JP2013254636A - High pressure discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the work for winding a metal wire in a spiral form at an equal interval and holding the metal wire in the state in an outer tube protection mechanism of a high pressure discharge lamp.SOLUTION: An electric discharge lamp includes: a luminous tube including a pair of electrodes; a cylindrical translucent sleeve enclosing the luminous tube; a frame extending along an axis line direction at the outer side of the translucent sleeve; a metal wire wound in a spiral form so as to contact with outer surfaces of the translucent sleeve and the frame; and a translucent outer tube housing the luminous tube, the translucent sleeve, and the frame. In the electric discharge lamp, engagement parts, with which the metal wire engages, are formed on the outer surface of the frame at a predetermined interval. The metal wire wound in the spiral form is engaged with the engagement parts of the frame.

Description

  The present invention relates to a high-pressure discharge lamp, and more particularly to a protective structure for a translucent outer tube.

  The high-pressure discharge lamp has an arc tube and a transparent outer tube covering the arc tube. The high-pressure discharge lamp has a feature of high brightness and high efficiency, but since the internal pressure of the arc tube becomes high at the time of lighting, the arc tube may burst. Therefore, the high pressure discharge lamp is provided with an outer tube protection mechanism or an outer tube rupture prevention mechanism for protecting the outer tube so that the outer tube does not rupture even if the arc tube ruptures.

  As an outer tube protection mechanism, a method of covering the arc tube with a translucent sleeve and winding it with a wire is known. Patent Document 1 describes a structure in which a metal wire is wound so that a pressing force is applied to a frame member and a translucent sleeve. Patent Document 2 describes a structure in which a metal wire is wound so that a pressing force is applied to the frame member and the translucent sleeve, and both ends thereof are welded to the frame member. Patent Document 3 describes an example in which an alumina fiber yarn is spirally wound around an outer peripheral surface of a shroud.

Patent No.4431981 Patent 4624425 Patent 4791897

  In recent years, ceramic metal halide lamps employing ceramic arc tubes instead of quartz glass arc tubes have been used. A ceramic metal halide lamp can achieve high efficiency and high color rendering with a luminous efficiency of 80 lm / W or higher and an average color rendering index (Ra) of 80 or higher. In the case of a ceramic metal halide lamp, the arc tube hardly ruptures under normal use conditions. However, when bursting, if there is an input that is several times the rated power due to a short circuit of the ballast, etc., abnormally large energy may be generated, leading to a major accident that was not normally expected There is also danger. Therefore, in the case of a ceramic metal halide lamp, it is necessary to provide an outer tube protection mechanism corresponding to a larger breakdown energy than in the case of a normal discharge lamp.

  Therefore, in the ceramic metal halide lamp, in order to strengthen the outer tube protection mechanism, the number of turns of the metal wire is increased.

  However, when the number of turns of the metal wire is increased, it becomes difficult to wind the metal wire in a spiral shape at equal intervals. Furthermore, it is difficult to hold the metal wire wound in a spiral shape at equal intervals.

  An object of the present invention is to facilitate winding and holding a metal wire in a spiral shape at equal intervals in an outer tube protection mechanism of a high-pressure discharge lamp.

  In view of the above object, according to the present invention, an arc tube containing a pair of electrodes, a cylindrical translucent sleeve surrounding the arc tube, and an axially extending outside of the translucent sleeve. A frame, a translucent sleeve, a metal wire spirally wound so as to be in contact with the outer surface of the frame, the arc tube, the translucent sleeve, and a translucent outer tube that houses the frame In the discharge lamp, the outer surface of the frame is formed with an engaging portion for engaging the metal wire at a predetermined interval, and the spirally wound metal wire is engaged with the frame. It is comprised so that it may engage with a part.

  According to an embodiment of the present invention, the engaging portion may be a recess. Furthermore, the engaging portion may be a trough formed between two adjacent convex portions.

  According to an embodiment of the present invention, the metal wire is spirally wound 4 to 8 times, and a pitch of the metal wire spiral may be 8 ± 2 mm.

  According to an embodiment of the present invention, the metal wire may be a hard molybdenum wire, and both ends of the metal wire may be fixed to the frame by welding.

  According to the present invention, in the outer tube protection mechanism of a high-pressure discharge lamp, it is possible to facilitate winding and holding a metal wire in a spiral shape at equal intervals.

FIG. 1 is a diagram illustrating an example of a discharge lamp according to the present embodiment. FIG. 2 is a diagram showing a cross-sectional configuration of the discharge lamp according to the present embodiment. FIG. 3A is a plan view for explaining an example of the internal structure of a discharge lamp according to the prior art. FIG. 3B is an elevation view illustrating an example of the internal structure of a discharge lamp according to the prior art. FIG. 4A is a plan view illustrating an example of the internal structure of the discharge lamp according to the present embodiment. FIG. 4B is an elevation view illustrating an example of the internal structure of the discharge lamp according to the present embodiment. FIG. 5A is a diagram illustrating an example of a structure of a contact portion between a frame of a discharge lamp and a metal wire according to a conventional technique. FIG. 5B is a diagram illustrating an example of the structure of the contact portion between the frame of the discharge lamp and the metal wire according to the present embodiment. FIG. 5C is a diagram illustrating another example of the structure of the contact portion between the frame of the discharge lamp and the metal wire according to the present embodiment.

  Hereinafter, embodiments of a discharge lamp according to the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

An example of a discharge lamp according to the present embodiment will be described with reference to FIG. The discharge lamp has a translucent outer tube 7 and an arc tube 1 accommodated therein. A base 8 is attached to the end of the outer tube 7, and a stem 2 is attached to the base 8. The inside of the outer tube 7 is held in a high vacuum state. In the arc tube 1, several kinds of metal halides and mercury having an encapsulation density of about 6.0 mg / cm ³ are encapsulated.

  The circumference of the arc tube 1 is surrounded by a cylindrical translucent sleeve 6. Both ends of the translucent sleeve 6 are supported by support plates 5a and 5b. Both ends of the arc tube 1 are fixed to the support holes of the support plates 5a and 5b. The translucent sleeve 6 and the support plates 5 a and 5 b are supported by the frame 3. The arc tube 1 includes a pair of electrodes 1a and 1b. The base-side electrode 1b is connected to the base-side nickel wire 14b via an arc tube enclosing wire (not shown), further electrically connected to the base-side lead wire 10, and connected to one of the encapsulating wires of the stem 2. Yes. Similarly, the other electrode 1a is connected to the nickel wire 14a via the other arc tube enclosing wire (not shown), and is further electrically connected to the frame 3 and connected to the other enclosing wire of the stem 2.

  As shown, a metal wire 12 is wound along the outer surface of the frame 3 and the translucent sleeve 6. In the illustrated example, the metal wire 12 is wound seven times. The metal wire 12 may be a hard molybdenum wire having a wire diameter of 0.25 mm, for example. At fixed points 12 a and 12 b on the frame 3, both ends of the metal wire 12 are welded and fixed to the frame 3.

  The outer tube protection mechanism includes a translucent sleeve 6 and a metal wire 12. In the present embodiment, an engaging portion for engaging the metal wire 12 is formed at a portion of the outer surface of the frame 3 where the metal wire 12 contacts, which will be described in detail later.

  FIG. 2 shows a cross-sectional configuration of the discharge lamp of FIG. Here, a state in which the metal wire 12 is wound along the outer surface of the frame 3 and the translucent sleeve 6 is shown. A cylindrical translucent sleeve 6 is provided so as to surround the arc tube 1. The frame 3 is disposed on both diametrical sides of the translucent sleeve 6. The metal wire 12 is wound so as to contact the outer surface of the frame 3 and further contact the outer surface of the translucent sleeve 6.

  A conventional outer tube protection structure for a discharge lamp will be described with reference to FIGS. 3A and 3B. 3A and 3B show a plan configuration and an elevation configuration of the internal structure provided in the outer tube of the discharge lamp. The periphery of the arc tube 1 is surrounded by a translucent sleeve 6. Both ends of the arc tube 1 are fixed to support plates 5a and 5b. The translucent sleeve 6 and the support plates 5 a and 5 b are supported by the frame 3. Getters 29 are provided on both sides of the translucent sleeve 6.

  A starting circuit is provided between the translucent sleeve 6 and the stem 2. The starting circuit is electrically connected to the arc tube 1 in parallel. The starting circuit includes a bimetal unit 22, a non-linear ferroelectric ceramic capacitor (FEC) 23, a tungsten coil 24, and the like. For details of the starting circuit, refer to Japanese Unexamined Patent Application Publication No. 2010-3414.

  A metal wire 12 is wound along the outer surface of the frame 3 and the translucent sleeve 6. In the illustrated example, the metal wire 12 is wound three times. At fixed points 12 a and 12 b on the frame 3, both ends of the metal wire 12 are welded and fixed to the frame 3.

  Here, a procedure for winding the metal wire 12 around the frame 3 and the translucent sleeve 6 will be briefly described. First, in the first step S101, one end of the metal wire 12 is joined to the fixed point 12a on the frame 3 by spot welding or the like. In the second step 102, the metal wire 12 is wound around the frame 3 and the translucent sleeve 6 while being pulled so as to generate a certain tension. For example, when only a spring is attached to the metal wire 12, the tension can be easily controlled to be constant. For example, a tension of about 1 kgf may be applied. In the third step 103, the other end of the metal wire 12 is joined to the fixed point 12b on the frame 3 by spot welding or the like while the tension is applied to the metal wire 12. In this way, the metal wire 12 can be wound while being brought into contact with the frame 3 and the translucent sleeve 6 so as to apply a predetermined pressing force.

  With reference to FIG. 4A and FIG. 4B, the outer tube | bulb protection structure of the discharge lamp by this embodiment is demonstrated. 4A and 4B show a plan configuration and an elevation configuration of the internal structure provided in the outer tube of the discharge lamp. A metal wire 12 is wound along the outer surface of the frame 3 and the translucent sleeve 6. In the present embodiment, the metal wire 12 is wound seven times in a spiral shape. In addition, the metal wire 12 does not necessarily need to be wound 7 times, and may be wound 4 to 8 times, for example.

  In order to ensure a predetermined outer tube protection function, the pitch of the metal wires 12 needs to be less than a predetermined dimension. The pitch of the metal wires 12 is an interval between adjacent windings measured along the axial direction, and is preferably about 8 ± 2 mm. The number of turns of the metal wire 12 is determined by the pitch of the metal wire 12 and the dimension of the translucent sleeve 6 in the axial direction. The metal wire 12 may be a hard molybdenum wire having a wire diameter of 0.25 mm, for example. At fixed points 12 a and 12 b on the frame 3, both ends of the metal wire 12 are welded and fixed to the frame 3.

  When the arc tube of the discharge lamp is ruptured, it bursts starting from the vicinity of the position where the center plane orthogonal to the axial direction of the arc tube and the outer surface of the arc tube 1 intersect, and the translucent sleeve 6 around that is May destroy. However, the ruptured arc tube 1 and the broken translucent sleeve 6 collide with the metal wire 12, and the kinetic energy is absorbed or the scattering direction is greatly changed. Therefore, fragments having energy that can break the translucent outer tube 7 cannot reach the inner surface of the translucent outer tube 7.

  With reference to FIG. 5A, the structure of the contact portion between the frame 3 and the metal wire 12 in the outer tube protection structure of the conventional discharge lamp will be described. In the conventional discharge lamp, the metal wire 12 is spirally wound so as to contact the outer surface of the frame 3. As described above, the metal wire 12 is wound around the frame 3 with a predetermined pressing force or winding force applied thereto. By this force, the frame 3 is elastically deformed slightly. Therefore, the metal wire 12 is wound around the elastically deformed frame 3.

  Since the outer surface of the frame 3 is not provided with unevenness, the contact point of the metal wire 12 on the frame 3 may be shifted along the axial direction. Such displacement of the contact point may occur in the process of winding the metal wire 12, but may also occur due to vibration or the like after the metal wire 12 is wound.

  With reference to FIG. 5B, the structure of the contact portion between the frame 3 and the metal wire 12 in the outer tube protection structure of the discharge lamp according to the present embodiment will be described. In the present embodiment, a plurality of engaging portions are formed on the outer surface of the frame 3 at equal intervals. In the present embodiment, a recess 3A is formed as the engaging portion. The recesses 3 </ b> A are formed at intervals corresponding to the pitch of the metal wires 12. When the metal wire 12 is wound along the outer surface of the frame 3 and the translucent sleeve 6, the metal wire engages with the recess 3 </ b> A of the frame 3. The metal wire 12 is wound in a state where the metal wire 12 is in contact with the recess 3 </ b> A of the frame 3. When the metal wire 12 is wound around the frame 3, a predetermined pressing force or winding force may be applied as described above, but the pressing force or winding force may not be added. In the present embodiment, the contact point of the metal wire 12 on the frame 3 does not shift along the axial direction.

  The recess 3A of the frame 3 may be formed on at least a part of the outer surface of the frame, and does not need to be formed on the entire peripheral surface or half peripheral surface of the frame. The recess 3A may be formed so as to extend in a direction orthogonal to the axial direction of the frame, but is inclined along the direction of the metal wire 12, that is, relative to the direction orthogonal to the axial direction of the frame. You may form so that it may extend in a direction.

  The frame is formed by bending a long wire having a circular cross section or a rectangular cross section. The recess 3A may be formed before the wire is bent, or may be formed after the wire is bent. The recess 3A can be formed by various machining processes, and it is not necessary to limit the machining method. The processing method for forming the recess 3A may be a processing method for removing material, but may be a processing method only for plastic deformation.

  With reference to FIG. 5C, another example of the structure of the contact portion between the frame 3 and the metal wire 12 in the outer tube protection structure of the discharge lamp according to the present embodiment will be described. In the present embodiment, a plurality of engaging portions are formed on the outer surface of the frame 3. In this embodiment, the convex part 3B as an engaging part is formed. The convex portions 3 </ b> B are formed at intervals corresponding to the pitch of the metal wires 12. A trough 3b is formed between two adjacent convex portions 3B. Various methods can be used as a method of forming the convex portion 3B. For example, the convex portion 3B may be formed by soldering or welding.

  When the metal wire 12 is wound along the outer surface of the frame 3 and the translucent sleeve 6, the metal wire engages with the valley portion 3 b of the frame 3. The metal wire 12 is wound in a state where the metal wire 12 is in contact with the valley portion 3 b of the frame 3. In the present embodiment, the contact point of the metal wire 12 on the frame 3 does not shift along the axial direction.

  Although the outer tube protection structure for a discharge lamp according to the embodiment of the present invention has been described above, these are examples and do not limit the scope of the present invention. Additions, deletions, changes, improvements, and the like that can be easily made by those skilled in the art with respect to the present embodiment are within the scope of the present invention. The technical scope of the present invention is defined by the appended claims.

DESCRIPTION OF SYMBOLS 1 ... Arc tube, 1a, 1b ... Electrode, 2 ... Stem, 3 ... Frame, 3A ... Frame recessed part, 3B ... Frame convex part, 3b ... Frame trough part, 5a, 5b ... Support plate, 6 ... Translucent 7 ... Translucent outer tube, 8 ... Base, 10 ... Base side lead wire, 12 ... Metal wire, 12a, 12b ... Fixing point, 14a, 14b ... Nickel wire, 22 ... Bimetal unit, 23 ... Non-linear strength Dielectric ceramic capacitor (FEC), 24 ... Tungsten coil, 29 ... Getter

Claims (5)

An arc tube containing a pair of electrodes, a cylindrical translucent sleeve surrounding the arc tube, a frame extending along the axial direction outside the translucent sleeve, the translucent sleeve and the frame In a discharge lamp having a metal wire spirally wound so as to contact the outer surface of the light emitting tube, and the light-emitting tube, the light-transmitting sleeve, and a light-transmitting outer tube that houses the frame,
An engagement portion is formed on the outer surface of the frame to engage the metal wire at a predetermined interval, and the spirally wound metal wire is engaged with the engagement portion of the frame. A discharge lamp characterized by comprising. The discharge lamp according to claim 1, wherein
The discharge lamp according to claim 1, wherein the engaging portion is a concave portion. The discharge lamp according to claim 1, wherein
The discharge lamp according to claim 1, wherein the engaging portion is a trough formed between two adjacent convex portions. The discharge lamp according to any one of claims 1 to 3,
The metal wire is spirally wound 4 to 8 times, and the pitch of the spiral of the metal wire is 8 ± 2 mm.   The discharge lamp according to any one of claims 1 to 4, wherein the metal wire is a hard molybdenum wire, and both ends of the metal wire are fixed to the frame by welding.

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