JP2005302624A - High pressure vapor discharge lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high pressure vapor discharge lamp more enhancing efficiency without damaging an advantage such as high color rendering and long life of an existing lamp in a metal vapor discharge lamp using existing translucent ceramics having high color rendering and long life as an arc tube. <P>SOLUTION: In an arc tube comprising translucent ceramics in which a narrow tube in which an electrode is inserted into both ends and a light emitting part are molded in one body, the thickness t (mm) of the arc tube between electrodes is made 0.4≤t≤1.0, a tube wall load of the arc tube is made 22.1-29.8 W/cm<SP>2</SP>, and when the distance between electrodes is represented by L1 (mm), the maximum inner diameter of the arc tube between the electrodes is represented by D1 (mm), and the minimum inner diameter is represented by D2 (mm), the following relation is satisfied. D1/L1≤1.50 and D2/L1≥1.00. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a metal halide lamp using translucent ceramics as an arc tube material.

In recent years, many lamps using translucent alumina instead of quartz as an arc tube material have been commercialized. Translucent alumina has higher heat resistance and corrosion resistance than quartz. For this reason, by increasing the tube wall load of the arc tube and optimizing the encapsulated additive, high efficiency, high color rendering, and long life have been obtained. However, recently, higher efficiency has been demanded from the viewpoint of energy saving.
JP 2003-86130 A JP 2003-86131 A Japanese Patent No. 3444899

In a lamp using a light emitting tube made of translucent polycrystalline alumina, when the tube wall load of the light emitting tube is increased in order to achieve high efficiency while maintaining high color rendering (Ra 90 or more), the addition enclosed when the lamp is turned on The vapor pressure of an object will rise too much, resulting in a reduction in efficiency.
When an additive that contributes to efficiency, such as Ce, is used for the luminescent metal sealed in the arc tube, the efficiency can be increased, but the color rendering property is lowered.
Therefore, when trying to increase the efficiency by reducing the thickness of the light emitting part of the arc tube, the arc tube made by burning a disk and a thin tube at both ends of a conventional cylindrical light emitting part, During lighting, cracks occur in the shrink-fitted portion between the light emitting portion and the disc portion, resulting in arc tube leakage and a short life.
The present invention relates to a metal vapor discharge lamp using conventional translucent ceramics having high color rendering and long life as an arc tube material, and does not impair the advantages of the conventional lamp of high color rendering and long life, and further increases the efficiency. An object is to provide a steam discharge lamp.

In order to solve the above-mentioned problems, the present invention provides a luminous tube made of translucent ceramics in which a thin tube having electrodes inserted at both ends and a light emitting part are integrally molded, and the thickness t [mm] of the luminous tube between the electrodes. 0.4 ≦ t ≦ 1.0, the tube wall load of the arc tube is in the range of 22.1 to 29.8 W / cm ² , the distance between the electrodes is L1 [mm], and the maximum of the arc tube between the electrodes When the inner diameter is D1 [mm] and the minimum inner diameter is D2 [mm], D1 / L1 ≦ 1.50 and D2 / L1 ≧ 1.00.
The arc tube is filled with at least one of Dy, Ho or Tm halides and Na and Tl halides.
The tube wall load referred to here is the lamp power / the total inner surface area of the light emitting portion, and the boundary between the light emitting portion and the thin tube portion is the inner diameter of the boundary portion = the inner diameter of the narrow tube end × 1.1. To do.

As described above, in the arc tube having the tube wall load in the range of 22.1 to 29.8 W / cm ² made of the translucent ceramic in which the thin tube and the light emitting portion are integrally molded, the thickness of the arc tube between the electrodes is increased. When the thickness is t [mm], the distance between the electrodes is L1 [mm], the maximum inner diameter of the arc tube between the electrodes is D1 [mm], and the minimum inner diameter is D2 [mm], 0.4 ≦ t ≦ 1. 0, D1 / L1 ≦ 1.50 and D2 / L1 ≧ 1.00 are satisfied, and at least one of Dy, Ho or Tm halides and Na and Tl halides are sealed in the arc tube. As a result, arc tube cracks, rapid light flux reduction, disappearance, etc. do not occur, and higher efficiency (100 lm / W or more) can be obtained while maintaining high color rendering (Ra 90 or more).

Embodiments of the present invention will be specifically described below with reference to the drawings.
FIG. Is a metal halide lamp having an arc tube in which a light emitting portion made of translucent polycrystalline alumina having a rated power consumption of 150 W according to the present invention and thin tubes provided at both ends thereof are integrally molded.
FIG. FIG. 3 is a cross-sectional view of an arc tube having a tube wall load of 26 W / cm ² according to the present invention, and FIG. 3 is an enlarged view of the light emitting portion thereof. A pair of electrodes are arranged in the arc tube having an inner volume of 1.3 cm ³ so that the arc length L1 = 10 mm, and halides such as Hg, Dy, Ho, Tm, Na, and Tl are contained as an enclosure together with a rare gas. It is enclosed. The maximum inner diameter of the arc tube between the electrodes is D1 = 11.7 mm, the minimum inner diameter is D2 = 10.4 mm, and the thickness t of the arc tube between the electrodes is 0.4 to 1.0 mm.
At this time, the lamp characteristics were an efficiency of 103 lm / W, an average color rendering index Ra = 93, and no arc tube cracking occurred during lamp operation.

Next, the lamp power was measured in the range of 120 to 180 W using the arc tube. The results are shown in Table 1.

From the results in Table 1, a graph was created with the tube wall load on the X-axis and the efficiency on the Y-axis (FIG. 4), and the following approximate expression could be derived.
Formula 1. Y = −0.1498X ² + 7.5945X + 6.8
Further, when a graph was created with the tube wall load as the X axis and Ra as the Y axis (FIG. 5), the following approximate expression could be derived.
Formula 2. Y = −0.7693X + 73
As described above, it is understood from the two formulas that the tube wall load should be set in the range of 22.1 to 29.8 W / cm 2 in order to obtain lamp characteristics with an efficiency of 100 lm / W or more and an average color rendering index Ra of 90 or more. .

Next, the same experiment was conducted for a 70 W class lamp. In the arc tube having an inner volume of 0.4 cm ³ , a pair of electrodes are arranged so that the arc length L1 = 6 mm, and halides such as Hg, Dy, Ho, Tm, Na, and Tl are contained as an enclosure together with a rare gas. It is enclosed. The maximum inner diameter of the arc tube between the electrodes is D1 = 8.5 mm, the minimum inner diameter is D2 = 7.7 mm, and the thickness t of the arc tube between the electrodes is 0.4 to 1.0 mm. Using this arc tube, lamp power was measured in the range of 50-90W. The results are shown in Table 2.

From the results in Table 2, a graph was created with the tube wall load on the X axis and the efficiency on the Y axis (FIG. 6), and the following approximate expression could be derived.
Formula 3. Y = −0.1503X ² + 7.6091X + 6.8
In addition, a graph was created with the tube wall load as the X axis and Ra as the Y axis (FIG. 7), and the following approximate expression could be derived.
Formula 4. Y = −0.7339X + 73.8
As described above, in order to obtain a lamp characteristic with an efficiency of 100 lm / W or more and an average color rendering index Ra90 or more from the two formulas, the tube wall load may be set in the range of 22.1 to 29.8 W / cm 2, as with 150 W. I understand that.

In addition, with respect to the arc tube, a tube with a thick and thin arc tube between the electrodes was made as a prototype and measured at a lamp power of 150 W. When the wall thickness t was greater than 1.0 mm, the efficiency was lower than 100 lm / W at a tube wall load of 26 w / cm ² . Further, when the wall thickness t is less than 0.4 mm, the efficiency is increased, but arc tube cracks are generated during lamp operation.
In addition, when the relationship between the maximum inner diameter of the arc tube between the electrodes and the distance between the electrodes is D1 / L1> 1.5, the temperature of the inner wall of the arc tube when the lamp is turned on is lowered, the inner wall of the arc tube is blackened, The lamp extinguishes due to a drop or a rise in lamp voltage, resulting in a short life.
When the relationship between the minimum inner diameter of the arc tube between the electrodes and the distance between the electrodes is D2 / L1 <1.0, the metal halide enclosed in the arc tube reacts with the inner wall of the arc tube during lamp operation. When it became severe, the intensity of the eroded portion was weakened and arc tube cracking occurred.

From the above results, in the arc tube made of translucent ceramics in which the thin tube and the light emitting part are integrally molded,
When the thickness of the arc tube between the electrodes is t [mm], 0.4 ≦ t ≦ 1.0, the tube wall load of the arc tube is in the range of 22.1 to 29.8 W / cm ² , and When the distance between the electrodes is L1 [mm], the maximum inner diameter of the arc tube between the electrodes is D1 [mm], and the minimum inner diameter is D2 [mm]
D1 / L1 ≦ 1.50 and D2 / L1 ≧ 1.00
By satisfying the above conditions, a lamp having excellent characteristics such as high color rendering (Ra 90 or more) and high efficiency (100 lm / W or more) could be obtained without causing arc tube cracks or large changes in light color.

1 is an external view of a ceramic metal halide lamp having an arc tube in which a thin tube and a light emitting portion according to the present invention are integrally formed. FIG. It is sectional drawing of the ceramic arc tube by which the thin tube concerning this invention and the light emission part were shape | molded integrally. FIG. 3 is an enlarged sectional view of a light emitting portion of a ceramic arc tube in which a thin tube and a light emitting portion according to the present invention are integrally formed. It is a graph which shows the relationship between the tube wall load and efficiency in a 150 W class lamp. It is a graph which shows the relationship between the tube wall load and the average color rendering index in the lamp of 150W class. It is a graph which shows the relationship between tube wall load and efficiency in a 70 W class lamp. It is a graph which shows the relationship between the tube wall load and the average color rendering index in the lamp of 70W class.

Explanation of symbols

1. Outer tube 2. 2. base Stem 4a. Post 4b. Support column 5, arc tube 6. Arc tube sleeve 7a. Electrode system 7b. Electrode system

Claims (2)

In a light emitting tube having a thin tube with electrodes inserted at both ends, the light emitting part is made of translucent ceramics, and the thin tube and the light emitting unit are integrally molded,
When the thickness of the arc tube between the electrodes is t [mm],
0.4 ≦ t ≦ 1.0,
Wall loading of the arc tube is in a range of 22.1~29.8W / cm ^2, and,
When the distance between the electrodes is L1 [mm], the maximum inner diameter of the arc tube between the electrodes is D1 [mm], and the minimum inner diameter is D2 [mm]
D1 / L1 ≦ 1.50 and D2 / L1 ≧ 1.00
A metal vapor discharge lamp characterized by that. 2. The metal vapor discharge lamp according to claim 1, wherein at least one of Dy, Ho or Tm halides and Na and Tl halides are sealed in the arc tube.

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