JP2931058B2 - Fluorescent lamp - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a three-wavelength band fluorescent lamp.

(Prior Art) In recent years, in the field of fluorescent lamps for general illumination, a three-wavelength band fluorescent lamp has been developed and put to practical use. The phosphor used in this lamp is a mixture of three kinds of phosphors of red, green, and blue having a relatively narrow band emission spectrum distribution at an appropriate ratio.

Here, a europium-activated yttrium oxide-based phosphor (Y ₂ O ₃ : Eu) is used as a red phosphor, and a cerium and terbium-activated lanthanum phosphate-based phosphor (LaPO ₄ :
Ce, Tb) is mainly used in Japan, and as a blue phosphor, europium-activated barium magnesium aluminate phosphor (BAM) is in the range of alkaline earth chlorophosphate (SCA) with strontium as the main alkaline earth. Phosphors are used.

(Problems to be Solved by the Invention) The above-described fluorescent lamps have a drawback that the luminous output tends to decrease with time and that the luminous color changes.

In particular, fluorescent lamps that use BAM as a blue phosphor are superior in terms of luminous flux compared to those that use SCA, but they use both BAM and SCA because of large color shift, but they have sufficient characteristics. Did not get.

An object of the present invention is to solve the above-mentioned drawbacks and to provide a three-wavelength band light emitting fluorescent lamp with small color shift.

(Means for Solving the Problems) The present invention relates to a three-wavelength band fluorescent lamp, comprising a europium-activated yttrium oxide-based red phosphor, a cerium- and terbium-activated lanthanum phosphate-based green phosphor, and a compound represented by the following general formula: The blue phosphor includes the above-described europium and manganese-activated alkaline earth aluminate blue phosphors, and their content ratio is 15 to 70% by weight of the red phosphor, 20 to 65% by weight of the green phosphor, and blue phosphor. A fluorescent lamp characterized in that a fluorescent film is formed of a mixed phosphor adjusted to a range of 5 to 40% by weight.

General _{formula: (Ba 1-xy Eu x} M y) O · a (Mg 1-pq Mn p Zn q) O · bAl 2 O 3 However, in the formula, M is at least one of Sr and Ca Represents an element, and a, b, x, y, p and q are numerical values in the following ranges.

a + 3≤b≤4a + (3/2), (7/3) a-1≤b≤ (11/9) a + (17/3), 0.03≤x≤0.4, 0≤y≤0.4, 0.03≤x + y≤ 0.4, 0.001 <(ap / x) ≦ 0.2, 0 ≦ q ≦ 0.3, 0 <p + q ≦ 0.3.

The red, green, and blue phosphors preferably have median particle diameters of 2.5 to 6 μm, 2 to 5.5 μm, and 5.5 to 7.5 μm, respectively.

(Action) The inventors of the present invention have investigated the cause of color misregistration mainly in a three-wavelength band light emitting fluorescent lamp employing a BAM phosphor excellent in light flux as a blue phosphor. The degradation rate of efficiency is higher than the other two types of phosphors, which breaks the color balance. The emission color of the blue phosphor changes over time. Mercury in the fluorescent lamp is a phosphor with a small particle size. In particular, they were found to be adsorbed by blue phosphors with a small particle size and changed to mercury oxide to absorb blue light. It was also found that the color shift of the BAM phosphor was mainly due to the cause.

After further studies, it was found that the europium and manganese-activated alkaline earth aluminate phosphors having a very limited composition showed little change in the emission color of the phosphor itself with respect to the above. Body (Y
_The above-mentioned problem has been solved by using a ₂ O ₃ : Eu) red phosphor and a (LaPO ₄ : Ce, Tb) green phosphor in a limited mixing ratio.

FIG. 1 is a ternary phase diagram of an alkaline earth aluminate phosphor activated with europium and manganese. Here, the oxide A is represented by (Ba _{1 -XY} Eu _{X MY} ) O, and a part of Ba is replaced by Eu as an activator and M indicating Sr or Ca. It is necessary to maintain the emission color by making BaO at least 60 mol% of A. In addition, it is necessary to ensure emission luminance by making 3 mol% or more of the oxide A EuO. If it exceeds 40 mol%, it is not possible to improve the emission luminance. Is preferred. That is, 0.03 ≦ X ≦ 0.4 and 0.03 ≦ X + Y ≦ 0.4, and in particular, 0.03 ≦ X ≦ 0.2
5, and preferably 0 ≦ Y ≦ 0.1.

The oxide B is represented by (Mg _1-pq Mn _p Zn _q ) O, and a part of Mg can be replaced by the activator Mn and Zn. It is necessary to secure emission luminance by using MgO. That is, 0 ≦ q ≦ 0.3,
0 <p + q ≦ 0.3, particularly preferably 0 ≦ q ≦ 0.05.

Further, by setting the g atomic ratio (ap / x) of Mn to Eu to 0.2 or less, it is possible to obtain a preferable emission color as a blue component, and if it is less than 0.001, the effect of suppressing the color shift due to Mn to be small. Does not appear. That is, 0.001 <(ap / x) ≦ 0.
2, preferably 0.005 ≦ (ap / x) ≦ 0.1, more preferably 0.01 ≦ (ap / x) ≦ 0.1.

The oxide C is Al ₂ O ₃ , and when the amount of the oxide A is 1 mol, the number of moles of the oxide B is a and the number of moles of the oxide C is b, and the following relationship is obtained: a + 3 ≦ b ≦ 4a + ( (3/2), (7/3) a-1 ≦ b ≦ (11/9) a + (17/3) By maintaining the above, it is possible to prevent the color shift phenomenon of the emission color due to the above-mentioned causes.

The europium and manganese activated alkaline earth aluminate phosphor has a main emission wavelength of 440 to 460 nm. Cerium and terbium-activated lanthanum phosphate-based green phosphor having a main emission wavelength of 540 to 550 nm is 30 to 65 wt% of the blue phosphor of 5 to 40 wt%, and europium having a main emission wavelength of 605 to 615 nm. By coating a phosphor mixture containing 15 to 70% by weight of an activated yttrium oxide-based red phosphor on the inner surface of a glass bulb to form a phosphor film, a three-wavelength band light-emitting fluorescent lamp with little color shift over time. Can be obtained.

The red, green and blue phosphors have a median particle size of 2.5 to 6 μm and 2 to 5.5 μm, respectively.
By adjusting m and the range from 5.5 to 7.5 μm, the cause of the above color shift can be suppressed.

In addition, the measurement of the magnitude of the color misregistration is based on the initial (100 hours after lighting) emission color of the fluorescent lamp on the CIE chromaticity coordinates (x _i ,
and y _i), the light emission color after lighting for 1000 hours (x _f, When _{y f), ds = {x} f -x i) 2 + (y f -y i) 2} 1/2 and defines It was determined that the smaller the ds, the less the color shift.

_{(Example) (Ba 1-xy Eu x} M y) O · a (Mg 1-pq Mn p Zn q) O · bAl 2 O
₃ Blue phosphor, LaPO ₄ : Ce, Tb green phosphor, and Y ₂ O ₃ : Eu
Using a red phosphor, mixing at the mixing ratio shown in the table, adding to a butyl acetate solution in which nitrocellulose was dissolved to prepare a phosphor slurry, applying it to the inner surface of a glass bulb, and applying a straight tube slim line fluorescent lamp FSL64T6 Created. The composition ratio of the blue phosphor was prepared as shown in the table. Next, the emission color at 100 hours and 1000 hours after lighting was measured, and the color shift ds was measured.
I asked.

In addition, a lamp was prepared in the same manner as described above using phosphors in which the values of a and b were out of the range of the present invention among the composition ratios of the blue phosphor, and the emission color was measured to obtain a comparative example. The results are shown in the table.

As is clear from the table, the color shift of the lamp using the blue phosphor of the present invention is considerably smaller than that of the lamp of the comparative example.

(Effects of the Invention) By adopting the above configuration, the present invention can provide a three-wavelength-range light-emitting fluorescent lamp with a small color shift over time.

[Brief description of the drawings]

FIG. 1 is a ternary phase diagram showing the composition ratio of a blue phosphor used in the present invention.

Claims (2)

(57) [Claims] 1. A three-wavelength band fluorescent lamp comprising a europium-activated yttrium oxide-based red phosphor, a cerium- and terbium-activated lanthanum phosphate-based green phosphor, and europium- and manganese-activated alkali represented by the following general formula: Including the earth aluminate blue phosphor, the content ratio thereof is adjusted to the above-mentioned red phosphor 15-70 wt%, green phosphor 20-65 wt%, and blue phosphor 5-40 wt%. A fluorescent lamp, wherein a fluorescent film is formed of the mixed phosphor thus obtained. General _{formula: (Ba 1-xy Eu x} M y) O · a (Mg 1-pq Mn p Zn q) O · bAl 2 O 3 However, in the formula, M is at least one of Sr and Ca Represents an element, and a, b, x, y, p and q are numerical values in the following ranges. a + 3≤b≤4a + (3/2), (7/3) a-1≤b≤ (11/9) a + (17/3), 0.03≤x≤0.4, 0≤y≤0.4, 0.03≤x + y≤ 0.4, 0.001 <(ap / x) ≦ 0.2, 0 ≦ q ≦ 0.3, 0 <p + q ≦ 0.3. 2. A red phosphor, a green phosphor and a blue phosphor, each having a median particle diameter of 2.5 to 6 μm, 2 to 5.5 μm and 5.5 to 7.5 μm, respectively. ).