JPH07169440A - Metal halide lamp - Google Patents

Abstract

PURPOSE:To provide a metal halide lamp of high efficiency and high color rendering, having a light color near black body radiation and excellent in lifetime characteristic, where a correlated color temperature of 2800-3700 K can be realized. CONSTITUTION:LanthaNoid metal halide including at least one kind of DyI3, TmI3 and HoI3, and 40-60wt% of NaI and 6-10wt% of TII with respect to the total weight of the enclosed halide are enclosed inside a light emitting tube 1. A tube wall load as lamp electric power with respect to the whole surface area of the light emitting tube 1 is set to 19-24W/cm<2>, where the lamp electric power is set to 65-75W and a correlated color temperature is set to 2800-3700K.

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.

[0002]

2. Description of the Related Art Conventionally, as a metal halide lamp having a high color rendering property and a low color temperature, one using a Sn-based halide is known. In addition, as a high color rendering metal halide lamp, one using a rare earth metal halide is known, but this has a relatively high correlated color temperature, and therefore a low color temperature of 2800 to 3700K cannot be realized. It was

[0003]

The conventional metal halide lamp using a Sn-based halide has a problem that the electrode is apt to break due to the erosion of tungsten at a low temperature portion of the electrode. Also, in order to achieve high color rendering, the vapor pressure of the halide enclosed in the arc tube must be raised sufficiently, but for that purpose, the wall load of the arc tube (W / c
m ² ) must be increased. However, when the load on the tube wall is increased too much, the arc tube swells, which causes a problem that life characteristics are deteriorated.

On the other hand, the conventional high color rendering metal halide lamp using the lanthanoid metal halide has a large proportion of light emission on the short wavelength side in the spectral distribution and a high correlated color temperature. When the vapor pressure of the metal halide in the arc tube is increased in order to lower the correlated color temperature and the vapor pressure of the metal halide in the arc tube is increased, the highly reactive lanthanoid metal halide reacts with the arc tube wall and the life characteristics deteriorate. There was a problem.

The present invention has been made in order to solve such a problem and has excellent life characteristics and a correlated color temperature of 28.
It provides high color rendering metal halide lamps that can achieve 00-3700K.

[0006]

Metal halide lamps of the problem-solving means for the present invention has electrodes on both ends, and the internal iodide dysprosium (DyI _3), iodide thulium (TmI ₃₎ and iodide holmium (HoI ₃ ), A lanthanoid metal halide containing at least one of the above), sodium iodide (NaI) in an amount of 40 to 60% by weight based on the total amount of the enclosed halide, and thallium iodide (TlI ) And a buffer gas are enclosed in an arc tube, and an outer tube containing the arc tube, and a tube wall load of the lamp power with respect to the total inner surface area of the arc tube is 19 to 24 W / cm ² . The lamp power is 65 to 75 W and the correlated color temperature is 2800 to 3700K.

[0007]

[Operation] With this configuration, the total amount of enclosed halides is almost
Since NaI occupies 1/2, the vapor pressure of NaI increases and N
The emission of the emission line spectrum of a near 589 nm and the spectrum of the molecular emission extending to the long wavelength side becomes large, and a low color temperature can be realized. When the NaI encapsulation ratio is 40% by weight or more, the correlated color temperature can be 3700K or less. Further, by setting the NaI encapsulation ratio to 60% by weight or less, the average color rendering index Ra is 80 even at the lower limit value of the lamp power and the tube wall load which is the lamp power with respect to the total inner surface area of the arc tube. The above can be done. At this time, the lanthanoid metal halide supplements the radiation on the short wavelength side, which is insufficient for the radiation from Na. In addition, TlI is for optimizing the light color to be close to the blackbody radiation locus and realizing high efficiency by the emission line spectrum around 535 nm. Originally, as the lamp light color, the light color on the black body radiation on the chromaticity coordinate diagram is preferred. If the encapsulation ratio of TlI exceeds 10% by weight, the y-coordinate becomes large and the color becomes greenish. On the other hand, when the encapsulation ratio of TlI is less than 6% by weight, the y coordinate becomes small and the color becomes pinkish. Further, the wavelength near 535 nm, which is the emission line spectrum of TlI, is close to the peak value of the relative luminous efficiency, and inclusion of TlI is an important factor for maintaining high efficiency. In other words, by setting the encapsulation ratio of TlI to 6 to 10% by weight, it is possible to realize a light color close to that of black body radiation and maintain high efficiency.

[0008] Further, by setting the tube wall load to 19 W / cm ² or more, the enclosed metal vapor pressure can be sufficiently increased,
The average color rendering index Ra can be 80 or more. On the other hand, by setting the tube wall load to 24 W / cm ² or less, the rated life is 600
The luminous flux maintenance factor at 0 hours can be 70% or more.
At this time, since the encapsulation ratio of the lanthanoid-based metal halide is smaller than in the conventional case, the reaction with the arc tube wall is suppressed, and good life characteristics are obtained.

[0009]

[Embodiment] As shown in FIG. 1, a 70 W metal halide lamp according to an embodiment of the present invention has an arc tube 1 made of quartz provided in an outer tube 2, and the outer tube 2 is filled with 50000 Pascals of nitrogen gas. Has been done. The arc tube 1 has an inner diameter of 9 mm, has electrodes (not shown) at both ends, has 10000 pascals of argon as a buffer gas, and has a composition ratio of DyI ₃ , TlI, and NaI of 37: 8: 55.
4.0 mg of halide and 14 mg of mercury are enclosed. A heat reflection film 3 made of ZrO ₂ or the like is formed on the outer surfaces of both ends of the arc tube 1, and the arc tube 1 is surrounded by a translucent tube 4. The openings at both ends of the translucent cylinder 4 are closed with metal plates 5. The arc tube 1 and the transparent tube 4 are held in the outer tube 2 by a stem wire 6. In FIG. 1, 7 is Zr-A
l getter, 8 indicates the base.

Table 1 shows the lamp voltage, initial color temperature characteristics, average color rendering index Ra, and luminous flux maintenance factor characteristics when the 70 W metal halide lamp (embodiment of the present invention) was vertically lit, in comparison with the conventional one. Show.

[0011]

[Table 1]

In the conventional Sn-based lamp, electrode breakage occurs in 2 out of 5 lamps during the life of the lamp, and in the conventional lanthanoid-based lamp, the color temperature is 4300K, and the target color temperature of the present invention is obtained. I couldn't do it. On the other hand, it was confirmed that the lamp of the present invention had a low color temperature and a high color rendering, and had excellent life characteristics.

Next, the relationship between the tube wall load, which is the lamp power, and the average color rendering index Ra with respect to the total inner surface area of the arc tube of the 65 W metal halide lamp which is an embodiment of the present invention, the tube wall load and the rated life of the 75 W metal halide lamp. Fig. 2 shows the relationship between the luminous flux maintenance factors at 6000 hours. Considering the fluctuation of power supply voltage, we examined lamps of 65W, 70W and 75W. The straight line A in FIG. 2 shows Ra of the 65 W metal halide lamp, and the straight line B shows the luminous flux maintenance factor of the 75 W metal halide lamp.

As is clear from FIG. 2, the pipe wall load is 19
When W / cm ² or more, the average color rendering index Ra becomes 80 or more even in a lamp with a lamp power of 65 W. Lamp power
For lamps of 65 W and above, the metal vapor pressure in the arc tube is 6
Since it is higher than the 5W lamp, higher color rendering can be achieved. That is, by setting the tube wall load to 19 W / cm ² or more, the average color rendering index Ra can be set to 80 or more in a lamp having a lamp power of 65 to 75 W. In addition, the pipe wall load is 24
When it is set to W / cm ² or less, the luminous flux maintenance factor becomes 70% or more at the rated life of 6000 hours even in the case of the lamp having the lamp power of 75W. For lamps with a lamp power of 75 W or less, the luminous flux maintenance factor characteristics are better than those of 75 W lamps. In other words, the wall load is 24W /
When the lamp power is 65 to 75 W, the luminous flux maintenance factor of 70% or more can be achieved at the rated life of 6000 hours by setting the cm ² or less. As described above, the lamp of the present invention has a good average color rendering index Ra and has excellent life characteristics.

FIG. 3 shows the relationship between the encapsulation ratio of NaI, the average color rendering index Ra and the correlated color temperature Tc of the 70 W metal halide lamp of the embodiment of the present invention. The encapsulation ratio of TlI at this time is constant at 8% by weight.

As is clear from FIG. 3, when the NaI encapsulation ratio is less than 40% by weight, the correlated color temperature Tc exceeds 3700K. On the other hand, when the inclusion ratio of NaI exceeds 60% by weight,
Correlated color temperature Tc is less than 2800K, average color rendering index R
a is also less than 80. That is, by setting the NaI encapsulation ratio to 40 to 60% by weight, a metal halide lamp having an average color rendering index Ra of 80 or more and a correlated color temperature Tc of 2800 to 3700K can be obtained.

FIG. 4 shows the relationship between the encapsulation ratio of TlI and the light color of the 70 W metal halide lamp according to the embodiment of the present invention. The NaI encapsulation ratio at this time was constant at 55% by weight.

FIG. 4 shows chromaticity ranges of incandescent lamp colors and warm white in fluorescent lamps, which are determined by JIS Z9112-1990.
The □ mark indicates a TlI encapsulation ratio of 10% by weight, and the O mark indicates a TlI encapsulation ratio of 6% by weight. As is clear from FIG. 4, when the encapsulation ratio of TlI exceeds 10% by weight, the temperature goes out of the chromaticity range of warm white and a greenish light color is obtained. Also, Tl
When the encapsulation ratio of I is less than 6% by weight, it goes out of the chromaticity range of the light bulb color and becomes a pinkish light color. In other words, by adjusting the TlI encapsulation ratio to 6-10% by weight, it is possible to realize a warm white color and a bulb color close to black body radiation.

[0019] In the above embodiment has described the case encapsulating DyI _3, TlI and NaI within the arc tube, instead of DyI _3, be used TmI _3, HoI _3, similar results were obtained.

[0020]

As described above, the present invention provides a high color rendering metal halide lamp of 65 to 75 W which has a correlated color temperature of light color close to black body radiation of 2800 to 3700 K and excellent life characteristics. Is something that can be done.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view of a 70W metal halide lamp according to an embodiment of the present invention.

FIG. 2 is a diagram showing the relationship between the tube wall load, which is the lamp power, the average color rendering index Ra, and the luminous flux maintenance factor at a rated life of 6000 hours, with respect to the total inner surface area of the arc tube.

FIG. 3 is a relationship diagram of NaI encapsulation ratio, average color rendering index Ra, and correlated color temperature Tc.

[Fig.4] Relationship between TlI encapsulation ratio and light color

[Explanation of symbols]

 1 luminous tube 2 outer tube 3 heat reflection film 4 translucent cylinder 5 metal plate 6 stem wire 8 base

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shingo Tsutsumi 1-1, Saiwaicho, Takatsuki City, Osaka Prefecture Matsushita Electronics Industrial Co., Ltd.

Claims (1)

[Claims] 1. A has electrodes at both ends, and the internal iodide dysprosium (DyI _3), lanthanide metal containing at least one kind of iodide thulium (TmI ₃₎ and iodide holmium (HoI ₃₎ 40 to 60% by weight sodium iodide (NaI) based on the total amount of halide and enclosed halide and 6 to 10% by weight of thallium iodide (Tl) based on the total amount of enclosed halide.
I) and a buffer gas filled with an arc tube, and an outer tube containing the arc tube, the tube wall load which is the lamp power with respect to the total inner surface area of the arc tube is 19 to 24 W / cm ² . Yes, a metal halide lamp characterized by a lamp power of 65 to 75 W and a correlated color temperature of 2800 to 3700K.