JP2003059456A - Metal halide lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal halide lamp having high efficiency and high color rendering performance, having a white light color and having a correlation color temperature of 5,000 K or less. SOLUTION: This metal halide lamp has an arc tube 1 having a pair of electrodes inside, and sealed with mercury, rare gas, and metallic halide, has a color temperature of a light emitting color of 5,000 K or less, contains dysprosium halide and indium halide as the metallic halide, sets the ratio of the indium halide to the dysprosium halide in a range of 0.02 to 0.45, and sets a tube wall load of the arc tube 1 in a range of 20 to 40 W/cm<2> .

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Recently, metal halide lamps have come to be used as a light source for not only outdoor lighting but also indoor lighting such as store lighting because they have characteristics of high efficiency and high color rendering. .

Conventionally, the average color rendering index Ra is 90 with high efficiency.
DyI ₃ -TlI-I as a metal halide lamp having the above high color rendering properties and a correlated color temperature exceeding 5000K.
It is known that a mixed iodide of nI (InI ₃ ) -CsI is used (Journal of the Lighting Society, Vol. 60, No. 1, pages 26 to 32).

[0004]

In order to use the metal halide lamp as a light source for indoor lighting, the chromaticity required for indoor lighting, that is, the correlated color temperature is 5000.
It is necessary to obtain a white light color at a relatively low color temperature below K. In order to obtain this white light color, it is necessary to bring the chromaticity point as close as possible to the black body locus.

However, in the conventional metal halide lamp, Tl is used in order to obtain high efficiency.
At a correlated color temperature of 000K or less, the chromaticity point largely deviates from the black body locus, and white reproducibility deteriorates. In order to bring this chromaticity point closer to the black body locus, the tube wall load of the arc tube should be increased, but if it is attempted to get close enough to the black body locus at a correlated color temperature of 5000 K or less, the tube wall load becomes high. Too much, Dy reacts with the quartz of the arc tube and the life characteristics are extremely deteriorated. Therefore, it has been difficult to obtain a metal halide lamp having a high efficiency, a high color rendering property, a correlated color temperature of 5000 K or less, and a white light color.

The present invention has been made to solve the above problems, and provides a metal halide lamp having a high efficiency, a high color rendering property, a white light color, and a correlated color temperature of 5000 K or less. It is a thing.

[0007]

A metal halide lamp according to the present invention has a pair of electrodes therein, an arc tube filled with mercury, a rare gas and a metal halide, and has a color temperature of 5,000 K or less. , The metal halide contains dysprosium iodide and indium iodide, and the metal halide does not contain sodium halide, and the weight ratio of the indium iodide to the dysprosium iodide is 0.
The range is from 02 to 0.45, and the tube wall load of the arc tube is from 20 to 40 W / cm ² .

[0008]

With this structure, the correlated color temperature can be set to 5000 K or less, the efficiency is high, the color rendering is high, and the light color can be white.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a metal halide lamp having a rated power of 150 W according to an embodiment of the present invention has a pair of electrodes inside, and an arc tube made of quartz in which mercury, a rare gas and a metal halide are enclosed. Have one. The distance between the electrodes of the arc tube 1 is 13.5 mm, and the maximum inner diameter of the central portion is 13 mm. A stem wire 2 and a power supply wire 3 are respectively connected to the pair of electrodes, and these electrodes are connected to the stem 4
It is connected to the pin 6 of the base 5 fixed to the end of the outer tube 9 via. The arc tube 1 is covered with a glass tube 7 and a metal plate 8 provided so as to close the openings at both ends of the glass tube 7. The arc tube 1 is provided in the outer tube 9. The metal plate 8 has a support arm 10, and the support arm 10 is in contact with the inner surface of the outer tube 9. In the arc tube 1, mercury 1
4 mg, argon 10000 Pa, DyI ₃ -TlI-
4.0 mg of a mixed iodide of CsI-InI was encapsulated,
Also in this case, DyI ₃ : TlI: CsI = 70: 1
For 0:20, the total amount of mixed iodide enclosed was not changed and D
Lamps with different ratios of yI ₃ and InI, namely In
Two types of sample lamps, one having I / DyI ₃ = 0.12 (hereinafter referred to as sample A) and one having InI / DyI ₃ = 0.34 (hereinafter referred to as sample B) were manufactured. Ra of these sample A and sample B is 95. As a comparative example, a mixed iodide containing no InI, that is, InI
A lamp with / DyI ₃ = 0 (hereinafter referred to as sample C) was also manufactured. The spectral distributions of these lamps are shown in FIGS. 2 and 3, respectively. 2 and 3, the curve A is the sample A,
The curve B shows the sample B and the curve C shows the sample C, respectively. The correlated color temperatures of these lamps were 4470K for sample A, 4120K for sample B, and 5500K for sample C at a tube wall load of 24W / cm ² .

As is clear from FIGS. 2 and 3, In
It can be seen that the emission in the vicinity of 400 to 450 nm is decreased by increasing the mixing ratio of I, and the emission in the vicinity of 600 to 700 nm which is the molecular emission of Dy is increased with the decrease. However, in this case, as a matter of course, 455n
In emission near m is observed, but the correlated color temperature does not rise. That is, the inventor found that the addition of InI, which is expected to increase the emission around 455 nm and raise the correlated color temperature, rather shows a novel phenomenon of lowering the correlated color temperature. Moreover, this phenomenon becomes remarkable when the tube wall load is increased.

Further, InI / DyI ₃ is 0.01,
Four kinds of lamps of 0.02, 0.45, and 0.50 were manufactured in the same manner as above, and the correlated color temperatures were measured by changing the tube wall load of the arc tube. The results shown in FIG. 4 were obtained. was gotten.

FIG. 4 shows the change in correlated color temperature with respect to the tube wall load of the arc tube with InI / DyI ₃ as a parameter. By increasing the tube wall load and increasing the ratio of InI / DyI ₃ , it is possible to bring the correlated color temperature to 4000 K or less. However, since increasing the tube wall load adversely affects the life characteristics, it is desirable to achieve a desired light color and color rendering property with the tube wall load as low as possible.

If the tube wall load of the arc tube is less than 20 W / cm ² , the correlated color temperature of 5000 K or less should be maintained within the range of the tube wall load having practical life characteristics even if the value of InI / DyI ₃ is changed. Cannot be achieved, and if it exceeds 40 W / cm ² , the practical limit of the life characteristics of the lamp will be exceeded. Therefore, the load on the wall of the arc tube is preferably in the range of ^{20 to} 40 W / cm ² .

As is clear from FIG. 4, InI / DyI
_{When 3} is less than 0.02, the tube wall load is 40 W / cm ²
If it is not exceeded, the correlated color temperature of 5000 K or less cannot be obtained. Therefore, in this case, since the tube wall load exceeds 40 W / cm ² , a lamp having practical life characteristics cannot be obtained. On the other hand, if the tube wall load is set to less than 20 W / cm ² , it is 500 within the range of the tube wall load that has practical life characteristics even if the value of InI / DyI ₃ is changed.
The correlated color temperature below 0K could not be obtained. Similarly, when InI / DyI ₃ exceeds 0.45, it is 5 in the range of tube wall load having practical life characteristics.
It was not possible to achieve a correlated color temperature of 000K or less.
Further, the luminous efficiency of the lamp decreases as the value of InI / DyI ₃ increases. Therefore, in order to obtain practical efficiency, the value of InI / DyI ₃ needs to be 0.45 or less.

As described above, according to the metal halide lamp of the present invention, it is possible to obtain a high luminous efficiency and a high color rendering property of Ra of 90 or more with a correlated color temperature of 5000 K or less, and practical life characteristics. It is possible to obtain a white light color that is provided and has a chromaticity close to a black body locus and is suitable for indoor lighting such as store lighting.

In the embodiment of the present invention, DyI ₃ : Tl
Although the case where the ratio of I: CsI is fixed is described, similar results were obtained with different ratios. Also, or other halides ₃ such DyBr besides DyI _3, similar results be mixed other rare earth halide.

[0018]

As described above, the metal halide lamp of the present invention has a correlated color temperature of 5000 K or less, high efficiency, high color rendering properties, practical life characteristics, and store lighting. A white light color suitable for indoor lighting can be obtained.

[Brief description of drawings]

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

FIG. 2 is also InI / DyI ₃ = 0.12 and In
Spectral distribution chart of I / DyI ₃ = 0

FIG. 3 is also InI / DyI ₃ = 0.34 and In
Spectral distribution chart of I / DyI ₃ = 0

FIG. 4 is a characteristic diagram showing a change in correlated color temperature with respect to a tube wall load.

[Explanation of symbols]

1 arc tube 2 stem line 3 power supply lines 5 mouthpiece 9 outer tube

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Fumi Nakayama             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Shingo Tsutsumi             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F-term (reference) 5C015 QQ24 QQ35 QQ58 SS03                 5C039 HH02 HH06 HH15

Claims (2)

[Claims] 1. A luminescent tube having a pair of electrodes inside and containing mercury, a rare gas, and a metal halide, and having a color temperature of emission color of 5000 K or less, and dysprosium as the metal halide. Including iodide and indium iodide, and does not include sodium halide as the metal halide, the weight ratio of the indium iodide to the dysprosium iodide in the range of 0.02 to 0.45, Moreover, the metal halide lamp is characterized in that the tube wall load of the arc tube is set in a range of ²⁰ to 40 W / cm ² . 2. The metal halide lamp according to claim 1, wherein the arc tube is a quartz arc tube.