JPH11250856A - High color rendering small metal halide lamp - Google Patents

Abstract

Abstract: PROBLEM TO BE SOLVED: To reduce the aging of a lamp voltage rise and a color temperature with time, and to eliminate an early devitrification phenomenon of a quartz glass arc tube, to provide a long life and an average color rendering evaluation of a color temperature of 3000 to 7000K. A high color rendering small metal halide lamp having a number (Ra) of 90 or more is provided. SOLUTION: An arc tube made of translucent quartz glass having an inner volume of 2 CC or less, a pair of electrodes facing inside the arc tube, and a halide of dysprosium in addition to at least mercury and a rare gas in the arc tube. And a cesium halide in the metal halide lamp, wherein the dysprosium halide and the cesium halide are mixed with each other.
It is characterized by being enclosed in a molecular composition ratio of 8:62 to 46:54.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an enclosure for a small metal halide lamp having high color rendering for indoor lighting.

[0002]

2. Description of the Related Art In recent years, when indoor lighting of a store or the like is performed,
In order to provide efficient illumination according to the place and purpose of use, a small and high color rendering metal halide lamp has been required. For example, 2500 to 3000 having a low color temperature
K can create a calm atmosphere, and a high color temperature of 6000 to 7000K can create an active outdoor atmosphere.

[0003] Such a metal halide lamp having various color temperatures can be obtained by changing an additive to be enclosed in an arc tube and utilizing an emission spectrum peculiar to the additive. Generally, a Sc-Tl-Na (scandium-thallium-sodium) -based metal halide lamp is used in a low color temperature range, and a Dy-Tl (dysprosium-thallium) -based or Dy-Nd (dis Prosium-neodymium) metal halide lamps are used.

[0004]

In order to achieve high color rendering (Ra ≧ 90) of a Dy-Tl metal halide lamp, it is necessary to enclose a large amount of Dy which emits light in the entire wavelength band of visible light. However, when the ratio of Dy is increased, the operating temperature becomes higher. When the arc tube is made of quartz glass, the reaction between Dy and quartz glass becomes faster than the recombination of Dy and halogen atoms, and the lamp becomes lighter. There is a problem that the voltage rise and the change with time of the color temperature are increased, which causes an early devitrification phenomenon of the arc tube.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in a high color rendering small metal halide in which a Dy-Tl-based additive is sealed using a quartz glass arc tube. Provided is a high color rendering small metal halide lamp which has a long life and has an average color rendering index (Ra) of not less than 90 at a color temperature of 3000 to 7000 K, which is capable of reducing the change over time and eliminating the early devitrification phenomenon of a quartz glass arc tube. The purpose is to:

[0006]

In order to solve the above-mentioned problems, an invention according to claim 1 includes a light-transmitting quartz glass luminous tube having an inner volume of 2 CC or less, and a pair of opposing insides of the luminous tube. An electrode and a metal halide lamp in which the arc tube is filled with at least mercury and a rare gas in addition to a dysprosium halide and a cesium halide, wherein the dysprosium halide and the cesium halide are 38: A high color rendering small metal halide lamp which is sealed in a molecular composition ratio of 62 to 46:54, has a lamp color temperature of 3000 to 7000 K, and has an average color rendering index (Ra) of 90 or more.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the illustrated embodiments. FIG. 1 is a block diagram showing an embodiment of the present invention. In a quartz glass arc tube 1, dysprosium (Dy), thallium (Tl) and cesium (C
s), iodide of lead (Pb), mercury and a rare gas for starting are enclosed.
Are sealed. Note that, specifically, in a 2 cc arc tube, 2.0 mg of a mixed crystal of dysprosium iodide (DyI ₃ ) and cesium iodide (CsI), 0.6 mg of thallium iodide (TlI), and 0.6 mg of iodide 0.25 mg lead (PbI ₂ ), 7 mg mercury, 6600 argon gas
Pa is enclosed.

The quartz glass sleeve 3 is held by a stainless steel sleeve auxiliary member 4 and is incorporated together with the arc tube 1 into a hard glass outer tube 5. 6 is a heat insulating film, 7 is a mixed crystal (Zr-Al) getter of zirconium and aluminum, 8 is an insulating quartz glass thin tube, 9
Denotes a filament holder, 10 denotes a ceramic heat shield plate, and 11 denotes a base. When the lamp thus configured is turned on with an input power of 150 W, the color temperature becomes 350
A high color rendering small metal halide lamp having a Ra of 95 at 0K can be obtained.

FIGS. 2 to 4 show the results of life tests of the present invention and the conventional lamp (each N = 3) when the high color rendering small metal halide lamp of the Dy-Tl system is operated at an input power of 150 W. It is shown. When the lamp of the present invention and the conventional lamp are compared on average with respect to each of the lamp voltage rise, luminous flux and color temperature after 6000 hours, the lamp voltage rise value is reduced by 57% from FIG. That the luminous flux is increased by 10% from FIG. 3,
FIG. 4 shows that the fluctuation range of the color temperature is small. Also,
FIG. 5 is a spectral distribution diagram of a lamp according to an embodiment of the present invention at the initial lighting stage. The lamp has a Ra of 95 and a color temperature of 3800K.

In the present invention, the dysprosium halide and the cesium halide are converted from 38:62 to 4
The operation of the dysprosium halide and the cesium halide in the light-transmitting quartz glass arc tube having a transmissivity of 2 CC or less is performed by enclosing with the molecular composition ratio up to 6:54. This is because the temperature can be controlled to be 600 ° C. or more and 650 ° C. or less.

Due to the above operating temperature, recombination of dysprosium and iodine during lamp operation is promoted, the reaction between dysprosium and quartz glass does not proceed, and a good light emitting mechanism is maintained. This good light emission mechanism suppresses a rise in the lamp voltage, thereby suppressing a change in color temperature and a devitrification phenomenon of the arc tube, and a lamp life of 9000 hours or more.

[0012]

As described above, according to the present invention, the operating temperature of the dysprosium halide can be reduced,
Good dysprosium light emission mechanism can be maintained, lamp voltage rise and color temperature change are small, early devitrification of the arc tube does not occur, lamp life is 9000 hours, Ra is 9
A high color rendering small metal halide lamp having a color temperature of 0 or more and a color temperature of 3000 to 7000K can be obtained. Further, by setting the molecular composition ratio, the strength of a mixed crystal of dysprosium iodide (DyI ₃ ) and cesium iodide (CsI) is increased, which is generated when the mixed crystal is handled and sealed in an arc tube. Chips and cracks are also reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention.

FIG. 2 shows a change in a lamp voltage rise value of the present invention and a conventional lamp (N = 3 each) when the lamp is lit at an input power of 150 W.

FIG. 3 shows a change in luminous flux between the present invention and a conventional lamp (each N = 3) when the lamp is lit at an input power of 150 W.

FIG. 4 shows a change in color temperature between the present invention and a conventional lamp (each N = 3) when the lamp is lit at an input power of 150 W.

FIG. 5 is a spectral distribution diagram of a lamp according to an embodiment of the present invention at the beginning of lighting.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Quartz glass arc tube 2 Electrode 3 Sleeve 4 Sleeve auxiliary material 5 Outer tube 6 Thermal insulation film 7 Getter 8 Insulated quartz glass tube 9 Filament holder 10 Heat shield plate 11 Base

Claims (1)

[Claims] 1. An arc tube made of translucent quartz glass having an internal volume of 2 cc or less, a pair of electrodes facing the arc tube, and a halogen of dysprosium in addition to at least mercury and a rare gas in the arc tube. A metal halide lamp in which a halide of cesium and a cesium halide are sealed.
A high color rendering small metal halide lamp which is enclosed in a molecular composition ratio of 8:62 to 46:54, has an average color rendering index (Ra) of 90 or more, and has a color temperature of 3000 to 7000K.