JP2003068248A - Non-mercury metal halide lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-mercury metal halide lamp that has electrodes and forms a narrow arc. SOLUTION: The non-mercury metal halide lamp comprises a light emission tube 1, in which a pair of electrodes 3, 3 faces each other, where a rare gas and a zinc-halogen compound 7 are included, but mercury is not included, inside of the light emission tube 1.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a mercury-free metal halide lamp. Particularly, it relates to a lamp for a point light source used in combination with a reflecting mirror or the like.

[0002]

2. Description of the Related Art Metal halide lamps in which a metal halide is enclosed in an arc tube are becoming popular as lamps for general lighting and automobile headlights. Conventional metal halide lamps include a lamp having an electrode inside the arc tube (hereinafter referred to as “electrode type lamp”) and a lamp having no electrode inside the arc tube (hereinafter referred to as “electrodeless lamp”).

As a concrete example of a conventional electrode type metal halide lamp, for example, there is one disclosed in JP-A-57-92747. The electrode type lamp disclosed in the publication has a rare gas, mercury, sodium halide, and, for example, a cerium halide in the arc tube. It is described in the publication that high luminous efficiency and white light characteristics can be realized thereby.

A specific example of the conventional electrodeless metal halide lamp is, for example, Japanese Patent Laid-Open No. 1-1320.
There is one disclosed in Japanese Patent No. 39. The electrodeless lamp disclosed in the publication has sodium halide, cerium halide and xenon in the arc tube. It is described in the publication that white light can be emitted from the lamp.

[0005]

However, it has been found that the conventional lamp has a problem that the width of the arc becomes thick. If the width of the arc is large, a metal halide lamp that does not meet the standard may be created. For example, in a metal halide lamp for an automobile headlight, a standard is defined for an arc width, and therefore, it is necessary to set an arc width within a range defined by the standard.

At the Japan Light Bulb Industry Association, the Japan Light Bulb Industry Association standard, HID light source for automobile headlights (JEL215)
When the relative brightness distribution in the center cross section of the arc (center position between electrodes) is measured, the width of the brightness value of 20% of the maximum value is defined as the width of the arc, and the width of the arc is 1.10 mm. It must be within ± 0.40 mm. This standard, when the lamp is incorporated into the lamp,
This is for performing light distribution control.

According to Japanese Patent Laid-Open No. 57-92747,
It is stated that an electrode-type lamp having a rare gas, mercury, a halide of sodium (Na), and a halide of cerium (Ce) can realize a stable and stable discharge arc. Therefore, the inventor of the present application manufactured a lamp according to the publication. The manufactured lamp has mercury of 0.65 mg, Na halide of 0.16 mg, and halogen Ce of 0.2 in an arc tube having an internal volume of 0.025 cc.
mg encapsulated. When this lamp was turned on with power consumption of 35 W, the width of the arc was 1.8 mm. This is far outside the standard. That is, C
The electrode type metal halide lamp containing the halide of e and mercury has a problem that the width of the arc becomes thick.

The electrodeless lamp disclosed in Japanese Patent Laid-Open No. 1332039/1990 has a problem that an arc spreads over the entire arc tube. This is a characteristic of the electrodeless lamp, and the size of the arc tube is directly the size of the arc. Although attempts are being made to reduce the size of the arc tube, downsizing of the arc tube is difficult due to problems such as breakage of the lamp, and the attempt is still not sufficient. For example, when the same energy as that disclosed in this publication is applied to a smaller arc tube than that disclosed in that publication, the temperature of the arc tube rises excessively, and as a result, after lighting. It was confirmed by an experiment conducted by the inventor of the present invention that it bursts in several hours. Therefore, in the electrodeless metal halide lamp, in order to combine with a reflecting mirror or the like, when a light source that is very close to a point light source is desired, there arises a problem that its use becomes difficult.

Recently, environmental problems have been emphasized, and a metal halide lamp containing no mercury is desired in consideration of the global environment at the time of disposal. Japanese Patent Laid-Open No. 1-132039
The electrodeless type lamp disclosed in the publication is a mercury-free metal halide lamp, but as described above, it is very difficult to realize a point light source because it is an electrodeless type.

The present invention has been made in view of the above points, and its main object is to provide a mercury-free metal halide lamp having a narrow arc width.

[0011]

A mercury-free metal halide lamp according to the present invention comprises an arc tube having a pair of electrodes facing each other in the tube, and the arc tube contains a rare gas and a halide of zinc. And does not contain mercury.

In one embodiment, the arc tube further contains at least one of a scandium halide and a sodium halide.

[0013] In one embodiment, the total amount of halides enclosed in the arc tube is 0.2 mg / cc or more and 15 mg / cc in a value per 1 cc of the arc tube inner volume.
It is cc or less.

In one embodiment, the rated power of the mercury-free metal halide lamp is set to 25 W or more and 55 W or less.

In one embodiment, the rare gas contains at least Xe (xenon), and the filling pressure of the rare gas is 0.1 MPa or more and 2.5 MPa or less at room temperature.

[0016] In one embodiment, means for applying a magnetic field to the arc tube is further provided.

The mercury-free metal halide lamp is preferably a lamp for a point light source.

A mercury-free metal halide lamp according to an embodiment includes an arc tube having a pair of electrodes facing each other in the tube, and a rare gas, a cerium halide, a zinc halide, and an aluminum halogen lamp are contained in the arc tube. And at least one selected from the group consisting of indium bromide and indium bromide, and free of mercury.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The inventor of the present invention has conducted extensive studies to develop an electrode-free mercury-free metal halide lamp having a narrow arc width, and as a result, succeeded in completing such a mercury-free metal halide lamp. did.

Embodiments according to the present invention will be described below with reference to the drawings. In the following drawings, for simplification of description, components having substantially the same function are designated by the same reference numeral. The present invention is not limited to the embodiments below.

A mercury-free metal halide lamp according to an embodiment of the present invention will be described. FIG. 1 schematically shows the cross-sectional structure of the mercury-free metal halide lamp of this embodiment.

The lamp of the present embodiment is provided with an arc tube 1 having a pair of electrodes (3, 3) facing each other in the tube. A pair of sealing parts 2 for hermetically sealing the arc tube 1 extend from the arc tube 1, and the electrode 3 is connected to a lead wire 5 made of molybdenum via a metal foil 4 in the sealing part 2. It is connected. In other words, the electrode 3 is electrically connected to one end of the molybdenum foil 4 sealed by the sealing part 2,
It is electrically connected to the lead wire 5 connected to the other end of the molybdenum foil 4.

The electrode 3 is a tungsten electrode composed of tungsten (the diameter of the electrode rod is about 0.25 mm), and the tip of the electrode 3 has a distance between the tips (that is, a distance between the electrodes) of about 3. It is arranged in the arc tube 1 so as to be 7 mm. The arc tube 1 is made of quartz glass, and the internal volume of the arc tube 1 is about 0.025 cc. Inside the arc tube 1, about 0.2 mg of cerium iodide (CeI ₃ ), about 0.19 mg of scandium iodide (ScI ₃ ) and about 0.16 mg of sodium iodide (N 3
aI) and a halide 7, which is not shown in the figure, and xenon gas (Xe) of about 1.4 MPa at room temperature. However, mercury is not enclosed in the arc tube 1.

This lamp is lit so that the straight line connecting the electrodes is substantially horizontal. That is, it is lit horizontally.
It should be noted that the lighting may be performed vertically or obliquely. In this embodiment, the lighting power is 35W. A major difference in structure between the conventional electrode-type metal halide lamp and the metal halide lamp of the present embodiment is that the metal halide lamp of the present embodiment does not contain mercury.

Surprisingly, the electrode-free type mercury-free metal halide lamp of the present embodiment is a halogenated Ce.
Despite the fact that it is a lamp with a sealed lamp, it has a narrow arc width and high brightness. Here, a method of measuring the arc width and the arc brightness will be described with reference to FIG.

FIG. 2 schematically shows the structure of a measuring device for measuring the arc width and the arc brightness. The measuring lamp 20 is electrically connected to a ballast and a power supply (21) for operating the lamp. Lamp 20
Of the CC through the filter 22 provided near the arc tube of
The D camera 23 photographs the arc of the lamp 20, and the image captured by the CCD camera 23 is displayed on the monitor 24.

The width of the arc was measured according to the Japan Light Bulb Industry Association Standard (JEL215) for HID light sources for automobile headlights. The arc width defined by the Japan Light Bulb Association (JEL215) is the width of 20% of the maximum brightness value when the relative brightness distribution of the arc in the central cross section of the arc (center position between electrodes) is measured.

FIG. 3 shows an example of the luminance distribution of the arc. The vertical axis in FIG. 3 represents the ratio of the maximum luminance of the arc, and the horizontal axis represents the arc position. In general, the brightness of the arc is highest at the center cross section (center position between the electrodes) of the arc, and is substantially symmetrical with respect to the center cross section (center position between the electrodes).

The maximum brightness value and the arc width of the lamp of this embodiment were measured by the method described above.

Table 1 below shows a list of the inclusions of each lamp measured by the inventor of the present application.

[0031]

[Table 1]

The lamp 1 is the mercury-free metal halide lamp in this embodiment, and the lamp 2 is a conventional lamp (comparative example) in which 0.65 mg of mercury is added to this lamp. The lamps 3 to 7 are also mercury-free metal halide lamps of the present embodiment in which mercury is not enclosed.

Lamps 3 to 5 contain ScI ₃ at 0.03 m.
g, NaI of 0.02 mg, and zinc iodide (ZnI ₂ ) of 0.1 mg were added (Lamp 3), and aluminum iodide (AlI ₃ ) of 0.1.
1 mg (Lamp 4), and 0.1 mg of antimony iodide (SbI ₃ ) was added (Lamp 5). The lamp 6 is one in which 0.2 mg of indium bromide (InBr) is filled instead of CeI ₃ of the lamp 1. Then, the lamp 7 is
0.2 mg of Br was added.

The inventor of the present application conducted an experiment on the lamps 1 to 7 and examined the arc width and the luminance characteristics. The result is shown in FIG. The vertical axis in FIG. 4 represents the maximum brightness of the lamp, and is shown as a relative value when the maximum brightness value of the lamp 2 (comparative example) is 1. The horizontal axis in FIG. 4 represents the arc width (mm). A lamp having a high brightness value and a narrow arc width is a lamp that is closer to a point light source and has excellent characteristics of improving the light collection efficiency when used in combination with a reflecting mirror or the like.

As can be seen from FIG. 4, the arc width of the lamp 1 and the lamps 3 to 7 became narrower than that of the lamp 2 (comparative example). That is, by sealing a halide of Ce, a halide of Zn, a halide of Al, a halide of Sb, and indium bromide in a lamp that does not contain mercury, it is possible to reduce the arc width. The present inventor has found out. As shown in FIG. 4, the arc width of the lamps 5, 4 and 7 is 1.2 mm, the arc width of the lamps 3 and 6 is 1.1 mm, and the arc width of the lamp 1 is 1 mm. It was 0.0 mm.

Further, the lamps 1 and 7 have improved luminance as compared with the lamp 2 (comparative example). That is, the lamp 2
Compared with (Comparative Example), the lamp 1 had 1.5 times the brightness, and the lamp 7 had the brightness 1.2 times. Lamp 1 and lamp 7
Both of them have a common cerium halide content. Therefore, by encapsulating a Ce halide in an electrodeless lamp that does not contain mercury, a lamp with a narrow arc width and high brightness can be realized.

Further, lamp 1, lamps 3 to 7, and
ScI₃0.19 mg, NaI 0.16 mg
Lamp voltage and radiation of lamp 8
The light efficiency was measured. The lamp, so that you can easily understand
8 is from the lamp 1 to CeI ₃With the lamp removed
It

The measurement results are shown in FIG. As can be seen from FIG. 5, Lamp 1 shows the highest efficiency. That is, the lamp 1 in which the halogenated Ce is enclosed is 116 lm / W,
It turned out to be very efficient. Therefore, in order to realize a highly efficient lamp, the configuration of the lamp 1 is preferable. Regarding the lamp voltage, the lamp 8
Is a lamp voltage of 28 V, while lamps 1, 3 ...
7, it can be seen that the lamp voltage is higher than that. That is, encapsulating Ce halide, Zn halide, Al halide, Sb halide, and indium bromide has the effect of increasing the lamp voltage. If the lamp voltage can be increased, the current of the lamp can be decreased, so that the consumption of the electrodes can be suppressed. Further, if the lamp voltage can be increased, the lighting can be performed with a small current, and the lighting circuit (ballast) can be downsized.

The effect found by the inventor of the present application that the arc width becomes narrow and the brightness becomes high by encapsulating a Ce halide in a mercury-free electrode type lamp is as follows.
The lamp power, the distance between the electrodes, the internal volume of the arc tube 1, the amount of Sc iodide and Na iodide, or the type and amount of the halide other than Ce, such as the type and amount, can be obtained regardless of other components. Therefore, the present invention is not limited to those conditions. Further, if it is desired to obtain the effect of narrowing the arc width, not only the mercury-free metal halide lamp in which the halide of Ce is enclosed but also the halide of Zn, the halide of Al, the halide of Sb, the indium bromide are used. An enclosed mercury-free metal halide lamp is also applicable. However, in order to realize a high-luminance and high-efficiency lamp with a narrow arc width, which is not found in conventional lamps, it is preferable to use the configuration of the lamp 1 of this embodiment.

Increasing the total amount of the halide enclosed makes it possible to obtain the effect of increasing the lamp voltage.
Increasing total halide encapsulation tends to provide good performance for the lamp. However, if a quantity of halide exceeding 30 mg / cc per unit volume of the arc tube is enclosed, the enclosure that does not evaporate even during lamp lighting rises along the arc tube wall to the center of the arc tube. Phenomena can occur. When this phenomenon occurs, the arc is hidden in the shadow of the raised inclusion, and good characteristics cannot be exhibited. Therefore, it is preferable that the enclosed amount of the halide is 30 mg / cc or less per unit inner volume of the arc tube.

In the lamp 1 of this embodiment, Sc iodide and Na iodide are enclosed in addition to the Ce halide. The main reason for encapsulating these halides is to improve the luminous flux of the lamp.

The total amount of Sc iodide and Na iodide enclosed is preferably 2 mg / cc or more and 15 mg / cc or less. Sc iodide and Na iodide react with glass or sneak into the base of the electrode when the lamp is left on for a long time, and as a result, the amount of iodide that can emit light decreases. Therefore, it is preferable to encapsulate 2 mg / cc or more.

FIG. 6 shows the relationship between the total amount of enclosed Sc and Na iodides and the luminous flux of the lamp. The horizontal axis in FIG. 6 indicates the total amount of Sc and Na iodide enclosed (Sc + Na total amount).
And the vertical axis represents the luminous flux (lm) of the lamp. As shown in FIG. 6, when the total amount of Sc iodide and Na iodide is too large, absorption of light emission occurs,
The luminous flux falls. Therefore, it is preferable that the total amount of Sc iodide and Na iodide is not more than a predetermined amount. For example, if it is about 15 mg / cc or less, a luminous flux of about 2700 lm can be secured. According to the Japan Light Bulb Industry Association standard for HID light sources for automobile headlamps, the luminous flux of the lamp must be 2700 lm or more. Therefore, in the range of use of automobile headlamps, the total amount of iodide of Sc and iodide of Na is 15 mg.
It is preferably less than / cc.

When the luminous flux is 2800 lm or more,
It is preferably 13 mg / cc or less. Further, when the luminous flux is 2600 lm or more, it is preferably 16 mg / cc or less. When the luminous flux is 2400 lm or more, 1
It is preferably 9 mg / cc or less.

Further, the enclosed amount of Ce halide is 0.
It is preferably 8 mg / cc or more and 15 mg / cc or less. The reason will be described with reference to FIG. 7. Figure 7
The horizontal axis represents the amount of Ce halide enclosed per unit inner volume of the arc tube (mg / cc), and the vertical axis represents the lamp voltage (V).

As shown in FIG. 7, the lamp voltage increases as the halide of Ce is filled. Lamp voltage is 3
Below 0V, the lamp current increases, ie the load on the electrodes increases, which is impractical. Therefore,
In order to obtain a lamp voltage of 30 V or higher, the amount of Ce halide charged per unit inner volume of the arc tube is 0.8 mg.
/ Cc or more is preferable.

Further, since increasing the enclosed amount of Ce halide tends to be good for lamp characteristics such as increase in luminous flux, it is preferable that the enclosed amount of Ce halide is relatively large. However, 1 per unit inner volume of arc tube
If 5 mg / cc or more of Ce halide is enclosed, the enclosure that has not evaporated even while the lamp is lit may rise to the center of the arc tube along the arc tube wall. When this phenomenon occurs, the arc is hidden in the shadow of the enclosed material, and there is a possibility that desired characteristics cannot be exhibited. Therefore, it is preferable that the enclosed amount of Ce halide is 15 mg / cc or less per unit inner volume of the arc tube.

Next, the amount of other halogenated substances enclosed in the lamps 3 to 6 of this embodiment will be described.

First, the lamp 3 will be described. Regarding Lamp 3, the amount of Zn halide enclosed is 0.2 mg.
/ Cc or more and 15 mg / cc or less is preferable.
The reason will be described with reference to FIG. The horizontal axis of FIG. 8 represents the amount (mg / cc) of Zn halide enclosed per unit inner volume of the arc tube, and the vertical axis represents the lamp voltage (V).

As shown in FIG. 8, in order to increase the lamp voltage to 30 V or higher, the amount of Zn enclosed in the halide is 0.
It is preferably 2 mg / cc or more. If 15 mg / cc or more is enclosed per unit inner volume of the arc tube, a phenomenon may occur in which the inclusions that have not evaporated on the arc tube wall rise to the center of the arc tube even when the lamp is lit. When this phenomenon occurs, the arc is hidden in the shadow of the enclosed material, and there is a possibility that desired characteristics cannot be exhibited. Therefore, Z
The enclosed amount of the halide of n is preferably 15 mg / cc or less per unit inner volume of the arc tube.

Next, the lamp 4 will be described. For lamp 4, the amount of Al halide enclosed is 0.5 mg.
/ Cc or more and 15 mg / cc or less is preferable.
The reason will be described with reference to FIG. The horizontal axis of FIG. 9 represents the amount of enclosed aluminum halide per unit inner volume of the arc tube (mg / cc), and the vertical axis represents the lamp voltage (V).

As shown in FIG. 9, in order to increase the lamp voltage to 30 V or more, the amount of Al halide enclosed is 0.
It is preferably 5 mg / cc or more. If 15 mg / cc or more is enclosed per unit inner volume of the arc tube, a phenomenon may occur in which the inclusions that have not evaporated on the arc tube wall rise to the center of the arc tube even when the lamp is lit. When this phenomenon occurs, the arc is hidden in the shadow of the enclosed material, and there is a possibility that desired characteristics cannot be exhibited. Therefore, A
It is preferable that the enclosed amount of the halide of 1 is 15 mg / cc or less per unit inner volume of the arc tube.

Next, the lamp 5 will be described. Regarding the lamp 5, the enclosed amount of Sb halide is 1.1 mg.
/ Cc or more and 15 mg / cc or less is preferable.
The reason will be described with reference to FIG. The horizontal axis of FIG. 10 represents the amount of Sb halide enclosed (mg / cc) per unit inner volume of the arc tube, and the vertical axis represents the lamp voltage (V).

As shown in FIG. 10, the lamp voltage is set to 30V.
To achieve the above, the amount of Sb halide enclosed is
It is preferably 1.1 mg / cc or more. Moreover, if 15 mg / cc or more is enclosed per unit inner volume of the arc tube,
Even when the lamp is turned on, a phenomenon may occur in which the inclusions that have not evaporated on the arc tube wall rise to the center of the arc tube. When that phenomenon occurs, the arc is hidden in the shadow of the inclusion,
There is a possibility that desired characteristics cannot be exhibited. Therefore, the amount of the Sb halide enclosed is preferably 15 mg / cc or less per unit inner volume of the arc tube.

Next, the lamp 6 will be described. In the lamp 6, the amount of InBr enclosed is preferably 0.1 mg / cc or more and 15 mg / cc or less. The reason will be described with reference to FIG. The horizontal axis of FIG. 11 is
The enclosure amount (mg / cc) of InBr halide per unit inner volume of the arc tube is shown, and the vertical axis shows the lamp voltage (V).

As shown in FIG. 11, the lamp voltage is set to 30V.
To achieve the above, the amount of InBr enclosed is 0.1 mg.
/ Cc or more is preferable. If 15 mg / cc or more is enclosed per unit inner volume of the arc tube, a phenomenon may occur in which the inclusions that have not evaporated on the arc tube wall rise to the center of the arc tube even when the lamp is lit. When this phenomenon occurs, the arc is hidden in the shadow of the enclosed material, and there is a possibility that desired characteristics cannot be exhibited. Therefore, InB
Encapsulation amount of r is 15 mg / cc per unit inner volume of arc tube
The following is preferable.

In the above-mentioned structure of the present embodiment, when the lamp is operated with the lamp power of about 25 W or more, a stable arc capable of sufficiently maintaining the lighting can be obtained. In addition, the larger the lamp power, the more luminous flux is obtained. However, in the usage range of the vehicle headlight, the upper limit of the power consumption of the lamp of the present embodiment may actually be about 55 W. Because the power consumption of halogen bulbs for automobile headlights currently in use is 5
This is because it is 5 W, and lighting in the range exceeding 55 W is uneconomical and not very preferable. In addition, even if it is uneconomical, if it is desired to use it, the upper limit may exceed 55 W.

Here, the filling pressure of Xe gas will be described. In order to obtain a lamp suitable for practical use, in the electrodeless metal halide lamp according to the present embodiment, the upper limit of the Xe gas filling pressure is preferably set to about 2.5 MPa (room temperature conversion value). . About 2.5 MPa
This is because, if enclosed above, in the configuration of the lamp of the present embodiment, there is a high possibility that airtightness inside the arc tube 1 will leak from the vicinity of the connecting portion between the electrode 3 and the molybdenum foil 4 during lighting operation, which is not preferable. . A more preferable upper limit of the Xe gas filling pressure is about 2.0 MPa. However, when the lamp according to the present embodiment is used as a light source for a vehicle headlight that is required to rise in a short time, the lower limit is more preferably about 0.1 MPa.

Further, the lamp of the present embodiment is susceptible to the force of gas convection caused by the arc tube temperature distribution because the arc width is narrow. Therefore, there is a phenomenon that the arc is curved. Therefore, as shown in FIG. 12, a means (for example, a permanent magnet) 8 for applying a magnetic field 9 having a component perpendicular to a straight line connecting the electrodes 3 of the lamp is provided near the lamp of the present embodiment. You may When such a magnetic field 9 is applied, the curvature of the arc can be suppressed. The principle by which the curvature of the arc of the mercury-free metal halide lamp can be suppressed by applying the magnetic field 9 is not always clear at the present time, but regarding the parameter that can suppress the curvature of the arc, Japanese Patent Application No. 2000-38.
No. 8000 (corresponding US patent application Ser. No. 09/7399)
No. 74, Applicant; Matsushita Electric Industrial Co., Ltd.). It has also been found that if the parameters satisfy the relations of the following formulas (1) and (2), it is possible to suppress arc bending and arc fluctuation,
It is described in detail in Japanese Patent Application No. 2001-155385 (applicant; Matsushita Electric Industrial Co., Ltd.). These specifications are incorporated herein by reference.

Regarding the mercury-free metal halide lamp, the equation 1 or the equation 2 showing the relation between the arc curving suppression and the arc fluctuation suppression is as follows.

0 <(100BW / f) −P ₀ d <100 (Equation 1) 0 <(10BW / f) −Pd <10 (Equation 2) where B (mT) is a pair of electrodes (3, 3) The magnetic field (9) applied to the center between the electrode tips when horizontally lit so that the straight line connecting the tips is substantially horizontal, and d (mm)
Is the distance between the tips of the pair of electrodes (3, 3), and P ₀
(MPa) is the internal pressure of the arc tube 1 during steady lighting, W (W) is the power consumed during steady lighting,
And f (Hz) is a stable frequency at the time of steady lighting. It should be noted that P (MPa) in the equation 2 is the pressure of the rare gas filled at 20 ° C.

The meanings of the terms in Equation 1 and Equation 2 will be briefly described. The term (100 BW / f) in Equation 1 and Equation 2
The term of (10 BW / f) in the inside is a term of the force that moves the arc generated due to the magnetic field 9 downward, while the term of P ₀ d in the equation 1 and Pd in the equation 2 are in the arc tube. Is the term of the force (buoyancy) that moves the arc upward due to the convection of the gas.

[0063] The operation than the pressure P _0, and that easily measured towards the filling pressure P of the rare gas, not an operational pressure P _0,
Since there is no particular problem even if it is specified by the rare gas filling pressure P, using Equation 2 is more advantageous in lamp design. In Formula 2, more preferable conditions are shown below. P is 0.1 (MPa) <P <2.5 (MP
It is preferably a). Also, P · d is P · d <
It is preferable that 8 (more preferably Pd ≦ 4.6). Furthermore, f is preferably 40 (Hz) <f. B is preferably B <500 (mT). And, d is preferably 2 <d (mm).

In a small lamp in which the inner diameter of the arc tube 1 is, for example, 5 mm or less, the arc curvature greatly affects the life characteristics of the lamp. That is, the arc bending causes a temperature rise in the upper part of the arc tube 1, causing a problem such as clouding of the quartz glass that is the material of the arc tube, and as a result, the lamp life may be shortened. Therefore, the magnetic field 9
It is considered that suppressing the curve of the arc by the force is effective in improving the quality of the life characteristics of the lamp. In addition, the fluctuation of the arc is not preferable because it causes the flickering, and the suppression of the fluctuation of the arc leads to the improvement of the lamp characteristics.

Since the magnetic field 9 required to suppress the arc bending varies depending on the lamp design, it is preferable to apply the magnetic field 9 suitable for each lamp. However, if each parameter is defined so as to satisfy the relationships of the above equations 1 and 2, it is possible to easily design a lamp in which arc bending and arc fluctuation are suppressed without trial and error, which is a great advantage. As the magnetic field applying means 8, a permanent magnet (for example, a ferrite permanent magnet) is preferable because a magnetic field can be easily applied. The magnetic field applying means 8 may be an electromagnet.

The magnetic field applying means 8 is used for suppressing arc bending and arc wobbling. By enclosing a Ce halide in a mercury-free electrode type lamp, the arc width becomes narrow and The effect of this embodiment of high brightness can be obtained without using the magnetic field applying unit 8. In addition, the effect that the arc width can be narrowed by enclosing Ce halide, Zn halide, Al halide, Sb halide, and indium bromide is also obtained by the magnetic field applying unit 8. It can be obtained without any exception.

[0067]

According to the present invention, since a rare gas and a halide of zinc are contained in an arc tube having a pair of electrodes facing each other in the tube, a mercury-free metal halide lamp having a narrow arc width is provided. be able to.

[Brief description of drawings]

FIG. 1 is a cross-sectional view schematically showing a configuration of an electrode type metal halide lamp containing no mercury according to an embodiment of the present invention.

FIG. 2 is a diagram schematically showing a configuration of an arc width / luminance measuring device.

FIG. 3 is a graph showing a luminance distribution of an arc.

FIG. 4 is a graph showing the relationship between the arc width of a lamp and the maximum brightness value.

FIG. 5 is a graph showing the relationship between lamp efficiency and voltage.

FIG. 6 is a graph showing the relationship between the total enclosed amount of scandium halide and sodium halide and the luminous flux.

FIG. 7 is a graph showing the relationship between the enclosed amount of cerium halide and the lamp voltage.

FIG. 8 is a graph showing the relationship between the enclosed amount of zinc halide and the lamp voltage.

FIG. 9 is a graph showing the relationship between the enclosed amount of aluminum halide and the lamp voltage.

FIG. 10 is a graph showing the relationship between the enclosed amount of antimony halide and the lamp voltage.

FIG. 11 is a graph showing the relationship between the amount of indium bromide enclosed and the lamp voltage.

FIG. 12 is a cross-sectional view schematically showing a configuration in which a magnetic field applying means 8 is provided in the mercury-free metal halide lamp of the present embodiment.

[Explanation of symbols]

1 arc tube 2 Sealing part 3 electrodes 4 Molybdenum foil 5 lead wires 7 Halide 8 Magnetic field applying means (permanent magnet) 9 magnetic field 20 lamps 21 Ballast and power supply 22 filters 23 CCD camera 24 monitors

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hideaki Kiryu             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor ▲ Yoshi ▼ Masato Ta             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F term (reference) 5C015 PP05 PP07 QQ03 QQ14 QQ52                       RR02 RR05                 5C039 HH05

Claims (5)

[Claims] 1. An arc tube having a pair of electrodes facing each other in the tube, wherein the arc tube contains a rare gas and a halide of zinc and does not contain mercury. Mercury metal halide lamp. 2. The anhydrous mercury metal halide lamp according to claim 1, wherein the arc tube further contains at least one of a scandium halide and a sodium halide. 3. The total amount of halide enclosed in the arc tube is a value per 1 cc of the arc tube internal volume,
The anhydrous mercury metal halide lamp according to claim 2, which has a content of 0.2 mg / cc or more and 15 mg / cc or less. 4. The mercury-free metal halide lamp according to claim 1, wherein the rated power of the mercury-free metal halide lamp is set to 25 W or more and 55 W or less. 5. The rare gas contains at least Xe (xenon), and the filling pressure of the rare gas is 0.1 MPa or more and 2.5 MPa or less at room temperature. A mercury-free metal halide lamp as described in one.