...Fluorescent film (21)...phosphor particles (22)...Large diameter fine particle binder (23)…Small diameter fine particle binder (3)...Stem (5)...filament

Claims (3)

[Claims] 1. A fluorescent film is formed on the inner surface of a glass bulb, and the fluorescent film is formed by binding fluorescent particles using a plurality of types of fine particle binders having different particle sizes. fluorescent lamp. 2. The fluorescent lamp according to claim 2, wherein the fine particle binder is mainly composed of calcium pyrophosphate fine particles and γ alumina fine particles having a smaller particle size. 3. A binder for a fluorescent lamp, characterized in that the main components are calcium pyrophosphate fine particles and γ alumina fine particles having a smaller particle size.