JP6202462B2 - Discharge lamp and vehicle lamp - Google Patents

Description

  Embodiments described below generally relate to a discharge lamp and a vehicle lamp.

  In recent years, the power consumption of discharge lamps has been reduced from the environmental aspect. However, when the power is low, the current is reduced, and thus there is a possibility that the discharge between the electrodes becomes unstable. Further, when the temperature of the light emitting part of the discharge lamp rises due to lighting, the tube voltage (voltage between the electrodes) rises, so that the current is further reduced, and flickering may occur or there may be no lighting.

JP 2004-172056 A

  The problem to be solved by the present invention is to provide a discharge lamp and a vehicular lamp that can suppress an increase in tube voltage during the product life.

A discharge lamp according to an embodiment includes: a light emitting unit having a discharge space in which a metal halide containing an indium halide is enclosed; a pair projecting into the discharge space and arranged to face each other at a predetermined distance A sealing portion provided at both ends of the light emitting portion in a direction in which the pair of electrodes extend, and an end portion of the electrode opposite to the discharge space side provided therein ; And a coil wound around the outside of the electrode provided inside the stopper . The ratio of indium halide contained in the metal halide is 0.1 wt% or more and 0.33 wt% or less, and is a direction orthogonal to a direction in which the pair of electrodes in the discharge space extends, The dimension of the longest part of the discharge space is 1.5 mm or more and 2.3 mm or less, and a gap is provided between the sealing portion and the electrode.

  According to the embodiment of the present invention, it is possible to provide a discharge lamp and a vehicular lamp that can suppress an increase in tube voltage during the product life.

1 is a schematic diagram for illustrating a discharge lamp 100 according to a first embodiment. It is a graph for demonstrating the relationship between the ratio of the halide of an indium, and the change of a tube voltage. It is a schematic graph for demonstrating the state of a temperature fall. It is a graph for demonstrating the relationship between the ratio of the halide of indium, and the fall of a light beam. It is a schematic graph for demonstrating the state of a temperature fall. 4 is a schematic diagram for illustrating the configuration of a vehicular lamp 200. FIG. 4 is a schematic diagram for illustrating a circuit of a vehicular lamp 200. FIG.

A first invention is a light emitting part having a discharge space in which a metal halide containing an indium halide is enclosed; a pair of electrodes protruding inside the discharge space and arranged to face each other at a predetermined distance A sealing portion provided at both ends of the light emitting portion in a direction in which the pair of electrodes extend, and an end portion of the electrode opposite to the discharge space side provided therein ; and the sealing portion A coil wound around the outside of the electrode provided inside the metal halide, and the ratio of the indium halide contained in the metal halide is 0.1 wt% or more and 0.33 wt% or less The dimension of the longest part of the discharge space is 1.5 mm or more and 2.3 mm or less in a direction orthogonal to the direction in which the pair of electrodes in the discharge space extends, and the sealing portion, Between the electrodes Is a discharge lamp gap is provided.
According to this discharge lamp, an increase in tube voltage during the product life can be suppressed.

The second invention is the first invention, by performing the turning on and off of the discharge lamp, a discharge lamp halide indium is provided in the gap.
According to this discharge lamp, it is possible to more reliably suppress an increase in tube voltage during the product life.
A third invention is the discharge lamp according to the first or second invention, wherein the metal halide further includes a sodium halide, a scandium halide, and a zinc halide.

A fourth invention is a vehicular lamp comprising: the discharge lamp according to any one of the above; and a lighting circuit electrically connected to the discharge lamp.
According to this vehicle lamp, an increase in tube voltage during the product life can be suppressed.

A fifth invention is the vehicular lamp according to the fourth invention, wherein the discharge lamp is attached so that a pair of electrodes provided on the discharge lamp are horizontal.
According to this vehicular lamp, horizontal lighting can be performed.

Hereinafter, embodiments will be illustrated with reference to the drawings. In addition, in each drawing, the same code | symbol is attached | subjected to the same component and detailed description is abbreviate | omitted suitably.
The discharge lamp according to the embodiment of the present invention can be, for example, an HID (High Intensity Discharge) lamp used for an automobile headlamp. Moreover, when it is set as the HID lamp used for the headlamp of a motor vehicle, what is called horizontal lighting can be performed.
Although the use of the discharge lamp according to the embodiment of the present invention is not limited to a vehicle headlamp, here, as an example, a case where the discharge lamp is an HID lamp used for a vehicle headlamp is an example. Will be described.
(First embodiment)
FIG. 1 is a schematic view for illustrating a discharge lamp 100 according to the first embodiment.
In FIG. 1, when the discharge lamp 100 is attached to the automobile, the front direction is the front end side, the opposite direction is the rear end side, the upper direction is the upper end side, and the lower direction is the lower end side. Yes.
As shown in FIG. 1, the discharge lamp 100 is provided with a burner 101 and a socket 102.

The burner 101 is provided with an inner tube 1, an outer tube 5, a light emitting unit 11, a sealing unit 12, an electrode mount 3, a support wire 35, a sleeve 4, and a metal band 71.
The inner tube 1 has a cylindrical shape and is formed of a material having translucency and heat resistance. The inner tube 1 can be formed from, for example, quartz glass.
The outer tube 5 is provided outside the inner tube 1 and concentric with the inner tube 1. That is, it has a double tube structure.

  The outer tube 5 and the inner tube 1 can be connected by welding the outer tube 5 near the cylindrical portion 14 of the inner tube 1. Gas is enclosed in a closed space formed between the inner tube 1 and the outer tube 5. The gas to be filled can be a gas capable of dielectric barrier discharge, for example, a kind of gas selected from neon, argon, xenon, nitrogen, or a mixed gas thereof. The gas sealing pressure is preferably 0.3 atm or less, particularly 0.1 atm or less at room temperature (25 ° C.), for example.

  The outer tube 5 is preferably formed of a material that has a thermal expansion coefficient close to that of the material of the inner tube 1 and has an ultraviolet blocking property. The outer tube 5 can be formed, for example, from quartz glass to which an oxide such as titanium, cerium, or aluminum is added.

The light emitting unit 11 has an elliptical cross-sectional shape and is provided near the center of the inner tube 1. Inside the light emitting unit 11, a discharge space 111 having a substantially cylindrical shape at the center and tapered at both ends is provided.
The dimension d of the longest part of the discharge space 111 (hereinafter referred to as the dimension d of the longest inner diameter of the light emitting part 11) is a direction orthogonal to the direction in which the pair of electrodes 32 of the discharge space 111 extends. It is preferable that the thickness is 5 mm or more and 2.3 mm or less. The dimension d of the longest inner diameter of the light emitting part 11 is, for example, the dimension between the inner walls 11a of the central part (diameter dimension when the central part is cylindrical).
Details regarding the dimension d of the longest inner diameter of the light emitting unit 11 will be described later.

A discharge medium is enclosed in the discharge space 111. The discharge medium includes a metal halide 2 and an inert gas.
That is, the light emitting unit 11 has a discharge space 111 in which a metal halide 2 containing an indium halide is enclosed.

  Metal halides 2 include indium halides, sodium halides, scandium halides, and zinc halides. As the halogen, for example, iodine can be exemplified. However, bromine or chlorine can be used instead of iodine.

The ratio of indium halide contained in metal halide 2 (weight of indium halide ÷ weight of metal halide 2 containing indium halide × 100) is 0.1 wt% or more and 0.33 wt% or less. can do.
In this case, the ratio of the indium halide contained in the metal halide 2 is that in the initial state (for example, the unused discharge lamp 100). As will be described later, the ratio of indium halide contained in the metal halide 2 gradually decreases by repeatedly turning on and off the discharge lamp 100.
Details regarding the proportion of indium halide contained in the metal halide 2 will be described later.

  The inert gas sealed in the discharge space 111 can be xenon, for example. The inert gas can adjust the sealing pressure according to the purpose. For example, in order to increase the total luminous flux, it is preferable that the sealing pressure is 10 atm or more and 20 atm or less at room temperature (25 ° C.). In addition to xenon, neon, argon, krypton, or the like, or a mixed gas in which these are combined can also be used.

The sealing part 12 has a plate shape and is provided at both ends of the light emitting part 11. That is, the sealing portion 12 has a plate shape and is provided at both ends of the light emitting portion 11 in the direction in which the pair of electrodes 32 extends.
The sealing portion 12 can be formed using, for example, a pinch seal method. Note that the sealing portion 12 may be formed by a shrink seal method and may have a cylindrical shape.
A cylindrical portion 14 is continuously formed at the end of one sealing portion 12 opposite to the light emitting portion 11 side via a boundary portion 13.

The electrode mount 3 is provided inside the sealing portion 12.
The electrode mount 3 is provided with a metal foil 31, an electrode 32, a coil 33, and a lead wire 34.
The metal foil 31 has a thin plate shape and is made of, for example, molybdenum.

  The electrode 32 has a cylindrical shape, and is formed of, for example, so-called tritated tungsten in which tungsten is doped with thorium oxide. The material of the electrode 32 may be pure tungsten, doped tungsten, rhenium tungsten, or the like.

One end of the electrode 32 is welded to the end of the metal foil 31 on the light emitting unit 11 side. The other end of the electrode 32 protrudes into the discharge space 111. The electrodes 32 are arranged such that the tips are opposed to each other with a predetermined distance.
That is, the pair of electrodes 32 protrudes into the discharge space 111 and is disposed to face each other with a predetermined distance.

The distance between the tips of the electrodes 32 can be, for example, 3.4 mm or more and 4.4 mm or less.
Moreover, the shape of the electrode 32 may not be a columnar shape whose diameter is constant in the tube axis direction. For example, the shape of the electrode 32 may be a non-cylindrical shape in which the diameter of the distal end portion is larger than the diameter of the proximal end portion, the distal end may be a sphere, or one of them as in the DC lighting type. The electrode diameter may be different from the other electrode diameter.

The coil 33 can be formed from, for example, a metal wire made of doped tungsten. The coil 33 is wound around the outside of the electrode 32 provided inside the sealing portion 12. In this case, for example, the coil 33 can have a wire diameter of about 30 μm to 100 μm and a coil pitch of 600% or less.
Details regarding the operation and effect of the coil 33 will be described later.

  The lead wire 34 can be a metal wire made of molybdenum, for example. One end of the lead wire 34 is placed on the end of the metal foil 31 opposite to the light emitting unit 11 side. The other end of the lead wire 34 extends to the outside of the inner tube 1.

The support wire 35 has an L shape and is connected to an end portion of the lead wire 34 extending from the front end side of the discharge lamp 100. The support wire 35 and the lead wire 34 can be connected by laser welding. The support wire 35 can be formed from nickel, for example.
The sleeve 4 covers a portion of the support wire 35 that extends in parallel with the inner tube 1. The sleeve 4 has, for example, a cylindrical shape and can be made of ceramic.
The metal band 71 is fixed to the outer peripheral surface on the rear end side of the outer tube 5.

The socket 102 is provided with a main body 6, a mounting bracket 72, a bottom terminal 81, and a side terminal 82.
The main body 6 is made of an insulating material such as resin. Inside the main body 6, a lead wire 34, a support wire 35, and a rear end side of the sleeve 4 are provided.

  The mounting bracket 72 is provided at the end of the main body 6 on the front end side. The mounting bracket 72 protrudes from the main body 6 and holds the metal band 71. The burner 101 is held by the socket 102 by holding the metal band 71 by the mounting bracket 72.

The bottom terminal 81 is provided inside the main body 6 on the rear end side. The bottom terminal 81 is made of a conductive material and is electrically connected to the lead wire 34.
The side terminal 82 is provided on the side wall on the rear end side of the main body 6. The side terminal 82 is made of a conductive material and is electrically connected to the support wire 35.

  And it connects with the lighting circuit 205 (refer FIG. 7) so that the bottom terminal 81 may become a high voltage | pressure side and the side terminal 82 may become a low voltage | pressure side. In the case of an automobile headlamp, the discharge lamp 100 is mounted so that the central axis thereof is substantially horizontal and the support wire 35 is positioned on the lower end side (downward). And lighting up the discharge lamp 100 attached in such a direction is called horizontal lighting.

  Here, when the discharge lamp 100 is turned on, the temperature of the light emitting unit 11 rises. When the temperature of the light emitting unit 11 rises, the amount of evaporation of the metal halide 2 increases. In this case, sodium halide, scandium halide, and zinc halide are evaporated and contribute to the tube voltage.

As the amount of evaporated halide in the discharge space 111 increases, the amount of emitted light increases and the temperature of the light emitting section 11 further increases. As the temperature of the light emitting unit 11 further increases, the amount of evaporated halide in the discharge space 111 further increases. When the amount of evaporated halide in the discharge space 111 increases, the tube voltage increases. Moreover, since the light-emitting part 11 chemically reacts with the halide due to lighting for a long time, the transmittance is reduced, and thus the temperature of the light-emitting part 11 rises.
That is, when the discharge lamp 100 is turned on, the tube voltage tends to increase with time.

A discharge lamp 100 used for an automotive headlamp or the like is controlled so that the rated power is substantially constant by a ballast circuit described later. For this reason, when the tube voltage rises, the current is reduced and the discharge is suppressed.
In this case, if the proportion of the indium halide contained in the metal halide 2 is reduced, an increase in tube voltage can be suppressed. However, if the proportion of indium halide contained in the metal halide 2 is simply reduced, the amount of indium halide evaporated at the start of lighting is reduced, and the current may be excessively increased due to lower tube voltage. is there.

  Furthermore, as the usage time of the discharge lamp 100 becomes longer, the light emitting portion 11 becomes gradually blackened or clouded (devitrified). When the light emitting unit 11 is blackened or clouded, light to be emitted to the outside of the light emitting unit 11 is shielded, and thus heat is generated in the light emitting unit 11. Therefore, if the usage time of the discharge lamp 100 is increased, the temperature of the light emitting unit 11 is likely to rise, and the tube voltage is likely to increase from the start of lighting.

As described above, in the discharge lamp 100, the tube voltage tends to increase due to various causes. Further, it is preferable that the tube voltage is within a predetermined range (for example, 40 V or more) at the start of lighting of the discharge lamp 100.
That is, it is preferable to suppress an increase in tube voltage during the product life of the discharge lamp 100 and to make the tube voltage within a predetermined range at the start of lighting.

Therefore, in the discharge lamp 100, the proportion of the indium halide contained in the metal halide 2 is 0.1 wt% or more and 0.33 wt% or less, and the dimension d of the longest inner diameter of the light emitting portion 11 is 1. 5 mm or more and 2.3 mm or less.
Further, a gap connected to the discharge space 111 is provided between the electrode 32 and the sealing portion 12.

FIG. 2 is a graph for illustrating the relationship between the ratio of the halide of indium and the change in tube voltage.
FIG. 2 shows the result of a flashing test performed under the same conditions as in the EU 120 minute mode, which is a life test condition for automobile headlamp discharge lamps determined by the Japan Light Bulb Industry Association.

The blinking test was performed under the following conditions.
The light emitting unit 11 has a dimension d of the longest inner diameter of 2.2 mm, an outer diameter of 5.2 mm, and a length of the light emitting unit 11 in the longitudinal direction of 7.8 mm.
The electrode 32 had a cylindrical shape, a diameter dimension of 0.28 mm, and a length dimension of 7.5 mm. Moreover, the protrusion length to the discharge space 111 of the electrode 32 was 2.2 mm.
The outer tube 5 was made of UV cut quartz glass. Argon (Ar), which is an inert gas, was sealed in the closed space formed between the inner tube 1 and the outer tube 5, and the sealing pressure of the inert gas was 0.1 atm at room temperature (25 ° C.).

The amount of metal halide 2 including indium halide was 0.2 mg. The halide was iodide.
The proportion of indium halide contained in the metal halide 2 was 0.05 wt%, 0.10 wt%, and 0.15 wt%.
In FIG. 2, A is 0.05 wt%, B is 0.10 wt%, and C is 0.15 wt%. Moreover, it controlled using the ballast (electrical ballast) so that it might be set to 60W at the time of lighting start, and 25W at the time of stable lighting.
And it blinked by the blink cycle of EU120 minute mode, and the change of tube voltage was measured.

  As can be seen from FIG. 2, when the ratio of the indium halide contained in the metal halide 2 is 0.1 wt% or more, the increase in tube voltage can be suppressed.

Here, if the ratio of the indium halide contained in the metal halide 2 changes, the reason why the tube voltage changes is not necessarily clear, but the following may be considered.
First, when the discharge lamp 100 is turned on, plasma is generated in the discharge space 111. At this time, the plasma is unevenly distributed on the upper end side of the discharge space 111 by convection. Therefore, the temperature on the upper end side of the light emitting unit 11 is higher than the temperature on the lower end side of the light emitting unit 11. In addition, the temperature of the electrode 32 made of a material close to plasma and having high thermal conductivity is higher than the temperature of the light emitting unit 11.

Next, when the discharge lamp 100 is turned off, the temperature decreases, so that the evaporated indium halide present in the discharge space 111 is condensed and accumulated on the lower end side of the discharge space 111.
Here, according to the knowledge obtained by the present inventor, the speed at which the temperature decreases differs between the electrode 32 and the lower end side of the discharge space 111 where the condensed indium halide accumulates. That is, the rate of temperature decrease of the electrode 32 made of a material having high thermal conductivity is faster than the rate of temperature decrease on the lower end side of the discharge space 111.

FIG. 3 is a schematic graph for illustrating the state of temperature drop.
In FIG. 3, S1 represents a temperature decrease of the electrode 32, and S2 to S4 represent a temperature decrease on the lower end side of the discharge space 111 in which condensed indium halide accumulates.
S2 and S3 are temperature curves on the lower side of the discharge space 111 when the discharge lamp 100 in service life is turned off. S4 is a temperature curve below the discharge space 111 at the beginning of the lifetime. When the temperature of the light emitting unit 11 rises during the lifetime, the temperature T at which S1 and S2 cross each other becomes lower than the temperature at which the evaporated indium halide condenses.

  When the discharge lamp 100 is extinguished, the temperature is lowered, and condensation starts when the temperature becomes lower than the temperature at which the evaporated indium halide condenses. At this time, condensation preferentially occurs in a place where the temperature is low.

  As can be seen from FIG. 3, in the case of S2 and S3, the temperature of S1 becomes lower than the temperatures of S2 and S3 over time. Therefore, in the case of S2 and S3, condensation occurs preferentially in the electrode 32.

  On the other hand, in the case of S4, since the temperature of S4 remains lower than the temperature of S1, condensation preferentially occurs on the lower end side of the discharge space 111.

Here, when condensation preferentially occurs in the electrode 32, the condensed indium halide enters the gap between the electrode 32 and the sealing portion 12. And the indium halide which penetrate | invaded into the clearance gap between the electrode 32 and the sealing part 12 is suppressed from evaporating again in the case of subsequent lighting.
It has been confirmed visually that indium halide enters the gap between the electrode 32 and the sealing portion 12.

That is, since the indium halide gradually accumulates in the gap between the electrode 32 and the sealing portion 12 while turning on and off repeatedly, the amount of indium halide contained in the metal halide 2 is gradually reduced. Become.
When the amount of indium halide is reduced, the amount of evaporated indium halide present in the discharge space 111 during lighting is reduced.
Therefore, the increase in tube voltage is suppressed as shown by B and C in FIG. Since C contains more indium halide than encapsulated B, there are many indium halides contributing to the tube voltage, and the effect is noticeable.

Further, when the amount of indium enclosed is small, the amount of indium halide contributing to the tube voltage is small, and the increase in tube voltage cannot be suppressed as indicated by A in FIG.

  As described above, if the ratio of the indium halide contained in the metal halide 2 is set to 0.1 wt% or more, an increase in tube voltage can be suppressed. However, when the ratio of the halide of indium contained in the metal halide 2 is increased, there is a problem that the influence of indium entering during the lifetime is too great and the luminous flux is lowered.

FIG. 4 is a graph for illustrating the relationship between the ratio of indium halide and the decrease in luminous flux.
As shown in FIG. 4, when the ratio of the indium halide contained in the metal halide 2 is 0.50 wt%, the reduction of the luminous flux becomes too large.
Therefore, the ratio of the indium halide contained in the metal halide 2 is preferably 0.1 wt% or more and 0.33 wt% or less.

Further, if the dimension d of the longest inner diameter of the light emitting unit 11 changes, the temperature drop on the lower end side of the discharge space 111 changes.
FIG. 5 is a schematic graph for illustrating the state of the temperature drop.
S1 in FIG. 5 represents a temperature drop of the electrode 32, and S5 and S6 represent a temperature drop on the lower end side of the discharge space 111 in which condensed indium halide accumulates.
The dimension d in S5 is smaller than the dimension d in S6.

If the dimension d is small, the distance from the plasma is small, so the temperature on the lower end side of the discharge space 111 during lighting is high.
Therefore, as shown in FIG. 5, the temperature immediately after the extinguishing in S5 is higher than the temperature immediately after the extinguishing in S6.

As can be seen from FIG. 5, in the case of S5, the temperature of S1 becomes lower than the temperature of S5 over time. Therefore, in the case of S5, condensation preferentially occurs at the electrode 32.
On the other hand, in the case of S6, since the temperature of S6 remains lower than the temperature of S1, condensation preferentially occurs on the lower end side of the discharge space 111.

For this reason, in the case of S5 having a small dimension d, indium halide gradually accumulates in the gap between the electrode 32 and the sealing portion 12 during repeated lighting and extinguishing, so that the indium contained in the metal halide 2 The amount of halide is gradually reduced.
As a result, an increase in tube voltage can be suppressed.
In the case of S6 having a large dimension d, the amount of indium halide contained in the metal halide 2 is substantially constant.
Therefore, the increase in tube voltage cannot be suppressed.

As described above, if the dimension d is reduced, an increase in tube voltage can be suppressed.
However, if the dimension d is too small, there is a risk of leakage and non-lighting.
Table 1 is a table for illustrating an appropriate range of the dimension d of the longest inner diameter portion of the light emitting unit 11.

表１から分かるように、発光部１１の内径の最も長い部分の寸法ｄを１．５ｍｍ以上、２．３ｍｍ以下とすれば、管電圧の上昇を抑制することができ、且つ、リークの発生による不灯を抑制することができる。

As can be seen from Table 1, if the dimension d of the longest inner diameter of the light emitting part 11 is 1.5 mm or more and 2.3 mm or less, the increase in tube voltage can be suppressed and the occurrence of leakage Non-lighting can be suppressed.

  If the ratio of indium halide contained in the metal halide 2 is gradually reduced by repeatedly turning on and off the discharge lamp 100, the tube voltage at the start of lighting seems to gradually decrease. However, if the usage time of the discharge lamp 100 becomes longer, the light emitting unit 11 becomes more blackened and clouded, so that the temperature at the start of lighting can be increased. Therefore, if the discharge lamp 100 satisfies the above-described conditions, the tube voltage at the start of lighting can be kept within a predetermined range.

Next, the gap between the electrode 32 and the sealing portion 12 will be further described.
The gap between the electrode 32 and the sealing portion 12 can be formed as follows.
For example, immediately after the sealing portion 12 is formed by a pinch seal method, a shrink seal method, or the like, no gap is formed because the electrode 32 and the sealing portion 12 are in close contact. In the cooling process after the sealing portion 12 is formed, the contraction amount of the electrode 32 is larger than the contraction amount of the sealing portion 12 due to the difference in the thermal expansion coefficient of the material. Therefore, a gap connected to the discharge space 111 is formed between the electrode 32 and the sealing portion 12.

  The metal foil 31 inside the sealing part 12 can be bent so as to follow the contraction of the sealing part 12. Therefore, it is possible to suppress the formation of a gap between the sealing portion 12 and the metal foil 31 in the cooling process after the sealing portion 12 is formed. That is, since the adhesion between the sealing portion 12 and the metal foil 31 can be maintained, airtightness can be maintained in the region of the sealing portion 12 where the metal foil 31 is provided.

Here, if a gap is not formed between the electrode 32 and the sealing portion 12, it is difficult to obtain the effect of suppressing the increase in the tube voltage described above.
Therefore, in the discharge lamp 100, the coil 33 is wound around the outside of the electrode 32 so that a gap is easily formed.

When the coil 33 is wound around the outside of the electrode 32, the close contact between the electrode 32 and the sealing portion 12 is prevented at a portion where the coil 33 and the electrode 32 are in contact with each other. Therefore, the contact area between the electrode 32 and the sealing portion 12 can be reduced, and thus a gap is easily formed in the cooling process after the sealing portion 12 is formed.
Furthermore, since the coil 33 can be bent so as to follow the contraction of the sealing portion 12, a crack or the like that reaches the outer surface of the sealing portion 12 is generated in the cooling process after the formation of the sealing portion 12. The suppressing effect can also be enjoyed.
(Second Embodiment)
Next, a vehicle lamp 200 according to the second embodiment is illustrated.
The vehicular lamp 200 is a vehicular lamp that includes the discharge lamp 100 described above.
FIG. 6 is a schematic diagram for illustrating the configuration of the vehicular lamp 200.
In FIG. 6, “front” is the front of the automobile with the discharge lamp 100 attached, “rear” is the rear of the automobile with the discharge lamp 100 attached, “upper” is the upper side of the automobile with the discharge lamp 100 attached, and “lower” "Is below the automobile with the discharge lamp 100 attached.
FIG. 6 shows a case where the discharge lamp 100 is attached so that the pair of electrodes 32 provided on the discharge lamp 100 are horizontal. That is, the case of the discharge lamp 100 that is horizontally lit is illustrated.
FIG. 7 is a schematic diagram for illustrating a circuit of the vehicular lamp 200.

As shown in FIG. 6, the vehicular lamp 200 is provided with a discharge lamp 100, a reflector 202, a light shielding control plate 203, a lens 204, and a lighting circuit 205.
The reflector 202 reflects the light emitted from the discharge lamp 100 to the front side. The reflector 202 is made of, for example, a metal having a high reflectance. A space is provided inside the reflector 202, and the inner surface has a parabolic shape.

The front and rear end portions of the reflector 202 are open.
The socket 102 of the discharge lamp 100 is attached in the vicinity of the opening on the rear side of the reflector 202. The burner 101 of the discharge lamp 100 is located in the space inside the reflector 202.

The light shielding control plate 203 is provided inside the reflector 202, on the front side of the burner 101 and on the lower side of the burner 101.
The light shielding control plate 203 is made of a light shielding material such as metal. The light shielding control plate 203 is provided to form a light distribution called a cut line. The light shielding control plate 203 is movable, and switching from the low beam to the high beam is possible by tilting the light shielding control plate 203 downward.

  The lens 204 is provided so as to close the opening on the front side of the reflector 202. The lens 204 can be a convex lens. The lens 204 collects the light directly incident from the discharge lamp 100 and the light reflected and incident by the reflector 202 to form a desired light distribution.

The lighting circuit 205 is a circuit for starting the discharge lamp 100 and maintaining lighting.
As shown in FIG. 7, the lighting circuit 205 can include, for example, an igniter circuit 205a and a ballast circuit 205b.
A DC power source DS such as a battery and a switch SW are electrically connected to the input side of the lighting circuit 205. The discharge lamp 100 is electrically connected to the output side of the lighting circuit 205.

  The igniter circuit 205a includes, for example, a transformer, a capacitor, a gap, and a resistor. The igniter circuit 205 a generates a high-pressure pulse of about 30 kV and applies it to the discharge lamp 100. By applying a high-pressure pulse of about 30 kV to the discharge lamp 100, dielectric breakdown occurs between the pair of electrodes 32, and discharge occurs. That is, the discharge lamp 100 is started by the igniter circuit 205a.

  The ballast circuit 205b includes, for example, a DC / DC conversion circuit, a DC / AC conversion circuit, a current / voltage detection circuit, a control circuit, and the like. The ballast circuit 205b maintains the lighting of the discharge lamp 100 started by the igniter circuit 205a.

  As mentioned above, although several embodiment of this invention was illustrated, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, changes, and the like can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and equivalents thereof. Further, the above-described embodiments can be implemented in combination with each other.

  DESCRIPTION OF SYMBOLS 1 Inner tube, 2 Metal halide, 3 Electrode mount, 5 Outer tube, 11 Light emission part, 12 Sealing part, 31 Metal foil, 32 Electrode, 33 Coil, 34 Lead wire, 100 Discharge lamp, 101 Burner, 102 Socket, 111 discharge space, 200 vehicle lamp, 202 reflector, 204 lens, 205 lighting circuit, 205b ballast circuit

Claims (5)

A light emitting part having a discharge space in which a metal halide containing an indium halide is enclosed;
A pair of electrodes protruding into the discharge space and arranged to face each other at a predetermined distance;
A sealing portion provided at each end of the light emitting portion in the direction in which the pair of electrodes extend, and having an end on the opposite side of the discharge space from the electrode ;
A coil wound around the outside of the electrode provided inside the sealing portion;
Comprising
The proportion of indium halide contained in the metal halide is 0.1 wt% or more and 0.33 wt% or less,
The direction of the discharge space is perpendicular to the direction in which the pair of electrodes extend, and the dimension of the longest part of the discharge space is 1.5 mm or more and 2.3 mm or less,
A discharge lamp in which a gap is provided between the sealing portion and the electrode.   The discharge lamp according to claim 1, wherein an indium halide is provided in the gap by turning on and off the discharge lamp.   The discharge lamp according to claim 1, wherein the metal halide further includes a halide of sodium, a halide of scandium, and a halide of zinc. A discharge lamp according to any one of claims 1 to 3;
A lighting circuit electrically connected to the discharge lamp;
A vehicular lamp provided with   The vehicular lamp according to claim 4, wherein the discharge lamp is attached so that a pair of electrodes provided on the discharge lamp are horizontal.

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