JP2003027051A - Composite phosphor and fluorescent lamp using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel phosphor and to provide a fluorescent lamp using the same capable of saving the amount of rare earth elements to be used. SOLUTION: There are provided a composite phosphor prepared by adhering rare earth phosphor particles of a particle diameter of 0.05-1.0 μm to the surfaces of inorganic compound particles and a fluorescent lamp coated with a layer comprising the composite phosphor on the inside surface of a bulb. The inorganic compound particles desirably have a particle diameter of 5-15 μm. The inorganic compound is desirably the one containing at least one element selected from silicon, aluminum, yttrium, cerium, germanium, titanium, zinc, calcium, and barium.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel phosphor and a fluorescent lamp using the same.

[0002]

2. Description of the Related Art In recent years, fluorescent lamps have been developed mainly by improving the luminous flux, the appearance of colors and the feeling of brightness by using visible light of three wavelengths by using a rare earth phosphor. There is a tendency. Therefore, the development of phosphors has led to research on materials that are more efficiently improved than before and that are resistant to deterioration. For example, as reported on page 23 of the 259th Fluorescent Material Society of Japan, the blue fluorescent material called BAM had the drawbacks of poor efficiency and easy deterioration, but the composition ratio of the rare earth additive is examined. As a result, it was comparable to other phosphors. Also, Journal
of the Electrochemical Soc
IETY, 146 (1) 392-399 (1999), in recent years, a technique has been developed to reduce the surface area of the phosphor as much as possible to make it less susceptible to ultraviolet rays and ion sputtering in the lamp. It is being introduced.

It has also been reported that the surface of the phosphor is coated with a metal oxide such as yttria by a special method to prevent mercury from adhering to achieve a high luminous flux maintenance factor of the lamp.

[0004]

As described above, as the demand and supply of fluorescent lamps using rare earth phosphors increases, the amount of rare earth elements to be used increases. However, there is a problem that the rare earth element has a small reserve and the unit price per unit weight is high. It is also necessary to protect valuable resources from the perspective of protecting the natural environment. Furthermore, the amount of rare earth element used in the phosphor is increasing, and even if the rare earth element is recovered from the waste of the phosphor, enormous energy is required, which has not been realized.

Therefore, the present invention has been made to solve the above conventional problems, and an object of the present invention is to provide a fluorescent lamp which can reduce the amount of rare earth elements used by using a novel phosphor. To do.

[0006]

In order to achieve the above object, the composite phosphor of the present invention comprises a rare earth phosphor particle having a particle size of 0.05 μm or more and 1.0 μm or less on the surface of an inorganic compound particle. It is characterized by being attached. This makes it possible to reduce the amount of commonly used rare earth phosphor.

Further, in the composite phosphor of the present invention, it is preferable that the particles of the inorganic compound have a particle size of 5 μm or more and 15 μm or less.

In the composite phosphor of the present invention, the inorganic compound contains at least one element selected from the group consisting of silicon, aluminum, yttrium, cerium, germanium, titanium, zinc, calcium and barium. It is preferable. As a result, it becomes possible to endure discharge for a long period of time and to perform excitation and light emission of the phosphor without hindrance.

Further, in the composite phosphor of the present invention, it is preferable that the rare earth phosphor particles are composed of two or more kinds of phosphors. This makes it possible to combine and emit single-wavelength light such as red, blue, and green with one phosphor particle.

Further, a fluorescent lamp using the composite phosphor of the present invention has a discharge space filled with a discharge gas in the bulb, and a current is passed through the discharge space to emit light. In addition, a layer comprising the composite phosphor of the present invention is formed. This allows
A fluorescent lamp capable of reducing the amount of rare earth elements used becomes possible.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.

The rare earth phosphor used in the present invention has been conventionally used.
It is possible to use all of the rare earth phosphors that have been used. Concrete
As a rare earth phosphor that has been industrialized, Sr
₁₄(PO _Four)₆Cl₂: Eu²⁺, (Sr, Ca)_Ten(P
O_Four)₆Cl₂: Eu²⁺, (Sr, Ca)_Ten(PO_Four)₆C
l₂・ NB₂O₃: Eu²⁺, (Sr, Ca, Mg)_Ten(P
O_Four)₆Cl₂: Eu²⁺, LaPO_Four: Ce³⁺, Tb³⁺, L
a₂O₃・ 0.2SiO₂・ 0.9P₂O_Five: Ce³⁺, Tb
³⁺, Sr₂Si₂Oα ・ 2SrCl₂: Eu²⁺, Ba₃Mg
Si₂Oα: Eu²⁺, (Sr, Ba) Al₂Si₂Oα:
Eu²⁺, Y₂SiO_Five: Ce³⁺, Tb³⁺, BaAl
_nO₁₃: Eu²⁺, CeMgAl₁₁O₁₉: Tb³⁺, BaM
gAl_TenO₁₇: Eu²⁺, BaMgAl_TenO₁₇: Eu²⁺，
Mn²⁺, Sr_FourAl₁₄O_{2 Five}: Eu²⁺, SrMgAl_TenO
₁₇: Eu²⁺, Y₂O₃: Eu³⁺, YVO_Four: Dy³⁺, Y
(P, V) O_Four: Eu³⁺, SrB_FourO₇F: Mn²⁺, Gd
MgB_FiveO_Ten: Ce³⁺, Tb³⁺, YVO_Four: Eu³⁺3.
5MgO / 0.5MgF₂・ CeO₂: Mn⁴⁺, Y₂Si
O_Five: Ce³⁺, Tb³⁺, Y₂O₃・ Al₂O₃: Tb³⁺, Y₃
Al_FiveO₁₂: Ce ³⁺, Sr₂Si₂O₉・ 2SrCl₂: E
u²⁺, Sr_Ten(PO_Four)₆Cl₂: Eu²⁺Etc are used
Therefore, it can be preferably used in the present invention.

As the rare earth phosphor, powder having a particle size of 1 to 10 μm is usually used. However, since the phosphor particles having a particle size of 1 μm or less have a small apparent surface area, the absorption efficiency of the excitation wavelength of the rare earth phosphor is lowered, and the quantum efficiency is apparently lowered. Therefore, it is not generally used. However, such a phosphor fine particle having a size of 1 μm or less does not lower the luminous efficiency if it is effectively irradiated with the excitation wavelength.

1 and 2 are schematic views of the composite phosphor of the present invention. FIG. 1 shows the case where one kind of rare earth phosphor 1 is used. FIG. 2 shows the case where two or more kinds of rare earth phosphors 3 are used. The composite phosphor of the present invention is obtained by coating the surface of an inorganic compound particle 2 with a rare earth phosphor particle 1 or 3. For this reason, not only can the excitation light be efficiently received on the phosphor surface, but also the ultraviolet rays that have not been irradiated to the phosphor can be reflected by the particles of the inorganic compound, and the phosphor particles can be irradiated. As a result, the luminous efficiency of the apparent phosphor is improved, and the phosphor can emit light in the same manner as the conventionally used phosphor. Therefore, the composite phosphor of the present invention can reduce the amount of rare earth element used conventionally, and can increase the luminous efficiency more than ever with a small amount.

The particles of the inorganic compound in the present invention are
Particles having an average particle diameter of 5 μm or more and 15 μm or less are preferable. Particles having a size of less than 5 μm are not preferable because the efficiency of reflection by irradiation with ultraviolet rays is reduced, and the efficiency of light emission of the phosphor adhered to the surface is reduced. Further, particles exceeding 15 μm cannot be applied uniformly using a conventional phosphor suspension, which is not practical. However, if the inorganic compound powder contains particles of less than 5 μm and particles of more than 15 μm in less than 20% of the whole,
It does not reduce the luminous efficiency and does not affect the formation of the coating film.

The inorganic compounds are silicon, aluminum, yttrium, cerium, germanium, titanium,
It is preferably an oxide of zinc. Since the particles of the inorganic oxide do not easily change the crystal form or particle structure with respect to ultraviolet rays and have a high efficiency of reflecting ultraviolet rays to the outside, they are optimal as particles for coating the fine particles of the rare earth phosphor of the present invention. Is.

It is also preferable to apply a coating of an inorganic compound to the inner surface of the bulb so that the glass bulb is not directly irradiated with ultraviolet rays. This inorganic compound is an oxide of silicon, aluminum, yttrium, cerium, germanium, titanium, or zinc, and has a preferable structure for the same reason as the inorganic oxide particles of the above composite phosphor.

The fluorescent lamp of the present invention can be manufactured by using the above composite fluorescent material in the same manner as a conventional fluorescent lamp. In addition, in the sintering process and the exhaust process, which are the manufacturing steps of the fluorescent lamp, the lamp can be manufactured under the same conditions as conventional ones.

[0019]

EXAMPLES The present invention will be described below based on examples.

Example 1 A blue phosphor generally used in a fluorescent lamp is BaMgAl ₁₀ O ₁₇ : Eu ²⁺ (hereinafter, referred to as
The emission wavelength is about 450 nm. The phosphor powder was irradiated with excitation light of 254 nm, and the intensity of emitted light at 450 nm was measured for each particle size.

FIG. 4 is a diagram showing the luminance characteristics of the composite phosphor of the present invention and the conventional phosphor. The conventional phosphor has the highest brightness when the particle size is about 2 to 5 μm, as shown by the curve 7 in FIG. 4, and the brightness is extremely reduced when the particle size is smaller than that. From this, it can be seen that the phosphor of 1 μm or less cannot be used because the luminous efficiency is practically poor. Therefore, conventional fluorescent lamps do not use phosphors having a particle diameter of 1 μm or less.

However, in the present invention, the particle size is 5
The emission brightness was measured using a phosphor having different particle diameters deposited on alumina having a particle diameter of μm and a phosphor having different particle diameters deposited on alumina having a particle diameter of 15 μm. As shown by the curves 8 and 9 in FIG. 4, it was found that even a phosphor having a particle diameter of 1 μm or less can obtain high emission brightness. It slightly differs depending on the particle size of the phosphor-supporting particles to be used, and the larger the particle size of the carrier particles is, the more the peak of the brightness shifts toward the smaller particle size of the phosphor. In addition, 8 is a brightness characteristic curve of the composite phosphor using the supporting particles of 5 μm of the present invention, and 9 is a brightness characteristic curve of the composite phosphor using the supporting particles of 15 μm of the present invention.

Next, a method for preparing the composite phosphor of the present invention will be described. 1 kg of alumina powder and 300 g of phosphor powder having each desired particle size were mixed with a dry mixer all day and night. After that, when the particle shape was confirmed with an electron microscope, it was 1.0 μm.
For phosphors of m or less, there is no gap on the surface of the alumina powder B
The composite phosphor particles were coated with AM particles.

As described above, 1.0 that has not been used conventionally
By depositing a phosphor having a particle size of less than or equal to μm on alumina having carrier particles of 5 to 15 μm, it can be made sufficiently usable like a conventional phosphor.

Similarly, an alumina powder having an average particle diameter of 10 μm
Body and phosphor LaPO that emits green light _Four: Ce³⁺, Tb³⁺
(Hereinafter referred to as LAP) is mixed with a dry mixer all day and night.
As a result, green-emitting composite phosphor particles were obtained. This luminescence
As for the BAM phosphor of FIG. 4, the particle size is 0.05 to
Shows the brightness enhancement effect of LAP phosphor in the range of 1.0 μm
However, high brightness with a relative ratio of 90% or more was obtained.

Similarly, an average particle diameter of 10 μm
Mina powder and phosphor Y that emits red light ₂O₃: Eu³⁺(Below
(Below, YOX) is mixed with a dry mixer all day and night to prepare
The produced composite phosphor also has a particle size of 0.05 to 1.
An improvement in brightness was recognized in the range of 0 μm.

Further, 15 g and 50 g of the powders of BAM, LAP and YOX each having an average particle diameter of 0.3 μm are added.
g and 35 g were mixed and mixed with a dry mixer all day and night. Thereafter, 500 g of alumina powder having an average particle diameter of 10 μm was further added, and the mixture was mixed with a dry mixer all day and night. Then, the powder taken out was observed with an electron microscope and a laser microscope. As a result, BAM and LA were observed on the surface of the alumina particles.
It was observed that the respective phosphors of P and YOX were composite phosphor particles in which they were randomly deposited. Further, when the powder was irradiated with excitation light of 254 nm, the above-mentioned three types of spectral distributions were observed, and the peak ratio of each emission wavelength was approximately 3: 10: 7. The wavelength distribution was obtained. In this way, three kinds of phosphors having arbitrary compositions can be supported on the single supported particles, and a composite phosphor with high brightness which emits light according to the composition ratio was obtained.

(Example 2) A fluorescent lamp was manufactured using the composite fluorescent material shown in Example 1, and the luminous flux was compared with that of a fluorescent lamp using a conventional fluorescent material. In the experiment, as shown in FIG. 3, the glass bulb 4 (inner diameter 26 mm, thickness 1.0 m
m, length 1200 mm) was provided with coils 5 at both ends, a fluorescent material was applied to the inner surface of the bulb, and a fluorescent lamp in which mercury, argon, and neon gas were sealed at 400 Pa was used. In addition,
6 is a base.

First, 1000 g of the target composite phosphor and 2% by weight of nitrocellulose dissolved in butyl acetate solution 1d.
m ³ was mixed and stirred to prepare a uniform slurry. The amount of coating on the inner surface of the cleaned glass bulb is 2.5 g, 3.5
g, 4.5 g, 5.5 g and 6.5 g were applied and dried. Then, apply this coated valve at 530 ° C.
After firing for 10 minutes and cooling, coils were attached to both ends.
Vacuum exhaust was performed from the exhaust pipe, the target amount of mercury and argon / neon mixed gas was enclosed, and the container was sealed. Then, the base was attached to complete the lamp. The types of lamps compared are shown below.

Sample 1 of the present invention has a particle size of 0.3 μm.
Of BAM adhered to alumina having a particle size of 10 μm, LAP having a particle size of 0.3 μm to alumina having a particle size of 10 μm, and YOX having a particle size of 0.3 μm having a particle size of 10 μm Of the three types of composite phosphors adhered to the alumina of 15:50:35
The mixture is mixed with the slurry in 1. and applied to a valve.

Sample 2 of the present invention has a particle size of 0.3 μm.
BAM and LAP with particle size 0.3μm and particle size 0.3μ
m YOX is mixed at a mass composition ratio of 15:50:35, and then the mixture is applied to alumina having a particle diameter of 10 μm to prepare a composite phosphor, and the slurry is prepared with the composite phosphor to prepare a bulb. It is applied.

The conventional sample 3 is a BA having a particle size of 5 μm.
It is a conventional product in which M, LAP having a particle diameter of 5 μm, and YOX having a particle diameter of 5 μm are mixed in a slurry at a mass composition ratio of 15:50:35 and applied to a valve.

Next, the luminous fluxes of the three types of fluorescent lamps were compared. The results are shown in Table 1. The mixing ratio is finely adjusted in order to compare the light fluxes at the same color temperature.

[0034]

[Table 1]

In Table 1, the maximum value of the luminous flux of the conventional sample 3 was 3635 lm when the coating amount was 4.5 g, and the luminous flux decreased when the coating amount was smaller or larger than that. In comparison, sample 1 and sample 2 of the present invention
Is 0.4% more than before when the same amount of coating is 4.5g.
Although the luminous flux was low to some extent, the luminous flux exceeded it when the coating amount increased, and the coating amount was 6.5 g, which was 2% or more higher than the conventional sample. The amounts of the phosphors actually used in Samples 1 and 2 of the present invention are mostly the mass of the supported alumina, and the true phosphor content is 1.3 g at a coating amount of 6.5 g. From this, by using the composite phosphor of the present invention, the luminous flux of the fluorescent lamp can be improved by several% as compared with the use of the conventional phosphor, and the amount of the phosphor used is ⅓ or less of the conventional amount. I was able to suppress it. Since there is no difference in the luminous flux between sample 1 and sample 2, it can be seen that the luminous flux is not affected even if the method of adjusting the composite phosphor is changed.

[0036]

Industrial Applicability The composite phosphor of the present invention and the fluorescent lamp using the same can provide a fluorescent lamp which can reduce the amount of phosphor to be used as compared with the prior art and which has a high luminous flux. As a result, the amount of rare earth element contained in the phosphor can be reduced. Further, by introducing the phosphor of the present invention into a fluorescent lamp, the luminous efficiency is improved as compared with the conventional product, and thus the energy consumption can be reduced.

Further, since the particles of the composite phosphor of the present invention are fine, it is possible to reduce the manufacturing cost of the phosphor, the color shift at the time of manufacturing the lamp, and the number of steps for color matching, and as a result, the manufacturing cost of the lamp is reduced. Is possible.

[Brief description of drawings]

FIG. 1 is a schematic view of a composite phosphor of the present invention using one kind of rare earth phosphor.

FIG. 2 is a schematic view of a composite phosphor of the present invention using two or more kinds of rare earth phosphors.

FIG. 3 is a cross-sectional view of a main part of a fluorescent lamp using the composite phosphor of the present invention.

FIG. 4 is a diagram showing luminance characteristics of a composite phosphor of the present invention and a conventional phosphor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Rare earth phosphor 2 Inorganic compound (particles carrying phosphor) 3 Two or more different rare earth phosphors 4 Glass bulb 5 Coil 6 Base 7 Luminance characteristic curve with respect to particle diameter of conventional phosphor 8 Supporting 5 μm of the present invention Luminance characteristic curve 9 of composite phosphor using particles 9 Luminance characteristic curve of composite phosphor using 15 μm-supported particles of the present invention

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiromi Tanaka             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Higashi Toru             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F-term (reference) 4H001 CA02 CA07 XA08 XA12 XA13                       XA15 XA39 XA56 XA57 YA58                       YA63 YA65

Claims (5)

[Claims] 1. A particle size of 0.05 μm or more and 1.0 μm
A composite phosphor obtained by depositing the following rare earth phosphor particles on the surface of an inorganic compound particle. 2. The particle size of the inorganic compound particles is 5 μm.
The composite phosphor according to claim 1, having a size of not less than m and not more than 15 μm. 3. The method according to claim 1, wherein the inorganic compound contains at least one element selected from the group consisting of silicon, aluminum, yttrium, cerium, germanium, titanium, zinc, calcium and barium. Composite phosphor. 4. The composite phosphor according to claim 1, wherein the particles of the rare earth phosphor are composed of two or more kinds of phosphors. 5. A fluorescent lamp having a discharge space filled with a discharge gas in a bulb, wherein a current is passed through the discharge space to emit light, the inner surface of the bulb being described in any one of claims 1 to 4. A fluorescent lamp having a layer formed of a composite phosphor.