JPH09213276A - Metal halide lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the emission effect and the color rendering property, by applying a europium activated yttrium vanadate phosphor, and a managanium activated fluorogermanate phosphor, having an exciting spectrum neat a specific wavelength respectively, to the inner surface of an outer bulb. SOLUTION: On the inner surface of the outer bulb of a metal halide lamp, a mixture phosphor of a europium activated yttrium vanadate phosphor having an exciting spectrum near the wavelength 220 to 430nm, and a manganium activated fluorogermanate phosphor having an exciting spectrum near the wavelength 220 to 500nm are coated. A quartz luminous tube is held in the outer bulb. In the luminous tube, mercury, a rare gas, scandium iodide, and sodium iodide are sealed to form a metal halide lamp. Consequently, the spectral strength of the red light near the wavelength 660nm is increased, and the mean color rendering valuation number increased as well as the emission efficiency is improved, and a good lamp performance is obtained.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention improves the luminous efficiency and color rendering by applying a mixed phosphor of europium-activated yttrium vanadate phosphor and manganese-activated fluorogermanate phosphor to the inner surface of the outer bulb. Regarding metal halide lamps.

[0002]

2. Description of the Related Art Generally, in a metal halide lamp, the luminous efficiency and color rendering of the lamp are improved by adding various metal halides together with mercury and a rare gas into the arc tube. Among such metal halide lamps, a metal halide lamp in which scandium iodide and sodium iodide are added to the tube (Sc-Na-based metal halide lamp) has high emission efficiency in the visible wavelength range, and is excellent in light emission efficiency and color rendering. It is used for various purposes.

Further, in a metal halide lamp having a transparent outer bulb, the light from the arc tube directly hits the eyes, so that it may look very dazzling and feel uncomfortable. Therefore, a fluorescent lamp in which a phosphor is applied to the inner surface of the outer bulb is often used. On the other hand, the high-pressure mercury lamp emits a large amount of yellow-green light peculiar to the mercury spectrum, and the red light is extremely insufficient, so that its color rendering property is poor, and particularly, the color rendering property for the red part is extremely poor. (Average color rendering index Ra = 14, relative color temperature Tc = 570
(0K)

Therefore, this type of high pressure mercury lamp has a wavelength of 3
Excited by 13 nm and 365 nm UV rays, 5
94 nm, 615 nm, 619 nm, 650 nm and 7
Showing spectra each having a peak at 00 nm,
Europium-activated yttrium vanadate phosphor, which has good emission characteristics even at the temperature of the outer bulb while the lamp is on, is applied to the inner surface of the outer bulb. Then, the luminous efficiency and the color rendering are improved. This excites the phosphor generated from the arc tube of the high pressure mercury lamp at 313 nm and 365.
This is because the intensity of ultraviolet rays of nm is high, and the emission of the fluorescent material is about 20% of the emission of the entire lamp.

Comparing the transparent type and fluorescent type lamp characteristics in a high pressure mercury lamp, the fluorescent type has a luminous efficiency of about 7% higher, the color temperature can be lowered by about 1600 K, and the luminescent color becomes white light. The number is also about 26 higher. As described above, the effect of the phosphor in the high-pressure mercury lamp is very large, and the fluorescent high-pressure mercury lamp is widely used as general outdoor lighting.

[0006]

The phosphor used in the metal halide lamp is the europium-activated yttrium vanadate phosphor as in the above, but the wavelengths 313 nm and 365 nm for exciting the phosphor are used.
The spectral intensity of the ultraviolet light is weaker than that of the high pressure mercury lamp, and the light emission of the phosphor is about 2% of the light emission of the entire lamp as compared with the high pressure mercury lamp.

[0007] In particular, comparing the characteristics of the transparent and fluorescent lamps in the Sc-Na metal halide lamp, the effect of the fluorescent lamp is small, and the effect of improving the color rendering and lowering the color temperature is 1/1 that of the high pressure mercury lamp. It is about 4 to 1/5. Also, because the luminous flux is the absorption of visible light by the phosphor,
It is about 5% lower than the transparent type. This is because in the fluorescent metal halide lamp, the effect of improving the lamp characteristics by the phosphor is small, and rather it is used to diffuse the light from the arc tube and reduce the glare.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a fluorescent metal halide lamp having improved lamp characteristics such as luminous efficiency and color rendering of the lamp.

[0009]

To achieve the above object, the present invention provides a europium-activated yttrium vanadate phosphor having an excitation spectrum near a wavelength of 220 nm to 430 nm and a manganese having an excitation spectrum at a wavelength of 220 nm to 500 nm. A mixed phosphor of active fluorogermanate phosphors is characterized in that a quartz arc tube is held in an outer sphere coated on the inner surface thereof. Further, mercury, rare gas, scandium iodide and sodium iodide are enclosed in the arc tube.

[0010]

With the above structure, the spectral intensity of red light near a wavelength of 660 nm is increased, the luminous efficiency is increased, the average color rendering index is increased, and the lamp characteristics are improved.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing emission spectra of two kinds of phosphors used in the present invention. The europium-activated yttrium vanadate phosphor shown by the solid line in the figure is 594.
nm, 615 nm, 619 nm, 650 nm and 700
showing spectra with emission peaks in nm,
It emits red light. Further, the manganese-activated fluorogermanate phosphor shown by the dotted line in the figure shows a spectrum having an emission peak at 658 nm and emits deep red light.

FIG. 2 is a diagram showing the excitation spectra of the above-mentioned two kinds of phosphors and the spectral energy distribution of the Sc—Na system metal halide lamp. As is clear from this figure,
The excitation spectrum of the europium-activated yttrium vanadate phosphor is distributed around 220 nm to 430 nm, and that of the manganese-activated fluorogermanate phosphor is 220 nm-
It is distributed around 500 nm. Therefore, the europium-activated yttrium vanadate phosphor was not excited.
The manganese-activated fluorogermanate phosphor is excited in the visible wavelength range of 30 nm to 500 nm and emits deep red light. As a result, the fluorescent metal halide lamp in which the mixed phosphor is applied to the inner surface of the outer bulb has an increased spectral intensity of red light, which is apt to be lacking in conventional metal halide lamps, and improves the luminous efficiency and color rendering of the entire lamp. Done.

Hereinafter, description will be given based on a specific embodiment. 75% by weight of europium-activated yttrium vanadate phosphor emitting red light and 25% by weight of manganese-activated fluorogermanate phosphor emitting deep red light are mixed with an appropriate amount of a binder. This was applied to the inner surface of the outer bulb by an electrostatic coating method so that the adhered amount was 1.0 mg / cm ^2, and then baked at about 600 ° C. to prepare a lamp. Then, in order to confirm the characteristics of the phosphor, a 400 W Sc-Na-based metal halide lamp sealed in a transparent outer bulb was turned on for 100 hours, and after the characteristics were stabilized, various characteristics of the lamp were measured. The results are shown in Table 1 (No1)
Shown in Next, the arc tube mount of the lamp was recombined with the bulb coated with the phosphor of the present invention to form a lamp, and its characteristics were measured. (No. 2 in Table 1) Further, the lamp was changed to a conventional bulb coated with a phosphor, and the characteristics were measured. (No. 3 in Table 1) In Table 1, Ra represents the average color rendering index, the unit of color temperature is (K), the unit of total luminous flux is (lm), and the unit of luminous efficiency is (lm / W).

[0014]

[Table 1]

As is clear from Table 1, the metal halide lamp according to the present invention is superior in each characteristic as compared with the conventional lamp. Further, FIG. 3 shows the spectral distribution of the fluorescent metal halide lamp of the above embodiment of the present invention.

In the above embodiment, as the mixed phosphor, the case where the europium-activated yttrium vanadate phosphor and the manganese-activated fluorogermanate phosphor were mixed in a weight ratio of 3: 1 was described. However, this mixing ratio is
70% yttrium vanadate phosphor activated with europium
If the ratio of the manganese-activated fluoro-germanate phosphor is 20 to 30% by weight, almost the same characteristics as described above can be obtained. In addition, 1.0 mg on the inner surface of the outer bulb
/ Cm ² I explained the case of deposition, 0.5mg
/ Cm ² to 1.2 mg / cm ² , almost the same characteristics as described above can be obtained. Furthermore, although the Sc-Na-based metal halide lamp has been described, it is also applicable to other Dy-Tl-based metal halide lamps and the like.

[0017]

As described above, the metal halide lamp according to the present invention uses a mixed phosphor of europium-activated yttrium vanadate phosphor and manganese-activated fluorogermanate phosphor. Characteristic,
In particular, a lamp having excellent luminous efficiency and color rendering can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing emission spectra of two kinds of phosphors according to the present invention.

FIG. 2 is a diagram showing an excitation spectrum of a phosphor used in the present invention and a spectral energy distribution of a Sc—Na-based metal halide lamp.

FIG. 3 is a spectral distribution characteristic diagram of a fluorescent metal halide lamp according to an example of the present invention.

Claims (2)

[Claims] 1. A mixed phosphor of europium-activated yttrium vanadate phosphor having an excitation spectrum near a wavelength of 220 nm to 430 nm and manganese-activated fluoro-germanate phosphor having an excitation spectrum at a wavelength of 220 nm to 500 nm. A metal halide lamp in which a quartz arc tube is held in an outer bulb attached to the. 2. The metal halide lamp according to claim 1, wherein mercury, a rare gas, scandium iodide and sodium iodide are enclosed in the arc tube.