JP6628208B2 - Xenon flash lamp - Google Patents

Description

  The present invention relates to a xenon flash lamp.

  A xenon lamp is a type of high-intensity discharge lamp, and is a lamp that utilizes light emission due to discharge in xenon gas. Among them, a xenon flash lamp is used as a light source using light pulses.

2005-19131 "Flash Discharge Lamp, Flash Discharge Lamp Lighting Device and Light Irradiation Device" (Release Date: 2005/01/20) Applicant: Harrison Toshiba Lighting Co., Ltd. Japanese Patent Application Laid-Open No. 2005-56638 "Flash lamp" (Published date: 2005/03/03) Applicant: Iwasaki Electric Co., Ltd.

  FIG. 1 is a diagram showing a typical light emission distribution of a xenon lamp. Xenon lamps are characterized by a continuous spectrum from the ultraviolet region (UV wave region) to the infrared region (IR wave region), and have a light emission distribution very similar to sunlight.

  The present inventors have studied to improve the luminous efficiency of such a xenon flash lamp in a specific wavelength region, here a UV wave region.

  Therefore, an object of the present invention is to provide a xenon flash lamp with improved luminous efficiency in the UV wave region.

  Furthermore, the present invention relates to a xenon flash lamp having improved luminous efficiency in the UV wave region, having a good lamp starting property and having a structure in which a whitening phenomenon or a blackening phenomenon does not occur on the lamp tube wall in the initial stage of lamp operation. The purpose is to provide.

  The xenon flash lamp according to the present invention is, in one aspect, a xenon flash lamp having a double-tube structure including a light-emitting portion of a large-diameter tube and electrode arrangement portions of small-diameter tubes at both ends thereof, at least a tip of a cathode electrode. The portion and the distal end of the small-diameter tube are aligned in the lamp axis direction.

  In the xenon flash lamp, a trigger band may be further arranged on the outer periphery of the small-diameter tube surrounding the tip of the cathode electrode.

  In the xenon flash lamp, the tip of the anode electrode and the tip of the small-diameter tube may be aligned in the lamp axis direction.

  In the xenon flash lamp, the electrode arrangement portion may have a shrink structure in which the electrode and the small-diameter tube are heated and welded.

  According to the present invention, it is possible to provide a xenon flash lamp having improved luminous efficiency in the UV wave region.

  Further, according to the present invention, there is provided a xenon flash lamp having an improved luminous efficiency in a UV wave region, having a structure in which a lamp starting property is good and a whitening phenomenon and a blackening phenomenon do not occur on a lamp tube wall at an early stage of lamp operation. Flash lamps can be provided.

FIG. 1 is a diagram showing a typical light emission distribution of a xenon lamp. FIG. 2 is a diagram illustrating a xenon flash lamp conventionally used. FIG. 3 is a diagram showing characteristics of light quantity (wavelength 254 nm) and current with respect to the inner diameter of the arc tube shown in Table 1. FIG. 4 is a diagram illustrating a xenon flash lamp having a double tube structure according to the present embodiment. FIG. 5A is a view for explaining a lamp having a structure in which a tip portion of a cathode electrode is positioned in a small-diameter portion tube with respect to a small-diameter portion tube tip of a double-tube xenon flash lamp. FIG. 5B is a view for explaining a lamp having a structure in which the tip of the cathode electrode is positionally aligned with the tip of the small-diameter tube of the xenon flash lamp having a double-tube structure. FIG. 5C is a view for explaining a lamp having a structure in which the tip of the cathode electrode is positioned in the large-diameter tube with respect to the small-diameter tube of the double-tube xenon flash lamp.

  Hereinafter, embodiments of a xenon flash lamp according to the present invention will be described with reference to the accompanying drawings. In the drawings, the same elements are denoted by the same reference numerals, and redundant description will be omitted. These embodiments are merely examples for understanding the present invention, and do not limit the technical scope of the present invention.

  FIG. 2 is a diagram illustrating a conventional xenon flash lamp 100. The conventional lamp 100 is a straight tube lamp in which the tube inner diameters of the electrode disposition portions 20 and 40 at both ends and the central light emitting portion 30 are cylindrical with the same tube inner diameter. The cathode electrode 50 is formed on one of the electrode placement portions 20, and the anode electrode 60 is formed on the other electrode placement portion 40. Several annular trigger lines 80-2 are wound around the outer periphery of the tube to assist in starting the lamp, and the annular trigger lines are interconnected by a trigger line 80-1.

  The electrode arrangement section 20 incorporating the cathode electrode 50 and the electrode arrangement section 40 incorporating the anode electrode 60 may each have a heated and sealed contact structure. Such a close contact structure is called a shrink structure.

  The lighting condition is such that the capacitor is charged using the applied voltage of 3.3 kV, and this charged voltage is applied between the anode and the cathode of the lamp.

The dimensions of the conventional lamp 100 are as follows.
Distance between electrodes (light emission length): L = 550 to 850 mm
Inner diameter of arc tube: ID = 8mm, tube wall thickness: 1mm
Electrode diameter: 6.4mm or 7.5mm
At first, the present inventors conducted research and development by changing various lamp specifications with the aim of developing a xenon flash lamp capable of obtaining “strong light emission”. In this process, as compared with the conventional lamp shown in FIG. 2, the lamp inner diameter was increased, the resistance value between the electrodes during lighting was reduced, and a trial production of a lamp in which more current flows was studied.

  As a result of measuring the emission spectrum of the lamp having a larger lamp inner diameter, it was confirmed that stronger light emission was obtained in the UV wave region than the conventional lamp. A xenon flash lamp that can obtain strong light emission in the UV wave region is an optimal lamp for sterilization treatment.

  With respect to the conventional lamp 100 shown in FIG. 2, a lamp having a larger arc tube inner diameter ID was experimentally manufactured, and the light quantity and current in the UV wave region of the lamp at the time of lighting were measured. Table 1 shows experimental data on the relationship between the arc tube inner diameter ID and the amount of ultraviolet light of a lamp having a larger arc tube inner diameter ID. As the amount of ultraviolet light, for example, the amount of light having a wavelength of 254 nm in a UV wave region, which is considered to be effective for sterilization, was measured. In addition, a change in current with respect to the light emitting unit inner diameter ID is also shown. FIG. 3 illustrates the light amount and the peak current with respect to the arc tube inner diameter in Table 1.

  As shown in FIG. 3, as the inventors intended, the peak current (indicated by □ in the figure) increased almost proportionally as the arc tube inner diameter ID increased to 6 to 20 mm. . At this time, the light amount in the UV wave region (indicated by ■ in the figure) was also greatly increased. Accordingly, it was found that the inner diameter of the arc tube of the conventional lamp, 8 mm, should be further increased to increase the light amount (wavelength: 254 nm).

The electrode diameter of the conventional lamp 100 shown in FIG. 2 was two kinds, 7.5 mm and 6.4 mm. Here, when increasing the inner diameter of the arc tube, it is conceivable that the discharge portion and the electrode arrangement portion have the same inner diameter as in the conventional lamp 100 shown in FIG. However, when the pipe diameter is the same, the following problem occurs.
(1) If the inside diameter of the electrode arrangement part of the arc tube becomes large, the interval between the trigger band and the trigger wire that assists starting and the electrode tip becomes large, and a sufficient trigger effect cannot be obtained, and the lamp starting performance deteriorates. .
(2) When the inside diameter of the electrode arrangement portion of the arc tube becomes large, the gap between the electrode and the inner peripheral surface of the tube becomes large. Further, the accuracy of the seal itself is deteriorated, the yield of the product is deteriorated, and the reliability is reduced.
(3) In response to increasing the inner diameter of the electrode arrangement portion of the arc tube, it is conceivable to adopt a new large-diameter electrode adapted to this. However, a large-diameter electrode leads to an increase in cost, and an increase in the number of types of parts is not preferable for a lamp mass production factory.

  Accordingly, the present inventors have developed a double-tube lamp comprising a light-emitting portion of a large-diameter tube and an electrode arrangement portion of a small-diameter tube. That is, the same structure as the conventional lamp 100 was adopted for the electrode arrangement portion.

FIG. 4 is a diagram illustrating the xenon flash lamp 10 according to the present embodiment. The lamp 10 is formed by joining a light emitting portion 3 having a relatively large tube inner diameter and electrode placement portions 2 and 4 having relatively small tube inner diameters surrounding the electrode portions at both ends of the light emitting portion. The cathode electrode 5 is arranged on one side of the electrode arrangement section, and the anode electrode 6 is arranged on the other side. The electrode arrangement portion may have a shrink structure or a non-shrink structure. To assist in starting the lamp, several annular trigger lines 8-3 are wound around the outer periphery of the electrode arrangement portions 2 and 4, and an annular trigger line 8-2 is wound around the outer periphery of the light emitting portion 3. The annular trigger lines are interconnected by a trigger line 8-1.
The lighting conditions of the lamp 10 are the same as those of the conventional lamp 100.

The dimensional specifications of the lamp 10 according to the present embodiment are as follows.
Distance between electrodes (light emission length): L = 550 mm
Large diameter part IDa = 16 mm, small diameter part IDb = 10 mm of arc tube, wall thickness: 1 mm
Electrode diameter: 6.4mm or 7.5mm
Filled gas: Xenon 58.2Pa (equivalent to 437 torr)

  A large number of xenon flash lamps 10 having a double tube structure shown in FIG. 4 were experimentally manufactured and tested, and it was found that some of the lamps failed to start. Further, it was also found that a blackening phenomenon and a whitening phenomenon occurred on the inner wall of the arc tube of some lamps.

  The present inventors have analyzed the cause, and found that the blackening phenomenon and the whitening phenomenon depended on the position of the electrode tip with respect to the tip of the small-diameter tube (that is, the boundary between the small-diameter tube and the large-diameter tube). It was found to happen. Further, the blackening and whitening of the inner wall of the arc tube occur more frequently near the cathode electrode than near the anode electrode.

  Therefore, the present inventors made a lamp in which the position of the tip of the cathode electrode was changed with respect to the boundary between the small-diameter tubular body and the large-diameter tubular body, and the occurrence of blackening or whitening of the arc tube inner wall occurred. Was investigated.

FIG. 5A is a view for explaining a lamp having a structure in which a tip portion of a cathode electrode is located inside a small-diameter portion tube body with respect to a small-diameter portion tube end portion of a double-tube xenon flash lamp. FIG. 5B is a diagram illustrating a lamp having a structure in which the tip of the cathode electrode is aligned with the tip of the small-diameter tube. FIG. 5C is a diagram illustrating a lamp having a structure in which the tip of the cathode electrode is located inside the large-diameter tube with respect to the small-diameter tube.
Table 2 shows the results of the startability of the lamps of FIGS. 5A and 5B and the appearance of the arc tube inner wall.

  Here, for the evaluation of the startability, two lamps were prepared for each lamp and tested. The test conditions were evaluated at a capacitor charging voltage of 2.5 kV applied to the lamp, and evaluated by 1,000 times of repeated starting and lighting.

  The appearance of the inner wall of the arc tube was evaluated by preparing two lamps for each lamp. The test was performed at a capacitor charging voltage of 3.6 kV applied to the lamp (capacitor used: 600 μF), turned on once every 30 seconds, and evaluated after 10,000 shots.

  As shown in FIG. 5A, some lamps whose cathode electrode tip position is Sa = −5 mm with respect to the tip end of the small-diameter portion tube with the lamp axis rightward direction as a positive value as viewed in the drawing, did not start. Furthermore, there was a lamp in which the whitening phenomenon 12 occurred on the inner wall of the arc tube near the cathode electrode. It was found that when the cathode electrode 5 was inside the small-diameter tube, the arc generated from the electrode came into contact with the quartz tube, and the tube was whitened by the heat of the arc.

  In the lamp shown in FIG. 5B with Sb = 0 mm where the tip of the small-diameter tube and the tip of the cathode electrode are aligned, there was no starting failure. Further, the inner wall of the arc tube near the cathode electrode was in a clean state without any change.

  In the lamp shown in FIG. 5C in which the cathode electrode tip position is Sc = + 5 mm with respect to the small-diameter tube tip, some lamps did not start. Further, there was a lamp in which the blackening phenomenon 14 occurred on the inner wall of the arc tube near the cathode electrode. The cathode electrode 5 is formed of a cathode electrode body 5a made of tungsten and a cathode electrode tip 5b impregnated with an emitter for electron emission, which is joined to the tip of the body. The cathode electrode tip 5b is made of a compound of tungsten and barium oxide. In the case where the cathode electrode tip is located inside the large-diameter tube, an arc may be generated not from the cathode electrode tip portion 5b but from the cathode electrode main portion 5a. This causes the chemical phenomenon 14.

  From the above results, it has been found that the lamp structure in which the tip of the small-diameter portion tube and the tip of the cathode electrode match each other has the best startability and the appearance of the inner wall of the arc tube.

  With respect to the anode electrode, the startability of the lamp and the appearance of the inner wall of the arc tube were evaluated in which the small-diameter portion tube tip and the cathode electrode tip position were matched, but there were no problems in the startability and the appearance of the arc tube inner wall.

(Advantages and effects of this embodiment)
(1) Since the electrode arrangement portion is a small-diameter tube, the interval between the electrode tip and the trigger band can be maintained in a close state, a sufficient trigger effect can be obtained, and good startability can be secured.
(2) In particular, in the cathode electrode, a trigger band can be arranged near the cathode electrode tip 5b, and an arc is always generated from the cathode electrode tip 5b. That is, it is possible to prevent arc generation from the cathode electrode main body 5a. For this reason, an arc is not generated from the sword electrode main body 5a, and the blackening phenomenon does not occur due to the scattering of tungsten.
(3) An increase in the electrode temperature can be suppressed by forming the electrode arrangement portion in a shrink structure. For this reason, the blackening phenomenon due to the scattering of the electrode material can be suppressed.

[Summary]
As described above, the xenon flash lamp according to the embodiment of the present invention has been described, but the present invention is not limited thereto. Additions, deletions, and changes that can be easily made by those skilled in the art with respect to the present embodiment. Improvements are within the scope of the present invention. The technical scope of the present invention is determined by the description in the appended claims.

2: electrode arrangement part, 3: light emitting part, 4: electrode arrangement part, 5: cathode electrode, 5a: cathode electrode main part, 5b: cathode electrode tip part, 6: anode electrode, 8-1: trigger line, 8- 2: Trigger wire of large-diameter tubular body, 8-3: Trigger band of small-diameter tubular body, 10: Xenon flash lamp, lamp, 12: Whitening phenomenon, 14: Blackening phenomenon, 20: Electrode arrangement part, 30: Light emitting part, 40: Electrode arrangement part, 50: Cathode electrode, 60 Anode electrode, 80-1: Trigger wire, 80-2, 80-3: Annular trigger wire, 100: Conventional lamp ID: Arc tube inner diameter, light emission Inner diameter, inner diameter, L: emission length,

Claims (3)

In a xenon flash lamp using light emission by discharge in xenon gas,
The xenon flash lamp has a double-tube structure including a light-emitting portion of a large-diameter tube having a constant inner diameter, and an electrode arrangement portion of a small-diameter tube having a constant inner diameter joined to both ends thereof ,
The distance L between the electrodes of the xenon flash lamp is in the range of 550 to 850 mm,
The inner diameter ID of the light emitting portion of the large-diameter tube is in the range of 8 <ID ≦ 20 mm,
At least the tip of the cathode electrode and the tip of the small diameter tube are aligned in the lamp axis direction ,
A xenon flash lamp , wherein a trigger band is arranged on an outer periphery of the small-diameter tube surrounding the tip of the cathode electrode . The xenon flash lamp according to claim 1, further comprising:
A xenon flash lamp, wherein the tip of the anode electrode and the tip of the small-diameter tube are aligned in the lamp axis direction. The xenon flash lamp according to claim 1, further comprising:
The electrode arrangement portion electrode and the can and a small diameter portion tube body has a shrink structure welded is heated, a xenon flash lamp.

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