JPH06290745A - Fluorescent lamp - Google Patents

Abstract

PURPOSE:To improve external appearance without generating an interference fringe in the case of forming an ultraviolet absorbing film by using a plurality of kinds of fine grain metal oxide. CONSTITUTION:In a fluorescent lamp, a film 11, containing no binder to consist of an ultraviolet absorptive fine grain metal oxide, is formed in the inside of a bulb, and a fluorescent material film 12 is formed in the inside of this film 11. The fine grain metal oxide film 11 is characterized by mixing two or more kinds of the fine grain metal oxides, providing respectively 0.1mum or less mean grain size in a plurality of kinds of these fine grains, and further setting a grain size difference from each other to 0.05mum or less, to distribute the fine grain metal oxides of 50% or more the total unit in a range of this grain size difference. By this constitution, since a grain size difference from each other in a plurality of kinds of the fine grain metal oxides is decreased, a refraction difference is reduced so as to prevent an interference fringe from its generation, and the appearane is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent lamp in which a metal oxide film is formed on the inner surface of a bulb, and a phosphor film is formed inside the film.

[0002]

2. Description of the Related Art Generally, in a fluorescent lamp, a fluorescent film is formed on the inside of a glass bulb in which electrodes are sealed, and ultraviolet rays, which are the resonance emission lines of mercury atoms enclosed in the bulb, are applied to the fluorescent film. Irradiation is performed, ultraviolet rays are converted into visible light by this phosphor film, and this visible light is emitted to the outside.

However, such a fluorescent lamp is
There is a problem that blackening occurs on the bulb wall as the lighting time elapses, and the luminous flux decreases. There are various causes for the blackening, and it is said that the chemical reaction between mercury and the glass material forming the bulb is one of the causes.
That is, the glass forming the bulb is larger or smaller,
It contains sodium Na, and, for example, in the case of a typical soda lime glass that constitutes a bulb of a fluorescent lamp, it contains about 15 to 17% by weight of sodium Na. Such sodium precipitates on the surface when the bulb temperature rises, and promotes its precipitation when further irradiated with ultraviolet rays. Such sodium Na reacts with mercury in the discharge space to turn black. Will be generated.

It is considered that the ultraviolet rays radiated from the mercury atoms in the discharge space are not converted into visible light by the phosphor coating and thus do not reach the glass, but the conversion rate of visible light in the phosphor coating is 100%. Rather, some of the UV light is not converted by the phosphor coating and passes through the phosphor coating to reach the bulb wall. For this reason, the glass bulb is stimulated by receiving ultraviolet rays, and sodium Na is deposited.

From the above, the present inventors have found that the inside of the bulb does not contain a binder and absorbs UV-absorbing particulate metal oxides such as zinc oxide ZnO and titanium oxide TiO 2.
We proposed a fluorescent lamp in which a coating consisting of ₂ etc. was formed and a phosphor coating was formed inside this metal oxide coating.
According to such a lamp, the ultraviolet absorbing fine particle metal oxide formed between the glass bulb and the phosphor coating,
It prevents contact between the bulb and the phosphor coating and also reduces the rate at which it absorbs or reflects UV light and reaches the bulb wall, thus preventing the precipitation of sodium and the reaction between sodium and the phosphor, thus premature blackening. It has been confirmed that it is possible to prevent aging.

[0006]

In this case, the above-mentioned ultraviolet absorbing fine particle metal oxide has a difference in wavelength absorption or reflection characteristics in the ultraviolet region depending on its type, that is, absorption and reflection depending on the type of fine particle metal oxide. There is a difference in the ultraviolet wavelength. Therefore, it is possible to block ultraviolet rays in a wide wavelength range by using two or more kinds of fine particle metal oxides rather than one kind.

However, when a plurality of kinds of fine particle metal oxides are used in this way, interference fringes are generated, and there is a lamp which causes a defective appearance. As a result of investigating and investigating the cause, it was found that interference fringes tended to occur remarkably when there was a large difference in particle diameter among a plurality of types of fine particle metal oxides. The reason for this is not clear, but the multiple types of fine particle metal oxides originally have a difference in refraction from each other, and in addition to this, if there is a difference in particle size, the difference in refraction is enlarged, resulting in interference fringes. It is presumed that.

The present invention has been made in view of the above circumstances. An object of the present invention is to improve the appearance without forming interference fringes when a coating film is formed by using plural kinds of fine particle metal oxides. It is intended to provide a fluorescent lamp.

[0009]

In order to achieve the above-mentioned object, the present invention forms a coating film made of a fine particle metal oxide which is substantially free of inder and has ultraviolet absorption property inside the bulb. A fluorescent lamp having a phosphor coating formed on the inside of an oxide coating, wherein the coating made of the fine particle metal oxide is a mixture of two or more fine particle metal oxides. The oxides each have an average particle size of 0.1 μm or less, and the difference in particle size between the oxides is 0.
Less than 05 μm, 50% of the total within the range of this particle size difference
The above-mentioned fine particle metal oxide is distributed.

[0010]

According to the present invention, since the difference in particle size among a plurality of types of fine particle metal oxides is reduced, the difference in refraction is reduced, the occurrence of interference fringes is prevented, and the appearance is improved.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on an embodiment shown in the drawings. FIG. 1A shows a straight tube type fluorescent lamp, and 1 is a glass bulb. The bulb 1 is made of soda lime glass and has a straight tube shape. Flare stems 2 and 2 are hermetically sealed at both ends of the valve 1, and a pair of lead wires 3 ... Each stem 2, 2
Filament electrodes 4 and 4 made of tungsten or the like are bridged between the lead wires 3 and 3, respectively.

The filament electrodes 4 and 4 are coated with an electron emitting substance such as BaO, SrO or CaO (not shown). Further, on the outer side of the end portion of the valve 1, the base 5,
5, the bases 5, 5 are provided with base pins 6, ... Connected to the lead wires 3. As shown in FIG. 1 (B), a coating film 11 made of fine particle metal oxide having an ultraviolet absorbing property and transmitting visible light is formed inside the bulb 1. The fine particle metal oxide film 11 includes zinc oxide ZnO fine particles, titanium oxide TiO ₂ fine particles, and aluminum oxide Al ₂ O.
It is formed of a mixture of two or more kinds of fine particles selected from the _three .

In this case, the plurality of types of fine particle metal oxides each have an average particle size of 0.1 μm or less and a mutual particle size difference of 0.05 μm or less. 50% or more of the fine particle metal oxide is distributed. The film thickness of the fine particle metal oxide film 11 is 0.5 μm or less. And, this one does not use a glassy binder such as silane which is usually used when forming various films on the outer surface of the valve, and an organic solvent which gives viscosity by mixing with fine particles of metal oxide in the coating liquid. Are mixed and applied inside the valve 1 and dried and baked to remove water and organic substances, and the van der Waals force (dispersion force) between the particles is formed.
For example, it adheres to the inner surface of the valve.

A phosphor coating 12 made of a rare earth phosphor is formed inside the particulate metal oxide coating 11. The rare earth phosphors are three types of rare earth phosphors that emit light in the respective wavelength regions of blue, green, and red. For example, red-based phosphors include yttrium salt (Y ₂ O ₃ : E).
u), a blue-based phosphor is a divalent europium-activated alkaline earth halophosphate phosphor or a divalent europium-activated alkaline earth aluminate phosphor (BaMg ₂ A)
l ₁₆ O ₂₇ : Eu) and (La, C
e, Tb) · (P, Si) O 4 is used, is constructed by mixing these three phosphor powder.

In the fluorescent lamp having such a structure, since the ultraviolet absorbing fine particle metal oxide coating 11 is formed between the inner surface of the glass bulb 1 and the rare earth phosphor coating 12, the fine particles are formed. The metal oxide film 11 prevents direct contact between the mercury and the bulb 1, and absorbs ultraviolet rays that pass through the shaded phosphor coating 12 and reach the bulb 1.

Therefore, since sodium Na is not deposited from the bulb 1 made of soda lime glass, and when it is deposited, direct contact between sodium and mercury is blocked, so that the phosphor can be rapidly discolored or Blackening is prevented,
The luminous flux maintenance factor can be kept high. Further, since the fine particle metal oxide film 11 does not contain a vitreous binder, impurities are not released from the binder into the bulb 1 and blackening is prevented.

The fine particle metal oxide coating 11 is zinc oxide Z.
Since these oxides are formed of a mixture of two or more kinds of fine particles selected from nO fine particles, titanium oxide TiO ₂ fine particles and aluminum oxide Al ₂ O ₃ , these oxides have higher absorptivity of ultraviolet rays than other oxides. Is high and does not block visible light, and thus has excellent luminous efficiency. In this case, each of these plural kinds of fine particle metal oxides has an average particle diameter of 0.1 μm or less, and has a mutual particle diameter difference of 0.0 μm or less.
It is 5 μm or less, and within the range of this particle size difference,
Since 0% or more of the fine particle metal oxide is distributed, the difference in refraction between the fine particle metal oxides is reduced and the occurrence of interference fringes is prevented. Therefore, the appearance of the arc tube is improved.

The results of experiments conducted on this point will be described.
Table 1 shows ZnO particles having an average particle size of 0.015 μm, TiO ₂ particles having an average particle size of 0.03 μm, Al ₂ O ₃ particles having an average particle size of 0.02 μm, and an average particle size of 0.2 μm.
m TiO ₂ fine particles and Al having an average particle size of 0.9 μm
The generation of interference fringes when the fine particle metal oxide film 11 is formed by investigating and mixing the ₂ O ₃ fine particles and mixing them, dispersing them in a water-soluble binder and water and applying them on the inner surface of the valve is also examined. The appearance was evaluated based on the occurrence of interference fringes.

[0019]

[Table 1]

From Table 1 above, when fine particles having an average particle size of 0.1 μm or less are mixed within a range of a particle size difference of 0.05 μm or less, no interference fringes are generated and the appearance is good. It was confirmed that It is presumed that this is because the difference in refraction between the fine particle metal oxides is small, the refraction difference between the fine particle metal oxides is originally small, and the refraction difference is not enlarged, and as a result, the occurrence of interference fringes is prevented.

Further, since the average particle size of each fine particle metal oxide is set to 0.1 μm or less, the sizes are uniform, the bondability is improved, and peeling is difficult. The present invention is not limited to the structure of the above-described embodiment, and for example, the shape of the fluorescent lamp may be a ring fluorescent lamp, a compact fluorescent lamp, or the like, and is not a cold cathode fluorescent lamp. May be.

Further, in the rapid start fluorescent lamp, a conductive coating (EC film) is formed on the inside of the bulb, and the particulate metal oxide coating 11 of the present invention is formed between the bulb wall and the conductive coating. Then, protection of the conductive coating can be expected.

[0023]

As described above, according to the present invention, since the coating film made of the particulate metal oxide having an ultraviolet absorbing property is formed between the glass bulb and the phosphor coating, the particulate metallic oxide can emit the ultraviolet light. Since the rate of absorption and reflection to reach the bulb wall is reduced, precipitation of sodium is prevented, reaction between sodium and mercury is prevented, and premature blackening can be prevented. In this case, since the coating film is formed by mixing a plurality of types of fine particle metal oxides, there is a difference in wavelength absorption and reflection characteristics between the fine particle metal oxides, and thus blocks a wide range of ultraviolet rays. Since the difference in particle size between these fine particle metal oxides is reduced, the difference in refraction is reduced and the occurrence of interference fringes is prevented, which improves the appearance.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, FIG. 1 (A) is a sectional view showing the entire straight tube fluorescent lamp, and FIG. 1 (B) is a lateral sectional view thereof.

[Explanation of symbols]

1 ... Valve 2 ... Stem
4 ... Electrode 11 ... Particulate metal oxide coating 12 ... Fluorescent coating

Claims (2)

[Claims] 1. A fluorescent substance coating is formed on the inside of a coating of a fine particle metal oxide which does not substantially contain a binder and which absorbs ultraviolet rays, on the inside of the bulb. It is a light lamp, and the film made of the fine particle metal oxide is a mixture of two or more kinds of fine particle metal oxides, and the plurality of kinds of fine particle metal oxides each have an average particle diameter of 0.1 μm or less, Further, the fluorescent lamp is characterized in that the mutual difference in particle size is 0.05 μm or less, and 50% or more of the total amount of the particulate metal oxide is distributed within the range of the particle size difference. 2. The ultraviolet absorbing fine particle metal oxide,
The fluorescent lamp according to claim 1, which is a mixture of fine particles selected from zinc oxide, titanium oxide, and aluminum oxide.