JP2014093160A - Discharge lamp and lighting fixture for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge lamp which is bright immediately after lighting, and brightness decrease of which is small during life period, and to provide a lighting fixture for vehicle.SOLUTION: A discharge lamp includes a light emission part internally having a discharge space filled with a metallic halide containing a halide of tin, and a pair of electrodes arranged to face each other at a predetermined distance and projecting into the discharge space. The ratio of halide of tin contained in the metallic halide is 0.5-1.4 wt%, and the distance between the light emission part and the inside wall is 0.9-1.2 mm.

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, if the power is low, the brightness may be insufficient.
In particular, if the luminous flux is greatly reduced during the life of the discharge lamp, it may not function as a headlamp for an automobile. For this reason, there is a need for a discharge lamp that has a low decrease in luminous flux during the lifetime.
Moreover, the discharge lamp used for the headlamp for motor vehicles is requested | required to become bright immediately after lighting from a safety viewpoint.
Therefore, it has been desired to develop a discharge lamp that is bright immediately after lighting and has a small decrease in luminous flux during the lifetime.

JP 2004-172056 A

  The problem to be solved by the present invention is to provide a discharge lamp and a vehicular lamp that are bright immediately after lighting and have a low luminous flux decrease during the lifetime.

  A discharge lamp according to an embodiment includes: a light emitting unit having a discharge space in which a metal halide containing a tin halide is enclosed; a pair projecting into the discharge space and arranged to face each other at a predetermined distance And electrodes. The ratio of tin halide contained in the metal halide is 0.5 wt% or more and 1.4 wt% or less, and the distance between the central axis of the electrode and the inner wall of the light emitting portion is 0. 0%. It is 9 mm or more and 1.2 mm or less.

  According to the embodiment of the present invention, it is possible to provide a discharge lamp and a vehicular lamp that are bright immediately after lighting and have a low luminous flux decrease during the lifetime.

It is a schematic diagram for illustrating the discharge lamp 100 according to the present embodiment. 4 is a graph for illustrating the ratio of tin halide contained in metal halide 2. FIG. It is a graph for demonstrating the mode of the increase of the light beam after a lighting start. 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 includes a light emitting portion having a discharge space in which a metal halide containing a tin halide is enclosed; a pair of electrodes projecting into the discharge space and arranged to face each other at a predetermined distance And a discharge lamp comprising: And the ratio of the tin halide contained in the metal halide is 0.5 wt% or more and 1.4 wt% or less, and the distance between the central axis of the electrode and the inner wall of the light emitting portion is: It is 0.9 mm or more and 1.2 mm or less.
According to this discharge lamp, it is possible to prevent the luminous flux from decreasing during the life of the discharge lamp, and it is possible to prevent the light from becoming dark immediately after the start of lighting of the discharge lamp.

The second invention is the discharge lamp according to the first invention, wherein the halide is an iodide.
According to this discharge lamp, it is possible to further suppress the reduction of the luminous flux during the life of the discharge lamp and the darkening immediately after the start of lighting.

The third invention is the first or second invention, wherein the discharge space is filled with an inert gas, and the filling pressure of the inert gas is 10 atm or more and 20 atm or less at room temperature (25 ° C.). This is a discharge lamp.
According to this discharge lamp, the total luminous flux can be increased.

According to a fourth aspect of the present invention, there is provided 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 vehicular lamp, it is possible to prevent the luminous flux from decreasing during the life of the discharge lamp, and it is possible to prevent the light from becoming dark immediately after the discharge lamp starts to be lit.
Moreover, a predetermined light flux can be obtained in a short time after the start of lighting.

A fifth invention is the vehicle 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.

FIG. 1 is a schematic view for illustrating a discharge lamp 100 according to the present 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 columnar central portion and tapered at both ends is provided.
A discharge medium is enclosed in the discharge space 111. The discharge medium includes a metal halide 2 containing a tin halide and an inert gas.
That is, the light emitting unit 11 has a discharge space 111 in which the metal halide 2 containing a tin halide is enclosed.

  The metal halide 2 includes a halide such as sodium, scandium, zinc, and indium, and a tin halide. As the halogen, for example, iodine can be exemplified. However, bromine or chlorine can be used instead of iodine.

The ratio of tin halide contained in metal halide 2 (weight of tin halide ÷ weight of metal halide 2 containing tin halide × 100) is 0.5 wt% or more and 1.4 wt% or less. can do.
Details regarding the proportion of tin 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. 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 on the end portion of the 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, 3.7 mm or more and 4.4 mm or less.
The distance L between the central axis 32a of the electrode 32 and the inner wall of the light emitting unit 11 is preferably 0.9 mm or more and 1.2 mm or less.
In addition, the detail regarding the distance L between the central axis 32a of the electrode 32 and the inner wall 11a of the light emission part 11 is mentioned later.

  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.

  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.

  The lighting circuit 205 (see FIG. 5) is connected so that the bottom terminal 81 is on the high voltage side and the side terminal 82 is on the low voltage 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, if the metal halide 2 containing a tin halide is enclosed in the discharge space 111, it is possible to prevent the luminous flux from decreasing during the life of the discharge lamp 100.
However, tin has the property of being easily vaporized and not contributing to the luminous flux. Therefore, there is a problem that tin that does not contribute to the luminous flux is vaporized and darkened immediately after the lighting of the discharge lamp 100 is started. For example, when the discharge lamp 100 is used for an automobile headlamp, it is required to be bright immediately after the start of lighting from the viewpoint of safety. Therefore, it is difficult to use the discharge lamp 100 in which the tin halide is enclosed for the headlamp of the automobile.

  Moreover, the discharge lamp 100 used for the headlamp of a car is generally lit at about 35 W during stable lighting. However, from the viewpoint of energy saving, lighting has been started at 30 W or less (for example, 20 W to 30 W). Since the discharge lamp 100 that is lit with such low power has a low luminous flux at the time of stable lighting, it becomes more difficult to secure the luminous flux immediately after the discharge lamp 100 starts to be lit.

That is, if a tin halide is simply included, it may become dark immediately after the start of lighting, and it is particularly difficult to use it for a headlight of an automobile.
According to the knowledge obtained by the present inventors, if the content ratio of tin halide and the distance L between the central axis 32a of the electrode 32 and the inner wall of the light emitting portion 11 are optimized, the discharge lamp 100 can be obtained. It is possible to prevent the luminous flux from decreasing during the lifetime of the lamp, and it is possible to prevent the light from becoming dark immediately after the discharge lamp 100 is turned on.

Next, the ratio of tin halide contained in the metal halide 2 will be further described.
FIG. 2 is a graph for illustrating the ratio of tin halide contained in the metal halide 2.
FIG. 2 shows the result of a lighting 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 lighting test was performed under the following conditions.
The light emitting unit 11 has an inner cylindrical dimension of 2.2 mm, an outer diameter of 5.2 mm, and a length of the light emitting part 11 in the longitudinal direction of 7.8 mm.
The distance L between the central axis 32a of the electrode 32 and the inner wall of the light emitting unit 11 is 1.1 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. 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 containing tin halide was 0.2 mg. The halide was iodide.

The ratio of tin halide (SnI ₂ ) contained in the metal halide 2 was 1.5 wt%, 1.0 wt%, and 0.5 wt%.
Control was performed using a ballast (electric ballast) so that the power was 60 W at the start of lighting and 25 W at the time of stable lighting.

  As can be seen from FIG. 2, when the ratio of tin halide contained in the metal halide 2 is 0.5 wt% or more, it is possible to prevent the luminous flux from decreasing during the lifetime of the discharge lamp 100.

Next, the distance L between the central axis 32a of the electrode 32 and the inner wall 11a of the light emitting unit 11 will be further described.
Table 1 is a table for illustrating the relationship between the distance L, the ratio of tin halide, and the luminous flux.
The measurement conditions of the luminous flux were the same as those in the lighting test described in FIG. 2, and the distance L and the ratio of tin halide were changed.
As described above, if a tin halide is simply included, there is a possibility that it will become dark immediately after the start of lighting.
Therefore, the light flux at 4 seconds after the start of lighting was measured, and the suitability was determined based on whether the light flux was 1000 lm or more.

表１から分かるように、距離Ｌを長くしすぎると（例えば、１．３ｍｍ）、金属ハロゲン化物２自体の発光が遅くなり、点灯開始後４秒における光束が１０００ｌｍ未満となる。 距離Ｌを短くしすぎると（例えば、０．８ｍｍ）、錫の気化が速くなり、点灯開始後４秒における光束が１０００ｌｍ未満となる。
また、距離Ｌが、０．９ｍｍ以上、１．２ｍｍ以下の範囲では点灯開始後４秒における光束が１０００ｌｍ以上となる。
ただし、距離Ｌが、０．９ｍｍ以上、１．２ｍｍ以下の範囲であっても、錫のハロゲン化物の割合が多くなると（例えば、１．５ｗｔ％）、点灯開始後４秒における光束が１０００ｌｍ未満となる。そのため、錫のハロゲン化物の割合は、１．４ｗｔ％以下とすることが好ましい。

As can be seen from Table 1, if the distance L is too long (for example, 1.3 mm), the light emission of the metal halide 2 itself is delayed, and the luminous flux in 4 seconds after the start of lighting is less than 1000 lm. If the distance L is too short (for example, 0.8 mm), the vaporization of tin is accelerated, and the luminous flux in 4 seconds after the start of lighting is less than 1000 lm.
Further, when the distance L is in the range of 0.9 mm or more and 1.2 mm or less, the luminous flux in 4 seconds after the start of lighting is 1000 lm or more.
However, even if the distance L is in the range of 0.9 mm or more and 1.2 mm or less, if the proportion of tin halide increases (for example, 1.5 wt%), the luminous flux in 4 seconds after starting lighting is less than 1000 lm. It becomes. Therefore, the ratio of tin halide is preferably 1.4 wt% or less.

  As can be seen from FIG. 2 and Table 1, the ratio of tin halide contained in the metal halide 2 is 0.5 wt% or more and 1.4 wt% or less, and the central axis 32a of the electrode 32 and the light emitting portion 11 If the distance L between the inner wall and the inner wall is set to 0.9 mm or more and 1.2 mm or less, it is possible to prevent the light flux from decreasing during the life of the discharge lamp 100 and immediately after the discharge lamp 100 starts lighting. Can also be made dark.

  As described above, when the discharge lamp 100 is used for a headlight of an automobile, it is required to be bright immediately after the start of lighting from the viewpoint of safety. In this case, it is preferable that a predetermined light flux is obtained in as short a time as possible after the start of lighting.

FIG. 3 is a graph for illustrating how the luminous flux increases after the lighting is started.
The measurement conditions of the luminous flux were the same as those in the lighting test described in FIG. Therefore, the distance L between the central axis 32a of the electrode 32 and the inner wall of the light emitting unit 11 is 1.1 mm.
Note that “100” in FIG. 3 indicates that the ratio of tin halide contained in the metal halide 2 is 1 wt% (in the case of the discharge lamp 100 according to the present embodiment), and “110” indicates the metal halide 2. In the case where the ratio of tin halide contained in is 1.5 wt%, “120” is the case where no tin halide is contained.

  As can be seen from FIG. 3, the ratio of tin halide contained in the metal halide 2 is 0.5 wt% or more and 1.4 wt% or less, and the center axis 32 a of the electrode 32 and the inner wall of the light emitting portion 11 If the distance L between them is 0.9 mm or more and 1.2 mm or less, a predetermined light flux can be obtained in a short time after the start of lighting.

Next, the vehicle lamp 200 including the discharge lamp 100 according to the present embodiment will be illustrated.
FIG. 4 is a schematic diagram for illustrating the configuration of the vehicular lamp 200.
In FIG. 4, “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. 4 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. 5 is a schematic diagram for illustrating a circuit of the vehicular lamp 200.

As shown in FIG. 4, 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. 5, 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, 3 electrode mount, 4 sleeve, 5 outer tube, 11 light emission part, 11a inner wall, 12 sealing part, 32 electrodes, 32a central axis, 34 lead wire, 35 support wire, 71 metal band, 100 discharge lamp, 101 burner, 102 socket, 111 discharge space, 200 vehicle lamp, 202 reflector, 203 shading control plate, 204 lens, 205 lighting circuit, 205a igniter circuit, 205b ballast circuit

Claims (5)

A light emitting part having a discharge space in which a metal halide containing a tin halide is enclosed;
A pair of electrodes protruding into the discharge space and arranged to face each other at a predetermined distance;
Comprising
The ratio of tin halide contained in the metal halide is 0.5 wt% or more and 1.4 wt% or less,
A discharge lamp in which a distance between a central axis of the electrode and an inner wall of the light emitting unit is 0.9 mm or more and 1.2 mm or less.   The discharge lamp according to claim 1, wherein the halide is iodide.   3. The discharge lamp according to claim 1, wherein an inert gas is enclosed in the discharge space, and an enclosure pressure of the inert gas is 10 atm or more and 20 atm or less at normal temperature (25 ° C.). 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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