JP3187952B2 - Three-wavelength phosphor and fluorescent lamp using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-wavelength phosphor suitable for a fluorescent layer of a fluorescent lamp having a high tube wall load, and a fluorescent lamp using the same.

[0002]

2. Description of the Related Art Fluorescent lamps include general lighting, recently, light sources for office automation equipment, pixel light sources for large screens,
It is widely used in backlights of liquid crystal displays and the like. In addition, since the three-wavelength fluorescent lamp is used for general lighting, it satisfies both high efficiency and high color rendering at the same time.
In recent years, it has been spreading remarkably. Such fluorescent lamps (low-pressure mercury vapor discharge lamps) fill a glass tube with a fluorescent layer on the inner wall with a mixed gas containing mercury and one or more rare gases. It is configured to generate a positive column discharge.

As a phosphor used in a three-wavelength fluorescent lamp, a phosphor that emits blue, green, and red light having a relatively narrow band emission spectrum distribution is used. In such a three-wavelength fluorescent lamp, three or more kinds of phosphors are mixed and used, so that the difference in deterioration of each phosphor during lighting greatly affects the quality of the fluorescent lamp.

On the other hand, the glass tube used in the above-described fluorescent lamp is not limited to a straight tube type, but may be a circular shape, a U shape, a clad shape, and the like. It is going on.

[0005]

As described above, as the size of the fluorescent lamp is reduced, the load on the tube wall of the fluorescent lamp tends to increase. The problem is becoming more pronounced. That is,
Fluorescent lamps with a high tube wall load have problems such as a lower lamp efficiency, a higher rate of luminous flux reduction, and a tendency for the coloring (blackening) phenomenon to occur early in comparison with ordinary lamps. . Among these, the blackening of fluorescent lamps has become a problem.

The cause of the blackening of the tube end, the spot-like blackening, and the blackening of the entire surface during the operation of the fluorescent lamp is considered to be the influence of the filament, the cathode material, the residual material of the organic binder, and the like. It is believed that mercury and its compounds contaminate the phosphor applied to the inner wall of the glass tube.

[0007] Further, there is an idea that the reduction of the luminous flux and the blackening are caused by the deterioration of the phosphor itself constituting the phosphor film.
This is due to coloring due to the formation of a color center by irradiation of ultraviolet rays, and deterioration of the particle surface due to collision of ions in the lamp. Phosphors containing a rare earth element as a host or activator are considered to be advantageous for such problems, and phosphors containing a rare earth element are generally used in fluorescent lamps with a high tube wall load. Used in However, since the phosphor used in the three-wavelength fluorescent lamp as described above is a mixture of three or more kinds of phosphors, when used as a phosphor film of the fluorescent lamp, the deterioration of each phosphor during lighting is deteriorated. If the degree is different, the color temperature of white fluctuates, and the quality of the fluorescent lamp is remarkably impaired, which is a serious problem in practical use. This phenomenon is particularly noticeable in a three-wavelength fluorescent lamp having a high tube wall load.

In view of the above, it is desired to suppress the occurrence of blackening (coloring phenomenon) which affects the life and quality of a three-wavelength fluorescent lamp. In addition, in the three-wavelength fluorescent lamp, apart from the blackening (coloring phenomenon) that occurs with the elapse of the lighting time as described above, a band-like blackening near the electrode that occurs at the initial lighting is also a problem. It is strongly desired to suppress the occurrence of coloring phenomena including early band-like blackening.

SUMMARY OF THE INVENTION The present invention has been made to address the above-described problems, and suppresses the occurrence of a coloring phenomenon (blackening), which is a cause of deterioration in the life and quality of a fluorescent lamp, as well as an early banding near an electrode. It is an object of the present invention to provide a three-wavelength phosphor in which the occurrence of blackening (coloring phenomenon) is suppressed, and further, the occurrence of coloring phenomenon under a high tube wall load is suppressed, and the fluorescent material has a low rate of decrease in luminous flux. The aim is to provide lamps.

[0010]

The three-wavelength phosphor of the present invention is a three-wavelength phosphor including at least a blue light-emitting phosphor, a red light-emitting phosphor, and a green light-emitting phosphor.
The blue light emitting phosphor and the red light emitting phosphor have at least one metal oxide particle selected from magnesium oxide, calcium oxide, strontium oxide, barium oxide and zinc oxide on the surface thereof, respectively. 0.02% by weight to 5.0% by weight.
The green light-emitting phosphor is characterized in that the amount of the metal oxide particles attached is less than 0.01% by weight. In the three-wavelength phosphor, the metal oxide particles are not substantially attached to the surface of the green light-emitting phosphor.

Further, the fluorescent lamp of the present invention comprises a light-transmitting glass tube filled with a filling gas containing mercury, a fluorescent layer provided on the inner wall of the light-transmitting glass tube, and a positive column in the filling gas. Means for maintaining discharge, wherein the tube wall load is
In a fluorescent lamp of 0.05 W / cm ² or more, the fluorescent layer contains the three-wavelength phosphor described above.

According to the present invention, in a three-wavelength fluorescent lamp having a high tube wall load, blackening (coloring phenomenon) caused by contamination by mercury or a compound thereof has a correlation with the tendency of charging the surface of the phosphor particles. By adhering the metal oxide fine particles to the particle surface, it is possible to control the above-mentioned charging tendency, thereby preventing the phosphor from being contaminated by mercury or a compound thereof, and furthermore, the early band-like black near the electrode. This is due to the effect of the cathode material and the like, and by preventing the metal oxide fine particles from being substantially attached to the surfaces of the green light-emitting phosphor particles, it is possible to prevent the occurrence of early band-like blackening near the electrodes. It is made by finding. That is, the metal oxide fine particles are not substantially adhered to the surface of the green light-emitting phosphor particles, thereby preventing early band-like blackening near the electrode and preventing other phosphor particles (blue or red light emission) from being generated. By causing metal oxide fine particles to adhere to the surface of the phosphor particles, the occurrence of blackening (coloring phenomenon) caused by mercury and its compounds is suppressed.

The three-wavelength phosphor of the present invention is a mixture of at least a blue light-emitting phosphor, a red light-emitting phosphor, and a green light-emitting phosphor so as to obtain a desired chromaticity. To add a blue-green light-emitting phosphor.

The blue or blue-green emitting phosphor used in the present invention has a general formula: a (M ₁ , Eu) O.bAl ₂ O ₃ (1) (where M ₁ is Zn, Represents at least one element selected from Mg, Ca, Sr, Ba, Li, Rb and Cs, wherein a and b are
It is a number that satisfies a> 0, b> 0, and 0.2 ≦ a / b ≦ 1.5. The same shall apply hereinafter), a divalent europium-activated aluminate phosphor represented by the general formula: a (M ₁ , Eu, Mn) O · bAl ₂ O ₃ ……… (2) Europium and manganese activated aluminate phosphor, General formula: (M ₂ , Eu) ₁₀ (PO ₄ ) ₆ · X ₂ ……… (3) (where M ₂ is from Mg, Ca, Sr and Ba X represents at least one element selected from the group consisting of F, Cl and Br), and a divalent europium-activated halophosphate phosphor.

The phosphor emitting red light is represented by the general formula: (Y _1-x , E _x ) ₂ O ₃ (4) (where x is a number satisfying 0.005 ≦ x ≦ 0.20) The same shall apply hereinafter.) A trivalent europium-activated yttrium oxide phosphor represented by the general formula: (Y _1-x , Eu _x ) ₂ O ₂ S ……… (5) Activated yttrium oxysulfide phosphor, trivalent europium-activated (phosphoric acid) yttrium vanadate phosphor represented by the general formula: (Y _1-x , E _x ) (P, V) O ₄ …… (6) An example is a body.

In the three-wavelength phosphor of the present invention, the surfaces of the blue or blue-green light emitting phosphor particles and the red light emitting phosphor particles as described above are coated with magnesium oxide, calcium oxide, strontium oxide, barium oxide and zinc oxide. At least one metal oxide particle selected from the group consisting of 0.02% to 5.0% by weight is attached to the phosphor.

The metal oxide to be adhered to the surface of the phosphor particles is selected in consideration of the above-mentioned tendency to charge, and has a function of preventing the phosphor particles from being contaminated by mercury or a compound thereof. Accordingly, the occurrence of the coloring phenomenon (blackening) is suppressed. The adhesion amount of such a metal oxide is in the range of 0.02% by weight to 5.0% by weight with respect to each phosphor particle. If the adhesion amount is less than 0.02% by weight, the effect of controlling the tendency of electrification by the metal oxide cannot be sufficiently obtained.
If the content exceeds 10% by weight, the luminous efficiency of the phosphor is significantly reduced.

[0018] As the phosphor which emits green light used in the present invention, the general _{formula: (RE 1-yz Tb y} Ce z) 2 O 3 · cSiO 2 · dP 2 O 5 · eB 2 O 3 ...... ( 7) (wherein, RE represents at least one element selected from Y, La and Gd, y, z and c, d, and e are y> 0,
z> 0, 0.1 ≦ y + z ≦ 0.7, c ≧ 0, d> 0, 5.0 × 10
^-6 ≦ e ≦ 6.0 × 10 ⁻³ , 0.8 ≦ c + d + e ≦ 1.30). The metal oxide particles as described above are not substantially adhered to the surface of such green light emitting phosphor particles. Even if metal oxide particles adhere, the content is set to less than 0.01% by weight based on the phosphor. As described above, the reason why the metal oxide particles are not attached to the surface of the green light emitting phosphor particles is as follows.
Conversely, when the metal oxide is deposited, early band-like blackening (coloring phenomenon) near the electrode, which is considered to be affected by the cathode material or the like, comes to be recognized, which causes a problem in appearance quality. When the amount of the metal oxide particles attached to the green light-emitting phosphor particles is less than 0.01% by weight, the influence of the cathode material and the like can be substantially eliminated, and like the case where the metal oxide is not attached, It is possible to suppress the occurrence of early band-like blackening near the electrodes.

Further, the fluorescent lamp of the present invention has a fluorescent layer containing the three-wavelength phosphor as described above,
In particular, it is effective for a high load type having a tube wall load of 0.05 W / cm ² or more.

[0020]

Next, an embodiment of the present invention will be described.

Example 1 First, magnesium nitrate [Mg (NO ₃ ) ₂ ] was added to 200 cc of pure water.
Dissolve 1.10 g. Then, in this aqueous solution of magnesium nitrate, (Sr _0.65 Ca _0.30 Ba _0.04 Eu _0.01 ) ₁₀ (PO ₄ ) ₆
25.86 g of a blue light-emitting phosphor represented by Cl ₂ and (Y _0.955 Eu
_0.045 ) Add 74.14 g of a red light-emitting phosphor represented by ₂ O ₃ and stir well. While stirring, add ammonia water [NH
₄ OH] to adjust the pH to the alkaline range. Then, a gelatinous substance of magnesium hydroxide is generated. In this state, after stirring is further sufficiently performed, washing is performed several times with pure water, and the suspension is subjected to suction filtration. Thereafter, the obtained filter cake is dried at 300 ° C to 400 ° C.

The thus obtained mixed phosphor particles of the blue light emitting phosphor and the red light emitting phosphor have a surface of 0.3% by weight.
Was coated with a layer of MgO particles.

Next, (La _0.50 Ce _0.35 Tb _0.15 ) ₂ O ₃ .0.
72.41 g of a green-emitting phosphor (without coating of a metal oxide layer) represented by 985P ₂ O ₅ / 0.0005B ₂ O ₃ was weighed, and this was used as a blue-emitting phosphor having a 0.3 wt% MgO fine particle layer on its surface. A three-wavelength phosphor was prepared by sufficiently mixing with 100.3 g of mixed phosphor particles of the body and the red light-emitting phosphor.

Subsequently, using this three-wavelength phosphor, a 4 W three-wavelength fluorescent lamp as shown in FIG.
FL4 (15.5mmφ, tube wall load: 0.11W / cm ² ) was prepared, initial luminescence output, band-like coloring (light brown) near the electrode after lighting for 100 hours, and luminescence output after lighting for 1000 hours and overall Was measured and evaluated.

In FIG. 1, the fluorescent lamp has a fluorescent film 2 attached to the inner surface of a glass bulb 1 and a discharge gas at a predetermined pressure, that is, a mixed gas of mercury and a rare gas such as argon. Have been. Electrodes 3 are attached to both ends of the glass bulb 1, and a predetermined voltage is applied to the electrodes 3 so that the fluorescent film 2 emits light by an excitation source.

On the other hand, as a comparative sample, 0.3% by weight was added to all the phosphor particles in the three-wavelength phosphor used in the above example.
The same fluorescent lamp was manufactured using the one coated with the MgO fine particle layer, and the characteristics were measured under the same conditions as in the example. In addition,
As the measurement results, both the initial light emission output and the light emission output after lighting for 1000 hours were obtained as relative values when the value of the fluorescent lamp of the comparative sample was set to 100%. Further, the degree of coloring of the fluorescent lamp bulb was set to a maximum of 10 points, and the less the coloring, the higher the score.

The initial light emission output of the fluorescent lamp according to the embodiment is
100.2%, which was slightly brighter because the surface of the green light-emitting phosphor particles was not coated with the MgO fine particles. Also 1
The degree of coloring of the bulb of the fluorescent lamp after lighting for 00 hours was 7.0 for the comparative sample, but was as high as 10.0 for the fluorescent lamp according to the example, confirming that early band blackening could be prevented. did. Furthermore, the emission output of the fluorescent lamp according to the example after lighting for 1000 hours was 108%, and the degree of coloring at that time was 9.5, confirming that the fluorescent lamp was also excellent in life characteristics.

Example 2 1.0 g of fine powder of zinc oxide [ZnO] (particle size: about 50 nm) is put into 200 cc of pure water, and sufficiently suspended. Next, 3 (Ba _0.30 Mg _0.67 Eu _0.03 ) O.8Al was added to the zinc oxide suspension.
31.25 g of a blue light-emitting phosphor represented by ₂ O ₃ and (Y _0.950
68.75 g of a red light-emitting phosphor represented by Eu _0.050 ) ₂ O ₃ is added, and the mixture is sufficiently stirred. Thereafter, 0.1 g of an acrylic emulsion and 0.05 g of ammonium polyacrylate were sequentially added and uniformly dispersed, and then the suspension was subjected to suction filtration.
The obtained filter cake is dried at a temperature around 120 ° C.

The thus obtained mixed phosphor particles of the blue light emitting phosphor and the red light emitting phosphor have a surface of 1.0% by weight.
Was coated with a ZnO fine particle layer.

Next, (La _0.55 Ce _0.35 Tb _0.10 ) ₂ O ₃ .0.
56.25 g of a green light-emitting phosphor (without coating of a metal oxide layer) represented by 995P ₂ O ₅ was weighed and weighed to 1.0% by weight as described above.
Was mixed sufficiently with 101.0 g of mixed phosphor particles of a blue light emitting phosphor and a red light emitting phosphor having a ZnO fine particle layer on the surface thereof to prepare a three-wavelength phosphor.

Using this three-wavelength phosphor, a fluorescent lamp similar to that of Example 1 was manufactured. Under the same conditions, the initial light emission output and the state of band-like coloring (light brown) near the electrode after lighting for 100 hours were measured. Measured and evaluated. Table 1 shows the results.
The comparative samples in the table are the measurement results of a fluorescent lamp manufactured under the same conditions as in the example, except that all the phosphor particles in the three-wavelength phosphor were coated with the ZnO fine particle layer.

Examples 3 to 10 As shown in Tables 1, 2 and 3, various phosphors were used and the type and coating concentration of the metal oxide coating these surfaces were changed. In the same manner as in 2, a three-wavelength phosphor was prepared. Further, fluorescent lamps were produced using the obtained three-wavelength phosphors, and the characteristics were evaluated in the same manner as in Example 2. These results are summarized in Tables 1, 2 and 3.

[0033]

[Table 1]

[Table 2]

[Table 3] Comparative Examples 1 and 2 As shown in Table 4, a three-wavelength phosphor was prepared in the same manner as in Examples 1 and 2, except that the amount of the metal oxide coating the surface of the phosphor was outside the range of the present invention. At the same time, a fluorescent lamp was manufactured using the three-wavelength phosphor, and the characteristics were evaluated in the same manner as in Example 2. Table 4 summarizes these results.

[0034]

[Table 4] As is clear from the measurement results in Tables 1 to 4, the fluorescent lamp using the three-wavelength phosphor according to the present invention maintains the initial luminous output slightly better than the comparative sample, while maintaining the initial luminous output. It can be seen that (band blackening near the electrode) is reduced. Further, it can be seen that this effect is more remarkably observed in a high-load fluorescent lamp (0.05 W / cm ² or more).

[0035]

As described above, according to the present invention, the luminance is high, the band-like blackening of the fluorescent lamp can be prevented at an early stage, and the coloring phenomenon (blackening) due to the lapse of the lighting time of the fluorescent lamp can be prevented. A three-wavelength phosphor excellent in life characteristics that can be suppressed can be obtained. Accordingly, it is possible to provide a high-quality three-wavelength fluorescent lamp which is useful as a fluorescent material for a fluorescent lamp, has a high luminous output, has a long service life, and has a long life.

[Brief description of the drawings]

FIG. 1 is a partially cutaway view of a fluorescent lamp according to an embodiment of the present invention.

[Explanation of symbols]

 1. Glass bulb 2. Fluorescent film 3. Electrode

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tomoji Tomura 72 Horikawacho, Saiwai-ku, Kawasaki-shi, Kanagawa Prefecture Toshiba Corporation Horikawa-cho Plant (72) Inventor Masaaki Tamaya 1st Kogashi-Toshibacho, Saiwai-ku, Kawasaki-shi, Kanagawa Stock (72) Shoji Naoki, Inventor 1-21-1, Funakoshi-cho, Yokosuka City, Kanagawa Prefecture Toshiba Lighting & Technology Corporation (56) References JP-A-63-317582 (JP, A) JP-A-1-104684 (JP, A) JP-A-62-100579 (JP, A) JP-A-4-23887 (JP, A) JP-A-5-70774 (JP, A) JP-A-62-281227 (JP, A) 2-308892 (JP, A) JP-B-46-28359 (JP, B1) (58) Field surveyed (Int. Cl. ⁷ , DB name) C09K 11/08-11/89 H01J 61/44

Claims (3)

(57) [Claims] 1. A three-wavelength phosphor including at least a blue light-emitting phosphor, a red light-emitting phosphor, and a green light-emitting phosphor, wherein the blue light-emitting phosphor and the red light-emitting phosphor have magnesium oxide, At least one metal oxide particle selected from calcium oxide, strontium oxide, barium oxide and zinc oxide is attached to the phosphor in a range of 0.02% by weight to 5.0% by weight,
The three-wavelength phosphor is characterized in that the green light-emitting phosphor has an adhesion amount of the metal oxide particles of less than 0.01% by weight. 2. The three-wavelength phosphor according to claim 1, wherein the metal oxide particles are not substantially attached to the surface of the green light-emitting phosphor. . 3. A light-transmitting glass tube filled with a filling gas containing mercury, a fluorescent layer provided on the inner wall of the light-transmitting glass tube, and means for maintaining a positive column discharge in the filling gas. A fluorescent lamp having a tube wall load of 0.05 W / cm ² or more, wherein the fluorescent layer contains the three-wavelength phosphor according to claim 1 or 2.