JPH0536383A - Low pressure mercury vapor discharge lamp - Google Patents

Abstract

PURPOSE:To lower the voltage at the time of starting discharge by forming the film of metal oxide on the surface of three-wave length light emission type rare earth fluorescent body, and setting charge quantity per a predetermined weight of the fluorescent body at the time of contact to the reduced iron powder having a specific particle diameter at a predetermined muC or more in red, green and blue group of the fluorescent body. CONSTITUTION:Transparent conductive film 5 such as tin oxide is formed on the inner surface of a bulb 1, and fluorescent body film 6 is formed on the surface of the film 5. MgO powder is adhered to the surface of the fluorescent body powder 10 of three-wave length light emission type rare earth fluorescent body to change the charged tendency to the positive direction at the time of contact of the fluorescent body to the reduced iron powder having a predetermined particle diameter. At this stage, red group fluorescent body Y2O3: Emu blue group fluorescent body BaMg2Al16O27: Emu, and green group fluorescent body are adhered to (Re, Tb, Ce) (P, Si)O4 (Re means rare earth element) at 0.2weight% respectively, and charged quantity against the red and blue group is set at OmuC or more, and charged quantity against the green group is set at +1.5muC or more. Voltage at the time of starting discharge is thereby lowered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-pressure mercury vapor discharge lamp using a three-wavelength light emitting phosphor, and more particularly to a means for improving its starting characteristics.

[0002]

2. Description of the Related Art A low-pressure mercury vapor discharge lamp, that is, a fluorescent lamp is used for general lighting, various OA equipment,
It is used as a pixel light source for huge screens, as a backlight for liquid crystal displays, as a compact lamp that replaces light bulbs, and because it has higher luminous efficiency than incandescent light bulbs, it is often used as a power-saving light source.

In such a low-pressure mercury vapor discharge lamp, a phosphor coating is provided on the inner surface of a bulb made of a glass tube, and the bulb is filled with a mixed gas containing mercury and one or more rare gases. , The positive column discharge is generated in this mixed gas.

The above discharge is usually maintained by supplying electrode energy to the mixed gas via two electrodes. This discharge mainly produces UV rays, most of which have wavelengths of 185 nm and 254 nm, which are converted into longer wavelength radiation by the phosphor coating formed on the inner surface of the bulb. This wavelength depends on the type of fluorescent substance, and wavelengths from near ultraviolet to visible to near infrared have been obtained. Further, the valve is not limited to the straight pipe type,
It can be circular, U-shaped, saddle-shaped, etc., and recently, it has become smaller and more complicated in shape.

By the way, recently, a fluorescent lamp with high efficiency and high color rendering property based on a new color vision theory has been studied, and a three-wavelength fluorescent lamp having an emission peak in a so-called three-wavelength region has been commercialized and has already been widely used. It is becoming popular. In particular, recently, application to an immediate start type, that is, a rapid start type fluorescent lamp has been studied.

[0006]

However, such a problem
In some fluorescent lamps using a wavelength emission type phosphor, the lighting start voltage Vs of the lamp increases depending on the type of the phosphor.

Although the cause of the increase in the lighting start voltage is unknown, the calcium halophosphate phosphor (composition of 3Ca ₃ (PO ₄ ) ₂ .Ca (F, C
l) ₂ : Compared with a fluorescent lamp using Sb, Mn), a fluorescent lamp using the above-mentioned three-wavelength emission type phosphor has a starting voltage increased by 7 to 10%, and in some cases, at the time of low temperature starting. There is a problem that exceeds the rated voltage.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a low-pressure mercury vapor discharge capable of lowering the discharge starting voltage Vs in a lamp using a three-wavelength light-emitting phosphor. It is intended to provide a lamp.

[0009]

According to the present invention, a coating made of a three-wavelength emitting rare earth phosphor having an emission peak in a region of three or more wavelengths is formed on the inner surface of a bulb, and mercury and a rare gas are formed in the bulb. In a low-pressure mercury vapor discharge lamp in which the above-mentioned three-wavelength emission type rare earth phosphor is formed, a metal oxide coating film is formed on the surface thereof, and when contacted with reduced iron powder having a particle diameter of 44 to 74 μm The amount of the charged electric charges of the red-type phosphor and the blue-type phosphor is 0 microcoulomb (μC) or more, and that of the green-type phosphor is +1.5 microcoulomb (μC) or more.

[0010]

The inventors of the present invention investigated, experimented and analyzed the relationship between the phosphor and the starting characteristics, and found that the charging tendency of the phosphor had a close influence on the starting voltage Vs.

That is, the most commonly used three-wavelength emission type phosphor is a rare earth type phosphor, and as a representative example, a red type phosphor is Y ₂ O ₃ : Eu,
The blue-based phosphor is BaMg ₂ Al ₁₆ O ₂₇ : Eu, and the green-based phosphor is (Re, Tb, Ce). (P, Si) O.
₄ (However, Re is a rare earth element) is used.

The charging tendency of these phosphors was examined. As is generally known, the charging tendency is that the particle size is 44 to
It is indicated by the amount of charged electric charge per 1 g of the phosphor when contacted with 74 μm reduced iron powder. The humidity condition is 20 to 40%.

As shown in Table 1 to be described later, the conventional red-based phosphor Y2 O3: Eu has a charge amount of -0.05 .mu.m.
C, and the starting voltage Vs of the 40W rapid start type fluorescent lamp when it is used alone is 197V. In addition, the blue-based phosphor BaMg ₂ Al ₁₆ O ₂₇ : Eu
Has a charge amount of −0.3 μC, and the starting voltage Vs of a 40 W rapid start type lamp when it is used alone is 206 V. In addition, the green phosphor (Re,
Tb, Ce) · (P, Si) O ₄ has a positive charge amount of +
It is 1.1 μC, and the starting voltage Vs of the 40 W rapid start type lamp when it is used alone is 230 V.

It has been found that these phosphors are effective in lowering the starting voltage Vs by controlling the charging tendency in the positive direction. The reason for this is not clear, but it is presumed that impurities such as carbon dioxide CO and carbon monoxide CO ₂ remaining in the bulb are adsorbed by the phosphor charged in the positive direction.

The inventors of the present invention adhered a metal oxide powder to each of the above phosphors to change the charging tendency, and measured the starting voltage Vs of each of these phosphors. The results are shown in Table 1 below.

[0016]

[Table 1] 2 shows the relationship between the charging tendency of each phosphor shown in Table 1 above and the lamp starting voltage.

As is clear from the measurement data shown in Table 1, it was found that the charging tendency of each phosphor and the starting voltage Vs have a close correlation, and the charging tendency of the phosphor is positive. It was found that the starting voltage can be reduced by controlling in the direction of.

The red-based phosphor Y ₂ O ₃ : Eu and the blue-based phosphor BaMg ₂ Al ₁₆ O ₂₇ : Eu can both lower the starting voltage by setting the charge amount to 0 μC or more. In addition, green-based phosphors (Re, Tb, Ce)
It was also found that in the case of (P, Si) O ₄ , setting the charged charge amount to +1.5 μC or more is effective in lowering the starting voltage.

Further, it can be seen from Table 1 that it is effective to use MgO as the metal oxide powder in order to control the charging tendency in the positive direction, and SiO ₂ causes the charging tendency to change in the negative direction. It was

In the case of the red phosphor Y ₂ O ₃ : Eu, when MgO is attached at 0.2% by weight with respect to the phosphor, as compared with the conventional case where MgO is not attached, The starting voltage Vs can be reduced by about 6V,
Further, if MgO is attached to the phosphor at 0.5% by weight, the starting voltage Vs can be reduced by about 7V.

Further, the blue-based phosphor BaMg ₂ Al ₁₆ O
_In the case of ₂₇ : Eu, if MgO is attached to the phosphor at 0.2% by weight, the starting voltage Vs of the lamp can be reduced by about 13V as compared with the case where no conventional MgO is attached, and If 0.5% by weight is attached to the phosphor, the starting voltage Vs can be reduced by about 15V.

Furthermore, a green-based phosphor (Re, Tb, C
e) In the case of (P, Si) O ₄ , when MgO is attached at 0.2% by weight with respect to the phosphor, the starting voltage Vs of the lamp is 20 V, as compared with the conventional case where MgO is not attached.
It can be lowered to a certain extent, and when MgO is attached to the phosphor at 0.5% by weight, the starting voltage Vs is 24V.
It can be lowered. As the oxide,
The same effect can be obtained by using at least one selected from CaO, SrO, BaO, and ZnO instead of MgO.

It is effective that these oxides are deposited in the range of 0.01 to 3.0% by weight with respect to the phosphor. That is, the amount of metal oxide is a very important factor for controlling the charging tendency of the phosphor, and when the amount of the adhered metal is more than 3.0% by weight, the emission output of each phosphor is significantly reduced. . 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 control of the charging tendency is not remarkable, and the starting voltage Vs cannot be improved.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on an embodiment shown in FIG.

The drawing shows a 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 bridged 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
By attaching MgO powder to the surface of No. 0, the charging tendency is changed in the positive direction.

That is, the above red-based phosphor Y ₂ O ₃ : E
u and the blue-based phosphor BaMg ₂ Al ₁₆ O ₂₇ : Eu are M
The amount of charge is controlled to 0 μC or more by adhering 0.2% by weight of gO to the phosphor, and the green-based phosphor (Re, Tb, Ce) · (P, Si) O
_In No. 4, the amount of charge is controlled to +1.5 μC or more by depositing MgO at 0.2% by weight with respect to the phosphor. The bulb 1 is filled with a predetermined amount of mercury and a rare gas such as argon. The starting voltage Vs of the fluorescent lamp having such a structure can be lowered by about 12 to 16 V as compared with the conventional lamp. this is,
Since the amount of charge on the phosphor is controlled in the positive direction,
It is presumed that impurities such as CO, CO ₂ and H ₂ O in the valve are adsorbed. On the other hand, the charging tendency in the case of the above embodiment is expressed by the charging order as shown in Table 2 below. Further, FIG. 3 shows the charging tendency of general powder.

[0029]

[Table 2]

From Table 2 above, the red phosphor Y ₂ O ₃ :
Eu and the blue-based phosphor BaMg ₂ Al ₁₆ O ₂₇ : Eu are
When 0.2% by weight of MgO is attached to the phosphor, the charging sequence shifts to the plus side, and the conventional charging sequence is on the plus side of NiO shown in FIG.
The than ₂ O ₃ were negative side, it can be seen that the process shifts to the plus side from Eu ₂ O _3.

Further, the green-based phosphor (Re, Tb, C
e). (P, Si) O ₄ shifts the charging order to the positive side by adhering MgO at 0.2% by weight to the phosphor, and the conventional charging order is more positive than Pt. However, it can be seen that, although it was on the minus side of Ta, it was on the plus side of Cu and shifted to the minus side of Ni. The three-wavelength light emitting phosphor of the present invention is not limited to the phosphors shown in the above embodiments. That is, Y (P, V) O ₄ : Eu, Y ₂ O
₄ S: Eu may be used. Further, as a blue-based phosphor, Sr ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu,

(Sr, Ca) ₁₀ (PO ₄ ) ₆ Cl ₂ : E
u or (Sr, Ca, Ba,) ₁₀ (PO ₄ ) ₃ C
l: Eu or (Ba, Ca, Mg) ₁₀ (PO ₄ ).
_It may be a divalent europium-activated blue phosphor such as ₆ Cl ₂ : Eu. Further, the green phosphor may be a rare earth phosphor represented by the following general formulas (1) to (3). General _{formula: (RE 1-ab Tb a} Ce b) 2 O 3 · eAl 2 O 3 · fSiO 2 · gP 2 O 5 ... (1) ( In the formula, RE is selected Y, from La and Gd At least one element is shown, and a, b, c, d,
e, f, g are a> 0, b> 0, 0.1 ≦ a + b ≦
0.7, e ≧ 0, f ≧ 0, g> 0, 0.8 ≦ e + f +
It is a number that satisfies g ≦ 1.30. ) General _{formula: (RE 1-ab Tb a} Ce b) 2 O 3 · hSiO 2 · iP 2 O 5 · jB 2 O 3 ... (2) ( In the formula, RE is Y, selected from La and Gd And at least one element, a, b and h,
i and j are a> 0, b> 0, 0.1 ≦ a + b ≦ 0.
7, h ≧ 0, i> 0, 5.0 × 10 ⁻⁶ ≦ j ≦ 6.0 × 1
It is a number that satisfies 0 ⁻³ and 0.8 ≦ h + i + j ≦ 1.30. ) General formula: (RE _1-km Tb _k Ce _m ) ₂ O ₃ · nMO · p (Al _1-q O _q ) ₂ O ₃ (3)

(Where RE is Y, La and Gd
At least one element selected from M, Mg and C
and at least one element selected from a, Sr, Ba and Zr, and k, m and n, p and q are 0 <
k + m <1.0, 0.5 <n <4.0, 2.0 <p
It is a number that satisfies <14.0 and 0 <q <1.0 × 10 ⁻⁴ . )

And, in addition to the three-wavelength emission type phosphor, the present invention further comprises, for example, 3.5MgO, 0.5MgF.
₂ , GeO ₂ : Mn (deep red) and 3 (Ba, Mg, M
n, Eu) O.8Al ₂ O ₃ (blue-green), etc. mixed 5
It may be applied to wavelength emission type fluorescence.

Furthermore, although the present invention is effective in further lowering the starting voltage when applied to a rapid start type fluorescent lamp, even a normal fluorescent lamp other than the rapid start type fluorescent lamp can be used. It is also applicable to straight tube type, ring type and compact bent type lamps.

[0036]

As described above, according to the present invention, 3
Since the charging tendency of the wavelength emission type phosphor is controlled in the positive direction, the starting voltage Vs can be lowered.

[Brief description of drawings]

FIG. 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 a lamp starting voltage.

FIG. 3 is a diagram showing the relationship between the electronegativity of metal ions and the charge amount.

[Explanation of symbols]

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

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Nobuhiro Tamura             1-chome Mita 4-28, Minato-ku, Tokyo Toshiba Rye             Inside TEC Co., Ltd. (72) Inventor Masaaki Tamaya             1st Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa             Inside the Toshiba Research Institute (72) Inventor Kenji Terashima             8th Shinsugita Town, Isogo Ward, Yokohama City, Kanagawa Prefecture             Ceremony company Toshiba Yokohama office

Claims (4)

[Claims] 1. A low-pressure mercury vapor discharge lamp in which a coating made of a three-wavelength emitting rare earth phosphor having an emission peak in a region of three or more wavelengths is formed on the inner surface of the bulb, and mercury and rare gas are enclosed in the bulb. In the above-mentioned three-wavelength-emitting type rare earth phosphor, the amount of electrified charge per 1 g of the phosphor is red when it is in contact with reduced iron powder having a particle size of 44 to 74 μm by forming an oxide film on the surface. A low-pressure mercury vapor discharge lamp characterized in that the light-emitting material and the blue-based fluorescent material are set to 0 microcoulomb or more and the green-based fluorescent material is set to +1.5 microcoulon or more. 2. A low-pressure mercury vapor discharge lamp in which a coating made of a three-wavelength emitting rare earth phosphor having an emission peak in a region of three or more wavelengths is formed on the inner surface of the bulb, and mercury and a rare gas are enclosed in the bulb. In the above-mentioned three-wavelength-emitting type rare earth phosphor, the charging sequence per 1 g of the phosphor is a red-based phosphor when an oxide film is formed on the surface of the phosphor and the powder is in contact with reduced iron powder having a particle diameter of 44 to 74 μm. Body and blue-based phosphors, the charging order is located on the plus side of Eu ₂ O ₃ , and the green-based phosphor is located on the plus side of Cu. Vapor discharge lamp. 3. The oxide coated on the surface of the three-wavelength emitting rare earth phosphor is an MO film (where M is Mg, Ca,
The low pressure according to claim 1, wherein the low pressure is made of at least one selected from Sr, Ba, and Zn and is deposited in the range of 0.01 to 3.0% by weight with respect to the phosphor. Mercury vapor discharge lamp. 4. The low-pressure fluorescent lamp according to claim 1, wherein the lamp is a rapid start type fluorescent lamp in which a conductive film for assisting starting is formed on an inner surface or an outer surface of a bulb. Mercury vapor discharge lamp.