JPS5842589B2 - Fluorescent high pressure mercury lamp - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a fluorescent high-pressure mercury lamp in which a phosphor is coated on the inner surface of an outer bulb surrounding an arc tube. A europium-activated yttrium phosphovanadate phosphor having an emission peak in the red region of The purpose is to improve luminous efficiency and color rendering properties by selecting the amount of adhesion within an appropriate range.

Generally, the synchrotron radiation from a high-pressure mercury lamp has an energy distribution as shown in Figure 1, and since it contains almost no red light component, its color rendering properties are extremely poor.In addition, synchrotron radiation in the ultraviolet region cannot be used effectively. The luminous efficiency is also poor.

Therefore, conventionally, phosphors have been coated on the inner surface of the outer bulb of high-pressure mercury lamps to improve color rendering and luminous efficiency. Phosphors based on yttrium vanadate, which emit a large amount of light at 700 nm, are often used.

When the above-mentioned phosphor is used, the i-spectrum is added to the emission spectrum of the high-pressure mercury lamp as shown by the broken line in FIG. 1, and the color rendering and luminous efficiency are much better than those of the conventional lamp.

However, even if the above-mentioned phosphors are used, it is difficult to say that the color rendering properties and luminous efficiency are sufficiently improved.
This is because there is no emission between m and 546 nm, so the overall spectrum does not approach a continuous spectrum.

Furthermore, in order to improve the luminous efficiency, it is necessary to have a strong luminous spectrum near 550 nm, where the relative luminous efficiency is the best.

For high-pressure mercury lamps, this purpose is to
6 nm and 578 nm, but these spectra alone are not sufficient.

This is because the intensity of these light emissions decreases due to absorption by the phosphor itself.

In order to solve this problem, if we use phosphors that have emission peaks at 495 nm, 545 nm, and 595 nm, and phosphors that emit light in the red region, as shown in Figure 2, the light emission can be improved. The spectrum becomes as shown in FIG. 3, approaching continuous light as a whole, and both color rendering properties and luminous efficiency can be improved.

In consideration of the above facts, the present invention uses a europium-activated yttrium phosphovanadate phosphor having an emission peak in the red region of 600 to 700 nm, and a 495 to 700 nm phosphor to be coated on the outer bulb of a high-pressure mercury lamp. By using a terbium-activated yttrium aluminate phosphor that has an emission peak in the blue-green region of 600 nm, and by selecting the mixing ratio and adhesion amount of these phosphors within a specific range, color rendering properties and luminous efficiency can be improved. Furthermore, it is an object of the present invention to provide a fluorescent high-pressure mercury lamp having excellent features in terms of mechanical strength, economic efficiency, and the like.

Hereinafter, the present invention will be specifically explained with reference to the drawings.

Figure 4 shows a fluorescent high-pressure mercury lamp with a general structure.
A phosphor layer 3 is provided on the inner surface of an outer sphere 2 that houses and supports an arc tube 1.
was formed.

As the phosphors to form the phosphor layer 3 of such a fluorescent high-pressure mercury lamp, europium-activated yttrium phosphovanadate phosphor (Y(PV)04:Eu) and terbium-activated yttrium aluminate phosphor (Y3At5012:
Experiments were conducted by using Tb) in combination and changing the blending ratio and amount of adhesion.

FIG. 5 shows the relationship between the total luminous flux and the average color rendering index when a 400 W fluorescent high-pressure mercury lamp is used and the mixing ratio of both types of light bodies is changed.

According to this, when the mixing ratio of the europium-activated yttrium phosphovanadate phosphor and the terbium-activated yttrium aluminate phosphor is 1:4 or less, the average color rendering index value decreases significantly; When the ratio is 1:4 or more, the total luminous flux decreases significantly.

FIG. 6 shows the relationship between the total luminous flux and the average color rendering index when the amount of phosphor attached to the inner surface of the outer sphere is changed.

According to this, the amount of adhesion is 1.0 per ci of outer sphere inner area.
If it is less than 0■, both the total luminous flux and color rendering properties will decrease significantly,
Also 6. b. Not only does the luminous flux drop significantly, but the manufacturing cost also increases, and problems arise in terms of mechanical strength.

According to the results of the above experiments, the mixing ratio of the europium-activated yttrium phosphovanadate phosphor and the terbium-activated yttrium aluminate phosphor to be coated on the inner surface of the outer sphere is in the range of 1:4 to 4:1 by weight. is appropriate, and the amount of adhesion of both types of light bodies is the inner area of the outer sphere lcr! , 1.0 to 6.0 per
It was confirmed that the range of η was appropriate.

To explain an embodiment of the present invention, taking a 400W high-pressure mercury lamp as an example, the inner surface of its outer bulb is coated with a nilopium-activated yttrium vanadate phosphor and a terbium-activated yttrium aluminate phosphor at a weight ratio of 1/in. As a result of measuring the optical characteristics of the fluorescent high-pressure mercury lamp according to the present invention, which is coated with 3η per 1crA of the inner surface of the outer bulb at a ratio of 2:3, it was found that the high-pressure mercury lamp with no coating applied on the inner surface of the outer bulb and the inner surface of the outer bulb. Compared to a conventional fluorescent high-pressure mercury lamp coated with only europium-activated yttrium phosphovanadate phosphor, the results are shown in the table below.

As is clear from the above description, according to the present invention, the color rendering properties, luminous efficiency, etc. of a fluorescent high-pressure mercury lamp can be improved, and the present invention has great industrial utility value.

[Brief explanation of the drawing]

Figure 1 is a spectral energy distribution diagram of an ordinary high-pressure mercury lamp, Figure 2 is a spectral energy distribution diagram of a blue-green phosphor used in the present invention, and Figure 3 is a spectral energy distribution diagram of a fluorescent high-pressure mercury lamp according to the present invention. FIG. 4 is a partially cutaway side view of the same mercury lamp, and FIGS. 5 and 6 are curve diagrams showing the relationship between the mixing ratio and adhesion amount of phosphors, the total luminous flux, and the average color rendering index.

Claims (1)

[Claims] Europium-activated yttrium phosphovanadate phosphor (Y(PV)0
4:Eu) and a terbium-activated yttrium aluminate phosphor (Y3) with an emission peak at 490 to 630 nm.
AΔρ1□:Tb), the weight ratio is -b, 1:4 ~
At a ratio of 4:1, the inner surface of the outer sphere vc1 is 1.0 per crA.
~6.01nf! Fluorescent high-pressure mercury lamp characterized by coating.