JPS5842942B2 - fluorescent lamp - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fluorescent lamp, and an object of the present invention is to provide a fluorescent lamp with improved color rendering properties without reducing luminous efficiency.

Recently, the conservation of resources, especially electricity, has become a serious social issue, and the appearance of fluorescent lamps with high luminous efficiency is desired in the field of lighting as well.

This is because if a fluorescent lamp with high luminous efficiency is used, the number of lamps installed per unit area can be reduced, resulting in power savings.

On the other hand, the color rendering properties of a light source are an indispensable and important factor in the quality of illumination, and fluorescent lamps having good color rendering properties are also required.

However, in conventional fluorescent lamps, luminous efficiency usually decreases as color rendering properties improve, and it has been technically difficult to simultaneously obtain good color rendering properties and high efficiency.

For example, conventionally, the average color rendering index (hereinafter abbreviated as Ra) is approximately 9.
Fluorescent lamps with color rendering properties improved to about 0 are usually made of red phosphors such as manganese-activated magnesium fluorogermanate, orange phosphors such as tin-activated strontium/magnesium orthophosphate, magnesium tungstate or antimony. Blue phosphor such as active calcium halophosphate, daylight color, white, warm white phosphor such as antimony and manganese-activated calcium halophosphate are mixed, and the emission energy of the mixed phosphor is 400 to 700 nm.
The color rendering properties are not very good, but the luminous efficiency is about 30 to 40% lower than that of the popular white fluorescent lamp.

The present invention has been made to address these conventional drawbacks, and is intended to simultaneously provide good color rendering properties and high luminous efficiency.

The details of this invention will be explained below.

The inventors of the present invention have studied means for achieving the above object, and have developed a blue-green borophosphate phosphor defined by the chemical composition formula below, which has an emission peak in the wavelength range of 480 to 490 nm. 3 to 50% by weight of an orange phosphor such as tin-activated strontium magnesium orthophosphate, and 3 to 50% by weight of trivalent europium-activated yttrium oxide and trivalent europium-activated yttrium vanadate. 0.2 to 20% by weight of a red phosphor and an antimony- or manganese-activated alkaline earth metal halophosphate phosphor or a mixed halophosphate phosphor with an antimony-activated alkaline earth metal halophosphate. It has been found that a fluorescent lamp in which a luminescent material mainly containing 20 to 65% by weight of phosphorescent material is adhered to the inner surface of the discharge tube has both good color rendering properties and high luminous efficiency.

Here, the blue-green phosphor is (m(s, 1-X-y-p Bax Cay EupO
)・(I n) P2O5B2O3 However, 0≦X≦0.5.0≦y≦0.2゜0.001≦
p≦0.15, 1.75≦m≦2.30゜0.05≦
n≦0.23.

) is a divalent europium-activated alkaline earth metal borophosphate phosphor.

Furthermore, it was discovered that similar effects can be obtained by adding 10% by weight or less of a green phosphor such as manganese-activated zinc silicate and manganese-activated zinc/magnesium germanate silicate to each of the above-mentioned color phosphors. .

The borophosphate phosphor used in this invention defined by the above chemical composition formula has a wavelength of 480 to 490 nm, which was previously proposed by some of the inventors of this invention in an unpublished patent application.
Antimony-activated halophosphoric acid is a blue-green phosphor with an emission peak at It exhibits a luminous efficiency that is at least comparable to, or about 50% higher than, that of calcium, and has the characteristic that the drop in luminous flux during lamp operation is extremely small.

This borophosphate phosphor has an emission peak at about 480 nm when it contains only strontium as an alkaline earth metal in the host crystal, but when it contains a predetermined amount of barium, the emission peak becomes slightly longer to about 490 nm. Move to the wavelength side.

This shift of the emission peak works advantageously in obtaining good color rendering properties when obtaining a fluorescent lamp with a relatively low color temperature.

This is because it is desirable to use a lamp with a low color temperature that emits less short-wavelength visible light such as blue light.

When calcium is contained, only a slight shift in the luminescence peak is observed if the content is within the above-mentioned limited range.

Also, the half-value width (
The width of the emission spectrum (measured at the emission intensity at 50% of the maximum emission intensity) also varies depending on the type of alkaline earth metal and its content, but is in the range of about 80 to 120 nm.

This change can be tolerated because it is corrected by the emission spectra of other phosphors to be combined and their mixing ratio.

Therefore, even if barium or calcium is not specifically exemplified below or contains barium or calcium in addition to strontium as an alkaline earth metal, as long as the content is within the above-mentioned limited range,
It was confirmed that the present invention can be used in the fluorescent lamp of the present invention.

The content of alkaline earth metals barium and calcium is within the above-mentioned limited range (0≦X≦0.5, O≦y≦0.2)
However, the best results in terms of luminous efficiency are generally obtained when only strontium or a very small amount of barium or (and) calcium is contained as the alkaline earth metal.

This is because the luminous output gradually decreases with increasing barium and/or calcium content.

Moreover, the barium content should not exceed 0.5 in terms of the value of X, and the calcium content should not exceed 0.2 in terms of the value of y.

This is because when these values are exceeded, the luminescence output decreases significantly, and blue light having a maximum luminescence in the blue region around 410 to 430 nm is emitted.

p of europium content is 0.001 <p<o, i 5
is selected to be.

The reason for this is that in this way a phosphor with a large luminous output can be obtained.

When the value of p is 0.005 to 0.05, the light emission output becomes extremely large, so a value within this range is particularly preferable.

The values of m and n are 1.75≦m≦2.30, 0.05
It should be ≦n≦0.23.

This is because the light emission output becomes small outside this range.

The maximum luminous output is m is 1.9 C) to 2.10. Since n is obtained when n is 0.14 to 0.18, values within this range are particularly suitable.

The borophosphate phosphor described above can be produced relatively easily.

N2+ is produced by mixing a predetermined amount of alkaline earth metal carbonates, phosphates, boric acid, europium oxide, etc. as starting materials.
Approximately 1000-1200'C in a reducing atmosphere such as H2
It can be obtained by firing at a temperature of

For example, 1.68 moles of SrHPO4. S,C030,28
The phosphor starting from 0.32 mol of H3B0 and 0.02 mol of Eu203 has a very suitable chemical composition 2 (Sro, 98 Euo).

20)・0.84P20.・It satisfies 0.16B203.

Note that this borophosphate phosphor contains Be,
Mg, Zn, Cd, Mn, Sc, Y, La.

Ce, TbtPb, GatAA', Si, Zv, Ge
Elements such as tS9 may be contained as long as they are in small amounts.

However, it has been confirmed that if the content exceeds 0.5 to 3.5% (depending on the type of element) of the total metal elements, it is undesirable because it causes adverse effects such as a decrease in luminescence intensity.

Table 1 shows the luminescent properties of the phosphors preferably used in the present invention.

Although the data may differ slightly due to differences in chemical composition, this table shows typical values.

FIG. 1 shows the emission spectra of these phosphors upon excitation with ultraviolet light.

The symbols in the figure correspond to those in Table 1.

Note that the strontium halophosphate phosphor in F is omitted because it is similar to the emission spectrum of the calcium halophosphate phosphor, and the emission peak wavelength has mainly changed.

This invention will be described in detail below.

The phosphors of each color are mixed, a binder is mixed in to attach the phosphors to the glass bulb, and the phosphors are coated and baked on the inner surface of the discharge tube of the fluorescent lamp using conventional technology. Attached.

Next, by installing electrodes at both ends of this glass bulb, evacuating it, filling it with a small amount of mercury and a rare gas, sealing it, and attaching a cap, many 40-watt straight tube fluorescent lamps with a tube diameter of 32 mm were made. Ta.

The amount of phosphor deposited ranged from 3 to 7 g.

Table 2 shows the types of phosphors (indicated by the symbols in Table 1) and their mixing ratios, as well as the obtained lamp characteristics.

For comparison, conventional lamp characteristics are shown in Table 3.

In Table 3, ww-30, ww, and wsD use calcium halophosphate alone and have the highest luminous efficiency among conventional lamps.

ww-30-DL. ww-DL,,w-DL,w
-8DL and D-8DL** are red phosphor manganese-activated magnesium fluorogermanate, orange phosphor tin-activated strontium magnesium orthophosphate, green phosphor manganese-activated zinc silicate, and halo This is a fluorescent lamp with improved color rendering compared to conventional fluorescent lamps, which is coated with a mixture of calcium phosphate.

The fluorescent lamp of the present invention has a high Ra value at a color temperature ranging from warm white to daylight, and has high luminous efficiency.

Figure 2 shows the relationship between Ra and luminous efficiency (1 m, /W) of the present invention and the conventional fluorescent lamp. This corresponds to the symbol of the conventional lamp in Table 3.

From this figure, it can be clearly seen that the fluorescent lamp of the present invention has a high Ra value and luminous efficiency.

That is, while the conventional fluorescent lamp has a remarkable decrease in luminous efficiency as the Ra value increases, the fluorescent lamp of the present invention has a high Ra value with less decrease in luminous efficiency.

FIG. 3 shows the spectral distribution of a fluorescent lamp according to Practical Example 4 of the present invention in comparison with a conventional lamp w-DL.

It can be seen that the fluorescent lamp of the present invention has less energy in the blue region of about 400 to 440 nm.

Since light in the blue region is difficult to perceive by the eye, it is advantageous to not radiate energy into the blue region in order to obtain high luminous efficiency.

This is the effect of using the blue-green divalent europium-activated borophosphate.

That is, as shown in FIG. 1, this borophosphate phosphor emits almost no light in the blue region (400 to 440 nm).

From the perspective of color rendering properties, it is desirable that the radiant energy in the blue region be lower than that of conventional lamps.

This shows the mercury emission line spectrum (405 nm) in the blue part.

436 nm), so the emission line spectrum is
This is because it is necessary to reduce the radiant energy from the phosphor or to suppress the mercury emission line spectrum.

In addition, since borophosphate phosphors have the property of absorbing and emitting not only ultraviolet light but also blue light, they have an advantageous effect in suppressing blue energy and obtaining high color rendering properties even more than conventional lamps. ing.

For reference, the reflection spectrum of the borophosphate phosphor is shown in FIG.

It can be seen that this phosphor has the property of absorbing blue light of 400 to 440 nm.

In order to confirm the above effect, we created a lamp with the same light color as in Example 4 by not using this borophosphate phosphor but instead using a blue-light antimony-activated calcium halophosphate phosphor. When I made it, the Ra value was 4 and the luminous efficiency was 5.
It was inferior by 1m/w.

In addition, in the fluorescent lamp of this invention, a material with a narrow half-width, such as trivalent europium-activated yttrium oxide, is used as the red phosphor, and the energy in the deep red region, which is difficult to perceive with the eye, is relatively low. This helps in achieving high luminous efficiency.

In this invention, it has been found that the use of trivalent europium-activated yttrium oxide as the red phosphor gives the best results in terms of luminous efficiency.

However, the use of trivalent europium activated yttrium vanadate, as seen in Foil Examples 3 and 6, provides somewhat higher Ra values and also provides fluorescent lamps with higher luminous efficiency when compared to conventional lamps.

It is also possible to use a mixture of these two types of red phosphors, in which case properties intermediate between the two can be provided.

Although not specifically exemplified in the above practical examples, the same results can be obtained using trivalent europium-activated yttrium phosphorus vanadate, which has the same luminous output and approximately similar emission spectrum as trivalent europium-activated yttrium vanadate. I confirmed that I can get it.

It was also confirmed that the tin-activated strontium-magnesium orthophosphate, which is an orange phosphor, can be replaced with tin-activated strontium-barium-magnesium phosphate, which has almost the same luminescent properties, and that similar results can be obtained.

The alkaline earth metal halophosphate phosphor can be used by mixing an antimony-activated halophosphate that emits blue light and an antimony- or manganese-activated halophosphate.

This mixing is convenient when adjusting the color temperature of the halophosphate phosphor.

It was confirmed that similar results could be obtained by using a mixture of manganese-activated zinc silicate and manganese-activated zinc/magnesium germanate silicate as the green phosphor.

In the claims of this invention, the blue-green phosphor comprises three
The reason why it is limited to ~50% by weight is that if it is less than 3%, the effect of improving color rendering properties will be reduced, and if it exceeds 50%, the emitted light color will be bluish-green and unnatural.

The reason why the orange phosphor is limited to 3 to 50% by weight is that if it is less than 3% by weight, the color rendering properties are poor;
This is because when the amount exceeds % by weight, the luminous efficiency decreases.

The reason why the red phosphor is restricted to 0.2 to 20% by weight is that if 0.2% by weight is not added, the color rendering properties are poor.
This is because if it exceeds 20% by weight, the emitted light color becomes reddish-purple, which becomes unnatural.

The reason why halophosphate phosphors are restricted to 20 to 65% by weight is because if it is less than 20% by weight, the luminous efficiency will be poor, and if it exceeds 65% by weight, the effect of improving color rendering will decrease. be.

The green phosphor content is restricted to 10% by weight or less because if it exceeds 10% by weight, it causes color shift during lamp lighting.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the emission spectrum of the phosphor used in the present invention, Fig. 2 is a diagram showing the relationship between the average color rendering index Ra and luminous efficiency of the inventive and conventional fluorescent lamps, and Fig. 3 The figure shows the spectral distribution of the present invention and the conventional fluorescent lamp, and FIG. 4 shows the reflection spectrum of the blue-green phosphor used in the present invention.

Claims (1)

[Scope of Claims] 1. 3 to 50% by weight of a divalent europium-activated alkaline earth metal borophosphate phosphor defined by the following chemical composition, and a tin-activated strontium magnesium phosphate phosphor or 3 to 50% by weight of at least one type of tin-activated strontium/barium/magnesium orthophosphate phosphor
and 0.2 to 20% by weight of at least one of a trivalent europium-activated yttrium oxide phosphor, a trivalent europium-activated yttrium vanadate phosphor, or a trivalent europium-activated yttrium phosphovanadate phosphor. , antimony, manganese activated alkaline earth metal halophosphate phosphor or mixed alkaline earth metal halophosphate phosphor with antimony activated alkaline earth metal halophosphate phosphor in an amount of 20 to 65% by weight. Fluorescent lamp mixed and applied. m(Sr1-X y-p BaxCayEuO)(1
-n) P2O3・n B 203 However, O< x≦0.5, 0≦yζ0.20.001
≦P≦0.15, 1.75≦m≦2.30゜0.05
It is assumed that jn≦0.23. 2. 3 to 5 divalent europium-activated alkaline earth metal borophosphate phosphors defined in claim 1.
0% by weight and 3 to 50% of at least one of a tin-activated strontium-magnesium orthophosphate phosphor or a tin-activated strontium-barium-magnesium orthophosphate phosphor.
and 0.2 to 20% by weight of at least one of trivalent europium-activated yttrium oxide phosphor, trivalent europium-activated yttrium vanadate phosphor, or trivalent europium-activated yttrium phosphovanadate phosphor. % and mixed alkaline earth metal halophosphate phosphor with antimony, manganese activated alkaline earth metal halophosphate phosphor or antimony activated alkaline earth metal halophosphate phosphor. % and manganese-activated zinc silicate or manganese-activated zinc silicate germanate.
A fluorescent lamp coated with a mixture of not more than 10% by weight of at least one magnesium phosphor.