JP2008181680A - Metal halide lamp, lighting device, automotive headlamp device - Google Patents

Abstract

[PROBLEMS] To improve the deterioration of the life characteristics of a mercury-free metal halide lamp.
A metal halide lamp includes a discharge vessel 11 having a discharge space 14 and sealing portions 12a and 12b. A discharge medium containing a metal halide and a rare gas and not containing mercury is enclosed in the discharge vessel 11. A pair of electrodes 3a2 and 3b2 are disposed opposite to each other in the discharge space 14, and base side end portions of these electrodes 3a2 and 3b2 are joined to the metal foils 3a1 and 3b1, respectively. Lead wires 3a3 and 3b3 are joined to the other end portions of the metal foils 3a1 and 3b1, respectively. In this state, the metal foils 3a1 and 3b1 are hermetically sealed by the sealing portions 12a and 12b. Concave and convex portions 4a and 4b are formed in a region including the vicinity of the junction between the metal foil 4 and the electrode shaft 3a. The concavo-convex portions 4a and 4b suppress the reaction with free halogen or metal halide, thereby realizing a longer lamp life.
[Selection] Figure 1

Description

  The present invention relates to a metal halide lamp, a lighting device for the lamp, and an automotive headlamp device.

Conventional mercury-free metal halide lamps that do not use mercury have a problem in that the metal foil made of molybdenum foil or the like that ensures the airtightness of the discharge vessel is likely to react with the discharge medium. In order to prevent the reaction with the discharge medium and to improve the life characteristics due to the absence of mercury. (For example, Patent Document 1)
JP 2002-260581 A

  In the technique of Patent Document 1 described above, even when the coating film is formed on the entire metal foil, a crack occurs in the coating film due to the difference in thermal expansion coefficient between the coating film and the metal foil during sealing. Since the discharge medium permeates through the crack, there is a problem that a crack or the like is generated in the sealing portion, causing a factor that adversely affects the long life.

  SUMMARY OF THE INVENTION An object of the present invention is a metal halide lamp that essentially does not use mercury, a metal halide lamp that has been improved such as a decrease in life characteristics caused by not using mercury, a metal halide lamp lighting device using the lamp, and an automobile An object of the present invention is to provide a headlight device for use.

  In order to solve the above-described problems, a metal halide lamp of the present invention includes a discharge vessel having a discharge space and sealing portions provided at both ends of the discharge space, and a metal halide sealed in the discharge vessel. A discharge medium containing noble gas and essentially free of mercury; a pair of electrodes disposed opposite to each other in the discharge space; and a base side end of each of the pair of electrodes; and A metal foil hermetically sealed by a sealing portion; a pair of external leads joined to the other end side of the metal foil and led out of the sealing portion; and the electrode of the metal foil And an uneven portion formed in a mesh shape by alternately connecting recesses and projections with a roughness of 0.5 μm ≦ Ra ≦ 3 μm and 1.5 μm ≦ Rz ≦ 10 μm. It is characterized by doing.

  According to the present invention, by forming an uneven portion at the joint between the metal foil and the electrode, the reaction between the metal foil and free halogen or metal halide in the discharge medium can be suppressed, and the lamp has a long service life. Can be achieved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  1 to 4 are diagrams for explaining a first embodiment of the metal halide lamp according to the present invention, FIG. 1 is a schematic configuration diagram, and FIG. 2 is a front view showing an enlarged main part of FIG. FIG. 3 is a front view showing the main part of FIG. 2 further enlarged, and FIG. 4 is a cross-sectional view taken along the line aa ′ of FIG.

  In FIG. 1, reference numeral 1 denotes an inner tube constituting a metal halide lamp. Sealing portions 12a and 12b are formed at both ends of a discharge vessel 11 at the center, and cylindrical non-tubes are formed at both ends. Sealing portions 13a and 13b are formed. The inner tube 1 can be used as long as it is a material excellent in heat resistance and translucency. For example, quartz glass can be used.

  Inside the discharge vessel 11, a discharge space 14 having a substantially cylindrical shape at the center and a tapered shape at both ends in the axial direction is formed. The volume of the discharge space 14 is preferably 100 μl or less for a short arc type discharge lamp, and the volume of the discharge space is preferably 10 μl to 40 μl when an automotive headlamp is used.

  In the discharge space 14, a discharge medium composed of the metal halide 2 and a rare gas is enclosed. The discharge medium is essentially free of mercury. Next, a specific example of the discharge medium will be described.

  First, as the metal halide 2, halides of various metal elements can be used. For example, a first halide that mainly contributes to light emission is used. As the first halide, a halide of one or more kinds of metal elements selected from sodium (Na), scandium (Sc), and a rare earth metal is used. Na and Sc are particularly efficient luminous materials.

  The metal halide 2 may contain one or a plurality of halides of a metal having a relatively high vapor pressure and less light emission in the visible light region as compared with the first halide as the second halide. it can. The metal that does not easily emit light in the visible light region has a higher energy level than the metal of the first halide and may be in a state where the metal of the first halide mainly emits light. By adding the second halide, a lamp voltage close to that of a lamp containing mercury can be obtained, and the electric and light emission characteristics of the mercury-free metal halide lamp can be improved. The second halide contributes to chromaticity improvement and the like.

  Examples of the second halide include magnesium (Mg), iron (Fe), cobalt (Co), chromium (Cr), zinc (Zn), nickel (Ni), manganese (Mn), aluminum (Al), and antimony. One or more metal halides selected from (Sb), beryllium (Be), rhenium (Re), gallium (Ga), indium (In), titanium (Ti), zirconium (Zr) and hafnium (Hf) Is used.

  Further, the metal halide 2 may contain a third halide. In the third halide, for example, tin (Sn) is added as a component that contributes to suppression of free halogen, and cesium (Cs) is added as a component that corrects the distribution of the arc temperature to reduce heat loss.

  As the halogen constituting the metal halide 2, iodine (I) is most suitable in terms of low reactivity, and the reactivity increases in the order of bromine (Br), chlorine (Cl), and fluorine (F). It can be appropriately selected as necessary. Further, different halogen compounds such as iodide and bromide can be used in combination.

  With respect to the amount of metal halide 2 enclosed, for example, the first halide that mainly contributes to light emission can be enclosed in the range of 5 mg to 110 mg per 1 cc of the internal volume of the discharge vessel (volume of the discharge space). A more preferable range is 5 mg to 35 mg per 1 cc of the internal volume of the discharge vessel. In such a range, the rise of the luminous flux can be accelerated and the light color can be stabilized. The second halide can be enclosed in the range of 0.05 mg to 200 mg per 1 cc of the internal volume of the discharge vessel. About other halides, it adjusts suitably.

  In addition to starting and buffer gas, the rare gas acts to emit main light immediately after starting. Generally, there is no particular limitation as long as it does not pass through the discharge vessel 11, but argon (Ar), krypton (Kr), or xenon (Xe) is recommended when the hermetic vessel 11 is formed of quartz glass. When light emission immediately after start-up depends on a rare gas, xenon is optimal because xenon has the highest luminous efficiency.

  When the enclosure pressure of the rare gas is increased, the lamp voltage is increased, and the lamp input can be increased for the same lamp current to improve the rising characteristics of the luminous flux. Good rise characteristics of the luminous flux are convenient for any purpose of use, but are particularly important for automotive headlamp devices and liquid crystal projectors. For example, the rare gas is sealed at a pressure of 3 atm or more, and is preferably sealed in a range of 5 to 15 atm.

  Further, “essentially no mercury is enclosed” is not limited to the state where mercury is not enclosed at all, and it is acceptable that less than 2 mg of mercury, preferably 1 mg or less of mercury exists per 1 cc of internal volume of the discharge vessel. Means. However, it is environmentally desirable that mercury is not encapsulated. In the case where the electrical characteristics of the discharge lamp are maintained by the conventional mercury vapor, the short arc type is filled with 20 mg to 40 mg of mercury per 1 cc of the internal volume of the discharge vessel, and in some cases, 50 mg or more of mercury. It can be said that the amount of mercury used in is essentially low.

  In FIG. 1 again, mounts 3a and 3b are sealed inside the sealing portions 12a and 12b. The mounts 3a and 3b include metal foils 3a1 and 3b1, electrodes 3a2 and 3b2, and lead wires 3a3 and 3b3.

  The metal foils 3a1 and 3b1 are strip-shaped thin metal plates having a high melting point such as molybdenum. As shown in FIG. 3, concave and convex portions 4a and 4b formed by the concave portions 31 and the convex portions 32 are formed at and near the joint portion between the metal foil 3a1 and the electrode 3a2, and at the joint portion between the metal foil 3b1 and the electrode 3b2. Yes.

  Here, the irregularities 4a and 4b have a roughness of 0.5 μm ≦ Ra ≦ 3 μm and 1.5 μm ≦ Rz ≦ 10 μm, and are flat as the concave portions 31 and the convex portions 32 are alternately linked to form a mesh shape. It is formed so that these parts do not continue. Here, Ra represents arithmetic average roughness, and Rz represents ten-point average roughness.

  The concavo-convex portions 4a and 4b suppress the reaction between the metal foils 3a1 and 3b1 and the free halogen or metal halide in the discharge medium by increasing the distance through which the concave portions 31 and the convex portions 32 are transmitted. In order to suppress the reaction between the metal foils 3a1, 3b1 and free halogen or metal halide, the concavo-convex parts 4a, 4b are formed so as to cover the entire area of both surfaces of the metal foils 3a1, 3b1 (see FIG. 4).

  In this embodiment, the reaction between the metal foil and the free halogen or metal halide in the discharge medium can be suppressed by the uneven portions formed on the surface of the metal foil. For this reason, it is possible to suppress the occurrence of foil breakage, cracks in the sealing portion, leakage due to the metal foil reaction, and further explosion, and it is possible to obtain a long-life mercury-free less metal halide lamp. .

  FIG. 5 is a sectional view for explaining a second embodiment relating to the metal halide lamp of the present invention. In this figure, the state which expanded the one surface of metal foil is shown. In this embodiment, the surface of the concavo-convex portions 4a and 4b is covered with a coating film 51 filled with fine particles 5a made of at least one selected from metals and metal oxides.

  Since the coating film 51 is sealed by the sealing portions 12a and 12b together with the metal foils 3a1 and 3b1, a high melting point material that does not change in quality under heating conditions of 1500 ° C. for 5 seconds to 60 seconds is preferable.

  The fine particles 5a forming the coating film 51 are fine particles in order to make it difficult for free halogen gas and metal halide gas to diffuse in the coating film. By forming the coating film 51 with metal oxide fine particles of about 20 nm to 100 nm as tried this time, for example, a good halogen resistance effect can be obtained.

  Examples of the metal material of the coating film 51 include platinum (Pt), tantalum (Ta), tungsten (W), molybdenum (Mo), rhenium (Re), niobium (Nb), vanadium (V), zirconium (Zr), Examples thereof include at least one selected from hafnium (Hf), holmium (Ho), dysprosium (Dy), yttrium (Y), scandium (Sc), and boron (B). The metal material is not limited to being used as a single metal, but may be used as an alloy containing the above metal element.

As the metal oxide, silica (SiO ₂ ), alumina (Al ₂ O ₃ ), zirconia (ZrO ₂ ), hafnia (HfO ₂ ), yttria (Y ₂ O ₃ ), holmium oxide (Ho ₂ O ₃ ). , Dysprosium oxide (Dy ₂ O ₃ ), scandium oxide (Sc ₂ O ₃ ), and tantalum oxide (Ta ₂ O ₅ ). These compounds may be used as a mixture of plural kinds, or may be a complex oxide such as yttrium aluminum garnet (YAG).

  Since the coating film 51 made of the above-described material can suppress the reaction with halogen or metal halide, the occurrence of cracks in the sealing portions 12a and 12b and further the occurrence of rupture due to this reaction are greatly reduced. It becomes possible to suppress. Therefore, the lifetime of the mercury-free metal halide lamp can be extended more reliably.

  The coating film 51 first suppresses the reaction between the metal foils 3a1 and 3b1 and, in particular, free halogen or metal halide in the discharge medium, and these gases diffuse in the coating film to cause the metal foils 3a1 and 3b1. Reaching the surface can be suppressed by the fine particles 31.

  The coating film 51 is formed so as to cover a region including a joint portion between the metal foils 3a1, 3b1 and the electrodes 3a2, 3b2. That is, the portion where the free halogen gas or metal halide gas in the discharge medium enters is the end of the joint between the metal foils 3a1 and 3b1 and the electrodes 3a2 and 3b2, and the coating film is coated so that at least such portions are covered. Form. The coating film 51 may be formed only on one side region of the metal foils 3a1, 3b1 including the joints with the electrodes 3a2, 3b2, but both ends and further on the end portions on the discharge space 14 side of the metal foils 3a1, 3b1. You may form so that the whole surface of metal foil including an edge part and the discharge space 14 side end surface may be covered.

  The method for forming the coating film is not limited to the above, and a region including the joint portions of the metal foils 3a1 and 3b1 with the electrodes 3a2 and 3b2 by applying a solution baking method, an electrostatic coating method, or the like. A coating film may be formed.

  When applying the coating and firing method of the solution, first, a metal oxide fine particle is dispersed in an organic solvent, water, or the like to prepare a slurry solution, which is applied to necessary portions of the metal foils 3a1 and 3b2 and dried. Thereafter, the coating film 51 can be formed, for example, by firing the molybdenum metal foils 3a1 and 3b1 under conditions that do not significantly oxidize or deteriorate.

  The coating film 51 may be formed on the metal foils 3a1 and 3b1 before the electrodes 3a2 and 3b2 are joined, or may be formed after the electrodes 3a2 and 3b2 are joined to the metal. When the coating film is formed after bonding the electrode to the metal foil, the coating film covers not only the surface of the metal foil but also the base side surface of the electrodes 3a2 and 3b2 in the vicinity of the bonding portion of the electrode with the metal foil. Can be formed. The film thickness of the coating film 51 is 50 nm or more and 10% or less of the maximum thickness of the metal foils 3a1 and 3b1.

  In this embodiment, the fine particles filled in the coating film formed on the uneven portion can further suppress the reaction between the metal foil and the free halogen or metal halide in the discharge medium. It is possible to further extend the life of the mercury-free metal halide lamp by further suppressing the occurrence of foil breakage, cracks in the sealing portion, leaks, and rupture due to the reaction of the metal foil.

  FIG. 6 is a cross-sectional view corresponding to FIG. 5 for describing a third embodiment relating to the metal halide lamp of the present invention.

  In this embodiment, the surfaces of the concavo-convex portions 4a and 4b are covered with a coating film 61 formed of needle-like particles 61a made of at least one selected from metals and metal oxides. The coating film 61 is formed so as to cover a region including a joint portion between the metal foils 3a1 and 3b1 and the electrodes 3a2 and 3b2. The thickness of the coating film 61 is 50 nm or more and 10% or less of the maximum thickness of the metal foils 3a1 and 3b1, as in the embodiment of FIG.

  In this embodiment, the needle-like particles of the coating film formed on the concavo-convex portion further suppress the reaction between the metal foil and the free halogen or metal halide in the discharge medium, thereby realizing a longer life of the mercury-free metal halide lamp. be able to. Furthermore, the acicular particles filled in the coating film can also serve to prevent peeling from the metal foil.

  FIG. 7 is a cross-sectional view corresponding to FIG. 5 for describing a fourth embodiment relating to the metal halide lamp of the present invention.

  In this embodiment, the surfaces of the concavo-convex portions 4a and 4b are covered with a coating film 71 formed of fine particles 51a made of at least one selected from metals and metal oxides and needle-like particles 61a. The coating film 71 is formed so as to cover a region including a joint portion between the metal foils 3a1 and 3b1 and the electrode shafts 3a2 and 3b2. The thickness of the coating film 71 is 50 nm or more and 10% or less of the maximum thickness of the metal foil 4 as in the embodiment of FIG.

  In this embodiment, it is possible to earn a distance until reaction with free halogen or metal halide based on the fine particles constituting the coating film formed on the concavo-convex portion and the acicular particles. For this reason, it becomes possible to further suppress the reaction with free halogen or metal halide, and to realize further extension of the life of the mercury-free metal halide lamp.

  Next, examples of mercury-free less metal halide lamps according to the first to fourth embodiments and evaluation results thereof will be described with reference to FIGS.

  FIG. 8 is a diagram illustrating a conventional example without uneven portions formed on the surface of the metal foils 3a1 and 3b1, and Examples 1 to 4 with uneven portions, and FIG. 9 is based on the conventional examples and the respective embodiments. It explains the lamp life.

As for the discharge vessel 11, an airtight vessel made of quartz glass having an outer diameter a of 6.5 mm and an inner diameter b of 3 mm as shown in FIG. 1 was used. The electrodes 3a2 and 3b2 were made of tungsten having an outer diameter c of 0.4 mm, and the inter-electrode distance d between the electrodes 3a2 and 3b2 was 4.2 mm. Among the discharge media, for the metal halide, ScI ₃ , NaI and ZnI ₂ are used, and these ratios are set to ScI ₃ : NaI: ZnI ₂ = 3: 5: 2 by volume ratio, and 1 mg is enclosed in the total amount. did. Xe was used as the rare gas, and this Xe was sealed at 10 atm.

  Furthermore, the metal foils 3a1 and 3b1 were made of molybdenum having a thickness of 20 μm and a length of 10 mm, and the roughness of the uneven portions 4a and 4b on the surface was Ra = 1 μm and Rz = 3.5 μm.

As a conventional example, a smooth metal foil with Ra of less than 0.1 is used. In Example 1, the uneven portions 4a and 4b were formed on the surfaces of the metal foils 3a1 and 3b1. In Example 2, a coating film 51 of Al ₂ O ₃ fine particles 51a having an average particle diameter of 20 nm was formed on the surface of the concavo-convex parts 4a and 4b by an aqueous solution coating method with a film thickness of 0.3 μm. In Example 3, a film of Mo needle-like particles 9 was formed to a thickness of 0.3 μm. In Example 4, the coating film 71 in which the needle-like particles 61a of Mo and the Al ₂ O ₃ fine particles 51a having an average particle diameter of 20 nm are mixed is formed with a film thickness of 0.3 μm by an aqueous solution coating method. In addition, the coating film is not formed in the metal foil 3a1, 3b1 surface of a prior art example and Example 1. FIG.

  FIG. 9 shows the results of measuring the lifetime of each of the above-described mercury-free metal halide lamps according to Examples 1 to 4 and the conventional example at a lamp power of 35 W.

  As is clear from FIG. 9, each of the mercury-free metal halide lamps according to Examples 1 to 4 has a longer lifetime than the conventional mercury-free metal halide lamp. It can be seen that the lamp life is longer in the case where the coating film is formed than in the case where is formed. It can be seen that the life of the coating film 61 is extended by the acicular particles 61a even in the combination of the concavo-convex portions 4a and 4b and the coating film, as compared with the coating film 51 of the fine particles 51a. Furthermore, it can be seen that the lamp life is further extended in the coating film 71 in which the fine particles 51a and the acicular particles 61a are mixed.

In place of the material of each coating film described above, SiO ₂ film, ZrO ₂ film, HfO ₂ film, Y ₂ O ₃ film, Ho ₂ O ₃ film _, Ta ₂ O ₃ film, Al ₂ O ₃ film, Si Also for mercury-free metal halide lamps using ₃ N ₄ film, AlN film, TiN film, Ta film, W film, Re film, Nb film, V film, Zr film, Ho film, Dy film, Y film, and Sc film, respectively. Similarly, it was confirmed that it had good life characteristics.

  FIG. 10 is a front view corresponding to FIG. 2 for explaining a fifth embodiment relating to the metal halide lamp of the present invention. FIG. 10 also shows the one electrode 3a2 side, and the other electrode side is the same and is not shown.

  In this embodiment, the uneven portion 4a and the coating film 51 are formed on the surface of the uneven portion 4a at a portion where the electrode 3a2 is bonded to the metal foil 3a1 and a portion of the electrode 3a2 which is not overlapped with the metal foil 3a1. The portion of the electrode 3a2 that forms the coating film 51 on the surface of the concavo-convex portion 4a extends not only to the portion embedded in the sealing portion 12a but also to a portion of the portion exposed to the discharge space 14.

  In this case, with respect to the distance L from the tip of the electrode 3a2 to the root embedded in the sealing portion 12a of the electrode 3a2, the coating film 51 is formed from the root of the electrode 3a2 to 30% of the distance L. The range. In other words, the coating film 51 is not formed on the concavo-convex portion 4a and the upper surface between the position of 30% of the distance L from the base portion of the electrode 3a2 and the tip portion of the electrode 3a2.

By covering the uneven portion 4a covered with the coating film 51 up to a part of the electrode 3a2 exposed in the discharge space 14, it is possible to make the electrode 3a2 difficult to energize, and thus it is possible to suppress the occurrence of a back arc. It becomes. At this time, by forming the coating film 51 with a material having a specific resistance higher than that of the electrode 3a2, in particular, a metal oxide such as SiO ₂ , Al ₂ O ₃ , Sc ₂ O ₃ , and Dy ₂ O ₃ , the back arc is generated. It can suppress more reliably.

  Next, an evaluation result of the mercury-free metal halide lamp according to the fifth embodiment will be described as Example 5.

In Example 5, metal foils 3a1 and 3b1 on which irregularities 6 having a thickness of 25 μm, a length of 10 mm, a roughness of Ra = 1 μm, and Rz = 3.5 μm were formed, and electrodes 3a2 and 3b2 were welded thereto. Then, the following coating films 51 were formed respectively. In Example 5, a film of Al ₂ O ₃ fine particles 51a having an average particle diameter of 20 nm was formed with a film thickness of 0.3 μm by an aqueous solution coating and baking method.

  The coverage of the electrodes 3a2 and 3b2 by the coating film 51 was set to 1 mm from the root portion embedded in the sealing portions 12a and 12b of the electrodes 3a2 and 3b2 to the electrode tip direction on the discharge space side. Except for these conditions, an Hg-less metal halide lamp was manufactured in the same manner as in Example 1 described above.

  The mercury-free metal halide lamp of Example 5 has the same configuration except that the coating film 51 is not formed. A lamp flashing test was performed at a lamp power of 35 W.

  As a result, according to the Hg-less metal halide lamp of Example 5, it was confirmed that the occurrence of back arc was significantly less than that in the past. Further, as to the life characteristics, good results were shown as in Examples 1 to 4.

  In this embodiment, in addition to extending the lamp life, it is possible to greatly suppress the occurrence of back arc and reduce the occurrence of flickering abnormal discharge.

  FIG. 11 is a schematic configuration diagram for explaining a case where the metal halide lamp according to the present invention is applied to an automotive headlamp. The same reference numerals are given to the same components as those in FIG. The description will focus on the different parts.

  In FIG. 11, the arc tube constituting the main part of the metal halide lamp has a double tube structure, and an inner tube 1 made of, for example, quartz glass is disposed inside the arc tube. The inner tube 1 has an elongated shape in the lamp axis direction, and a substantially elliptical discharge vessel 11 is formed at a substantially central portion thereof. Plate-shaped sealing portions 12a and 12b are formed at both ends of the discharge vessel 11, and cylindrical non-sealing portions 13a and 13b are formed at both ends thereof.

  A socket 7 is connected to the non-sealing portion 13a side of the arc tube. The metal band 70 attached to the outer peripheral surface of the outer tube 9 near the non-sealing portion 13a is connected to the four metal tongue pieces 72 formed on the opening end of the socket 7 on the inner tube 1 holding side. (In FIG. 11, two are shown). And in order to strengthen a connection further, the contact point of the metal band 70 and the tongue piece 72 is welded. A terminal to which a lead wire 3a3 and a support wire (not shown) are connected is formed at the bottom of the socket 7.

  The other ends of the lead wires 3a3 and 3b3 whose one ends are connected to the end portions of the metal foils 3a1 and 3b1 extend outside the sealing portions 12a and 12b along the tube axis. One end of an L-shaped support wire 6 made of nickel is connected to the lead wire 3 b 3 extending to the outside, and the other end extends in the direction of the socket 7. A portion of the support wire 6 parallel to the tube axis is covered with an insulating sleeve 8 made of ceramic.

  Outside the inner tube 1 configured as described above, a cylindrical outer tube 9 in which a metal oxide having an ultraviolet blocking effect is added to quartz glass along the tube axis is provided substantially concentrically with the inner tube 1. It has been. The inner tube 1 and the outer tube 9 are connected by welding the outer tube 9 in the vicinity of the cylindrical unsealed portions 13a and 13b at both ends of the inner tube 1, and the inner space is in an airtight state. In the space, for example, a rare gas such as nitrogen, neon, argon, xenon, or the like can be sealed or mixed.

  FIG. 12 is a perspective view for explaining a schematic configuration of an embodiment when the metal halide lamp for an automotive headlamp described in FIG. 11 is applied to the automotive headlamp apparatus of the present invention.

  In the figure, 121 is a reflecting mirror and 122 is a front cover. The reflecting mirror 121 is formed into a deformed paraboloid by molding plastics, and is configured to attach and detach a metal halide lamp (not shown) shown in FIG. 11 from the top back surface. The front cover 122 is integrally formed with prisms or lenses by molding transparent plastics, and is airtightly attached to the front opening of the reflecting mirror 121.

  FIG. 13 is a circuit diagram for explaining a first embodiment relating to the lighting device of the present invention. In this embodiment, a metal halide lamp is configured to be lit by direct current. In the figure, 131 is a DC power source, 132 is a chopper, 133 is a control unit, R is a lamp current detecting means, VR is a lamp voltage detecting means, 134 is a starting unit, and 135 is a metal halide lamp.

  As the DC power supply 131, a battery or a rectified DC power supply is used. In the case of an automobile, a battery is generally used. However, it may be a rectified DC power source that rectifies AC. If necessary, the electrolytic capacitor C is connected in parallel to perform smoothing.

  The chopper 132 converts the DC voltage into a voltage having a required value and controls the metal halide lamp 135 as required. When the DC power supply voltage is low, a step-up chopper is used, and when it is high, a step-down chopper is used.

  The control unit 133 controls the chopper 22. For example, immediately after the lamp is turned on, a lamp current more than three times the rated lamp current is supplied from the chopper 132 to the metal halide lamp 135, and thereafter, the lamp current is gradually reduced as time passes, and control is performed so that the rated lamp current is eventually achieved. . In addition, the control unit 133 performs constant power control of the chopper 132 by generating a constant power control signal when a detection signal of the lamp current and the lamp voltage is fed back. Further, the control unit 133 includes a microcomputer in which a temporal control pattern is previously incorporated, and is configured to control the lamp current.

  The lamp current detection means R is inserted in series with the lamp, detects the lamp current, and inputs the control input to the control unit 133. The lamp voltage detection means VR is connected in parallel with the lamp, detects the lamp voltage, and inputs the control voltage to the control unit 23. The starting unit 134 is configured to supply a pulse voltage of 20 kV to the metal halide lamp 135 at the time of starting.

  Then, when the metal halide lamp is DC-lit using the metal halide lamp lighting device of this embodiment, a required light flux is generated immediately after lighting. As a result, it is possible to realize lighting with a luminous flux of 25% and a luminous flux of 80% after 4 seconds 1 second after turning on the power necessary as a vehicle headlamp. Further, since a DC-AC conversion circuit is not required, the cost can be reduced by about 30% compared to AC lighting. Further, the weight can be reduced by 15%. Along with this, the lighting circuit becomes inexpensive.

  FIG. 14 is a circuit diagram for explaining a second embodiment relating to the lighting device of the present invention. The same parts as those in FIG. This embodiment is different in that the metal halide lamp is configured to be AC-lit.

  141 is an alternating current conversion means, and this alternating current conversion means 141 consists of a full bridge inverter. That is, a pair of series circuits of a pair of switching means Q1, Q2 and Q3, Q4 are connected in parallel between the output ends of the chopper 132 to form a bridge circuit, and the oscillation output of the oscillator 142 is converted into four switching means Q1 to Q1. The switching means Q1, Q4 and Q2, Q3 in the diagonal direction are alternately supplied to Q4 to generate high-frequency alternating current between the output ends of the bridge circuit.

  The metal halide discharge lamp 135 is turned on by high frequency alternating current. In this AC lighting type configuration, the same control as in FIG. 13 is performed.

  According to each embodiment of the lighting device of the present invention of AC and DC, the above-described metal halide lamp of the present invention having excellent life characteristics can be safely maintained over a long period of time as a vehicle headlamp. .

The block diagram for demonstrating 1st Embodiment regarding the metal halide lamp of this invention. The front view which expanded and showed the principal part of FIG. The front view which expanded and showed the principal part of FIG. A-a 'sectional drawing of FIG. Sectional drawing for demonstrating 2nd Embodiment regarding the metal halide lamp of this invention. Sectional drawing equivalent to FIG. 5 for demonstrating 3rd Embodiment regarding the metal halide lamp of this invention. Sectional drawing equivalent to FIG. 5 for demonstrating 4th Embodiment regarding the metal halide lamp of this invention. Explanatory drawing for demonstrating each Example of the coating layer apply | coated to the metal foil of the metal halide lamp of this invention. Explanatory drawing for demonstrating the lifetime of the metal halide lamp by each Example of FIG. The front view for demonstrating 5th Embodiment regarding the metal halide lamp by this invention. The schematic block diagram for demonstrating the case where the metal halide lamp of this invention is applied to the headlamp for motor vehicles. The perspective view for demonstrating embodiment regarding the headlamp apparatus for motor vehicles of this invention. The circuit diagram for demonstrating 1st Embodiment regarding the lighting device of this invention. The circuit diagram for demonstrating 2nd Embodiment regarding the lighting device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inner tube 11 Discharge container 12a, 12b Sealing part 13a, 13b Unsealing part 14 Discharge space 2 Metal halide 3a, 3b Mount 3a1, 3b1 Metal foil 3a2, 3b2 Electrode 3a3, 3b3 Lead wire 4a, 4b Uneven part 31 Concave portion 32 Convex portion 51a Fine particles 61a Needle-like particles 51, 61, 71 Coating film 6 Support wire 7 Socket 8 Insulating sleeve 9 Outer tube 121 Reflecting mirror 122 Front cover 131 DC power supply 132 Chopper 133 Control unit 134 Start unit 135 Metal halide lamp R Lamp Current detection means VR Lamp voltage detection means 141 AC conversion means 142 Oscillators Q1-Q4 Switching means

Claims (8)

A discharge vessel having a discharge space and sealing portions provided at both ends of the discharge space;
A discharge medium enclosed in the discharge vessel, comprising a metal halide and a noble gas, and essentially free of mercury;
A pair of electrodes disposed opposite to each other in the discharge space;
Metal foils joined respectively to the base side end portions of the pair of electrodes and hermetically sealed by the sealing portion;
A pair of external leads respectively joined to the other end side of the metal foil and led out of the sealing portion;
In the region including the junction with the electrode of the metal foil, the roughness was 0.5 μm ≦ Ra ≦ 3 μm, 1.5 μm ≦ Rz ≦ 10 μm, and the concave and convex portions were alternately linked to form a network. A metal halide lamp comprising an uneven portion.   The metal halide lamp according to claim 1, wherein a coating film made of fine particles made of at least one selected from a metal and a metal oxide is formed on the surface of the uneven portion.   3. The metal halide lamp according to claim 2, wherein the coating film is formed of acicular particles made of at least one selected from metals and metal oxides.   2. The coating film is formed of fine particles made of at least one selected from metals and metal oxides and needle-like particles made of at least one selected from metals and metal oxides. Metal halide lamp.   2. The metal halide lamp according to claim 1, wherein the coating film is formed so as to cover a range including a part of the electrode on a side of a joint portion with the metal foil.   6. The metal halide lamp according to claim 5, wherein the coating film is made of a material having a specific resistance larger than that of the electrode. A metal halide lamp according to any one of claims 1 to 6,
A metal halide lamp lighting device comprising: a lighting circuit for lighting the metal halide lamp with a direct current. A metal halide lamp according to any one of claims 1 to 6,
An automotive headlamp device comprising: a main body of an automotive headlamp device, wherein the metal halide lamp is disposed and has an optical axis along a longitudinal direction of the discharge vessel of the metal halide lamp.

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