JP2003217508A - Light emitting tube for lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting tube for a lamp with high reliability using translucent ceramics as an envelope of which, the characteristics in relation with the light emitting substance enclosed in the envelope is made clear. <P>SOLUTION: For the light emitting tube for a lamp having an envelope 1 made of translucent ceramics, in which, light emitting substance emitting light by the discharge generated between a pair of electrodes is enclosed, the light emitting substance contains at least one compound chosen from dysprosium halide, holmium halide, and erbium halide; indium halide, cesium halide, and neodymium halide, and the ratio of neodymium halide to the total volume of dysprosium halide, holmium halide, and erbium halide is set less than 45 mol%. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arc tube for a lamp, which is formed by enclosing a light emitting substance which emits light by a discharge between a pair of electrodes in an envelope formed of translucent ceramic.

[0002]

2. Description of the Related Art An arc tube for a lamp used in a metal halide lamp (hereinafter sometimes simply referred to as "arc tube")
Conventionally, as the light-transmitting envelope, a quartz-made envelope has been mainly used, but the development of a light-transmitting ceramic envelope is also in progress. The envelope made of translucent ceramic is
Compared with a quartz envelope, it is less likely to react with the enclosed luminescent material, and therefore the envelope can be made compact. In addition, an arc tube for a lamp that uses an envelope made of translucent ceramic emits light using an envelope made of quartz in relation to the type of the luminescent material enclosed in the envelope. It has different characteristics than the tube.

[0003]

However, since there are various choices of the luminescent material to be enclosed in the envelope,
The characteristics of the envelope formed of translucent ceramics and the luminescent material enclosed in the envelope have not been sufficiently elucidated. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an arc tube for a lamp using a translucent ceramic in an envelope, in relation to a luminescent substance enclosed in the envelope. To clarify the characteristics,
The point is to provide a highly reliable arc tube for a lamp.

[0004]

By providing the structure according to claim 1, a light emitting substance which emits light by discharge between a pair of electrodes is enclosed in an envelope formed of translucent ceramic. In the arc tube for a lamp configured as described above, the luminescent material contains at least one of dysprosium halide, holmium halide and erbium halide, and indium halide, cesium halide and neodymium halide, The ratio of neodymium halide to the total amount of dysprosium halide, holmium halide and erbium halide is set to 45 mol% or less.

At least one of dysprosium halide, holmium halide and erbium halide, and indium halide, cesium halide and neodymium halide are used as the light-emitting substance enclosed in the envelope of the arc tube for a lamp. Those including and have already been developed in the case of using a quartz envelope.
By encapsulating such a material as a luminescent substance, an arc tube having a color temperature of around 6000 K and good color rendering can be manufactured. In the material forming the above-mentioned luminous substance, the main effect of containing neodymium halide is to improve the lamp efficiency. On the other hand, in the case of a so-called horizontal lighting type in which the arc tube is used in a horizontal posture, The arc of the discharge is curved upward, and the arc approaches the envelope, which causes the temperature of the envelope to rise. Further, the indium halide has a function of lowering the temperature of the arc of the discharge inside the arc tube.

When the envelope of the arc tube for a lamp is made of quartz and the above-mentioned material is included in the luminescent material, the influence of neodymium halide will be explained by the curve of the arc in the arc tube. It was understood that the vessel swelled to some extent, and the bulge could be reduced by adding indium halide, and it was not considered to be a factor that causes fatal damage to the arc tube. However, the inventor of the present invention has found that when the envelope of the arc tube for a lamp is formed of translucent ceramic and the above-mentioned materials are included in the light emitting substance, the light emitting tube is turned on depending on the composition ratio of the light emitting substance. The operation may cause fatal damage such as cracking of the arc tube. Whether or not such damage is caused depends on the ratio of neodymium halide to the total amount of dysprosium halide, holmium halide and erbium halide. We have found that we are dependent. The ratio of neodymium halide to the total amount of dysprosium halide, holmium halide and erbium halide is understood as one of the parameters that determines the color temperature of the light emitted by the arc tube for the lamp. It was not recognized as a parameter that affects the cracking of the arc tube for lamps.

Based on the above findings, the inventor of the present invention has found that the ratio of neodymium halide to the total amount of dysprosium halide, holmium halide and erbium halide and the damage to the arc tube due to the lighting operation of the arc tube. As a result of investigating the relationship with the occurrence of the
It was confirmed that the damage to the arc tube due to the lighting operation of the arc tube can be prevented by setting the content to be mol% or less. As described above, in the arc tube for a lamp using the translucent ceramic in the envelope, the characteristics in relation to the light emitting substance sealed in the envelope are clarified, and the arc tube for the lamp having high reliability is provided. We have been able to provide it.

Further, by providing the structure according to claim 2, the ratio of neodymium halide to the total amount of dysprosium halide, holmium halide and erbium halide is set to 25 mol% or less. . That is, the inventor of the present invention has found that the ratio of neodymium halide to the total amount of dysprosium halide, holmium halide and erbium halide is also related to the luminous flux maintenance factor, and the ratio is 2
It has been found that when the content exceeds 5 mol%, the luminous flux maintenance factor tends to decrease.

Therefore, from the viewpoint of preventing the damage of the arc tube due to the lighting operation of the arc tube and preventing the reduction of the luminous flux maintenance factor, the ratio of neodymium halide to the total amount of dysprosium halide, holmium halide and erbium halide. It has been possible to provide an arc tube for a lamp, which is capable of obtaining a good luminous flux maintenance rate without damaging the arc tube by setting the ratio to 25 mol% or less. The luminous flux maintenance factor is the ratio (%) of the luminous flux of the light emitted from the arc tube to the luminous flux at the initial lighting, and how much luminous flux of the luminous tube is based on the luminous flux at the initial lighting as the lighting time elapses. Is a quantity that indicates whether or not is maintained.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a lamp arc tube according to the present invention will be described below with reference to the drawings. [Configuration of Lamp Arc Tube LT] The lamp arc tube LT (hereinafter sometimes simply referred to as “arc tube LT”) is shown in FIG.
As shown in FIG. 2, a pair of electrodes 2 are hermetically sealed with a brazing material 3 on an envelope 1 made of translucent ceramic. A halide and mercury are enclosed, and, for example, argon is enclosed as a buffer gas. In the arc tube LT, discharge is generated by applying a high voltage between the pair of electrodes 2, and the light emitting substance emits light by the discharge between the pair of electrodes 2. More specifically, the metal halide enclosed in the envelope 1 is
At least one of dysprosium halide, holmium halide and erbium halide, and indium halide, cesium halide and neodymium halide. Dysprosium halide, holmium halide and erbium halide all have similar emission spectra and other characteristics as a luminescent substance, and any one of them may be used. You may use it combining suitably.

The envelope 1 of the present embodiment comprises a thick tube portion 1b for forming a discharge space and thin tube portions 1a arranged on both sides of the thick tube portion 1b for inserting electrodes 2 therein. In this embodiment, translucent alumina among translucent ceramics is used as the material. In the thin tube portion 1a,
A spacer 7 is arranged to fill a space between the inner wall of the thin tube portion 1a and the electrode 2. The material of the spacer 7 is the same as the material of the envelope 1. As illustrated in FIG. 2, the arc tube LT having the above-described configuration is enclosed in an outer bulb 4 made of hard glass together with, for example, nitrogen gas to form a lamp LP called a so-called HID lamp. Note that FIG. 2 illustrates a lamp shape including the base 5. Note that the lamp LP of the present embodiment is premised on being used in a substantially horizontal posture, and the arc tube LT is designed as a horizontal lighting arc tube.

In the arc tube LT having the above structure, the electrode 2 is inserted into the thin tube portion 1a of the envelope 1 together with the spacer 7 and then the electrode 2
The brazing filler metal 3 formed in an appropriate dosage form is held in the sealing position of the brazing filler metal in the heating furnace, and the heating light is irradiated to the sealing filler to melt the brazing filler metal 3. The electrode 2 is sealed.
The heating light may be laser light or light from a heating lamp condensed by a mirror, and the brazing material 3 may be, for example, Al ₂ O ₃ —SiO ₂ —Dy ₂ O ₃ based sealing glass. Good. The pair of electrodes 2 are sequentially heat-sealed, but when the electrodes 2 are sealed for the second time, the electrodes 2 are sealed in an argon gas atmosphere as the buffer gas.

As described above, the luminescent substance to be put into the envelope 1 in the manufacturing process of the arc tube LT is at least one of dysprosium halide, holmium halide and erbium halide and indium halide. , Metal halides with cesium halides and neodymium halides and mercury. The composition ratio of these luminescent materials is set such that the ratio of neodymium halide to the total amount of dysprosium halide, holmium halide and erbium halide is 45 mol% or less from the viewpoint of preventing damage to the arc tube during lighting operation. Has been done. When the luminous flux maintenance factor is further improved, the ratio of neodymium halide to the total amount of dysprosium halide, holmium halide and erbium halide is set to 25 mol% or less. In addition to improving the luminous flux maintenance factor, the correlated color temperature, which is strongly demanded by the market as a lighting for camera photography such as studio lighting, is 55
When constructing a lamp of 00K or more, the ratio of neodymium halide to the total amount of dysprosium halide, holmium halide and erbium halide is set to 15 mol% or more.

Hereinafter, the rationale for setting the ratio of neodymium halide to the total amount of dysprosium halide, holmium halide and erbium halide in such a range is as follows: dysprosium halide, holmium halide and erbium halide. The case where dysprosium halide is used will be described as an example. The ratio of neodymium halide to the total amount of dysprosium halide contained in the luminescent material is 15 mol%, 25 mol%, 45 mol% and 6
Arc tube L during light emitting operation when changed to 0 mol%
With or without T damage and 90 in a predetermined lighting cycle
The measurement results of the luminous flux maintenance factor after lighting for 00 hours are shown in Tables 1 and 2. Table 1 shows the ratio of the total amount of rare earth halides to the volume of the arc tube LT as 6.5 (μmol /
cm ³ ), and the results are shown in Table 2.
The ratio of the total amount of rare earth halides to the volume of
The results are for 9.7 (μmol / cm ³ ),
All of them exemplify the characteristics of iodide as an example of halide.

As another change parameter, the ratio of indium halide (specifically, indium iodide) to the total amount of rare earth halide is 10 mol.
% And 30 mol%, and with the indium halide ratio set to 10 mol%, the ratio of cesium halide (specifically, cesium iodide) to the total amount of rare earth halides is 50 mol%, 75 m
It is changed to ol% and 100 mol%. Table 1
In Table 2, for reference, when the ratio of neodymium halide to the total amount of dysprosium halide is 0 mol% and when the ratio of indium halide to the total amount of rare earth halide is 0 mol%.
The measurement result when it is set to% is also shown. Further, in Tables 1 and 2, as the measurement results of the characteristics other than the luminous flux maintenance factor, the lamp efficiency is indicated in the item “efficiency”, the correlated color temperature is indicated in the item “color temperature”, and the item “Ra” is indicated in the item “Ra”. The average color rendering index is also shown.

[0016]

[Table 1]

[Table 2]

As is clear from Tables 1 and 2, when the ratio of neodymium halide to the total amount of dysprosium halide is 45 mol% or less under the condition that the light emitting substance contains indium halide. While there is no damage (damage) to the pipe LT,
When the ratio of neodymium halide to the total amount of dysprosium halide is 60 mol%, the luminous tube LT
Are all damaged. Next, based on the data in Tables 1 and 2, the ratio of indium halide to the total amount of rare earth halide was set to 10 mol% and the ratio of cesium halide to the total amount of rare earth halide was set to 50 mol%. In case of 9000
FIG. 3 shows the relationship between the luminous flux maintenance factor at the time of lighting and the ratio of neodymium halide to the total amount of dysprosium halide.

As is apparent from FIG. 3, when the ratio of neodymium halide to the total amount of dysprosium halide exceeds 25 mol%, the luminescence maintenance rate decreases. Further, when the ratio of neodymium halide to the total amount of dysprosium halide is less than 15 mol%, the emission retention rate is significantly decreased, and the ratio of neodymium halide to the total amount of dysprosium halide is 15 mol%. %, The correlated color temperature is about 550
When the temperature becomes 0K or higher, a lamp suitable for lighting at the time of taking a photograph can be provided to meet the demand from the market. Table 1
And the data shown in Table 2 exemplify the data of iodide as an example of halide, and only the data of dysprosium halide among dysprosium halide, holmium halide and erbium halide are illustrated. However, it shows the same tendency as described above for other halides, and when holmium halide or erbium halide is used instead of dysprosium halide, dysprosium halide,
The same tendency is exhibited when holmium halide and erbium halide are used in an appropriate combination.

From the above, from the viewpoint of preventing damage to the arc tube during the lighting operation, the ratio of neodymium halide to the total amount of dysprosium halide, holmium halide and erbium halide is set to 45 mol% or less. Further, when the luminous flux maintenance factor is further improved, the ratio of neodymium halide to the total amount of dysprosium halide, holmium halide and erbium halide is set to 25 mol% or less to further improve the luminous flux maintenance factor. In addition, when a lamp having a correlated color temperature of 5500 K or more is formed, the ratio of neodymium halide to the total amount of dysprosium halide, holmium halide and erbium halide is 15 mo.
It is set to 1% or more. Incidentally, the ratio of indium halide to the total amount of rare earth halides is most preferably set to around 10 mol% in view of the lamp efficiency and the luminous flux maintenance factor.

[0020]

According to the structure of the first aspect, in the arc tube for a lamp having the envelope formed of the translucent ceramic, whether or not the arc tube is damaged during the lighting operation of the arc tube. Is dependent on the ratio of neodymium halide to the total amount of dysprosium halide, holmium halide and erbium halide, the total amount of dysprosium halide, holmium halide and erbium halide is based on the finding that By setting the ratio of neodymium halide to 45 mol% or less, it has become possible to provide a highly reliable arc tube for a lamp. Further, according to the structure of the above-mentioned claim 2, from the viewpoint of preventing damage to the arc tube due to lighting operation of the arc tube and preventing reduction in luminous flux maintenance rate, dysprosium halide, holmium halide and erbium halide. By setting the ratio of neodymium halide to the total amount of 25 mol% or less, it has become possible to provide an arc tube for a lamp that does not damage the arc tube and can obtain a good luminous flux maintenance factor.

[Brief description of drawings]

FIG. 1 is a partial sectional view of an arc tube for a lamp according to an embodiment of the present invention.

FIG. 2 is a lamp according to an embodiment of the present invention.

FIG. 3 is a diagram showing a measurement result of a luminous flux maintenance factor according to the embodiment of the present invention.

[Explanation of symbols]

1 envelope

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yasaburo Takeji             No. 1 Inobaba-cho, Nishinosho, Kichijoin, Minami-ku, Kyoto-shi               Within Japan Battery Co., Ltd. (72) Inventor Jiro Honda             No. 1 Inobaba-cho, Nishinosho, Kichijoin, Minami-ku, Kyoto-shi               Within Japan Battery Co., Ltd. F-term (reference) 5C015 QQ20 QQ24 QQ25 QQ26 QQ32                       RR05

Claims (2)

[Claims] 1. An arc tube for a lamp, which is configured by enclosing a luminescent substance that emits light by a discharge between a pair of electrodes in an envelope formed of translucent ceramic, wherein the luminescent substance is: At least one of dysprosium halide, holmium halide and erbium halide, and indium halide, cesium halide and neodymium halide are included, and dysprosium halide, holmium halide and erbium halide are included. An arc tube for a lamp, wherein the ratio of neodymium halide to the total amount is set to 45 mol% or less. 2. The arc tube for a lamp according to claim 1, wherein the ratio of neodymium halide to the total amount of dysprosium halide, holmium halide and erbium halide is set to 25 mol% or less.