JPH07105912A - Fluorescent lamp - Google Patents

Abstract

PURPOSE:To heighten the special color rendering evaluation number, suppress drop of the total light flux to possible minimum and enable massproducing by adding a deep red phosphor to a red phosphor. CONSTITUTION:As the first phosphor, a phosphor of two valent europium- activated barium/calcium/strontium halophosphate is provided whose peak wavelength lies around 450nm and which emits blue light. As the second phosphor, a phosphor of cerium/terbium-activated lanthanum phosphate is provided whose peak wavelength lies around 544nm and which emits green light. As the third phosphor, a phosphor of europium-activated yittrium oxide is provided whose peak wavelength lies around 611nm and which emits red light. As the fourth phosphor, a phosphor of europium-activated cadrinium oxide is provided whose peak wavelength lies around 623nm and which emits a deep red light. These four types of phosphors are mixed together and applied to the inside of a glass tubing as the bulb of a fluorescent lamp concerned having similar diameter and length to conventional. Thereby the total light flux can be increased while the color rendering characteristic remains high, and a high efficiency be ensured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent lamp having high color rendering and high luminous efficiency.

[0002]

2. Description of the Related Art Recently, many fluorescent lamps having excellent luminous efficiency and long life have been used in place of incandescent light bulbs.

In a fluorescent lamp, an electrode in which a coil-shaped tungsten filament coated with an electron emissive material is attached in a glass tube bulb whose inner surface is coated with a phosphor film, and a rare gas such as argon for facilitating discharge initiation. Gas and a proper amount of mercury are enclosed.

When the electrode (cathode) is preheated by applying an electric current, thermoelectrons are emitted from the filament into the bulb, and the thermoelectrons are attracted and moved by the high voltage of the electrode (anode) on the opposite side. The discharge starts at. Electrons moving by this discharge collide with mercury atoms in the bulb to generate ultraviolet rays, and the ultraviolet rays excite the phosphor on the inner surface of the bulb to emit visible light to the outside of the bulb. White, daylight, blue, pink, etc. are obtained as the emission color depending on the type of the applied phosphor.

In a general fluorescent lamp, for example, an antimony / manganese activated halophosphate phosphor was applied to obtain colored light such as white or daylight, but in recent years, a three-wavelength type with improved efficiency and color rendering properties has been obtained. The so-called fluorescent lamp has been widely used.

This three-wavelength type fluorescent lamp is, for example, a europium-activated barium-magnesium aluminate phosphor that emits blue light having an emission peak near 450 nm (Japanese Patent Laid-Open No. 5-58200).
The details are disclosed in Japanese Patent Publication No. 6-152882. ), Europium-activated barium calcium strontium halophosphate phosphor (described in detail in JP-A-48-33159), and cerium-terbium-activated lanthanum phosphate emitting green light with an emission peak near 545 nm. Phosphors (disclosed in JP-A-54-56086), cerium / terbium activated magnesium aluminate phosphors (disclosed in JP-A-52-22836), and emission peaks. Is 611n
The fluorescent substance of three colors such as europium-activated yttrium oxide fluorescent substance which emits red light around m is mixed in an appropriate ratio and applied inside the bulb. The illumination of this lamp makes the color of the irradiated object more natural. It has the effect of making you feel beautiful and bright.

However, the fluorescent lamp in which the above phosphors are mixed in an appropriate ratio has a red special color rendering index (R9) of 20 to 40 when the light color of the lamp is adjusted to a correlated color temperature of around 5000 Kelvin. Was enough. 611 as this improvement
As a deep red phosphor having an emission peak of wavelength longer than nm, (1) manganese-activated magnesium fluorogermanate phosphor having an emission peak near 655 nm,
(2) Europium-activated yttrium vanadate phosphor having an emission peak near 619 nm; and (3) Europium-activated yttrium phosphovanadate phosphor,
(4) It has been reported that the special color rendering index (R9) is improved by adding a europium-activated yttrium oxysulfide phosphor having an emission peak near 626 nm.

Of the above deep red phosphors (1),
Although (2) and (3) have the effect of improving the special color rendering index (R9), the addition of them causes a large decrease in the total luminous flux. On the other hand, when (4) is used in a lamp, there is a problem in practical use because it is blackened early due to liberation of contained sulfur (S).

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is possible to minimize the decrease of the total luminous flux while improving the special color rendering index (R9), and there is no problem in mass production. An object is to provide a fluorescent lamp.

[0010]

The fluorescent lamp according to claim 1 of the present invention has a first fluorescent substance having an emission peak at 430 to 470 nm and emitting blue light, and an emission peak of 540.
A second phosphor having a wavelength of ˜570 nm that emits green light, and a third phosphor that has an emission peak near 611 nm and that emits red light and that comprises europium-activated yttrium oxide;
It is characterized in that a coating film made of a mixed phosphor having a fourth phosphor made of europium-activated gadolinium oxide, which emits deep red and has an emission peak near 623 nm, as a main component was formed on the inner surface of the glass bulb.

The fluorescent lamp according to claim 2 of the present invention comprises:
The first phosphor is a divalent europium-activated barium-magnesium aluminate phosphor, a divalent europium-manganese co-activated barium-magnesium aluminate phosphor, or a divalent europium-activated barium halophosphate-calcium-strontium phosphor. And the second phosphor is made of at least one of a cerium / terbium-activated lanthanum phosphate phosphor or a cerium / terbium-activated barium aluminate / magnesium phosphor.

The fluorescent lamp according to claim 3 of the present invention comprises:
In the mixed phosphor, the first phosphor is 1 to 50% by weight, and the second phosphor is
20 to 45% by weight of the phosphor of No. 3 and 15 to 7 of the third phosphor.
5% by weight, the fourth phosphor is 0.5 to 25% by weight,
In addition, the total amount of the third phosphor and the fourth phosphor is 30
It is characterized by being ~ 76 wt%.

The fluorescent lamp according to claim 4 of the present invention is
It is characterized in that the fourth phosphor is 1 to 50% by weight with respect to the total amount (weight) of the third phosphor and the fourth phosphor.

[0014]

By adding a deep red (fourth) phosphor to the red (third) phosphor, the color rendering is improved and the decrease of the total luminous flux is suppressed to a small level.

[0015]

EXAMPLES Examples of the present invention will be described below.

The first phosphor has a peak wavelength of 450 n
A divalent europium-activated barium / calcium / strontium halophosphate phosphor that emits blue light in the vicinity of m is 26% by weight, and the peak wavelength is 544n as the second phosphor.
30% by weight of cerium / terbium-activated lanthanum phosphate phosphor that emits green light in the vicinity of m, and europium-activated yttrium oxide (Y ₂ O ₃ that emits red light with a peak wavelength of 611 nm as the third phosphor near 611 nm : E
u ³⁺ ) phosphor in an amount of 32% by weight, and as a fourth phosphor, europium-activated gadolinium oxide (Gd ₂ O ₃ : Eu ³⁺ ) having a peak wavelength near 623 nm and emitting deep red light.
A phosphor of 12% by weight was mixed with four kinds of phosphors, and the mixture was applied to the inner surface of a glass tube bulb having a tube diameter of about 32 mm and a length of about 1200 mm in the same manner as usual to manufacture a 40 W type straight tube lamp. .

This fluorescent lamp has a spectral distribution as shown in FIG. 1 and 2, the horizontal axis represents the emission wavelength (n
m), and the vertical axis represents relative energy (%).

The europium-activated gadolinium oxide phosphor, which is the fourth phosphor, is 623n as shown in FIG.
There was a peak wavelength in the vicinity of m, and a deep red emission color was exhibited as compared with the europium-activated yttrium oxide phosphor, which is the third phosphor.

The chromaticity of this fluorescent lamp was on a black body locus at a correlated color temperature of 5000 Kelvin. Also,
Total luminous flux (0 hours of lighting) is 3550 lumens, average color rendering index (Ra) is 88.8, and red special color rendering index (R9)
) Is 53, and a high-efficiency lamp that can improve the total luminous flux is obtained despite the higher special color rendering index (R9) than before.

Incidentally, the conventional three-wavelength type lamp described in the prior art has a total luminous flux (0 hours of lighting) of 3640 lumens,
The average color rendering index (Ra) is 88.1 and the red special color rendering index (R9) is 35. The lamp of the present invention sacrifices only 2.4% of the total luminous flux as compared with the conventional lamp, and the average color rendering index (Ra).
) Is 0.7 points, and the red special color rendering index (R9)
Was improved by 18 points.

Further, the lamp coated with the above-mentioned mixed phosphor has no blackening at the initial stage of lighting and has the same luminous flux maintaining characteristic during lighting as that of the conventional product, and is therefore suitable for mass production.

The gadolinium oxide phosphor has a peak wavelength of 611 nm, which is almost the same as that of the yttrium oxide phosphor when fired by an ordinary method (the crystal form is cubic), but if fired at a high temperature of 1300 ° C. or higher, it is crystallized. The shape changes to a monoclinic shape, and as shown in FIG. 2, it emits light at 623 nm.

Regarding the emission peaks and blending ratios of the above four kinds of phosphors, the first phosphor emitting blue light has an emission peak of 1 to 50% by weight at 430 to 470 nm.
The second phosphor that emits green light has an emission peak of 540 to 5
20 to 45% by weight at 70 nm, the third phosphor that emits red light has an emission peak of 15 to 75% by weight near 611 nm, and the fourth phosphor that emits deep red has an emission peak of 62%.
0.5 to 25% by weight in the vicinity of 3 nm, and the third phosphor and the fourth phosphor are mixed so that the total amount thereof is in the range of 30 to 76% by weight to form a coating on the inner surface of the glass bulb. It may be formed.

The present invention is not limited to the above-mentioned phosphors, but the first phosphor that emits blue light may be europium-activated barium-magnesium aluminate phosphor or europium-manganese-activated barium-aluminate magnesium. As the phosphor or the second phosphor that emits green light, a cerium / terbium-activated magnesium aluminate phosphor may be used alone or as a mixture with the above phosphor,
Also in the case of these phosphors, the effect of improving the red special color rendering index (R9) was obtained with the addition of the fourth phosphor that emits deep red light, as in the above-described examples.

In addition, in the experiments by the present inventors, when the above-mentioned four-component type phosphors are mixed and used, a third phosphor that emits red light and a fourth phosphor that emits deep red light are used. It was found that various characteristics greatly changed depending on the blending ratio. FIG. 3 shows the red special color rendering index (R9) and the total luminous flux ratio when the compounding ratio of the third phosphor and the fourth phosphor is changed. As is apparent from FIG. 3, the fourth phosphor is 1 with respect to the total amount (weight) of the third phosphor and the fourth phosphor.
If it is up to 50% by weight, the total luminous flux is the same as that of the conventional product (first, second,
It was found that a lamp having an improved red special color rendering index (R9) can be provided, maintaining 95% or more of the case where the same luminescence chromaticity is adjusted by mixing the third phosphor) and practically no problem.

The present invention is not limited to the above embodiment. For example, in the above embodiment, the straight tube type fluorescent lamp is described, but the lamp is not limited to the straight tube type, but the ring type, U type, W type.
Of course, it can be applied to a tubular valve with a bent shape.

[0027]

As described above in detail, according to the present invention, by adding the europium-activated gadolinium oxide (Gd ₂ O ₃ : Eu) phosphor, which has a light emission peak at 623 nm and emits deep red, color rendering is conventionally performed. It is possible to provide a highly efficient fluorescent lamp in which the total luminous flux is increased despite its high efficiency.

[Brief description of drawings]

FIG. 1 is a spectral distribution diagram of a fluorescent lamp according to an embodiment of the present invention.

FIG. 2 is a spectral distribution diagram of a europium-activated gadolinium oxide phosphor.

FIG. 3 is a comparison diagram of a blending ratio of phosphors and a color rendering property and a total luminous flux ratio.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoko Motoshima 72 Horikawa-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Stock Company Toshiba Horikawa-cho Factory

Claims (4)

[Claims] 1. A first phosphor having an emission peak at 430 to 470 nm and emitting blue light, and an emission peak at 540 to 540 nm.
A second phosphor at 570 nm, which emits green light, a third phosphor comprising europium-activated yttrium oxide, which emits red light with an emission peak near 611 nm, and a deep red light, which has an emission peak near 623 nm. A fluorescent lamp characterized in that a coating film made of a mixed phosphor containing, as a main component, a fourth phosphor made of europium-activated gadolinium oxide is formed on the inner surface of a glass bulb. 2. The first phosphor is a divalent europium-activated barium magnesium aluminate phosphor, a divalent europium-manganese co-activated barium magnesium aluminate phosphor, or a divalent europium activated barium halophosphate. It is characterized by being composed of at least one of calcium-strontium phosphor, and the second phosphor being composed of at least one of cerium-terbium-activated lanthanum phosphate phosphor or cerium-terbium-activated barium magnesium aluminate phosphor. The fluorescent lamp according to claim 1. 3. The first phosphor of the mixed phosphor is 1 to 5
0% by weight, the second phosphor is 20 to 45% by weight, the third phosphor is 15 to 75% by weight, and the fourth phosphor is 0.5 to 25%.
The fluorescent lamp according to claim 1 or 2, characterized in that the total amount of the third fluorescent material and the fourth fluorescent material is 30 to 76% by weight. 4. The first phosphor is 1 to 50% by weight with respect to the total amount (weight) of the third phosphor and the fourth phosphor. The fluorescent lamp according to item 3.