JPH01112651A - Fluorescent discharge lamp - Google Patents

Abstract

PURPOSE:To prolong the life of a fluorescent discharge lamp and equip it with excellent light penetration for visible range by forming a protection film consisting of metal oxide containing tin oxide on the inner wall surface of a bulb of discharge lamp, and thereby preventing drop of the light flux maintaining factor due to blackening of the inner wall of bulb. CONSTITUTION:The inner wall surface of the bulb 1 of a fluorescent discharge lamp is cleaned and covered with a protection film 2 consisting of metal oxide containing tin oxide. A fluorescent substance layer 3 is formed over this protection film 2 to a certain thickness and the protection film 2 is used for prevention of light flux decay (blackening). Through the action of this protection film 2, drop of the light flux maintaining factor due to blackening of the bulb inner wall is prevented to prolong the life of the discharge lamp, which will be equipped with excellent light penetration for the visible range.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a technique for preventing luminous flux reduction (blackening of the inner wall of a bulb) in a fluorescent discharge lamp, particularly in an electrodeless fluorescent discharge lamp.

[Background technology]

So-called electrodeless discharge lamps, which discharge gases such as rare gases or metal vapors inside the bulb by applying a high-frequency electric field from the outside without installing electrodes inside the bulb, are small, high-output, and long-life lamps. Because of these excellent characteristics, it has a wide range of applications, including not only illumination but also as a light source for document reading in optical equipment such as electronic copying machines and facsimiles, and is being actively researched and developed.

As mentioned above, the bulb of this electrodeless discharge lamp is usually filled with a rare gas such as argon, or an element that is desired to emit light such as mercury is also sealed with the rare gas in a state where it can easily vaporize. are doing.

These gas atoms or molecules collide with electrons that are ionized and continuously generated by high-frequency discharge, and are excited by absorbing the kinetic energy of the colliding electrons. When returning from the excited state to the ground state, a discharge spectrum is generated, most of which belongs to the ultraviolet region that cannot be detected by human vision. Therefore, in order to use it as a light source for illumination or for reading originals in optical equipment, it is necessary to go through a process of converting ultraviolet rays into visible light that can be felt by the human eye. In fluorescent discharge lamps, the phosphor layer formed inside the bulb is responsible for this conversion.

Generally speaking, in fluorescent discharge lamps, including such electrodeless types, the inner wall surface of the bulb darkens over time with use, and as a result, the luminous efficiency of the lamp decreases, which is called luminous flux reduction. Decrease in luminous flux maintenance rate) has been a long-standing problem.

Taking as an example an electrodeless fluorescent discharge lamp that uses argon and mercury, the most common filler gases, the following phenomena can be considered to be the cause of the luminous flux reduction, that is, the blackening of the inner wall surface of the bulb. .

■ Formation of alkaline amalgam Electrodeless fluorescent lamp bulbs are normally exposed to high temperatures (
200 to 300°C) such as quartz glass or hardened borosilicate glass [for example, Corning Co., Ltd.
Pyrex glass (trade name) is used, but these glasses contain very small amounts of Na, Na,
It contains alkali metals such as K and Li, and these metals react with mercury during discharge operation to form an alkali amalgam.

■ Penetration and precipitation of metallic mercury into the inside of the bulb Due to the high operating temperature, mercury ionizes and penetrates into the inside of the bulb, but these mercury ions are converted into photoelectrons inside the bulb that are generated when exposed to ultraviolet rays generated by discharge. It is attracted and reduced, becoming metallic mercury and depositing on the bulb surface.

■ Solarization of the bulb by ultraviolet rays ■ Production of mercury oxide A small amount of air and moisture remains inside the bulb after the lamp is formed, and the water, butyl acetate, and Because some of the nitrocellulose, polyethylene oxide, aluminum oxide sol, surfactant, etc. remain undecomposed, the oxygen contained in these components is stimulated by discharge during lighting, ultraviolet rays, etc. The active oxygen reacts with mercury to form mercury oxide.

In order to prevent the blackening of the inner wall surface of the bulb due to the causes mentioned above, conventional fluorescent discharge lamps with built-in electrodes, which have electrodes at both ends of the bulb, have been coated with alkali elution prevention film, ultraviolet cut H4, etc. Providing a membrane has been considered. These films are made of aluminum oxide, silicon oxide, titanium oxide, magnesium oxide, etc.
By coating the inner wall of the bulb with these metal oxides in the form of fine powder or sol, it is formed between the inner wall surface of the bulb and the phosphor layer.

However, the coating film described above cannot be said to be sufficiently effective, especially for small, high-output lamps such as electrodeless discharge lamps or compact fluorescent lamps. Therefore, the need for a film (protective film) for preventing luminous flux attenuation that satisfies the following two conditions is being questioned. Namely; ■ The film must have a high UV reflectance.

■ The membrane must have a strong barrier effect against mercury ion penetration.

Films that satisfy these requirements include Ce+ Zr, Tl, p
It has been found that films made of various oxides such as B, In, etc. are effective, and various studies have been made so far. However, although the film made of the above-mentioned metal oxides is very effective in preventing blackening of the inner wall surface of the bulb due to mercury,
Since it also has a high absorption rate for visible light, it has the disadvantage of large light loss.

[Purpose of the invention]

In view of these circumstances, an object of the present invention is to provide a fluorescent discharge lamp that prevents luminous flux reduction by preventing blackening of the inner wall surface of the bulb and has excellent light transmittance in the visible light range. do.

[Disclosure of the invention]

As a result of repeated studies to achieve the above objective, it was found that the protective film for preventing blackening was made of the above-mentioned Ce, Zr, Ti, Pb.
It was found that the object of the present invention could be achieved if it was composed of metal oxides such as , In, etc. and tin oxide, and the present invention was completed.

Therefore, in the present invention, a protective film for preventing luminous flux reduction and a phosphor layer for emitting light are formed on the inner wall surface of the bulb, and the ultraviolet rays obtained by discharging gases sealed in the bulb are emitted. The present invention provides a fluorescent discharge lamp in which visible light is converted into visible light in a phosphor layer, wherein the protective film is made of a metal oxide containing tin oxide.

The present invention will be explained in detail below with reference to the drawings.

FIG. 1 is a schematic cross-sectional view showing an embodiment of the fluorescent discharge lamp according to the present invention. The figure shows valve 1. A protective film 2 and a phosphor layer 3 are shown.

The valve 1 is not particularly limited, and may be made of a common material. In other words, when the lamp is a fluorescent discharge lamp with built-in electrodes, soda glass or lead glass is used as the bulb material, and when the lamp is an electrodeless type, it is heated at high temperatures (200 to 300 ℃) during operation. ℃
), quartz glass, borosilicate glass, etc. are used to withstand Additionally, in the case of a lamp that emits light of a specific wavelength, a special glass can be used accordingly.

The shape of the valve 1 is also straight pipe type or annular type.

U-shaped, flat plate, 5 spheres, etc. are not limited in any way,
It can be selected depending on its use.

After cleaning, the above-mentioned bulb 1 has a protective film 2 on its inner wall surface for preventing luminous flux reduction (preventing blackening), which is a feature of the present invention.
is formed.

As the metal oxide constituting this protective film 2, tin oxide (
SnO□) is an essential component, but other metal oxides used in combination include Ce0z, Zr0z, Ti1t, Pb
It can be arbitrarily selected from TiOx, Ingot, etc., and they are used alone or in combination.

The above metal oxides are prepared by preparing a coating solution by diluting and mixing starting materials such as metal alkoxides, metal complexes with organic ligands, organometallic compounds, etc. with an arbitrary solvent, and after coating, the resulting coating film is prepared. It is formed by firing at high temperature.

For example, compounds that form tin oxide are not particularly limited as long as they are soluble in organic solvents, such as di-n-butyltin diacetate, di-n-butyl, tin dilaurate, and di-n-butyltin diacetate. -Butyltin malate Examples include organic tin compounds such as tri-n-butyltin acetate, inorganic acid salts such as tin chloride, and carboxylic acid salts such as tin octylate.

Examples of metal oxides other than tin oxide include metal alkoxides (Ti(OCzHs)++Ti) with alcohols such as ethanol and isopropanol.
(i-OCsllt)4+Zr(i-OCzHt)4t
In(j-OCJy)s, etc.], acetylacetone (
CHICOCIl, C0CH, hereinafter abbreviated as acac]
Metal complexes with organic ligands such as (Ce(acac)!,
Ce (acac) 4, In (acac)
s etc.], carboxylic acid salts with carboxylic acids such as naphthenic acid (((CILz)4CH(CHrincOO), Pb,
((Cold)4CH(CHI)-Coo) 4Zr, n
= 4 etc.] can be used.

The diluent for the coating solution is not particularly limited, and examples thereof include lower alcohols such as ethanol, isopropanol and butanol, ketones such as acetone and methyl ethyl ketone, and esters such as ethyl acetate and butyl acetate. These may be used alone or in combination. The diluent may contain an inorganic acid such as hydrochloric acid, nitric acid, or sulfuric acid, or formic acid or acetic acid as a catalyst.

The blending ratio of the tin compound to which organic acids such as propionic acid, formamide, and water for hydrolysis may be added is such that the proportion of the tin compound in the form of an oxide is 1
It is preferable to adjust so that 0.5 to 1 mole of tin oxide is formed per mole. If the molar ratio of tin oxide to other metal oxides in the protective film 2 exceeds 1.0, there is a risk that a uniform film will not be obtained;
．． When it is less than 5, there is a tendency that the effects of the present invention obtained by adding tin oxide are not sufficiently exhibited.

The method for applying the coating liquid for the protective film 2 constructed in this manner onto the inner wall surface of the valve is not particularly limited as long as a uniform coating layer can be obtained. for example,
Dipping coating in which the valve is immersed in the coating liquid, spray painting in which the coating liquid is atomized and sprayed, or the like may be carried out by pouring the coating liquid into the valve.・The resulting coating film is fired by heating it to a temperature (approximately 470°C or higher) at which metal compounds such as alkoxides decompose and oxidize.
Although it is desirable that the treatment be carried out for a sufficient period of time or longer, the conditions are not limited to this, and the conditions can be set as appropriate depending on the type of metal compound used. However, if the firing is insufficient, carbon derived from organic components may remain in the film, causing the film to turn black, or oxygen in unreacted substances may form on the protective film, causing the metal in the phosphor layer to form on the protective film. (Mn.

There is a risk that the light transmittance may decrease due to the reaction with Hg, etc.) or mercury, etc., which is a sealed gas, to form a black metal oxide (MnzOs+HgO, etc.).

In this way, a protective film 2 is formed on the inner wall surface of the valve, that is,
Ce0t/5nOz, Zr0z/5nOt+ Ti0
z/5nOz, PbTies/Snow, ,In
A uniform total urine oxide film such as zO*/Snow is formed.

The thickness of the protective film 2 is not particularly limited;
The number of participants is preferably about 00 to 2000 people. Film thickness is 5
If the number is less than 0.00, the effect of blocking ultraviolet rays may be reduced. On the other hand, it is difficult to form a film with a thickness exceeding 2000 mm without cracking or peeling during firing.

The phosphor layer 3 is overlaid on the protective film 2 as described above, but the phosphor contained therein is not particularly limited. For example, halophosphate-based (Cats (
PO4)aFCl:Sb:Mn, 3Ca(Po4)Ca
Ft:Sb:'In, 3Caz (PO4) zca
Fi:Sb:Mn etc.], phosphate type (Cat(PO4
)i:Sn, Zn5(Po4)z:T1 etc.], silicate system [Ca5iOz:Pb:Mn, ZnzSiO4:Mn
+ (ZnBe) zsio4:Mn, etc.]. The phosphor N3 is formed by a conventional method such as dispersing these compounds in a suitable solvent or the like and applying the dispersion onto the protective film 2.

Inside the bulb l on which the protective film 2 and the phosphor layer 3 are formed, He, Ne, Ar, Kr, Xe,
Gases such as rare gases such as Rn, and gases made by adding elements for emitting light at a specific wavelength (ultraviolet region) to these rare gases are sealed.

As the element for the above-mentioned light emission, As+ Bit Br
.

Cd, Hg, P, Pb, S, Sb, Se,
Examples include Sn, Te, TI, Zn, etc., but are not limited to these.

However, alkali metals are not suitable because they react with quartz, which is the material of the bulb. Among these elements, elements that are easily vaporized or elements that are in a gaseous state from the beginning can be left alone as they are, while other elements can be encapsulated in the form of iodide, chloride, amalgam, etc. to make them easier to vaporize. In the present invention, there is no particular limitation on the amount of vapor gas to be filled, and it can be set as appropriate depending on the type of fluorescent discharge lamp to be formed. For example, in the case of an electrodeless fluorescent discharge lamp, the gas pressure of the enclosed element should be optimized at the operating temperature (200 to 300°C), that is, the radiation efficiency of the ultraviolet rays generated from the enclosed element during operation. The amount to be included may be adjusted so that the amount is maximized.

Comparing the performance of the fluorescent discharge lamp according to the present invention with a conventional fluorescent discharge lamp having a protective film made of a metal oxide that does not contain tin oxide, it is found that not only the initial illuminance but also the luminous flux maintenance rate after 100 hours of continuous lighting. The lamp life has been significantly extended. Regarding the spectral transmittance characteristics in the visible light range, as shown in Fig. 2 (see Example 1 and Comparative Example 1 below), the fluorescent discharge lamp, which is an embodiment of the present invention, is shown by a broken line. (Electrodeless type, protection 11i1: Ti0
z/5n02 series, film thickness 1000 people), conventional fluorescent discharge lamps (electrodeless type, protective film: Ti0z series,
The transmittance has improved compared to the film thickness of 1,040 mm), demonstrating the remarkable effectiveness of adding tin oxide.Up to now, we have focused our explanation on electrodeless fluorescent discharge lamps. However, the fluorescent discharge lamp according to the present invention is not limited to this; it can be applied to any type of fluorescent discharge lamp, such as general fluorescent discharge lamps with built-in electrodes or compact fluorescent discharge lamps, which have the same problem of blackening of the inner wall surface of the bulb. It goes without saying that this is intended for fluorescent discharge lamps.The configuration is not limited to that shown in FIG. 1, for example, if the fluorescent discharge lamp is a reflection type or an aperture type, A reflective film made of titanium oxide or the like may be provided between the protective film 2 and the phosphor layer 3 to control light distribution.

Next, examples of the present invention will be described together with comparative examples.

■ 1 light emitting 1 几 击 rift (Example 1) Pyrex glass bulb (diameter 16, length 300
After washing the sample (n), it was immersed in a coating liquid having the following composition.

Titanium tetraisopropoxide: 18g ethanol
:80g hydrochloric acid
:0.4g water :
1.6g di-n-butyltin malate: 20g was immersed and pulled out of the solution at a constant speed of 200 mm/min to form a coating film, and then baked at 120°C for 15 minutes and at 600°C for 60 minutes. A titanium oxide/tin oxide-based protective film (film thickness 900 to 1000 layers) was obtained.

Next, a calcium halophosphate (C
A phosphor layer of a+o(POa)*FC1:Sb:Mn) was formed, and argon gas and mercury were sealed to produce an electrodeless fluorescent discharge lamp.

(Comparative Example 1) A titanium oxide-based protective film was prepared in the same manner as in Example 1, except that no tin compound was added to the coating solution. Obtained.

(Example 2) The same valve as in Example 1 was used, and after cleaning, it was immersed in a coating liquid having the following composition.

Zirconium naphthenate 228g butanol
2 g di-n-butyl tin malate = 6 g After immersion, it was pulled out of the solution at a constant speed of 270 m+a/min to form a coating film, and then baked in the same manner as in Example 1 to form a zirconium oxide/tin oxide based Protective film (film thickness 10
00 to 1100 people).

Thereafter, an electrodeless fluorescent discharge lamp was produced in the same manner as in Example 1.

(Comparative Example 2) An electrodeless fluorescent discharge lamp having a zirconium oxide protective film was produced in the same manner as in Example 2, except that no tin compound was added to the coating solution.

(Example 3) Pyrex glass bulb (diameter 12 mm, length 25 mm)
0 mm) was washed and then immersed in a coating liquid having the following formulation.

Cerium dolacetylacetonate: 15g butanol
, 85g 10% ethanol solution of tin chloride: 10g or less, carried out in the same manner as in Example 1, to form a cerium oxide/tin oxide protective film (film thickness: 900 to 1000)
I got it.

Next, on this protective film, (3Ca(Po4)CaFz
:Sb:Mn, Ca5iOt:Pb:Mn) system phosphor layer was formed, and then argon gas and mercury were filled in to obtain an electrodeless fluorescent discharge lamp.

(Comparative Example 3) An electrodeless fluorescent discharge lamp having a cerium oxide-based protective film was manufactured in the same manner as in Example 3 except that no tin compound was added to the coating liquid.

(Example 4) Coating liquid consisting of the following formulation; Indium triacetylacetonate = 15g acetone
285g 10% ethanol solution of tin chloride: 10g was prepared, and the rest was carried out in the same manner as in Example 3.
00 to 900 people) was fabricated.

(Comparative Example 4) An electrodeless fluorescent discharge lamp having an indium oxide-based protective film was produced in the same manner as in Example 4 except that no tin compound was added to the coating solution.
The thickness of the protective film in Examples 1 to 4 is the same as that obtained in the corresponding Examples 1 to 4, respectively.

(Example 5) The same procedure as in Example 1 was carried out except that the amount of di-n-butyltin malate added was set to Log, and a titanium oxide/tin oxide-based protective film (thickness: 1100 to 1200 mm) was prepared.
was formed.

Next, a phosphor layer similar to that in Example 3 was formed on this protective film, and argon gas and mercury were sealed therein to produce an electrodeless fluorescent discharge lamp.

(Comparative Example 5) An electrodeless fluorescent discharge lamp was produced in the same manner as in Example 1 except that no protective film was formed, that is, a phosphor layer was formed directly on the inner wall surface of the bulb.

(8) Bulbs and tube surfaces In Examples 1 to 5 and Comparative Examples 1 to 4, the spectral transmittance in the visible light range of each bulb having a protective film formed on its inner wall was measured.

In addition, each of the fluorescent discharge lamps of Examples 1 to 5 and Comparative Examples 1 to 5 thus produced was lit at high frequency, and the luminous flux maintenance rate was measured after continuous lighting for 100 hours.

The above results are shown in Table 1. The spectral transmittance characteristics in the visible light range of the bulbs of Example 1 and Comparative Example 1 are also shown in FIG.

As shown in Table 1 and Figure 2, the spectral transmittance in the entire visible light range and the spectral transmittance after 100 hours of continuous lighting were higher in the examples containing tin oxide in the protective film than in the comparative examples. It was found that the luminous flux maintenance rate of both cases was improved.

〔Effect of the invention〕

The fluorescent discharge lamp according to the present invention is as described above, and a protective film made of a metal oxide containing tin oxide is formed on the inner wall surface of the bulb. In other words, the decline in the luminous flux maintenance factor of the lamp is prevented, and the lamp life is significantly extended.
This makes it possible to realize a fluorescent discharge lamp with excellent light transmittance in the visible light range.

[Brief explanation of the drawing]

Fig. 1 is a schematic cross-sectional view showing an embodiment of the fluorescent discharge lamp according to the present invention, and Fig. 2 shows the difference in spectral transmittance characteristics in the visible light range depending on the presence or absence of tin oxide in the protective film. An example is the hail graph. 1... Bulb 2... Protective film 3... Phosphor layer agent Patent attorney Takehiko Matsumoto

Claims (2)

[Claims] (1) A protective film for preventing luminous flux reduction and a phosphor layer for emitting light are formed on the inner wall surface of the bulb, and the phosphor layer emits ultraviolet light obtained by discharging gases sealed in the bulb. A fluorescent discharge lamp configured to convert visible light into visible light, wherein the protective film is made of a metal oxide containing tin oxide. (2) The fluorescent discharge lamp according to claim 1, wherein the amount of tin oxide in the protective film for preventing luminous flux reduction is 0.5 to 1 mol per mol of the other metal oxide.