JP2011023143A - Discharge lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate risk that a direction and an attachment position of a UV enhancer for irradiating ultraviolet rays for starting aid of a discharge lamp is changed to cause short-circuiting accidents, due to impact or vibration caused at transport of the lamp. <P>SOLUTION: The UV enhancer 7A equipped with a pipe part 10 penetrating the center of an airtight vessel 3 in which rare gas such as argon gas is filled is fitted inside the pipe 10 at a position leaning toward one end side of an arc tube 2, in a way penetrating an electrode lead 5a protruded from a terminal of a sealing part 4a sealing that end side of the arc tube 2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention protrudes from an arc tube in which at least a luminescent substance and a starting gas are sealed in a discharge vessel in which a pair of electrodes are arranged to face each other, and a terminal of a sealing portion that hermetically seals both ends of the arc tube. The present invention relates to a discharge lamp having a power supply wire for electrically connecting an electrode lead and a UV enhancer that emits ultraviolet rays for starting assistance toward a discharge vessel of an arc tube.

As this type of discharge lamp, for example, there is a metal vapor discharge lamp as shown in FIG. 8, and the discharge lamp 80 is mercury, which is a luminescent substance, in a discharge vessel 82 in which a pair of electrodes 83a and 83b are arranged facing each other. In addition, the arc tube 81 in which the metal halide and the starting gas are sealed, and the electrode leads 85a and 85b protruding from the ends of the sealing portions 84a and 84b that hermetically seal both ends of the arc tube 81 are electrically connected. A configuration in which power supply wires 86 and 87 to be connected and a UV enhancer 88 that emits ultraviolet rays for starting assistance toward the discharge vessel 82 of the arc tube 81 are accommodated in the outer bulb 90 to which the base 89 is attached. (See Patent Document 1). The electrodes 83a and 83b are connected to one contact and the other contact of the base 89 through power supply wires 86 and 87 connected to the electrode leads 85a and 85b, respectively.

The UV enhancer 88 is filled with a rare gas argon gas inside a UV discharge tube 91 having a tube wall formed of a ceramic material made of sintered polycrystalline alumina (Al ₂ O ₃ ). An internal electrode 93 made of a tungsten wire having a wire diameter of 170 μm welded to the tip of a lead-through conductor 92 made of a niobium wire having a wire diameter of 620 μm sealed on one end side of the discharge tube 91 is disposed. The internal electrode 93 is connected to the power supply wire 87 welded to the rear end of the conductor 92 via the lead-through conductor 92, and the UV discharge tube 91 is supported by the lead-through conductor 92 and is connected to the power supply wire 86. It is arranged nearby and is capacitively coupled to the power supply wire 86 to serve as a UV source.

However, the UV enhancer 88 is configured to support one end of the UV discharge tube 91 made of a ceramic material with the tip of the lead-through conductor 92 welded to the power supply wire 87, so that the discharge lamp 80 is transported and transported. The UV discharge tube 91 is greatly shaken by impact or vibration generated at the time, and the lead-through conductor 92 that receives the dynamic load of the discharge tube 91 is bent and deformed, and the UV discharge tube 91 supported at the tip of the conductor 92 is bent. And the lead-through conductor 92 welded to the power supply wire 87 is reversed, such that the necessary and sufficient amount of ultraviolet rays is not emitted from the discharge tube 91 toward the discharge vessel 82 of the arc tube 81. There is a risk of short circuit accidents coming into contact with the polar power supply wires 86, which become a serious quality claim factor.

Japanese National Patent Publication No. 11-513182

The main object of the present invention is to provide a discharge lamp in which the direction and position of the UV enhancer are not changed by a shock or vibration generated when the lamp is transported and transported, and a short circuit accident does not occur.

In order to solve the above problems, the present invention provides an arc tube in which at least a luminescent substance and a starting gas are sealed in a discharge vessel in which a pair of electrodes are arranged to face each other, and both ends of the arc tube are hermetically sealed. In a discharge lamp having a power supply wire for electrically connecting an electrode lead protruding from the end of the sealing portion to be radiated and a UV enhancer that emits an ultraviolet ray for starting assistance toward the discharge vessel, a rare gas is filled. The UV enhancer provided with a pipe portion penetrating the container in the airtight container is inserted into the pipe portion, the electrode lead or the sealing portion, or the feeding wire, and is biased to one end side of the arc tube. It is attached.

In the discharge lamp according to the present invention, a UV enhancer that emits ultraviolet rays for assisting starting toward the discharge vessel of the arc tube is disposed in a pipe portion that penetrates an airtight vessel filled with a rare gas, Since the electrode lead protruding from the terminal or the power supply wire that electrically connects the electrode lead is inserted and attached to a position biased to one end side of the arc tube, impact generated when the lamp is transported and transported There is no possibility that the UV enhancer will shake due to or vibration and the direction and mounting position of the enhancer will fluctuate or cause a short circuit accident.

The figure which shows the discharge lamp which concerns on Example 1 of this invention. Exploded view of the UV enhancer used in the discharge lamp of FIG. The figure which shows the discharge lamp which concerns on Example 2 of this invention. The figure which shows the discharge lamp which concerns on Example 3 of this invention. The figure which shows the discharge lamp which concerns on Example 4 of this invention. Exploded view of the UV enhancer used in the discharge lamp of FIG. The figure which shows the discharge lamp which concerns on Example 5 of this invention. Figure showing a conventional discharge lamp

One embodiment of a discharge lamp according to the present invention is an arc tube made of translucent ceramics in which a starting material such as a luminescent substance and argon gas is sealed in a discharge vessel in which a pair of tungsten electrodes are arranged opposite to each other; A feeding wire made of nickel-plated iron wire for electrically connecting an electrode lead made of niobium wire or molybdenum wire protruding from the end of a sealing portion (narrow tube portion / capillary portion) that hermetically seals both ends of the arc tube; A UV enhancer that emits ultraviolet rays for starting assistance toward the discharge vessel of the arc tube is a metal vapor discharge lamp accommodated in an outer bulb made of hard glass, the discharge lamp being a rare gas A UV enhancer provided with a pipe portion penetrating the center of the container in a cylindrical airtight container filled with argon gas containing mercury vapor or mercury vapor. The electrode lead or the sealing portion, or the through inserting a feeding wire, is attached at a position biased to one end side of the light emitting tube to be a rear end side of the lamp to the outer bulb.

The hermetic container of the UV enhancer is formed of translucent ceramics in its entirety, or at least a portion that emits ultraviolet rays for starting assistance toward the discharge container of the arc tube.

Further, the hermetic container of the UV enhancer is a double cylinder in which one end side of the inner cylinder and the one end side of the outer cylinder forming a pipe portion penetrating the container are integrated so as to connect one end side of the outer cylinder. It is assembled with a container body having a structure and a perforated cap that plugs the other end of the inner cylinder into a hole and closes the opening of the other end of the outer cylinder, or has an opening on one end. A bottomed cylindrical container main body having a holed bottom at the other end, a holed cap for closing the one end side opening of the container main body, a hole in the holed cap, and a bottom of the container main body. It is assembled with ceramic pipes or metal pipes that are inserted into open holes to close the holes.

Further, the UV enhancer is connected to the outside of the hermetic container through which the electrode lead protruding from one sealing portion of the arc tube or the end of the sealing portion is inserted into the pipe portion, from the end of the other sealing portion of the arc tube. An external electrode welded to a power supply wire for electrically connecting the protruding electrode lead is disposed, or a power supply wire for electrically connecting the electrode lead protruding from the end of one sealing portion of the arc tube An external electrode welded to an electrode lead protruding from the end of the other sealing portion of the arc tube is disposed outside the hermetic container inserted through the pipe portion. The external electrode is formed of a strip-shaped metal thin plate with one end wound around the body of the hermetic container.

A discharge lamp 1A of Example 1 shown in FIG. 1 includes an arc tube 2 in which mercury and a metal halide as a luminescent substance and a starting gas are sealed in a discharge vessel 3 in which a pair of tungsten electrodes are arranged to face each other. The electrode leads 5a and 5b made of niobium wire or molybdenum wire having a wire diameter of about 0.3 to 0.7 mm projecting from the ends of the sealing portions 4a and 4b for hermetically sealing both ends of the arc tube 2 are electrically connected. The power supply wires 6a and 6b made of nickel-plated iron wires having a wire diameter of about 0.5 to 1.0 mm, which serve as support columns for supporting the arc tube 2 at the same time, and the discharge vessel 3 of the arc tube 2 are used for starting assistance. The UV enhancer 7A that radiates ultraviolet rays is a metal vapor discharge lamp that is housed and disposed inside the outer bulb 8 made of hard glass.

The arc tube 2 of the discharge lamp 1A includes a discharge vessel 3 and a thin tube portion (capillary portion) having an outer diameter of about 2.0 to 4.0 mm that forms outer shells of sealing portions 4a and 4b that hermetically seal both ends thereof. ) 11 and 11 are integrally formed of high-purity and high-density translucent alumina ceramics.

In the UV enhancer 7A, a cylindrical airtight container 9 filled with argon gas or argon gas containing mercury vapor at a pressure of about 5 to 100 torr is provided with a cylindrical pipe portion 10 penetrating the center of the container 9. The electrode lead 5a protruding from the end of the sealing portion 4a of the arc tube 2 is inserted into the pipe portion 10 and attached to the electrode lead 5a, whereby the lamp 1A to the rear end side of the outer bulb 8 and The arc tube 2 is arranged at a position biased to one end side.

As shown in FIG. 2, the airtight container 9 of the UV enhancer 7A has an outer diameter of about 1.0 to 2.0 mm, an inner diameter of about 0.4 to 0.8 mm, and a length of about 10 to 2.0. outer diameter to form the body portion of the inner cylinder _{P 1} of one end side and the airtight container 9 of 6~9mm 4~8mm, an inner diameter of about 2 to 6 mm, the outer cylinder _{P 2} having a length of about 5~8mm the one end side integrated thereby in the outer cylinder and the container body 12 of the occluded double cylinder structure one end side of the P _2, the inner cylinder and the other end side and the other end of the outer tube P ₂ and inserted into the hole 14 of the P ₁ as connect The hole opening cap 13 made of a donut disk having a thickness of about 0.5 to 1.0 mm for closing the side opening is assembled by hermetically adhering with a melted and solidified glass frit. As shown in FIG. 1, the hole cap 13 is attached to the electrode lead 5 a with the portion of the perforated cap 13 facing the discharge vessel 3 of the arc tube 2.

2 is entirely formed of translucent ceramics, but the hole cap 13 is attached to the electrode lead 5a with the hole cap 13 facing the discharge vessel 3 of the arc tube 2 as shown in FIG. In this case, it is sufficient that at least the perforated cap 13 is made of translucent ceramics.

On the terminal side of the electrode lead 5a to which the hermetic container 9 of the UV enhancer 7A is attached, a feeding wire 6a bent in a bowl shape so that the tip portion is orthogonal to the electrode lead 5a is welded and attached to the electrode lead 5a. The hermetic container 9 is sandwiched between the end of the sealing portion 4a of the arc tube 2 and the power supply wire 6L, and protrudes from the end of the other sealing portion 4b of the arc tube 2 to the outside of the hermetic container 9. External electrode made of a strip-like stainless steel plate having a width of about 2 to 5 mm and a thickness of about 0.3 to 0.6 mm or a strip-like metal thin plate such as a nickel ribbon wire welded to a power supply wire 6b for electrically connecting the electrode lead 5b 15 is disposed so as to be wound around the body of the airtight container 9, and the airtight container 9 is securely fixed in place. The power supply wire 6b is formed from a member disposed inside the outer bulb 8 at a position biased to the other end side of the arc tube 2 that is the tip side of the lamp 1A to the outer bulb 8 due to high heat when the lamp is turned on. A getter 16 that absorbs the generated impure gas is welded.

In the discharge lamp 1A configured as described above, when a starting voltage is applied between the opposing electrodes disposed in the discharge vessel 3 of the arc tube 2 through the power supply wires 6a and 6b and the electrode leads 5a and 5b, The rare gas argon gas filled in the hermetic container 9 of the UV enhancer 7A is excited to generate ultraviolet rays, and part of the ultraviolet rays pass through the perforated cap 13 of the hermetic container 9 to discharge the discharge vessel of the arc tube 2. By radiating toward 3, the starting gas in the discharge vessel 3 is excited, and at the same time, initial electrons necessary for starting discharge are emitted from tungsten forming the electrode arranged in the discharge vessel 3. Thus, starting of the discharge lamp 1A is promoted.

The conventional UV enhancer 88 shown in FIG. 8 is provided with an internal electrode 93 for exciting the rare gas in an airtight container (UV discharge tube 91) filled with the rare gas. In the UV enhancer 7A, the electrode lead 5a inserted into the pipe portion 10 penetrating the center of the airtight container 9 filled with the rare gas functions as an internal electrode for exciting the rare gas in the airtight container 9. Since there is no need to separately provide an internal electrode in the container 9, there are advantages that the structure is simple, the manufacture is easy, and the manufacturing cost is not increased.

Further, the hermetic container 9 of the UV enhancer 7A is inserted into the pipe portion 10 penetrating through the center thereof through the electrode lead 5a protruding from the end of the sealing portion 4a of the arc tube 2 to thereby seal the sealing portion 4a of the arc tube 2. And an external electrode 15 made of a strip-like thin metal plate welded to the power supply wire 6b is wound around the body of the hermetic container 9 and the power supply wire 6a welded to the terminal side of the electrode lead 5a. Thus, the orientation and the mounting position of the hermetic container 9 are prevented from changing due to the impact and vibration generated when the discharge lamp 1A is transported and transported. As a result, it is possible to reliably emit start-up ultraviolet rays from the hermetic container 9 toward the discharge container 3 of the arc tube 2, and the electrode lead 5a with the hermetic container 9 attached contacts the power supply wire 6b of reverse polarity. There is no risk of a short circuit accident.

Further, in the UV enhancer 7A, the electrode lead 5a inserted into the pipe portion 10 penetrating the center of the hermetic container 9 functions as an internal electrode, and the external electrode disposed outside the internal electrode and the hermetic container 9 15, a discharge that excites the rare gas filled in the hermetic container 9 is generated, and an amount of ultraviolet rays necessary and sufficient for assisting the start of the lamp can be generated reliably.

In the discharge lamp 1B of Example 2 shown in FIG. 3, after welding the distal end portion of the feeder wire 6a bent into a bowl shape to the electrode lead 5a protruding from the end near the end of the sealing portion 4a of the arc tube 2, The electrode lead 5a is inserted into the pipe portion 10 of the airtight container 9 of the UV enhancer 7A, and a metal sleeve 17 serving as a stopper for preventing the airtight container 9 from being detached is welded to the end of the electrode lead 5a protruding from the pipe portion 10. By doing so, the airtight container 9 of the UV enhancer 7A is mounted on the electrode lead 5a while being sandwiched between the tip of the power supply wire 6a welded to the electrode lead 5a and the metal sleeve 17, and the electrode 1 is different from the discharge lamp 1A in FIG. 1 in that the direction of the hermetic container 9 attached to the lead 5a is opposite to that of the hermetic container 9 in FIG. In common with the first discharge lamp 1A.

In the discharge lamp 1B of FIG. 3, the power supply wire 6a that supports the electrode lead 5a protruding from the end of the sealing portion 4a of the arc tube 2 is sealed from the hermetic container 9 of the UV enhancer 7A attached to the electrode lead 5a. Since the welding is performed at a position close to the end of the portion 4a, even if a dynamic load of the airtight container 9 is applied to the electrode lead 5a due to impact or vibration generated when the lamp is transported and transported, the sealing portion is sealed by the dynamic load. There is an extraordinary effect that cracks are prevented from occurring in the narrow tube portion 11 forming the inside of 4a and the outer shell of the sealing portion 4a.

When the hermetic container 9 of the UV enhancer 7A is mounted on the electrode lead 5a in the orientation as shown in FIG. 3, at least the container main body 12 of the hermetic container 9 is formed of translucent ceramics. It ’s enough.

In the discharge lamp 1C of Example 3 shown in FIG. 4, a UV enhancer 7B provided with a pipe portion 10 penetrating the airtight vessel 9 filled with a rare gas such as argon gas is provided in the pipe portion 10. The terminal side of the sealing portion 4 a of the arc tube 2 is inserted and attached to a position biased to one end side of the arc tube 2. The hermetic container 9 of the UV enhancer 7B used for the discharge lamp 1C is different in size from the hermetic container 9 of the UV enhancer 7A shown in FIGS. 1 and 3, but the basic structure is the same. The detailed description regarding the structure of the airtight container 9 is abbreviate | omitted by attaching | subjecting the same code | symbol to.

The hermetic container 9 of the UV enhancer 7B has an inner diameter such that the pipe portion 10 penetrating the container can pass through the sealing portion 4a of the arc tube 2, and the sealing portion 4a of the pipe portion 10 is included in the pipe portion 10. After inserting the reinforcing ring 18 made of ceramics attached to the terminal side and the terminal, the tip of the power supply wire 6a bent in a hook shape near the terminal is welded to the electrode lead 5a and welded to the power supply wire 6b. The external electrode 15 made of a strip-shaped metal thin plate is wound around the container body 12 of the hermetic container 9 and held in place.

The airtight container 9 has a perforated cap 13 secured to the flange portion 19 formed at the opening of the container body 12 with a glass frit facing the discharge vessel 3 side of the arc tube 2. It is attached to the terminal side of the sealing part 4a. As a result, even if the airtight container 9 is subjected to such a strong impact that it cannot be held in place by the external electrode 15, the flange portion 19 formed at the opening of the container body 12 is wound around the container body 12. Since it is blocked by the external electrode 15 and the movement of the arc tube 2 in the direction of the discharge vessel 3 is prevented, and the movement in the reverse direction is prevented by the power supply wire 6a welded to the electrode lead 5a, the quality claim factor There is no risk of misalignment such as Further, if the hermetic container 9 is fixed to the sealing portion 4a of the arc tube 2 using a glass frit or the like, it is possible to reliably prevent the positional deviation.

The UV enhancer 7B shown in FIG. 4 has a power feeding body such as an electrode lead 5a sealed inside the sealing portion 4a of the arc tube 2 inserted into the pipe portion 10 passing through the airtight container 9 and the reinforcing ring 18. Functions as an electrode. It should be noted that the hermetic container 9 is located from the position shown in FIG. 4 as long as it prevents a part of the effective light radiated from the discharge container 3 of the arc tube 2 to reduce the light use efficiency and does not cause the shadow of the hermetic container 9. Alternatively, it may be provided close to the discharge vessel 3 of the arc tube 2.

In the discharge lamp 1D of the fourth embodiment shown in FIG. 5, a UV enhancer 20A that emits ultraviolet rays for starting assistance toward the discharge vessel 3 of the arc tube 2 is located at the center of a cylindrical airtight vessel 21 filled with a rare gas. A feeding wire 6b connected to the electrode lead 5b is inserted through the pipe portion 22 provided so as to penetrate, and is disposed at a position biased to one end side of the arc tube 2 which is the rear end side of the lamp 1D. Yes.

As shown in FIG. 6, the airtight container 21 of the UV enhancer 20 </ b> A includes a bottomed cylindrical container body 23 having an opening 24 at one end and a bottom 25 having a hole 26 at the other end, and the container A donut disk-shaped hole cap 27 for closing the one end side opening 24 of the main body 23, and a hole 28 formed in the hole 28 of the hole cap 27 and the bottom 25 of the container main body 23. As shown in FIG. 5, the container body 23 is attached to the power supply wire 6 b with the bottom 25 side facing the discharge container 3 of the arc tube 2.

As for the airtight container 21, the container main body 23 and the perforated cap 27 are both formed of ceramics, and at least the container main body 23 is formed of translucent ceramics. Further, the pipe portion 22 provided so as to pass through the center of the airtight container 21 by being inserted into the hole 26 formed in the bottom portion 25 of the container main body 23 and the hole 28 of the perforated cap 27 is similar in thermal expansion coefficient to ceramics. It is made of a metal pipe such as a niobium pipe. The container main body 23, the perforated cap 27, and the pipe portion 22 are hermetically bonded to each other with a glass frit.

The hermetic container 21 is fixed at a fixed position by welding one end or both ends of the pipe portion 22 through which the power supply wire 6b is inserted to the power supply wire 6b, and is connected to a power supply wire 6a having a polarity opposite to that of the power supply wire 6b. An external electrode 29 made of a strip-shaped metal thin plate welded to the electrode lead 5 a is wound around the container body 23.

Thereby, in the UV enhancer 20A, the power supply wire 6b inserted into the pipe portion 22 that penetrates the center of the hermetic container 21 functions as an internal electrode that excites the rare gas in the hermetic container 21, and generates ultraviolet rays. A part of the ultraviolet rays can be radiated toward the discharge vessel 3 of the arc tube 2, and at the same time, the direction and mounting position of the hermetic vessel 21 may fluctuate due to shock and vibration generated when the lamp is transported and transported. It is surely prevented.

Further, since the hermetic container 21 of the UV enhancer 20A is attached to the power supply wire 6b that is thicker and more rigid than the electrode lead 5a, there is no possibility that the orientation and the attachment position will be changed by an externally applied impact.

The pipe portion 22 penetrating the center of the hermetic container 21 may be a ceramic pipe formed of the same ceramic as the container main body 23 and the perforated cap 27. In this case, as shown in FIG. What is necessary is just to weld the stoppers 30 and 30 which consist of a pair of metal sleeve arrange | positioned at the both ends of the pipe part 22 to the electric power feeding wire 6b, and to fix the airtight container 21 in a fixed position.

In the discharge lamp 1E of the fourth embodiment shown in FIG. 7, a UV enhancer 20B that emits ultraviolet rays for starting assistance toward the discharge vessel 3 of the arc tube 2 is formed in the same shape as the airtight vessel 21 of the UV enhancer 20A in FIG. 5 is provided on the inner surface of the sealed airtight container 21 with a plurality of strips 31 made of a conductive material such as metal or carbon in parallel to the pipe portion 22, and as shown in FIG. The difference from the discharge lamp 1D of the third embodiment is that the electrode 29 is not provided.

The UV enhancer 20 </ b> B is a pipe portion 22 that penetrates through the center of the airtight container 21 to linear bodies 31, 31... Attached at regular intervals along the inner peripheral surface of the container main body 23 that forms the body of the airtight container 21. The structure has a structure in which electric charges having a polarity opposite to that of the feeding wire 6b inserted therein are concentrated to easily generate a discharge that excites the rare gas filled in the hermetic vessel 21. Instead of the filaments 31, 31..., Metal strips or small pieces having a thickness and thickness of the order of microns may be arranged in the airtight container 21. Instead of fixing the position, it may be simply enclosed in the airtight container 21.

The present invention contributes to the improvement of the quality and reliability of a discharge lamp provided with a UV enhancer for starting assistance.

DESCRIPTION OF SYMBOLS 1A-1E ... discharge lamp 2 ... arc tube 3 ... discharge vessel 4a ... sealing part 4b ... sealing part 5a ... electrode lead 5b ... electrode lead 6a ... Feed wire 6b ... Feed wire 7A ... UV enhancer 7B ... UV enhancer 7C ... UV enhancer 9 ... Airtight container 10 ... Pipe part 12 ... Container body 13 of the airtight container -Hole cap 15 ... External electrode 20A ... UV enhancer 20B ... UV enhancer 21 ... Hermetic container 22 ... Pipe part 23 ... Container body 27 of hermetic container ... Hole cap 29 ... External electrode 31 ... Linear body made of conductive material

Claims (8)

An arc tube in which at least a luminescent substance and a starting gas are sealed in a discharge vessel in which a pair of electrodes are arranged to face each other, and an electrode lead protruding from the end of a sealing portion that hermetically seals both ends of the arc tube In a discharge lamp having an electrically connected power supply wire and a UV enhancer that emits ultraviolet rays for starting assistance toward the discharge vessel, a pipe portion that penetrates the vessel is provided in an airtight vessel filled with a rare gas. The discharge lamp is characterized in that the UV enhancer is attached to a position biased to one end side of the arc tube by inserting the electrode lead or the sealing portion or the feeding wire into the pipe portion. 2. The discharge lamp according to claim 1, wherein the whole of the hermetic container or a part that emits ultraviolet rays for starting assistance toward the discharge container is formed of translucent ceramics. A container body of a double cylinder structure in which the airtight container is integrated so as to connect one end side of the inner cylinder and the one end side of the outer cylinder to form the pipe portion, and the one end side of the outer cylinder is closed; The discharge lamp according to claim 1 or 2, wherein the discharge lamp is assembled with a hole cap that plugs the other end of the cylinder into the hole and plugs the opening at the other end of the outer cylinder. The airtight container has an opening on one end side and a bottomed cylindrical container main body having a hole bottom on the other end side, and a holed cap for closing the one end side opening of the container main body, 3. The discharge lamp according to claim 1, wherein the discharge lamp is assembled with a hole of the perforated cap and the pipe portion formed of a ceramic pipe or a metal pipe that is inserted into the bottom hole of the container body to close the hole. The electrode lead protruding from one sealing portion of the arc tube or the end of the sealing portion is protruded from the end of the other sealing portion of the arc tube to the outside of the hermetic container inserted through the pipe portion. The discharge lamp according to claim 1, 2, 3, or 4, wherein an external electrode welded to a power supply wire for electrically connecting the electrode lead is disposed. From the end of the other sealing portion of the arc tube to the outside of the hermetic container through which the feed wire electrically connecting the electrode lead protruding from the end of the one sealing portion of the arc tube is inserted into the pipe The discharge lamp according to claim 1, 2, 3, or 4, wherein an external electrode welded to the protruding electrode lead is disposed. The discharge lamp according to claim 5 or 6, wherein the external electrode is formed of a strip-shaped metal thin plate having one end wound around the body of the hermetic container. The discharge lamp according to claim 1, 2, 3, 4, 5, 6 or 7, wherein a strip, a small piece or a linear body made of a conductive material is disposed in the hermetic container.

Images