JP2013004349A - Discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge lamp having a high heat resistance and capable of suppressing glare.SOLUTION: The discharge lamp is equipped with a long burner BN having a light-emitting part 11 and a disk-shaped flange FL capable of holding the burner BN so that the light-emitting part 11 may be located on the front end side. The flange FL has a metal part 7 which is installed so as to be orthogonal to the longitudinal direction of the burner BN, and the metal part 7 has a maximum spectral reflectance of 25% or less on the surface on the front end side. In order to make the maximum spectral reflectance to be 25% or less, for example, a prescribed rough surface 75 may only be formed on the surface on the front end side of the metal part 7.

Description

  Embodiments of the present invention relate to a discharge lamp used as a headlamp of a vehicle such as an automobile.

  A discharge lamp used for an automobile headlamp is composed of a burner and a socket. The socket is made of resin, and a flange is provided on the front end side thereof. The burner has a double tube structure with a light-emitting portion that emits light during lighting, and is held by a socket so that the light-emitting portion is located on the front end side of the flange.

  Recently, flanges using metals instead of conventional resins have been developed. Although the heat resistance of the flange can be improved by using a metal, it has been found that glare occurs when such a lamp is arranged in a lamp of an automobile headlamp.

JP 2010-534388 A International Publication No. 2009/130654 International Publication No. 2008/110969 International Publication No. 2009/130640

  The problem to be solved by the present invention is to provide a discharge lamp having high heat resistance and capable of suppressing glare.

  The discharge lamp of the embodiment is a discharge lamp comprising a long burner provided with a light emitting part, and a disc-shaped flange capable of holding the burner so that the light emitting part is located on the front end side thereof, The flange includes a metal plate provided to be orthogonal to the longitudinal direction of the burner, and the metal plate has a maximum spectral reflectance of 25% or less on the front end surface.

It is a figure for demonstrating the discharge lamp of 1st Embodiment. It is a figure for demonstrating the cross section of the discharge lamp of 1st Embodiment. It is a figure for demonstrating the state which looked at the discharge lamp of 1st Embodiment from the front end side. It is a figure for demonstrating the flange of 1st Embodiment. It is a figure for demonstrating the metal part of 1st Embodiment. It is a figure for demonstrating the base of 1st Embodiment. It is a figure for demonstrating the maximum spectral reflectance of Example 1 and a prior art example. It is a figure for demonstrating generation | occurrence | production of arithmetic mean roughness Ra, the largest spectral reflectance, and a glare. It is a figure for demonstrating the discharge lamp of 2nd Embodiment. It is a figure for demonstrating the discharge lamp apparatus of 3rd Embodiment. It is a figure for demonstrating the state which looked at the discharge lamp etc. from the front end side of the reflector of 3rd Embodiment. It is a figure for demonstrating the other example of a discharge lamp. It is a figure for demonstrating the other example of a metal part.

(First embodiment)
A discharge lamp according to a first embodiment will be described with reference to the drawings. FIG. 1 is a diagram for explaining a discharge lamp of the first embodiment, FIG. 2 is a diagram for explaining a cross section of the discharge lamp of the first embodiment, and FIG. 3 is a diagram of the first embodiment. It is a figure for demonstrating the state which looked at the discharge lamp from the front end side. In the present embodiment, as shown in FIG. 2, for the sake of convenience, the direction of arrow F that is forward when attached to an automobile or the like will be referred to as the front end, and the direction of arrow B will be referred to as the rear end.

  The discharge lamp shown in FIG. 1 is an HID lamp used in an automobile headlamp device, and includes a long burner BN and a flange FL.

  The burner BN has a double-pipe structure, and an inner pipe 1 is disposed inside the burner BN. The inner tube 1 has an elongated shape, and a light emitting portion 11 that is a portion that emits light during lighting is formed near the center thereof. The light emitting part 11 is substantially elliptical, and a plate-like seal part 12 is formed at both ends thereof, and a cylindrical part 14 is continuously formed at both ends thereof via a boundary part 13. As described above, the inner tube 1 includes a portion that emits light and has a high temperature. Therefore, the inner tube 1 is preferably made of a material having translucency and heat resistance such as quartz glass.

A discharge space 111 having a substantially cylindrical shape at the center and a tapered shape at both ends is formed inside the light emitting unit 11. A discharge medium is enclosed in the discharge space 111. The discharge medium has a so-called mercury-free configuration that contains a metal halide and a rare gas and does not contain mercury. Incidentally, the volume of the discharge space 111, in the case of vehicle headlights ^are, 10mm ^{3 ~30mm 3,} further it is preferred that a 15 mm ³ 25 mm ^3.

  The metal halide is composed of, for example, a halide of sodium iodide, scandium iodide, zinc iodide, or indium bromide. The combination of metal halides is not limited to this, and tin or cesium halides may be added.

  The rare gas is composed of xenon. The sealing pressure of the rare gas can be adjusted depending on the purpose. For example, in order to improve characteristics such as the total luminous flux, it is desirable that the sealing pressure is 10 atm or higher, particularly 13 atm or higher at normal temperature (25 ° C.). However, the upper limit is about 20 atm at present in production. In addition to xenon, neon, argon, krypton, or the like can be used as the rare gas, or a combination thereof can be used.

  The electrode mount 2 is sealed to the seal portion 12. The electrode mount 2 includes a metal foil 21, an electrode 22, a coil 23, and a lead wire 24.

  The metal foil 21 is a thin metal plate made of, for example, molybdenum, and is arranged so that its plate-like surface is parallel to the plate-like surface of the seal portion 12.

  The electrode 22 is, for example, an electrode made of so-called triated tungsten in which tungsten is doped with thorium oxide. One end of the metal foil 21 is overlapped and connected to the end of the light emitting unit 11 side, and the other end is disposed in the discharge space 111 so as to face each other with a predetermined distance between the electrodes. Yes. The distance between the electrodes is preferably 3.5 mm to 4.5 mm in terms of appearance in the case of an automotive headlamp.

  The coil 23 is a metal wire made of, for example, doped tungsten, and is wound spirally around the axis of the shaft portion of the electrode 22 sealed to the seal portion 12.

  The lead wire 24 is a metal wire made of molybdenum, for example. One end thereof is overlapped and connected to the metal foil 21 on the opposite side with respect to the light emitting portion 11, and the other end extends to the outside of the inner tube 1 along the tube axis. Among them, one end of a support wire 25 is connected to the lead wire 24 extending to the front end side of the lamp by laser welding. The support wire 25 is, for example, an L-shaped lead wire made of a nickel wire, and the long side is arranged along the burner BN. For example, a sleeve 3 made of ceramic is attached to the long side of the support wire 25 so as to cover the outer surface thereof.

  A cylindrical outer tube 4 is provided concentrically with the inner tube 1 on the outer side of the inner tube 1 configured as described above. These inner and outer pipes are connected by forming welded portions 41 at both ends. That is, the cylindrical portion 14 of the inner tube 1 and the outer tube 4 are welded. In a space kept airtight between the inner tube 1 and the outer tube 4, a kind of gas selected from neon, argon, xenon and nitrogen or a mixed gas is sealed at a pressure of 0.3 atm or less. . The outer tube 4 is preferably made of a material having a thermal expansion coefficient close to that of the inner tube 1 and having an ultraviolet blocking property, such as quartz glass to which an oxide such as titanium, cerium, or aluminum is added.

  A metal band 5 is provided on the rear end side of the burner BN composed of these. This metal band 5 is provided with a metal plate made of, for example, stainless steel along the outer peripheral surface of the outer tube 4 and is fixed to the burner BN by welding both ends thereof with a laser or the like.

  A flange FL is disposed near the metal band 5. The flange FL is a disk-shaped component, and can hold the burner BN so that the light emitting portion 11 is located on the front end side. In this embodiment, the diameter is about 31 mm, the thickness is about 2.5 mm, and it is composed of a resin part 6 and a metal part 7 as shown in FIG.

  The resin portion 6 is formed of a resin such as PPS or PEI, and is located on the periphery of the flange FL. The flange FL is formed with a potch portion 61, a notch 62, and a recess 63. The potch portions 61 are projections provided on the front end side of the resin portion 6, and three are formed at intervals of 120 degrees. This potch portion 61 is a portion serving as a base point when measuring dimensions. For example, the distance D1 from the tip of the potch 61 to the center between the electrodes in the light emitting unit 11 is defined as LCL (Light Center Length) of the discharge lamp. The distance D1 is set to 20 mm or less. For example, the distance D1 is 18.0 mm, which is set shorter than the conventional 27.1 mm. The notch 62 is a notch formed at the end of the resin part 6 and is formed in three. The recesses 63 are recesses provided on the front and rear end sides of the resin part 6 and are formed at intervals of 60 degrees.

  The metal part 7 is a metal plate made of stainless steel or the like, and is embedded in the resin part 6. The metal part 7 before being embedded in the resin part 6 has a shape as shown in FIG. 5, and a projecting piece part 71, a sleeve holding part 72, a hole part 73 and a notch part 74 are formed. The projecting piece 71 is a projecting piece projecting in the center direction of the metal part 7, and four pieces are integrally formed at intervals of 90 degrees. As shown in FIG. 1 and FIG. 2, the projecting piece 71 is bent obliquely in the rear end direction in the state of the discharge lamp, and holds the metal band 5 from four sides at the front end. The sleeve holding part 72 is a metal plate integrally formed so as to protrude in the central direction of the metal part 7. A circular hole 721 is formed at the center. The holes 73 are holes formed in the vicinity of the recess 63, and six holes are formed at intervals of 60 degrees. The notch 74 is a notch formed at the periphery of the metal part 7, and three are formed so as to correspond to the notch 62 of the resin part 6.

  Moreover, the metal part 7 is provided with the rough surface 75 on the surface of the front end side orthogonal to the longitudinal direction of the burner BN at least. The rough surface 75 is a reflection suppressing portion that can suppress the maximum spectral reflectance on the front end surface to 25% or less. The rough surface 75 can be formed by, for example, sand blasting, and the arithmetic average roughness Ra is 0.30 μm.

  A base 8 is disposed on the rear end side of the flange FL. The base 8 is made of, for example, stainless steel, iron, nickel, aluminum or the like, and includes a case portion 81 and a ring 82 on the front end side as shown in FIG. The case portion 81 is a hollow housing, and lighting circuit devices such as an igniter and a ballast are disposed in the internal space (not shown). Specifically, a resin case provided with circuit elements such as a transformer and a capacitor and metal terminals necessary for starting and stable lighting of the discharge lamp is disposed. The lighting circuit device is electrically connected to one end of a lead wire 24 and a support wire 25 extending in the rear end direction from the flange FL, and the burner BN has a power of about 25 W when stable and a stable power when starting. The power of about 55 W, which is more than twice the power, is input.

  The ring 82 is a cylindrical tube formed on the front end side of the case portion 81, and six protrusions 822 are formed on the front end side at intervals of 60 degrees. This protrusion 822 is used to connect the ring 82 and the flange FL. Specifically, the ring 82 and the flange FL can be fixed by inserting the protruding portion 822 into the hole 73 of the metal portion 7 and then bending the protruding portion so as to be accommodated in the recess 63. Become. In addition, it is better to strengthen the fixing by performing laser welding or the like on the overlapping portion of the bent protrusion 822 and the metal portion 7.

  Here, the discharge lamp of the present embodiment (Example 1) and a conventional discharge lamp (conventional example) that does not have a rough surface as shown in the patent literature are used as a vehicle headlight as in a third embodiment to be described later. It was attached to the light fixture and turned on. As a result, since the distance D1 became shorter than the conventional one, the high-temperature flange did not melt in both the first example and the conventional example, and had sufficient heat resistance, but glare occurred only in the conventional example.

  This glare is influenced by the surface state of the metal part. FIG. 7 shows the spectral reflectance on the front end side surface of the metal part of Example 1 and the conventional example. As can be seen from this result, the reflectance of the conventional example is higher than that of Example 1. In both cases, the reflectance is maximum at around 420 nm. The first example is about 20%, and the conventional example 2 is about 38%. From this result, it can be inferred that glare is less likely to occur if the spectral reflectance of the front end side surface of the metal part, particularly the maximum value of the reflectance generated near 420 nm, is low. Spectral reflectance is measured by placing a color difference meter (manufactured by JASCO Corp.) so that it is almost in contact with the surface of the metal part, and then irradiating the surface of the metal part with light of 400 to 700 nm so that incident light is perpendicular. The reflected light bounced vertically can be obtained by measuring with the measuring instrument.

Therefore, the occurrence of glare when the maximum spectral reflectance was changed by the arithmetic average roughness Ra was tested. The result is shown in FIG. The arithmetic average roughness Ra is obtained by measuring the range of 50 μm ^{2 on} an arbitrary surface of the metal part 7 using an ultra-deep shape measuring microscope (for example, VK-8500 manufactured by KEYENCE). The determination of glare is based on visual observation, where x is a state where glare is generated, ◯ is a state where glare is not conspicuous, and ◎ is a state where no glare is generated.

  As can be seen from the results, the glare is suppressed as the maximum spectral reflectance decreases. Specifically, when the maximum spectral reflectance is 25% or less, the occurrence of glare is suppressed, and when the maximum spectral reflectance is 20% or less, glare is prevented. Therefore, it is desirable that the maximum spectral reflectance of the front end side surface of the metal part 7 is 25% or less, preferably 20% or less. Since the projecting piece 71 is also a member that affects the occurrence of glare, it is desirable that the maximum spectral reflectance satisfies 25% or less. The same applies to the metal band 5. The maximum spectral reflectance is related to the arithmetic average roughness Ra. When the arithmetic average roughness Ra is 0.15 μm or more, the maximum spectral reflectance is 25% or less and the arithmetic average roughness Ra is 0.30 μm. In this way, the maximum spectral reflectance can be made 25% or less.

  In the first embodiment, the metal plate 7 is provided on the flange FL so as to be orthogonal to the longitudinal direction of the burner BN, and the arithmetic average roughness Ra of the surface on the front end side of the metal plate 7 is 0.15 μm or more. In addition, by setting the maximum spectral reflectance to 25% or less, it is possible to suppress the occurrence of glare while maintaining sufficient heat resistance.

(Second Embodiment)
FIG. 9 is a diagram for explaining the discharge lamp of the second embodiment. About each part of this 2nd Embodiment, the same part as each part of the discharge lamp of 1st Embodiment is shown with the same code | symbol, and the description is abbreviate | omitted.

  In this embodiment, the rough surface 75 on the front end side surface of the metal portion 7 is formed of an oxide film. When the metal part 7 is oxidized, the surface becomes rough and the gloss is lost, so that the maximum spectral reflectance can be further reduced. For example, the arithmetic average roughness Ra of Example 2 in which the rough surface 75 made of an oxide film was formed on the front end side surface of the metal part 7 was 0.20 μm, and it was visually glossy and discolored black. The maximum spectral reflectance of Example 2 was about 17% as shown in FIG. 9, and no glare was generated. Therefore, it is effective to reduce the maximum spectral reflectance by forming a rough surface 75 made of an oxide film on the surface of the metal portion 7. The maximum spectral reflectance and arithmetic average roughness Ra due to the oxide film can be adjusted by the processing temperature, processing time, and the like.

  In the second embodiment, an oxide film is formed on the front end side surface of the metal part 7 so that the arithmetic average roughness Ra is 0.15 μm or more, thereby further maintaining glare while maintaining sufficient heat resistance. Can be suppressed. A higher effect can be obtained by oxidizing the protrusion 71 and the metal band 5 in the same manner.

(Third embodiment)
FIG. 10 is a diagram for explaining a discharge lamp device according to a third embodiment.

  The discharge lamp device includes a reflector 91, a lens structure 92, and a discharge lamp DL.

  The reflector 91 includes a neck portion 911 and a reflection portion 912. The internal shape of the neck portion 911 is stepped, that is, a space 913 whose shape changes is formed inside the neck portion 911. Further, a contact surface 914 is formed at a step portion located on the rear end side of the neck portion 911. Further, three locking pieces 915 are formed inside the neck portion 911 on the rear end side with respect to the contact surface 914. The reflection portion 912 is formed continuously with the front end side of the neck portion 911, and a space 916 is formed therein so as to communicate with the space 913.

  The lens structure 92 includes a lens 921 and a lens holding portion 922, and is disposed in the opening portion of the reflector 91. The lens 921 is a lens that allows light emitted from the opening of the reflector 91 to enter the light incident surface 923 and exit from the light exit surface 924. The shape of the lens 92 can be variously changed according to a desired light distribution.

  The discharge lamp DL is the lamp described in the first embodiment, and is attached to the reflector 91 so that the flange FL is held between the contact surface 914 and the locking piece 915. The burner BN, in particular, the light emitting unit 11 is disposed in the space 913.

  FIG. 11 is a diagram for explaining a state in which the discharge lamp or the like is viewed from the front end side of the reflector. As can be seen from this figure, when the discharge lamp DL is viewed from the opening of the reflector 91, the metal portion 7 can be confirmed from the space 914 having a diameter R (for example, 26 mm) among the parts of the flange FL. In the present embodiment, since the rough surface 75 having a maximum spectral reflectance of 25% or less is formed on the surface of the metal part 7, the light generated in the light emitting part 11 reflects the metal part 7 to generate glare. Can be suppressed. In addition, since only the metal part 7 is exposed from the space 914 and the resin part 6 is not exposed, even if the discharge lamp DL is turned on, the resin part 6 is melted by the heat or deteriorated by ultraviolet rays. Can be prevented.

  Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope 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 the equivalents thereof.

  For example, the discharge lamp may be of a type that does not include a lighting circuit as shown in FIG.

  As shown in FIG. 13, the flange FL is a disc-shaped resin portion 6 provided so as to cover the cover-shaped metal portion 7, or is composed of only the metal portion as disclosed in Patent Document 4. May be. That is, in order to improve the heat resistance of the flange FL, the flange FL having a metal plate so as to be orthogonal to the longitudinal direction of the burner BN may be used. Further, the flange FL may be an ellipse or a flat circle.

  The surface on the front end side of the metal portion 7 may have the maximum spectral reflectance lowered by chemical treatment using coloring or chemicals.

  The number of projecting pieces 71 may be three or six, that is, it may be two or more, which is the number capable of holding the burner BN. Moreover, you may make it the protrusion piece part 71 protrude in the front-end side of the flange FL like FIG.

BN burner 1 Inner tube 11 Light emitting part FL Flange 6 Resin part 7 Metal part 75 Rough surface

Claims (3)

A discharge lamp comprising a long burner provided with a light emitting part, and a disc-shaped flange capable of holding the burner so that the light emitting part is located on the front end side thereof,
The flange includes a metal plate provided so as to be orthogonal to the longitudinal direction of the burner, and the metal plate has a maximum spectral reflectance of 25% or less on a front end surface. Discharge lamp.   2. The discharge lamp according to claim 1, wherein the metal plate has an arithmetic average roughness Ra of a front end surface of 0.15 μm or more.   The discharge lamp according to claim 2, wherein the metal plate includes an oxide film on a front end surface thereof.

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