JP2003086140A - External electrode type discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an external electrode type discharge lamp for a magnetometer improved in dark starting capability without filling of tritium and filled with helium or an alkaline metal. SOLUTION: By disposing, on the outside surface of a nearly cylindrical glass discharge container 1 filled with helium or the alkaline metal as a main luminescent constituent, three external electrodes each formed of a metal plate and comprising one center high-pressure electrode 2 and two end-part low-pressure electrodes 3 and 3' at the center part and in the vicinities of both end parts of the discharge container with spaces in the circumferential direction of the discharge container and by applying high-frequency voltages between the high-pressure electrode 2 and the low-pressure electrodes 3 and 3', these external electrode type discharge lamps 10 and 20 emit light to the outside of the discharge container 1 from two luminescent regions interposed between the respective external electrodes. The discharge lamps 10 and 20 are characterized in that another member of a non-magnetic conductive linear substance 41 is inserted and disposed by straddling a surface part in the discharge container corresponding to the center high-pressure electrode installation part a surface part in the discharge container corresponding to a non-installation part without the three external electrodes installed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an external electrode type discharge lamp. In particular, it relates to an external electrode type helium lamp used as a light source of a magnetometer or an external electrode type discharge lamp in which an alkali metal is enclosed.

[0002]

2. Description of the Related Art U.S. Pat. No. 3,206,671 and U.S. Pat. No. 3,350,632 disclose a discharge lamp filled with helium and a magnetometer operated by a gas cell also filled with helium. . This magnetometer lights a helium lamp with a high frequency of several tens to several hundreds of MHz, circularly polarizes the light of the lamp and transmits it through the inside of the helium gas cell, and the helium spectral line is separated according to the change of the magnetic field. , Systems that utilize sensing of changes in the helium spectrum caused by the so-called Zeeman effect have been used.

Inside the system, the helium lamp is used in a completely sealed dark condition container that does not allow outside light to enter, and the environment for operating the magnetometer is also used in the extremely cold region of -50 ° C. Sometimes. Under this condition, the number of initial electrons inside the lamp, which triggers the discharge, is extremely reduced, so that the lamp is in a state in which it is difficult to start, and there is a problem that a significant start delay occurs or the discharge is not started.

In order to avoid non-lighting of the lamp in the dark, not only helium but also a small amount of radioactive tritium is enclosed inside the lamp. Tritium is an isotope of hydrogen and does not emit light during lamp operation and does not affect discharge, but it emits beta rays when one neutron inside the nucleus becomes helium instead of a proton. Therefore, without affecting other characteristics of the helium lamp, electrons necessary for starting can be produced by the beta ray inside the lamp, and the startability can be greatly improved.

[0005]

However, since tritium is a radioactive substance that is a gas at room temperature, it is very difficult to control tritium, and the equipment for enclosing it in the lamp becomes complicated. And safety measures are troublesome. In addition, the handling is very strictly regulated in Japan. Therefore, considering the cost of the lamp, it is practically impossible to manufacture a lamp containing tritium in Japan.

As a conventional technique for solving the starting delay in a state where the outside light cannot be expected (in the dark), for example, Japanese Unexamined Patent Publication No. 10-
There is 188910. In this technique, in order to improve the dark starting characteristic of the external electrode type fluorescent lamp in which the phosphor is applied to the inner surface of the glass tube, the conductive linear substance is applied to the inner surface of the glass tube corresponding to the region where the low voltage side electrode is arranged. It is attached across the region and the inner surface region of the glass tube corresponding to the region where neither electrode is provided, and one of the conductive substances on the inner surface of the glass tube corresponding to the low voltage side electrode is applied by the high frequency and high voltage pulse of the power source. The electric field is concentrated with the portion serving as a negative electrode, and electrons are more likely to be emitted from the surface of the conductive material, so that the dark starting property is significantly improved as compared with the case where the conductive material is not present.

The present invention is limited to an external electrode type fluorescent lamp in which a fluorescent material is applied to the inner surface of a glass tube, and the conductive material of the glass is spread over a pair of external electrodes in the lamp axial direction. It is said that the coating is performed in the radial direction inside the tube, and that the lamp is attached at any position in the longitudinal direction of the lamp.

However, in a discharge lamp for a magnetometer in which helium or alkali metal is enclosed as a main light emitting component, the light is taken out from two areas between the central high voltage electrode and the end low voltage electrodes on both sides thereof. Since the external electrode type fluorescent lamp has one aperture portion along the tube axis, the conductive material must be attached over the longitudinal direction of the arc tube. It is very difficult to attach a conductive substance to the inner surface of a lamp with a small arc tube diameter in the longitudinal direction, unlike attaching a conductive substance to the end of the lamp as in conventional external electrode fluorescent lamps. Technology is required.

Therefore, an object of the present invention is to provide an external electrode type discharge lamp for a magnetometer in which helium or an alkali metal is enclosed, which has improved dark startability without enclosing tritium.

[0010]

In order to solve the above-mentioned problems, the present invention comprises a metal plate on the outer surface of a substantially cylindrical glass discharge vessel in which helium or an alkali metal is enclosed as a main light emitting component, and the discharge vessel central portion is formed. And three external electrodes consisting of one central high-voltage electrode and two end low-voltage electrodes in the circumferential direction of the discharge vessel with a space between the central high-voltage electrode and the end low-voltage electrodes. An external electrode type discharge lamp which emits light to the outside of the discharge vessel from two light emitting regions sandwiched between each external electrode by applying a high frequency voltage to A substance in the form of a discharge vessel inner surface corresponding to the central high-voltage electrode mounting portion,
The external electrode type discharge lamp is characterized in that the external electrode type discharge lamp is inserted and arranged over the inner surface portion of the discharge container corresponding to the non-arranged portion where the three external electrodes are not arranged. Further, the conductive linear substance is held in the arc tube by its own elastic force. Further, the value of Se / Sd is 0.02 or less, where Se is the cross-sectional area of the conductive linear substance and Sd is the cross-sectional area of the light emitting region. Further, as the conductive linear substance, tungsten, molybdenum, tantalum,
It is characterized by using gold, platinum, aluminum, or an alloy thereof.

[0011]

1 is a view showing an embodiment of a lamp of the present invention. FIG. 1 (a) is an overall view of the lamp 10 of the present invention, and FIG. 1 (b) is A- in FIG. 1 (a).
It is an A'sectional view. On the outer surface of the cylindrical discharge vessel 1,
The central high-voltage electrode 2, the end low-voltage electrodes 3 and 3 ′ are arranged at intervals in the circumferential direction of the discharge vessel 1, and the central high-voltage electrode 2 has a frequency of 50 kHz and a peak voltage of 100 when starting.
A high voltage of 0 V is applied, and a high frequency voltage of 50 MHz is applied after starting. Helium gas or the like is sealed inside the glass tube 1, and a conductive linear substance 41 is also arranged on the inner surface of the discharge vessel 1.

The conductive linear substance 41 exists inside the discharge vessel 1, but is shown by a solid line in FIG. 1 for convenience. As described above, the presence of the conductive linear substance 41 on the inner surface of the discharge vessel 1 can improve the startability in the lamp of the present invention, when the voltage is applied to the central high voltage electrode 2, the central high voltage is applied. Electrons that become the initial electrons inside the lamp by causing electricity to flow through the conductive linear substance 41 from the electrode 2 through the discharge vessel 1 and further through the discharge vessel 1 to the end low-voltage electrode 3 or 3 ′. Is generated, and the main discharge of the lamp is considered to start without causing a start delay.

Further, FIG. 2 is a layout view of the lamp 10 of the present invention when in use. As shown in FIG. 1 (a),
The lamp 10 has two light emitting regions S1 and S2 between a central high voltage electrode 2 connected to a high frequency power source 13 and two end low voltage electrodes 3 and 3'grounded. In the case of manufacturing a high-precision magnetometer capable of three-dimensional exploration, this is X,
The helium gas cells 6 and 6'are arranged so as to correspond to the Y and Z axis directions, and two sets of gas cells of each axis are used in order to improve the accuracy of magnetic exploration of each, so that the lamp 10 emits light. There are two areas. The two gas cells 6 and 6'arranged with respect to this one axis pass through the interference filters 11 and 11 'and the circular polarization elements 12 and 12', respectively, and transmit circularly polarized light in opposite directions. , The accuracy of the magnetometer is improved by taking the logical product of the magneto-optical resonance signals by the output signal voltage converted by the photo detectors 7 and 7 '.

Therefore, it is preferable that the emission spectrum and emission intensity of helium or alkali metal in the two emission regions of the lamp are the same. If the emission intensity of the two emission regions is different, the magnetic sensitivity of the gas cell will also be different. In this case, since it is impossible to adjust the intensity of the light emitting region of the lamp by the power source, the magnetic sensitivities of the two gas cells need to be calibrated by the input power of the gas cells. In that case, the sensitivity of the magnetometer decreases because the gas cell on the light emitting region side, which has low sensitivity, is calibrated.

FIG. 2 shows a gas cell 6 arranged in the X direction,
6 shows the positional relationship between 6'and the lamp 10 of the present invention. Further, FIG. 3 shows gas cells 6 and 6 arranged in the Y and Z directions.
And 20 shows the positional relationship of the lamp of the present invention. The lamp 10 of FIG. 2 and the lamp 20 of FIG. 3 are arranged so as to be offset from each other by 90 degrees on a plane parallel to each other. Between the gas cells 6, 6'and the lamps 10, 20 are arranged lenses 5, 5'interference filters 11, 11 'circularly polarizing elements 12, 12' for introducing light from the lamps 10, 20 into the gas cells 6, 6 '. The light transmitted through the gas cells 6, 6'is detected by the photodetectors 7, 7 '.
And is converted into a voltage signal.

The conductive linear substance 41 of the present invention has the inner surface of the discharge vessel 1 corresponding to the portion where the central high voltage electrode 2 is arranged and the discharge vessel 1 of either one of the two light emitting regions S1 and S2. If it is placed on the surface, it has a sufficient effect on the dark startability. However, since the emission intensity of the light emitting regions S1 and S2 where the conductive linear substance 41 is arranged is reduced by 5 to 10%, when the conductive linear substance 41 is arranged only in one of the light emitting regions, the light emission region S1 and S2 are reduced. There is a difference in emission intensity between the two emission regions S1 and S2. Further, even when the position of the conductive linear substance 41 in the light emitting portion is different on the left and right, the conductive linear substance blocks the light, which causes a difference in the emission intensity of the two light emitting regions S1 and S2. Therefore, the conductive linear substance 41
Are arranged in the same shape in the two light emitting regions S1 and S2, and are arranged symmetrically with respect to the central high-voltage electrode 2 in the lamp axial direction.

In the lamp shown in FIG. 1, the inner diameter of the discharge vessel is small, for example, 5 mm, and the total length of the lamp is long, for example, 80 mm. Therefore, aluminum tape, copper tape, silver paste, etc. are provided inside the discharge vessel in the longitudinal direction of the lamp. It is very difficult to fix such a conductive paint as a conductive substance symmetrically.

Therefore, a conductive linear substance formed in advance by a metal wire or a metal pipe is inserted into the inside of the lamp and brought into contact with the inner surface of the discharge vessel to generate a creeping discharge, whereby the above-mentioned initial electrons are generated inside the lamp. Invented to generate. According to the present invention, the installation of the conductive material inside the lamp can be greatly simplified.

Further, since the magnetometer using these lamps may be mounted on an aircraft or the like and the lamp may be vibrated, it is preferable that the conductive linear substance is fixed inside the lamp. Therefore, it is possible to easily dispose the conductive linear substance by imparting elasticity to the conductive linear substance itself and fixing it to the inner surface of the discharge vessel by the elasticity.

Further, in the present invention, the conductive linear substance 41
If the cross-sectional area of is sufficiently smaller than the cross-sectional area of the light emitting region, the influence of the conductive linear substance on the emission intensity will be small, and the mounting state of the conductive linear substance does not have to be symmetrical. , And found that the shape of the conductive linear substance can be designed more freely. When the value of Se / Sd is 0.02 or less, where Se is the cross-sectional area of the conductive linear substance and Sd is the cross-sectional area of the light-emitting region, the difference in light output between the left and right light-emitting parts is obtained. Is within 5%, which is practically no problem.

Furthermore, the conductive linear substance in the present invention requires careful selection of the material. Lamps 10, 20
Are located very close to the gas cells 6, 6 '.
An alternating magnetic field is applied to the gas cells 6 and 6 ′ to cause the splitting of the spectrum line due to the Zeeman effect in the helium spectrum emitted inside the gas cell. Therefore, when the conductive linear substance 41 is a magnetic substance such as nickel. Causes the conductive linear substance 41 to be magnetized, which affects the discharge of the lamp 10.

Therefore, it has been found that the change in the magnetic field, which should be sensed, cannot be sensed, and the magnetometer cannot operate. Further, since the conductive linear substance is directly exposed to the discharge of helium or alkali metal vapor, sputtering of the conductive linear substance may occur depending on the material. When sputtering occurs, the substance scattered by the sputtering adheres to the inner surface of the discharge container of the light emitting portion, which is a cause of attenuating the light output from the lamp, which is not preferable. Required life time of the lamp used in this magnetometer 2
In order to satisfy 000 hours, it is necessary to select a material having a high sputtering resistance to the ions in the plasma when the lamp is turned on.

The main light emitting component in the present invention is not limited to helium, but may be one in which an alkali metal such as potassium, sodium or cesium is enclosed as vapor. Although there are many general lamps in which helium is enclosed as a starting auxiliary gas, the discharge lamp targeted by the present invention is different from such a lamp in that it is enclosed as a main helium emission component. Further, there are many discharge lamps to which potassium, sodium, and cesium are added as a light emitting substance, but the discharge lamp targeted by the present invention is different from such a discharge lamp in that these metals are enclosed as the main light emitting component. is there. Therefore, the discharge lamp targeted by the present invention does not require a general main light emitting component such as mercury or xenon.

[0024]

EXAMPLES Specific examples of the external electrode type discharge lamp according to the present invention shown in FIG. 1 will be described in detail. The discharge vessel 1 is made of glass and has a tubular shape as a whole, and after the inside of the discharge vessel 1 has been evacuated to a predetermined degree, helium gas is supplied for example at 5 Torr.
It is filled, and both ends are closed so that the inside is sealed. The discharge vessel 1 is an aluminosilicate glass with little helium permeation and has a length of 80 mm and an outer diameter of 6.4 mm. The electrodes 3, 3 ′ are pipe-shaped and are provided on the outer surface of the glass tube 1 along the axial direction. This electrode is, for example,
It is made by processing a 0.3 mm-thick copper plate into a sheet metal, and is fixed to the discharge vessel with a silicon adhesive. The conductive linear substance 41 has a diameter of 1.0 m, for example.
A metal rod of m is arranged on the inner surface of the discharge vessel 1. In the figure, they are arranged linearly on the inner surface of the discharge vessel 1. By arranging them linearly, a large light emitting region of the discharge vessel can be secured. The material of the conductive linear substance 41 is copper.

Here, the conductive linear substance 41 is disposed on the inner surface of the discharge vessel 1 and the inner surface area of the discharge vessel 1 corresponding to the area where the central high-voltage electrode 2 is disposed, and all electrodes. It is located across the inner surface region of the discharge vessel 1 corresponding to the region not provided. Further, the conductive linear substance 41 may be arranged on the inner surface of the discharge vessel 1 corresponding to the region where the grounded other end low voltage electrodes 3 and 3 ′ are arranged.

Next, an experiment showing the starting characteristics of the external electrode type discharge lamp in which the helium is enclosed in the discharge vessel 1 will be described. FIG. 4 shows the experimental results, where the horizontal axis represents the time from the application of voltage between the central high-voltage electrode 2 and the end low-voltage electrodes 3 and 3 until the lamp is lit, and the vertical axis represents the horizontal axis. It represents the starting probability for the indicated time.

As a comparative example with the product of the present invention, one lamp each without the conductive linear substance 41 and one lamp without the conductive linear substance sealed with tritium are lit.
It was lit 100 times at 10-second intervals in an environment without external light, and the number of seconds each was started was measured.

In FIG. 4, the horizontal axis is the time until starting, and the vertical axis is the starting probability. For example, it can be read from the line derived from the plot that "what percentage of the lamp will start by a certain starting time". It is judged that the better the startability is, the more the engine starts 100% by the short start time. The lamps of the present invention, shown by line (A), all started within 5 ms. However, in the lamp shown in the line (B) which does not include the conductive linear substance 41, it is almost 0 to 5 in 5 ms.
Only 100% of the lamps are turned on, indicating that 70% of the lamps are turned on in 100 ms.

Also, in the lamp in which tritium is enclosed as indicated by the line (C), only 5 to 15% of the lamp is lit in 5 ms, and 70% is lit in 40 ms. Thus, it is clear how the lamp of the present invention is excellent in startability. The gas sealed in the discharge vessel 1 may be an alkali metal such as potassium, sodium, or cesium in addition to helium.

Another embodiment of the present invention is shown in FIGS. The structures of these examples except for the conductive linear substances 42 to 48 are the same as those of the lamp shown in FIG. 1, and the numbering is omitted. In FIG. 6, the conductive linear substance 42 has an outer diameter of 5
mm, wall thickness 0.3 mm, length 65 mm copper pipe is used.
The light of the light emitting part is taken out, and the other part is installed so as to contact the inner surface of the glass tube where the electrode is installed, and the inner surface of the glass tube of the high voltage side electrode part and the inner surface of the glass tube of the low voltage side electrode are short-circuited. . With this lamp, the same startability as that of the lamp of FIG. 1 was obtained.

In FIG. 7, a copper wire having a diameter of 1 mm is used as the conductive linear substance 43, but both ends are bent in a U shape so as to have a spring property, and are fixed by contacting with the inner surface of the glass tube. There is. Further, the central portion of the conductive linear substance 43 is also processed to have a convex shape so that the inner surface of the glass tube of the central high-voltage electrode portion comes into contact with the inner surface of the glass tube of the high-voltage electrode portion and the low-voltage electrode portion. The inner surface of the glass tube is short-circuited. With this lamp, the same startability as that of the lamp of FIG. 1 was obtained.

In FIG. 8, a copper wire having a diameter of 1 mm is used as the conductive linear material 44, but both ends have U-shaped spring properties, and the inner surface of the glass tube of the high voltage electrode at the center and the low voltage electrode at the end. Two pieces are installed to be brought into contact with and fixed to the inner surface of the glass tube of the high voltage side electrode section and the inner surface of the glass tube of the low voltage side electrode. With this lamp, the same startability as that of the lamp of FIG. 1 was obtained.

In FIG. 9, the conductive linear substance 45 is spot-welded to a titanium wire having a diameter of 1 mm and a titanium plate having a thickness of 0.2 mm, a width of 2 mm and a length of 10 mm processed into a circular shape. The diameter of the spot-welded circular plate material is made slightly larger than the inner diameter of the glass tube so that the plate material has a spring property and is fixed inside the lamp. The plate portion is brought into contact with the inner surfaces of the glass tubes of the central high-voltage electrode and the end low-voltage electrode, respectively, and the glass tube inner surface of the high-voltage side electrode section and the glass tube inner surface of the low-voltage side electrode are short-circuited. With this lamp, the same startability as that of the lamp of FIG. 1 was obtained.

In FIG. 10, the conductive linear material 46 has a wire diameter of 0.
A titanium mesh having a diameter of 05 mm and an opening ratio of about 95% was rolled into a pipe shape having an outer diameter of 5 mm and a length of 65 mm. The entire mesh has a spring-like property in the diameter direction of the glass, and contacts the inner surface of the glass tube where the central high-voltage electrode and the end low-voltage electrode are attached, so that the glass tube inner surface of the high-voltage side electrode section and the glass tube inner surface of the low-voltage side electrode It is short-circuited. With this lamp, the same startability as that of the lamp of FIG. 1 was obtained.

FIG. 11 shows that the conductive linear substance 47 has a diameter of 0.3.
mm titanium wire is processed into a coil with an outer diameter of about 5 mm at both ends and a part of the central part, the coil part is springy, and the inner surface of the glass tube with the central high voltage electrode and the end low voltage electrode attached To short-circuit the inner surface of the glass tube of the high voltage side electrode portion and the inner surface of the glass tube of the low voltage side electrode.
With this lamp, the same startability as that of the lamp of FIG. 1 was obtained.

FIG. 12 shows that the conductive linear substance 48 has a diameter of 0.7.
mm tungsten with a bending spring property at 4 places, contacting the inner surface of the glass tube with the central high-voltage electrode and the end low-voltage electrode attached, and the glass tube inner surface of the high-voltage side electrode section and the glass of the low-voltage side electrode The inner surface of the pipe is short-circuited. With this lamp, the same startability as that of the lamp of FIG. 1 was obtained. Further, Se / Sd when the cross-sectional area of the conductive linear substance 48 in this lamp is Se and the cross-sectional area of the light emitting region is Sd.
The value of is 0.0196. The shape of the conductive linear substance in the left and right light emitting parts of this lamp is not symmetrical, but the difference in light output between left and right is 4.8%, and the difference in light output between left and right does not affect the device. It was

In FIG. 13, the conductive linear substance 49 is disposed on the inner surface of the discharge vessel, the inner surface area of the discharge vessel corresponding to the area where the central high voltage electrode is disposed, and any electrode. A structure that is disposed over the inner surface area of the discharge vessel corresponding to the area not covered by the discharge vessel and that is not disposed in the inner surface area of the discharge vessel corresponding to the area where the end low-voltage electrodes are disposed. Show. With this lamp, the same startability as that of the lamp of FIG. 1 was obtained.

FIG. 5 shows the illuminance retention rate of the average value of the left and right light outputs of the lamp in which the material of the conductive linear substance is changed after 2000 hours. Tungsten, molybdenum, tantalum, gold, platinum and aluminum are shown. When used, an illuminance maintenance ratio of 70% or more was exhibited after 2000 hours of lighting, and a long-life He lamp having good starting characteristics could be obtained.

[0039]

As described above, since the external electrode type discharge lamp of the present invention can always have good starting characteristics, it is used by being mounted on the magnetometer and used in a dark state where external light cannot be expected. Even if it is left for a long time, the lamp can be started and lit without any problem with a simple structure without enclosing tritium.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a lamp of the present invention.

FIG. 2 is a diagram showing an arrangement when the lamp of the present invention is used.

FIG. 3 is a diagram showing an arrangement when the lamp of the present invention is used.

FIG. 4 is a diagram showing measurement results of starting characteristics.

FIG. 5 is a table showing an illuminance maintenance rate after 2000 hours of an average value of left and right light outputs of a lamp in which a material of a conductive linear substance is changed.

FIG. 6 is a diagram showing an embodiment of a lamp of the present invention.

FIG. 7 is a diagram showing an embodiment of a lamp of the present invention.

FIG. 8 is a diagram showing an embodiment of a lamp of the present invention.

FIG. 9 is a diagram showing an embodiment of a lamp of the present invention.

FIG. 10 is a diagram showing an embodiment of a lamp of the present invention.

FIG. 11 is a diagram showing an embodiment of the lamp of the present invention.

FIG. 12 is a diagram showing an embodiment of a lamp of the present invention.

FIG. 13 is a diagram showing an embodiment of a lamp of the present invention.

[Explanation of symbols] 1 discharge vessel 2 Central high voltage electrode 3, 3'end low voltage electrode 41 Conductive linear substances 42 Conductive linear substances 43 Conductive linear substances 44 Conductive linear substance 45 Conductive linear substances 46 Conductive linear substances 47 Conductive linear substance 48 Conductive linear substances 5,5 'lens 6,6 'gas cell 7,7 'photodetector 8 power supply 9, 9'power supply 10 lamps 11, 11 'interference filter 12,12 'circularly polarizing element 13 High frequency power supply 20 lamps

Claims (4)

[Claims] 1. An outer surface of a substantially cylindrical glass discharge vessel in which helium or an alkali metal is enclosed as a main light emitting component, and a metal plate is formed on the outer surface of the discharge vessel. By disposing three external electrodes composed of end low voltage electrodes and applying a high frequency voltage between the central high voltage electrode and the end low voltage electrodes, the two light emitting regions sandwiched between the respective external electrodes, An external electrode type discharge lamp that emits light to the outside of the discharge vessel, wherein a separate member of a non-magnetic conductive linear substance is the inner surface portion of the discharge vessel corresponding to the central high voltage electrode mounting portion, An external electrode type discharge lamp, wherein the external electrode type discharge lamp is inserted and arranged so as to straddle an inner surface portion of the discharge container corresponding to a non-arranged portion where three external electrodes are not arranged. 2. The external electrode type discharge lamp according to claim 1, wherein the conductive linear substance is held in the arc tube by its own elastic force. 3. When the cross-sectional area of the conductive linear substance is Se and the cross-sectional area of the light emitting region is Sd, the value of Se / Sd is 0.
The external electrode type discharge lamp according to claim 1 or 2, wherein the external electrode type discharge lamp is 02 or less. 4. The conductive linear substance is tungsten, molybdenum, tantalum, gold, platinum, aluminum,
Alternatively, the external electrode type discharge lamp according to claim 1, wherein the alloy is used.