JPH0536381A - Rapid start type fluorescent lamp - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a rapid start type fluorescent lamp in which yellowing of a phosphor layer and blackening of an EC film are prevented. [Structure] A transparent conductive film 5 and a phosphor layer 6 are formed on the inner surface of a bulb 1, and a phosphor layer is formed in a rapid start type fluorescent lamp in which mercury and a rare gas are enclosed. The fluorescent substance is -0.5 to + per 1 g of the fluorescent substance when contacted with reduced iron powder having a particle diameter of 74 to 44 μm.
It is characterized by being charged with an electric charge of 1.5 microcoulombs. Since the charging tendency of the phosphor is controlled, the adsorptivity of the phosphor and mercury and mercury compounds can be regulated, and yellowing of the phosphor and blackening of the EC film can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to means for preventing blackening of a phosphor layer or an EC film in a rapid start type fluorescent lamp.

[0002]

2. Description of the Related Art In a rapid start fluorescent lamp, a transparent conductive film (EC film = nesa film) made of, for example, tin oxide SnO is formed on the inner surface of an arc tube bulb.
A fluorescent substance film is formed on the inner surface of the EC film.
It is known as a fluorescent lamp which has an excellent starting property because the film plays a role of lowering the wall resistance.

In recent years, in order to obtain high efficiency and high color rendering properties, a combination of three color phosphors of red, blue and green which have a linear emission spectrum in a narrow wavelength range,
Rapid start type fluorescent lamps using so-called three-wavelength light emitting type phosphors have been developed.

In such a rapid start fluorescent lamp, a bulb is filled with a mixed gas containing mercury and one or more rare gases, and electrode energy is supplied to the mixed gas through two electrodes. As a result, a positive column discharge is generated in this mixed gas. This discharge mainly produces ultraviolet rays, most of which is 185
nm and 254 nm, and this ultraviolet ray is generated by the three-wavelength emission type phosphor formed on the inner surface of the bulb.
The red, blue, and green light emission spectra are converted to obtain mixed-color light of these three colors.

[0005]

However, in a rapid start type fluorescent lamp using such a three-wavelength light emitting type fluorescent substance, the fluorescent substance coating turns yellow due to long-term use and the luminous flux is changed. Or the blackening phenomenon due to dark brown band-like spots may occur on the EC film. Such discoloration and blackening are remarkable especially in blue-based phosphors and green phosphors.

[0006] When the cause of this is examined and investigated,
The above-mentioned phosphor easily adsorbs mercury and mercury compounds that have reacted with impurities such as carbon and hydrogen while the lamp is operating, and these adsorbed mercury and mercury compounds do not easily separate from the surface of the phosphor coating, and mercury is further absorbed. Impurity is taken in to form a mercury compound, and such a mercury compound turns yellow, and when such a mercury compound reaches near the EC film, the mercury compound and the EC film generate a slight discharge due to a potential difference. However, it is speculated that this discharge causes the mercury compound to turn black, resulting in blackening of the EC film.

As a means for preventing such a yellowing or blackening phenomenon, it is conceivable to lower the potential difference by increasing the electric resistance of the EC film. However, if this is done, the tube wall resistance increases. The starting voltage becomes high and the starting becomes difficult, and especially when trying to start in a low temperature atmosphere of 0 ° C. or less, the starting does not start easily, which causes drawbacks such as limited use of the lamp.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a rapid start type tilted light capable of preventing yellowing of a phosphor and blackening of an EC film. It is intended to provide a lamp.

[0009]

DISCLOSURE OF THE INVENTION The present invention provides a rapid start type fluorescent lamp in which a transparent conductive film and a phosphor layer are formed on the inner surface of a bulb, and mercury and a rare gas are enclosed in the bulb. The phosphor constituting the phosphor layer is charged with a charge of −0.5 to +1.5 microcoulombs per 1 g of the phosphor when contacted with reduced iron powder having a particle size of 74 to 44 μm. Is characterized by.

[0010]

The inventors of the present invention have conducted investigations, experiments and analyzes and found that in the rapid start type fluorescent lamp, the tendency of the fluorescent substance to be charged is closely related to the yellowing of the fluorescent substance and the blackening of the EC film. I did what I was doing.

[0011] That is, rapid Star - The three-wavelength emission type phosphor bet type fluorescent lamps, as red phosphors Y2 O3: Eu, BaMg ₂ as blue phosphors
Al ₁₆ O ₂₇ : Eu, as a green phosphor (Ra, T
b, Ce) · (P, Si) O ₄ is often used.

The charging tendency and the occurrence of blackening were investigated for such a phosphor. As is generally known, the charging tendency is indicated by the amount of charged electric charge per 1 g of the fluorescent substance when contacting with the reduced iron powder having a particle diameter of 44 to 74 μm. FIG. 2 shows the charging tendency of the phosphor and the adsorption amounts of mercury and a mercury compound on the phosphor after 500 hours of lighting. In this experiment, the red phosphor Y2 is used as the phosphor.
Using O3: Eu, the electrification tendency was changed by the method of depositing the metal oxide powder on the surface of the phosphor particles.

From the characteristics shown in FIG. 2, it was found that the adsorptivity of mercury and mercury compounds to the phosphor depends on the charging tendency of the phosphor. When the charging tendency of the phosphor is in the range of 0 to +1 μC / g, the adsorption amount of mercury and a mercury compound on the phosphor becomes the minimum, and the adsorption amount of mercury and a mercury compound is changed to less than this value or above. Will increase.

It has been found that the charging tendency of the phosphor is positively charged or negatively charged depending on the type of the metal oxide, and MgO charges the phosphor in the positive direction and at the same time, SiO ₂ tends to charge the phosphor in the negative direction.

And instead of Mg, Ca, Sr, B
Even if one kind of metal oxide selected from the oxides of a and Zn is used, the charging tendency of the phosphor can be changed in the positive direction.

In addition, instead of SiO ₂ , Sn, Ti,
The charge tendency of the phosphor can be changed in the negative direction by using at least one selected from the oxides of Ge, Ta, Nb, V, and Mo.

Further, it is effective if these oxides are deposited in the range of 0.01 to 3.0% by weight with respect to the phosphor. In other words, the amount of metal oxide is a very important factor for controlling the charging tendency of the phosphor, and when the amount of attachment is more than 3.0% by weight, the emission output of each phosphor remarkably decreases. .. On the other hand, when the adhesion amount is less than 0.01% by weight, the effect of adhering the metal oxide, that is, the effect of changing the charging tendency is not remarkable.

On the other hand, FIG. 3 shows the rate of occurrence of blackening of the EC film after lighting for 3000 hours by coating the photoconductors having various charging tendencies on the EC film of a 20 W straight tube type rapid start type fluorescent lamp. It was measured. Characteristic A in FIG. 3 is the case where the resistance value of the EC film is 0.50 KΩ / cm.

From the characteristics of FIG. 3, it was found that the EC film blackening occurrence rate depends on the charging tendency of the phosphor, which corresponds to the adsorptivity of mercury and mercury compounds to the phosphor shown in FIG. It became clear.

The amount of charge on the phosphor is -1 μC.
In the range of / g or less, the rate of EC film blackening increases as the negative value of the charging tendency increases. Further, EC film blackening occurs even in a region where the amount of charge of the phosphor is +2 μC / g or more. The amount of charge on the phosphor is -0.5 to +1.5 μC /
Within the range of g, no blackening of the EC film was observed even after 3000 hours of lighting. Then, in this case, a low temperature starting test was conducted at an ambient temperature of 0 ° C., but there was no particular increase in the starting voltage, and no abnormality was found in the starting characteristics.

Characteristic B in FIG. 3 is a measurement of the EC film blackening occurrence rate when the resistance value of the EC film is 1.0 KΩ / cm. In this case, since the resistance value of the EC film is large, the potential difference between the EC film and mercury is small across the phosphor film, and the dielectric breakdown of the phosphor film is reduced, so that the blackening of the EC film is considerably improved. Although it is recognized that the starting voltage becomes high, reliable starting becomes impossible in the case of low temperature starting at 0 ° C., and the starting characteristic becomes abnormal. For this reason,
The resistance value of EC film is 0.9 KΩ / cm or less, 0.1 KΩ / cm
cm or more is good.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in FIG.

The drawing shows a 20 W straight tube type rapid start type fluorescent lamp, and 1 is a glass bulb. Both ends of the valve 1 are airtightly closed by flare stems 2 and 2, and a pair of lead wires 3 ...

A hot cathode made of tungsten or the like, that is, filaments 4 and 4 are provided between the lead wires 3 and 3 of both the stems 2 and 2. The filaments 4, 4
Although not shown in the drawing, an electron emitting substance such as barium oxide is applied.

A transparent conductive film (EC film = nesa film) 5 such as tin oxide is formed on the inner surface of the bulb 1, and the phosphor film 6 is formed on the surface of the transparent conductive film 5. Are formed. This phosphor coating 6 uses a three-wavelength emitting rare earth phosphor, and Y is used for the red phosphor.
₂ O ₃ : Eu (red), BaMg _{2 for} blue phosphor
Al ₁₆ O ₂₇ : Eu, and (Re, T
b, Ce) · (P, Si) O 4 is used, is constructed by mixing these three phosphor powder. As shown in FIG. 1B, these phosphors are phosphor powders 1
The charge tendency is changed by adhering the metal oxide powder to the surface of No. 0.

That is, in these phosphors, the kind and the amount of the metal oxide are appropriately selected to control the charge amount of the whole phosphor within the range of -0.5 to +1.5 μC / g. Has been done. Further, the EC film 5 has an electric resistance value of 0.1 to 0.1.
It is set to 0.9 KΩ / cm. The bulb 1 is filled with a predetermined amount of mercury and a rare gas such as argon. The fluorescent lamp having such a configuration is lit up 300
Even after 0 hour, no yellowing or blackening of the phosphor is observed.

This means that the amount of charge on the phosphor is -0.5.
Since it is regulated within the range of to +1.5 μC / g, the adsorbability of the mercury compound is weakened by the reaction of the phosphor with the mercury atom and impurities, and the mercury atom and the mercury compound are easily separated from the phosphor. It is presumed that it prevents yellowing of the phosphor and blackening of the EC film.

When the phosphor is mixed with α-alumina (Al ₂ O ₃ ) in order to lower the starting voltage, α-alumina has a good electron emission property even if no external stimulus is applied. , The starting voltage can be lowered. The present invention is not limited to the use of a three-wavelength emission type phosphor, and the present invention is applicable not only to a straight tube type fluorescent lamp but also to a ring type lamp, a compact bent type lamp or the like.

[0029]

As described above, according to the present invention, by controlling the charging tendency of the phosphor, the adsorbability of the phosphor and mercury and mercury compounds can be regulated, and the phosphor can be controlled. It is possible to prevent yellowing and blackening of the EC film.

[Brief description of drawings]

1 shows an embodiment of the present invention, FIG. 1 (A) is a sectional view of a rapid start type fluorescent lamp, and FIG. 1 (B) is a state in which MgO powder is adhered to the surface of phosphor powder. Pattern diagram.

FIG. 2 is a diagram showing a relationship between a charging tendency of a phosphor and an adsorption amount of mercury and a mercury compound.

FIG. 3 is a diagram showing a relationship between a charging tendency of a phosphor and an EC film blackening occurrence rate.

[Explanation of symbols]

1 ... Valve, 2 ... Stem, 3 ... Lead wire, 4 ... Electrode, 5
… EC film, 6… Fluorescent film, 10… Fluorescent material, 20…
Metal oxide powder.

Front Page Continuation (72) Inventor, Kimiyoshi Nagasawa 1-4-2-4 Mita, Minato-ku, Tokyo Within Toshiba Lighting & Technology Co., Ltd. (72) Inventor Kenji Terashima 8 Shinsita-cho, Isogo-ku, Yokohama-shi, Kanagawa Incorporated company Toshiba Yokohama Office

Claims (4)

[Claims] 1. A rapid-start type fluorescent lamp in which a transparent conductive film and a phosphor layer are formed on the inner surface of a bulb, and mercury and a rare gas are enclosed in the bulb, wherein the phosphor layer is formed. The fluorescent substance has a particle diameter of 74 to 4
When contacting with 4 μm of reduced iron powder, −0.
A rapid start type fluorescent lamp characterized by being charged with an electric charge of 5 to +1.5 micro coulombs. 2. The phosphor described above, wherein particles of a metal oxide are adhered in a proportion of 0.01 to 3.0% by weight, whereby the phosphor has a concentration of −0.5 to +1.5 μg / g per 1 g of the phosphor.
2. The rapid-start type fluorescent lamp according to claim 1, which is charged with Ron's electric charge. 3. The rapid start type fluorescent lamp according to claim 2, wherein the metal oxide particles are MgO. 4. The transparent conductive film has an electric resistance value of 0.
The rapid start type fluorescent lamp according to any one of claims 1 to 3, characterized in that it is 1 to 0.9 KΩ / cm.