JP2010033864A - High-pressure discharge lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-pressure discharge lamp whose cylindrical glass member includes a truncated cone portion, with a step formed on a slant portion of the truncated cone portion, resulting in excellent pressure-resistance characteristics. <P>SOLUTION: The high-pressure discharge lamp 1 includes: a light-emission tube having a light-emission part 2 and sealing parts 3 on either end thereof; a cylindrical glass member 32 embedded inside at least one of the sealing parts 3; and a plurality of band-formed metal foils 4 disposed in a manner that they occupy an outer periphery of the cylindrical glass member 32 and extend along a longitudinal direction of the cylindrical glass member. The cylindrical glass member 32 includes a truncated cone portion whose diameter is reduced toward an end on a light-emission part side, and a step is formed on a slant portion of this truncated cone portion. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a high pressure discharge lamp. In particular, it relates to a sealing structure for a high-current high-pressure discharge lamp.

  Among discharge lamps, high-pressure discharge lamps are widely used in fields that utilize ultraviolet rays emitted therefrom, such as semiconductor device manufacturing fields, photochemical industry fields, and lighting fields.

  For example, in a high-current high-pressure mercury lamp, since the amount of mercury enclosed is large, the mercury vapor pressure (internal pressure) in the arc tube during lighting is very high. In addition, since the amount of heat generated during lighting is large, the sealing portion is required to have a structure with high heat resistance and excellent pressure resistance. For this reason, the conventional high-pressure discharge lamp is not a so-called 'rod seal structure' in which the glass forming the arc tube is directly welded to the power supply lead rod to form the sealing portion. A so-called 'foil seal structure' using a metal foil for sealing inside is generally employed.

The discharge lamp having the foil seal structure includes a light emitting part in which a light emitting space is formed and a sealing part connected to both ends of the light emitting part. A metal foil is embedded inside the sealing portion, and one end of the metal foil is electrically connected to the electrode and the other end is electrically connected to the external lead. For high-current type discharge lamps, a structure using a plurality of metal foils has been proposed.
Utility model registration No. 2583317

  However, the high-pressure discharge lamp having the above configuration is required to have higher illuminance and higher efficiency, and the amount of mercury and the amount of rare gas are becoming higher and higher. For this reason, the internal pressure of the light emitting part is also increased, and the problem of leakage (gas leakage) or breakage is occurring in the sealed part.

  The problem to be solved by the present invention is to provide a high-pressure discharge lamp excellent in pressure resistance.

  A high pressure discharge lamp according to the present invention includes a light emitting portion having a pair of electrodes therein, an arc tube having sealing portions at both ends thereof, a columnar glass member embedded in at least one sealing portion, and the columnar shape In the high-pressure discharge lamp comprising a plurality of strip-shaped metal foils arranged to extend along the longitudinal direction of the columnar glass member on the outer periphery of the glass member, the columnar glass member is directed toward the light emitting unit side end. It has a truncated cone part with a reduced diameter, and a step is formed on the slope part of the truncated cone part.

  Further, the discharge lamp is a DC lighting type lamp, and the columnar glass member is formed in a sealing portion on the cathode side.

  Further, a metal disk is disposed on the electrode side end surface of the columnar glass member, and one end of the metal foil is joined to the metal disk, and a base end of the electrode is electrically connected to the metal disk. It is characterized by being.

  By having the above-described configuration, the present invention can strengthen the adhesion between the metal foil and the glass, thereby suppressing the progress of the foil floating, resulting in leakage (gas leakage) and breakage in the sealing portion. Can be prevented.

  FIG. 1 shows the overall cross-sectional structure of a high-pressure discharge lamp according to the present invention. The discharge lamp 1 is entirely composed of a quartz glass arc tube comprising a substantially spherical light-emitting portion 2 and sealing portions 3 connected to both ends thereof. Inside the light emitting unit 2, a cathode 11 and an anode 12 are disposed as a pair of electrodes facing each other at an interval of, for example, 5.0 mm. The cathode 11 is, for example, a columnar rod made of thorium tungsten, the tip is formed in a conical shape, and the rear end is supported by the internal lead 110. The anode 12 is made of, for example, tungsten as a main component, and is a rod-like rod as a whole, and has a substantially bullet shape having a curved surface structure at the tip. The rear end is supported by the internal lead 120 like the cathode.

  Inside the light emitting part 2, a discharge space (light emitting space) is formed in a sealed state, and mercury is enclosed as a light emitting substance. Mercury is in a liquid state when the lamp is turned off, but becomes a gas state when the lamp is turned on, and emits ultraviolet rays having a wavelength of 365 nm or the like. The amount of mercury enclosed is, for example, 10 to 60 mg / cc per actual internal volume of the light emitting space, and this becomes a high pressure of about 10 to 30 atm during lighting. Further, a rare gas such as xenon, argon, or krypton, or a mixed gas thereof is enclosed as a starting auxiliary gas or as a luminescent gas.

  A holding cylinder 31 for holding the internal lead 110 and a rod-shaped glass member 32 are embedded in the cathode side sealing portion 3. The holding cylinder 31 is made of quartz glass and is an overall substantially cylindrical body having a through hole formed substantially at the center. The internal lead 110 of the cathode passes through the through hole portion. The glass member 32 is also made of quartz glass and is a solid rod member, and a plurality of, for example, six metal foils 4 made of strip-shaped (strip-shaped) molybdenum are arranged at equal intervals on the outer periphery thereof. ing. The electrode side end portion of the metal foil 4 is joined to a metal disk 33 disposed on the electrode side end surface of the glass member 32 by, for example, spot welding, and the outer end portion of the metal foil 4 is an external metal. The member 34 is joined by spot welding or the like. The external metal member 34 is a conductive ring-shaped member, and both are electrically connected so that the external lead 5 penetrates through the center hole of the ring. Note that a power supply mechanism (not shown) is connected to the external lead 5, so that the external lead 5, the external metal member 34, the metal foil 4, the metal disk 33, and the internal lead 110 are electrically connected to the cathode 11. A path is formed. At this time, since the metal foil 4 is formed by a plurality of sheets, the current flowing from the cathode 11 is divided by the number of the metal foils and becomes a path where the external metal member 34 joins again. The cathode 11, the internal lead 110, the holding cylinder 31, the disk 33, the glass member 32, the metal foil 4, the external metal member 34, and the external lead 5 are collectively referred to as an “electrode mount”. The anode 12 basically has the same configuration. For example, such a high-pressure discharge lamp is lit at a rating of 85 V and 5000 W.

  FIG. 2 shows a partially enlarged structure in the vicinity of the metal disk 33 of the cathode side sealing portion shown in FIG. The structure of the electrode side end of the glass member 32 is composed of a tip 320, a first inclined part 321a, a flat part 322 which is one form of a step, and a second inclined part 321b from the metal disk 33 side. A second inclined part 321 b continues to the cylindrical body part 323. These are physically integrated, and are formed by cutting the end of cylindrical quartz glass. The first inclined portion 321a and the second inclined portion 321b have a truncated cone structure (conical truncated cone portion) whose outer diameter gradually decreases. By providing the flat portion 322 between the first inclined portion 321a and the second inclined portion 321b, a step is formed between them, but the step is not limited to a flat structure.

  As described above, the metal foil 4 has an elongated strip shape (strip shape), and is disposed so as to be separated from each other and extend in the axial direction of the glass member 32. Therefore, the metal foil 4 corresponds to each shape along the surface shapes of the columnar portion 323, the second inclined portion 321b, the flat portion 322, and the first inclined portion 321a also at the electrode side end portion of the glass member 32. Thus, it extends while being in close contact with the outer surface, and is joined to the metal disk 33 by, for example, spot welding at the tip. As a numerical example, the width of the metal foil 4 is 5 to 15 mm, for example, 10 mm, the outer diameter of the columnar portion 323 of the glass member 32 is φ15 to 35 mm, for example, 25 mm, and the outer diameter of the metal disk 33 is 10 to 25 mm, for example, 15 mm.

  The reason why the inclined portion is provided at the electrode side end portion of the glass member 32 is to avoid the metal foil being bent at a right angle and to be directed toward the disk while gently bending the metal foil along the inclination. The metal foil itself is difficult to cut.

In the present invention, the inclined portion is divided into a plurality of portions such as the first inclined portion 321a and the second inclined portion 321b, and a step (flat) extending in a direction perpendicular to the axial direction of the glass member 32 therebetween. Part 322) is interposed.
That is, a minute gap is formed between the holding cylinder 31 and the internal lead 110 in order to prevent the occurrence of cracks due to contact between both. For this reason, the high pressure generated in the light emitting space reaches the tip portion 320 of the glass member 32 through this minute gap. In the first place, the sealing part enables the hermetic sealing and electrical connection by the metal foil closely contacting each other between the quartz glasses. When the generated high pressure is reached, a force in the direction of peeling the metal foil 4 from the glass member 32 (arrows F1 and F2 in FIG. 2) is generated.

  And this invention greatly reduces the effect | action in which the metal foil 4 peels from the glass member 32 by dividing the inclination structure in the electrode side edge part of the glass member 32 into plurality, and interposing the flat part 322 between them. . To explain this point in more detail, the force to peel off the metal foil is the resultant force in the direction perpendicular to the metal foil, and in the conventional structure where there is no step, all the force applied to the glass in the part that has floated up to that point. Becomes a driving force for peeling off the foil. In FIG. 2, forces F1 and F2 acting in the direction perpendicular to the metal foil are combined forces. If the flat portion 322 does not exist, the total force generated in the entire inclined portion becomes the peeling force. In contrast, in the structure in which the flat portion 322 is interposed as in the present invention, the direction of the force f1 applied to the foil at the flat portion 322 is different from the forces F1 and F2 applied to the first inclined portion 321a. The force applied to the first inclined portion 321a does not directly act on the inclined portion 321b. Specifically, due to the force f1 generated in the flat portion 322, a force f2 that pulls the metal foil in the longitudinal direction is generated in the second inclined portion 321b, thereby reducing the force F3 that works to peel off the metal foil.

  In the case of using a high pressure discharge lamp such as the present invention, particularly the metal foil or glass member of the above-described numerical example having an internal pressure of 25 atm or more during lighting, the first inclined portion 321a following the tip portion 320 is used. The length of the hypotenuse is about 10 mm, and the metal foil is peeled off from the glass member to cause so-called “foil peeling”. Therefore, it is desirable to provide the flat part 322 at a position where the length of the hypotenuse of the first inclined part 321a following the tip part 320 is smaller than 10 mm, more preferably within 5 mm.

The number of inclined portions 321 is not limited to two, and three or more inclined portions may be provided. FIG. 3 shows a structure having three inclined portions. That is, it has the front-end | tip part 320, the 1st inclination part 321a, the 1st flat part 322a, the 2nd inclination part 321b, the 2nd flat part 322b, and the 3rd inclination part 321c.
The number of inclined portions may be four or more.

The structure of the glass member according to the present invention, that is, the structure in which a step is interposed in the inclined portion of the electrode side end portion, is particularly effective when formed on the glass member embedded in the cathode side sealing portion. In the cathode side sealing part, the alkali ions contained in the glass member 32 or the glass material constituting the sealing part, or the alkali ions contained in the electrodes are attracted to the metal foil of opposite polarity, and the metal foil 4 and the glass member. It is because it concentrates on 32 contact parts.
However, it does not exclude the adoption for the glass member of the anode side sealing portion, and higher pressure resistance characteristics can be provided by providing the both sealing portions.

FIG. 4 shows another embodiment of the glass member of the high-pressure discharge lamp according to the present invention.
(A) shows an embodiment in which the inclination angle θ1 of the first inclined portion 321a and the inclination angle θ2 of the second inclined portion 321b are the same. The inclination angle in this case is a numerical value selected from a range of 15 to 30 °, for example, and is specifically 20 °. The advantage of this structure is that the shape processing of the glass member 32 is easy.

(B) shows an embodiment in which the inclination angle θ1 of the first inclined portion 321a is smaller than the inclination angle θ2 of the second inclined portion 321b. As a numerical example, the inclination angle θ1 of the first inclined part 321a is 10 °, and the inclination angle θ2 of the second inclined part 321b is 20 °. The advantage of this structure is that the force (F1 in FIG. 2) generated in the first inclined portion 321a becomes a force in a shallower direction than the force (F3 in FIG. 2) generated in the second inclined portion 321b. The influence of the force generated in the first inclined portion 321a on the second inclined portion 321b is further reduced. Therefore, the structure is effective for a lamp having a higher internal pressure.

(C) shows an embodiment in which the inclination angle θ1 of the first inclined portion 321a is larger than the inclination angle θ2 of the second inclined portion 321b. As a numerical example, the inclination angle θ1 of the first inclined part 321a is 60 °, and the inclination angle θ2 of the second inclined part 321b is 30 °. The advantage of this structure is that the angle at which the metal foil bends changes stepwise, making it easier to follow the glass member and effectively preventing the foil from wrinkling.

(D) shows an embodiment in which the inclination angle θ2 of the second inclined portion 321b is zero or 180 °. As a numerical example, the inclination angle θ1 of the first inclined portion 321 is 20 °. The advantage of this structure is effective when the length of the inclined portion in the axial direction is shortened and the sealing portion is desired to be shortened due to dimensional constraints from the apparatus.
4 (a) to 4 (d) are for showing the valuation of the magnitude relation of the inclination angle, and the angle itself in the drawing does not necessarily coincide with the numerical value described above.

In the embodiment shown in FIG. 1 and FIG. 2, the internal lead 110 that supports the electrode is fixed to the metal disk 33 at the end face. However, the structure is not limited to such a structure. The tip may be inserted through the metal disk 33 and inserted into the glass member 32.
Further, the holding cylinder 31 for holding the internal lead 110 is not limited to a cylindrical shape as a whole, and the glass member 32 side end may be gradually reduced in diameter.

FIG. 5 shows a sealing portion forming process which is a part of the manufacturing process of the high-pressure discharge lamp of the present invention. After the electrode mount is formed, the sealing portion 3 is inserted and arranged at a position corresponding to the sealing portion of the glass tube material (the glass tube is made up to the shape of the light emitting portion and the sealing portion). In this state, the glass tube material is melted and heated at a high temperature of about 2000 ° C. by a burner while rotating at high speed with a lathe. Since the thermal expansion coefficient of molybdenum constituting the metal foil is an average of 5.8 × 10 ⁻⁶ (1 / deg) in the range from room temperature to 2000 ° C., the metal foil extends about 1% in the length direction in the melting and heating. ((2000-20) × 5.8 × 10 ⁻⁶ = 0.01).
Therefore, if the length of the metal foil in the axial direction of the glass member 32 is 50 mm, the metal foil expands by about 0.5 mm at the time of melting and heating, which is a sealing part manufacturing process.
The present invention can prevent the metal foil from being peeled from the glass member by providing a step (flat portion) in the inclined portion of the glass member 32, but absorbs the expansion of the metal foil as described above (FIG. 5 arrows), and there is also an advantage in the manufacturing process that generation of undesired wrinkles can be prevented.

  As described above, the high-pressure discharge lamp according to the present invention is embedded in a light emitting part having a pair of electrodes inside, a light emitting tube made of a sealing part at both ends thereof, and at least one sealing part. In a configuration including a columnar glass member and a plurality of strip-shaped metal foils arranged to extend along the longitudinal direction of the columnar glass member on the outer periphery of the columnar glass member, the columnar glass member Since it has a truncated cone part that is reduced in diameter toward the end part, and a step is formed on the slope part of the truncated cone part, the adhesion between the metal foil and the glass can be strengthened. The progress of floating can be suppressed, and as a result, leakage (gas leakage) and breakage in the sealing portion can be prevented.

1 shows an overall schematic configuration of a high-pressure discharge lamp according to the present invention. 1 shows a partially enlarged view of a high-pressure discharge lamp according to the present invention. 1 shows a partially enlarged view of a high-pressure discharge lamp according to the present invention. 3 shows another embodiment of a high-pressure discharge lamp according to the present invention. The schematic diagram explaining the principle of the discharge lamp which concerns on this invention is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Discharge lamp 2 Light emission part 3 Sealing part 4 Metal foil 5 External lead 11 Cathode 12 Anode 31 Holding cylinder 32 Glass member 33 Disc 34 Metal member 320 Tip part 321 Inclination part 322 Flat part 323 Cylindrical part

Claims (3)

A light emitting part having a pair of electrodes inside and a light emitting tube having sealing parts at both ends thereof;
A columnar glass member embedded in at least one sealing portion;
In the high-pressure discharge lamp comprising a plurality of strip-shaped metal foils arranged so as to extend along the longitudinal direction of the columnar glass member at the outer periphery of the columnar glass member,
The columnar glass member has a truncated cone portion that is reduced in diameter toward the light emitting portion side end portion, and a step is formed on a slope portion of the truncated cone portion. The discharge lamp is a direct current lighting lamp,
2. The high pressure discharge lamp according to claim 1, wherein the columnar glass member is formed in a sealing portion on a cathode side.   A metal disk is disposed on the electrode-side end surface of the columnar glass member, one end of the metal foil is joined to the metal disk, and the base end of the electrode is electrically connected to the metal disk. The high-pressure discharge lamp according to claim 1.

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