JP2009277537A - High-pressure discharge lamp and lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-pressure discharge lamp with a silica glass translucent airtight container whose sealing portion has suitably improved strength in the severe conditions of the high-pressure discharge lamp, and to provide a lighting system. <P>SOLUTION: The high-pressure discharge lamp includes the silica glass translucent airtight container 1, a sealed metal foil 2 embedded inside the sealing portion 1b thereof, an electrode 3 having an electrode shaft portion 3b connected at its base end to the sealed metal foil, a sub coil 4 mounted in the sealing portion around the electrode shaft portion, and having a first region R1 including a first coil portion 4a having one end located on the side of a discharge space and the other end continuously extending toward the vicinity of a connection portion between the sealed metal foil and the electrode shaft portion, and a second region R2 including a severed portion Cs located adjacent to the other end of the first coil portion and a second coil portion 4b having one end opposed to the other end of the first coil portion via the severed portion and the other end located adjacent to the connection portion to the electrode shaft portion, and a discharge medium filled therein to produce a pressure of 1 MPa or greater during light-on. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a high-pressure discharge lamp using a sealing metal foil for a sealing portion and a lighting device including the same.

  When a translucent hermetic vessel made of quartz glass is used for the high-pressure discharge lamp, a sealed metal foil having a thickness of about 20 μm mainly composed of molybdenum in a sealing portion adjacent to the surrounding portion of the discharge space of the translucent airtight vessel. It is common to energize the inside while embedding airtightly and maintaining airtightness. Then, the base end portion of the electrode shaft portion is welded to one end side of the sealing metal foil, and the tip end portion of the current introduction conductor is welded to the other end side, so that current is supplied to the electrode via the sealing portion. Configured.

  In an ultra-high pressure type high pressure discharge lamp in which the pressure in the discharge space during lighting is 1 MPa or more and the temperature of the light-transmitting airtight container made of quartz glass is 500 ° C. or more, the high pressure discharge lamp has sufficient pressure resistance and heat resistance. Is required for each part. Especially in the sealed part of the translucent airtight container, the difference in thermal expansion coefficient between the electrode shaft part and the quartz glass covering the periphery is relatively large. It is well known that this occurs and a crack occurs in the quartz glass of the sealing part, which is one of the causes of breakage of the light-transmitting hermetic container at the time of lighting. In particular, since the temperature of the shaft portion of the electrode becomes higher as it approaches the electrode main portion, the portion closer to the discharge space is more susceptible to cracking in the sealing portion due to the influence of the thermal stress. It is also empirically known that problems such as breakage of the translucent airtight container occur.

  As a light source for automobile headlamps as a means to suppress the occurrence of cracks in the sealing part due to thermal stress due to the difference in thermal expansion coefficient between the electrode shaft part and the sealing part. A metal halide lamp to be used and a manufacturing method thereof have been proposed (see Patent Document 1). In Patent Document 1, the inner diameter of the subcoil attached to the rod-shaped portion of the electrode embedded in the sealing portion of the light-transmitting airtight container made of quartz glass is appropriately larger than the outer diameter of the rod-shaped portion of the electrode, and the sealing is performed. Is formed as a pitch that does not allow molten quartz glass to enter from between coil turns. Then, after welding one end of the subcoil to the sealing metal foil to which the rod-shaped portion of the electrode is welded, the position of the subcoil is held at about half the length of the subcoil and pulled to the discharge end side of the electrode rod. The pitch of the molybdenum foil side is extended and adhered.

  According to Patent Document 1, the pitch of the molybdenum foil side portion of the subcoil is extended. As a result, the translucent airtight container made of quartz glass and the rod-like portion of the electrode are in contact with each other, and the metal halide and mercury Since penetration is prevented, it is described that peeling between the translucent airtight container made of quartz glass and the sealing metal foil is prevented.

Japanese Patent Laid-Open No. 10-269941

  However, when the pressure in the discharge space at the time of lighting and the temperature of the light-transmitting hermetic container become high or when the lighting medium is turned on, a chemical reaction occurs between the discharge medium, quartz glass, and metal, resulting in a large intensity change. In the case of a high-pressure discharge lamp with particularly severe conditions such as when it tends to occur, each part is required to have high pressure resistance and heat resistance. In particular, in the sealing portion, the difference between the thermal expansion coefficients of the electrode shaft portion and the quartz glass surrounding the electrode shaft portion is so large that it cannot be ignored. It has been found that it is difficult to sufficiently increase the pressure to the extent required by the high-pressure discharge lamp described above.

  In order to sufficiently increase the strength of the sealing portion, it is necessary to improve pressure resistance and heat resistance. The pressure resistance is an index indicating how much pressure the translucent airtight container, particularly its sealing part, can withstand when the pressure in the translucent airtight container is increased. be able to. In order for the sealing part to withstand the high pressure in the light-transmitting airtight container when it is turned on, the sealing part has high pressure resistance and the sealing part can withstand repeated high temperatures during lighting and low temperatures during light extinction. There is a need. An index that can withstand repeated temperature changes when the sealing portion is turned on and off is heat resistance.

  When the heat resistance of the sealing part is insufficient, a crack occurs in the quartz glass part in contact with the electrode shaft part of the sealing part. Further, when the high-pressure discharge lamp is turned on, a stress caused by the internal pressure of the light-transmitting airtight container acts on the crack, and the light-transmitting airtight container is damaged. Furthermore, the crack is often generated when the temperature of the sealing portion changes greatly due to repeated lighting and extinction when the high-pressure discharge lamp is used, and it often grows.

  In addition, since the strength of the sealing part decreases from the initial state as the lighting time increases, if there are cracks in the sealing part, stress concentration occurs and the initial sealing part strength decreases. Therefore, it is ideal that no crack exists in the sealing portion.

  The present invention provides a high-pressure discharge lamp in which the strength of a sealing portion in a light-transmitting hermetic container made of quartz glass is improved to a suitable level even in a high-pressure discharge lamp having severe conditions, and an illumination device including the same. For the purpose.

  A high-pressure discharge lamp according to the present invention includes a light-transmitting hermetic container made of quartz glass provided with an enclosing part in which a discharge space is formed and a sealing part connected to an end of the encircling part; A sealing metal foil embedded hermetically in the sealing portion of the electrode; an electrode shaft portion whose base end is connected to the sealing metal foil, and an electrode main portion disposed at the tip of the electrode shaft portion and facing the discharge space An electrode provided; and mounted around the electrode shaft in the sealing portion of the light-transmitting hermetic container, with one end positioned on the discharge space side and the other end in the vicinity of the connection between the sealed metal foil and the electrode shaft A first region consisting of a first coil portion extending continuously toward the end, and a cut portion and one end adjacent to the other end of the first coil portion face the other end of the first coil portion via the cut portion. And a second region comprising a second coil portion having the other end adjacent to the connection portion with the electrode shaft portion. A current introduction conductor having a distal end connected to the sealing metal foil and a proximal end exposed to the outside from the sealing portion; a discharge sealed inside the translucent airtight container so as to exhibit a pressure of 1 MPa or more at the time of lighting. And a medium.

  In the present invention, the subcoil is mounted around the electrode shaft portion in the sealing portion of the translucent airtight container, and one end is positioned on the discharge space side and the other end is connected to the sealing metal foil and the electrode shaft portion. A first region consisting of a first coil portion extending continuously toward the vicinity of the portion, a severing portion adjacent to the other end of the first coil portion and one end to the other end of the first coil portion via the severing portion The quartz glass is in close contact with the entire circumference of the electrode shaft portion at the cut portion by providing the second region of the second coil portion that is opposed and has the other end adjacent to the connection portion with the electrode shaft portion. Therefore, it is possible to reliably prevent the discharge medium from entering the sealing metal foil, and as a result, the sealing metal foil is less likely to be peeled off. In addition, since the second coil portion is mounted, the quartz glass hardly adheres to the electrode shaft portion in the portion, and the heat acting between the electrode shaft portion and the quartz glass in the region close to the sealing metal foil. Stress is reduced. Further, the first coil portion in the first region of the subcoil located on the discharge space side of the electrode shaft portion in the sealing portion is interposed between the quartz glass and the electrode shaft portion, so that the quartz glass is directly attached to the electrode shaft portion. As a result, the occurrence of cracks is suppressed.

  As a result, the generation of cracks in the vicinity of the connection between the electrode shaft and the sealing metal foil is suppressed, and even when a thermal load is repeatedly applied by turning on and off the high-pressure discharge lamp, it shows high heat resistance and pressure resistance. The strength of the stop is improved, so that the internal pressure and temperature increase and / or the chemical reaction between the discharge medium, quartz glass, and metal tends to increase with the lighting time, etc. A good high pressure discharge lamp can be obtained even under particularly severe conditions.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a front view and an enlarged front view of a main part showing an embodiment for implementing a high-pressure discharge lamp of the present invention. In addition, the principal part enlarged front view has expanded and shown the part of the sealing part among the parts enclosed with the frame of the front view.

  The high-pressure discharge lamp of the present invention can be applied to various uses such as projection, automobile headlamps, and general lighting. The translucent airtight container 1, the sealing metal foil 2, the electrode 3, and the subcoil 4. The current introduction conductor 5 and the discharge medium are provided. The high-pressure discharge lamp of the form shown in the figure is for projection, and is provided with a base 6 and an external lead wire 7 in addition to the above configuration.

  The translucent airtight container 1 is made of quartz glass and includes a surrounding portion 1a and a sealing portion 1b. The surrounding part 1a bulges in a bulb shape, and a discharge space 1c is formed inside. In addition, the surrounding portion 1a can have a desired shape such as a spheroid, spindle, sphere, or cylinder in the shape of the internal discharge space. The sealing part 1b is connected to the end part of the surrounding part 1a, and seals the translucent airtight container 1. Sealing can be performed by appropriately adopting a shrink seal, a pinch seal, or a combination thereof. Further, the number of the sealing portions 1b is not particularly limited in the present invention, but in the case of this embodiment, a pair is formed continuously at both ends in the tube axis direction of the surrounding portion 1a and extends in the tube axis direction. ing.

  The sealing metal foil 2 is a heat-resistant and conductive foil made of, for example, molybdenum and having a thickness of about 20 to 30 μm, and at least an intermediate portion in the longitudinal direction thereof is airtight inside the sealing portion 2. It is buried and enables external energization while maintaining airtightness.

  The electrode 3 includes an electrode main portion 3a and an electrode shaft portion 3b. The electrode main part 3a is mainly composed of a heat-resistant metal such as tungsten, and causes discharge to occur in the discharge space 1c. Then, if desired, a pointed portion can be formed at the tip, or groove formation or coil winding for promoting heat dissipation can be performed on the side surface. The electrode shaft portion 3b is made of a heat-resistant metal such as tungsten, supports the electrode main portion 3a at its tip portion, and has a base end portion connected to the end portion on the discharge space side of the sealing metal foil 2 by welding or the like. The electrode shaft portion 3b may be integrally formed with the electrode main portion 3a, or may be formed separately and integrated.

  The subcoil 4 is a refractory metal wire made of tungsten or the like having a smaller diameter than the diameter of the electrode shaft portion, and is mounted around the electrode shaft portion 3b in the sealing portion 1b of the translucent airtight container 1. And a first region R1 and a second region R2. One end of the first region R1 is located on the discharge space 1c side, and the other end is relatively continuous with the sealing metal foil 2 from one end toward the connecting portion between the sealing metal foil 2 and the electrode shaft portion 3b. It consists of the 1st coil part 4a extended to a near position.

  2nd area | region R2 is located between 1st area | region R1 and the sealing metal foil 2, and consists of the cutting part Cs and the 2nd coil part 4b. The cut portion Cs is formed adjacent to the other end of the first coil portion 4a, and the distance in the length direction of the electrode shaft portion 3b is set to be extremely short. One end of the second coil portion 4b faces the other end of the first coil portion 4a via the cut portion Cs, and the other end is adjacent to the connection portion between the electrode shaft portion 3b and the sealing metal foil 2.

  Therefore, the subcoil 4 is cut off at a position relatively close to the connection portion between the electrode shaft portion 3b and the sealing metal foil 2, and is separated into the first coil portion 4a and the second coil portion 4b via the cut portion Cs. ing.

  The first coil portion 4a in the first region R1 mainly includes at least a portion where the pitch is set to be relatively small so that the quartz glass can be prevented from directly contacting the electrode shaft portion 3b. Further, the length of the first coil portion 4 a is arranged between the end portion of the sealing portion 1 b on the discharge space 1 c side to the front side in the vicinity of the connection portion between the electrode shaft portion 3 b and the sealing metal foil 2. Set to If it does so, the 1st coil part 4a will prevent that quartz glass contacts the electrode shaft part 3b directly. If desired, it is allowed to increase the pitch of a partial region on the side of the sealing metal foil 2 of the first coil portion 4a.

  The cut portion Cs of the second region R2 is adjacent to the other end of the first coil portion 4a, and provides a small gap between the first coil portion 4a and the second coil portion 4b. At the time of sealing, that is, in the heating step for forming the sealing portion 1b, the quartz glass is in close contact with the electrode shaft portion 3b at the part of the severing portion Cs. However, if the length in the axial direction of the cut-off portion Cs is too large, the sealing portion 1b is caused by thermal stress generated when the high-pressure discharge lamp is turned on and off due to the difference in thermal expansion coefficient between the electrode shaft portion 3b and quartz glass. This is not preferable because cracks are likely to occur.

  Further, the dimension cut portion Cs can be formed by dividing the sub-coil 4 integrated as a whole in advance into a first coil portion 4a and a second coil portion 4b prior to sealing. Alternatively, the integrally formed subcoil 4 is formed by heat treatment while the sealing process is being performed, when the high-temperature quartz glass comes into contact with the subcoil 4, so that the deformation progresses and finally the cutting is performed. There may be. Alternatively, as a result of sealing a part of the second coil portion 4b in advance prior to sealing and then sealing, a severing portion Cs is formed between the removed part and the other part. There may be.

  The second coil portion 4a in the second region R2 suppresses the area of the close contact portion with respect to the electrode shaft portion 3b of quartz glass in the severing portion Cs so as to become a necessary minimum level, and a portion of the second coil portion 4a. In this case, the second coil portion 4a is interposed between the quartz glass and the electrode shaft portion 3b to perform a relaxing action, so that the sealing metal foil 2 and the electrode shaft portion 3b can be connected even when lighting and turning off are repeated. It acts so that a crack does not occur in the vicinity of the part. As a result, the heat resistance of the sealing portion 1b is improved.

  Further, in the heat treatment during the sealing step, as a result of the second coil portion 4a being heated relatively strongly, even if the coil turn is deformed and the pitch or shape is disturbed, or part of the coil is lost, There is no substantial hindrance to the above functions. This means that part of the turn can be excised in advance prior to the sealing step if desired.

  Furthermore, it is preferable to seal after forming an electrode mount having a structure in which the coil terminal portion e on the side of the sealing metal foil 2 of the second coil portion 4 b is fixed to the sealing metal foil 2. Instead of fixing to the sealing metal foil 2, it may be fixed to the base end portion of the electrode shaft portion 3b. Thereby, in the heat treatment process of the sealing part 1b, when the vicinity of the connection part between the sealing metal foil 2 and the electrode shaft part 3b is sufficiently heated, the sub coil 4 is cut in the vicinity of the connection part of the sub coil 4. It becomes easy to form the cut part Cs. For this reason, when the subcoil 4 is mounted on the electrode shaft portion 3b, the subcoil 4 is cut off in the sealing step even if it is in the form of a single coil, and the first coil portion 4a and the second coil portion 4b are dimensioned. Easy to step. Further, when the size is cut, the second coil portion 4b is pulled toward the fixing portion, and the coil turn and pitch are disturbed and deformed, so that a stepped portion Cs having an appropriate length is easily formed.

  However, even if the sealing portion 1b is formed after the first coil portion 4a and the second coil portion 4b are formed after the subcoil 4 is separated from the electrode shaft portion 3b in advance by the cut portion Cs as described above, As long as the heating conditions are the same, it is possible to obtain the same sealing performance as in the embodiment in which severing occurs during heating.

  The current introduction conductor 5 is made of a conductive metal such as molybdenum, and its distal end is connected to the outer end of the sealing metal foil 2 by welding or the like, and the proximal end is connected to the outside of the translucent airtight container 1. Exposed.

  The discharge medium is enclosed in the translucent airtight container 1. Various known discharge media can be encapsulated to obtain the desired radiation by discharge. For example, in the case of a metal halide lamp, a light emitting metal halide, a rare gas, and a lamp voltage forming substance are enclosed. The lamp voltage forming substance is a medium that mainly forms the lamp voltage of a high-pressure discharge lamp, and can encapsulate mercury or a metal halide such as zinc having a relatively high vapor pressure and low light emission in the visible range. . In the case of an ultra high pressure mercury lamp, mercury and a rare gas are enclosed. In the case of a rare gas discharge lamp, a rare gas such as xenon is enclosed.

  In the present invention, since the strength of the sealing portion is improved, the sealing pressure of the rare gas is higher than that of the discharge medium containing mercury, so that the temperature and internal pressure of the sealing portion at the time of lighting are high. Is preferred.

In the illustrated embodiment, the discharge medium has a mercury-free configuration mainly composed of a metal halide that contributes to light emission, a metal halide such as zinc that mainly contributes to lamp voltage formation, and a rare gas. Further, scandium halide (ScX ₃ ) is used as a metal halide contributing to light emission. As halogen (X), it is preferable to use one or both of iodine and bromine. Zinc iodide ZnI ₂ is used as a metal halide that contributes to lamp voltage formation. As the rare gas, xenon is sealed at 1.0 MPa.

  The base 6 is disposed as desired, and functions to supply power to the high pressure discharge lamp and to support the high pressure discharge lamp as desired. In this embodiment, since it is a high-pressure discharge lamp for projection, it is used in combination with a reflecting mirror. Therefore, the high-pressure discharge lamp is supported by supporting the reflecting mirror. For this reason, the nozzle | cap | die 6 in this form is mounted | worn with only one of a pair of sealing parts 1b and 1b of the translucent airtight container 1. FIG. Accordingly, the base 6 has a bolt-shaped base terminal t connected to a current introduction conductor (not shown) led out from the one sealing portion 1b.

  The external lead wire 7 is disposed as desired, and is connected to the current introduction conductor 5 of the sealing portion 1b where the cap of the light-transmitting airtight container 1 is not attached. Then, a lighting circuit (not shown) is connected between the base terminal of the base 6 and the external lead wire 7, and the high pressure discharge lamp is lit.

  In addition, although not shown in figure, the outer tube which accommodates the translucent airtight container 1 inside can be arrange | positioned if desired.

Next, experimental results regarding the relationship between the configuration of the subcoil in the sealing portion and the pressure resistance performance will be described.
(1) A configuration in which a subcoil formed entirely at a pitch of 250% is mounted (Comparative Example 1).
(2) A configuration in which a sub-coil having a pitch of 400% in the vicinity of the connection portion between the sealing metal foil and the electrode shaft portion and a remaining portion of 250% is mounted (Comparative Example 2).
(3) A configuration in which the first coil portion and the second coil portion are separately formed via a cut portion located in the vicinity of the connection portion between the sealing metal foil and the electrode shaft portion in addition to the configuration of Comparative Example 2 (the present invention).

  As a result of trial manufacture of 10 mercury-free high-pressure discharge lamps having the same specifications other than the sealing portion for each of the configurations (1) to (3) and comparing the pressure resistance performance, the breakdown pressure is The configuration was 10 to 12 MPa, the configuration (2) was 11.5 to 13 MPa, and the configuration (3) was 12.5 to 18.5 MPa. Accordingly, it has been clarified that the pressure resistance increases in the order of the configuration of (1) <(2) <(3). That is, according to the present invention, the pressure resistance performance is higher than those of Comparative Examples 1 and 2.

  Next, the relationship between the length and the pressure resistance of the first region R1 and the second region R2 of the subcoil 4 in the present invention will be described with reference to FIG. FIG. 2 shows that the length of the second region R2 in the subcoil 4 is A and the total length (R1 + R2) is fixed to B, and the value of A in B is changed in the configuration of the present invention shown in (3). This shows the result of investigating the burst pressure. In the figure, the horizontal axis represents A / B (%), and the vertical axis represents the breaking pressure (MPa). Note that A / B (%) = 0 in the figure is the case of Comparative Example 2. The above A and B are also shown in FIG.

  According to the investigation results shown in FIG. 2, the present invention is preferable because the pressure resistance is clearly superior to the prior art within the range of 2 <A / B <42 (%), and in particular, 13 <A / B <. It can be understood that particularly high pressure resistance is obtained within the range of 37 (%).

  Next, an example of the configuration of the second coil portion in the present invention will be described with reference to the main part photograph of the electrode mount shown in FIGS. 3A is a first example of the second coil portion according to the present invention, FIG. 3B is a second example, and FIG. 3C is a comparative example. The photograph is taken from the side of the electrode mount, and it can be seen that the electrode shaft is connected to the side of the sealing metal foil in the thickness direction at the lower right side.

  In the first form shown in (a), a severed portion that is cut in the vicinity of the sealing metal foil of the subcoil attached to the electrode shaft portion by heating in the sealing step and appears below arrow Cs, The first coil part appearing below and the second coil part appearing below arrow 4b can be seen. In addition, the pitch of the 1st coil part and 2nd coil part which adjoins to the cutting part Cs deform | transforms and becomes small because the sub coil was cut | disconnected.

  In the second form shown in (b), the subcoil attached to the electrode shaft portion is cut in the vicinity of the sealing metal foil prior to the sealing step, and appears at the cut portion indicated by arrow Cs, below arrow 4a. The first coil part and the second coil part appearing below the arrow 4b can be seen. Further, the second coil part has one turn on the left side of the figure, but the other fronts are partially deleted from the front and back face positions shown in the photograph.

  The form of the comparative example shown in (c) is the comparative example 1 shown in (1) described above, and the subcoils appearing below the arrow 4 attached to the electrode shaft portion are integrated over the entire length.

  FIG. 4 is a schematic view showing an embodiment for carrying out the lighting device of the present invention. The illuminating device includes an illuminating device body 11, a high-pressure discharge lamp 12, and a lighting device 13, and constitutes a projector in this embodiment.

  The illuminating device main body 11 is a remaining portion obtained by removing the high-pressure discharge lamp 12 and the lighting device 13 from the illuminating device, and includes a case 11a, a lamp socket, an optical system 11b, and the like as constituent elements in this embodiment.

  The high-pressure discharge lamp 12 is incorporated in the reflecting mirror 14 and has the configuration shown in FIG.

  The lighting device 13 includes an electronic lighting circuit and an igniter. The high pressure discharge lamp 12 is started by the igniter and is lit by the electronic lighting circuit.

The front view and principal part expansion front view which show the form for implementing the high pressure discharge lamp of this invention Graph showing the relationship between the ratio of the length of the second region to the total length of the subcoil and the burst pressure The photograph which shows the example (a) and (b) of the form of the 2nd coil part in this invention with the comparative example (c) The schematic diagram which shows one form for implementing the illuminating device of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Translucent airtight container, 1a ... Enclosing part, 1b ... Sealing part, 2 ... Sealing metal foil, 3 ... Electrode, 3a ... Electrode main part, 3b ... Electrode axial part, 4 ... Subcoil, 4a ... 1st Coil portion, 4b ... second coil portion, 5 ... current introduction conductor, 6 ... cap, 7 ... external lead wire, Cs ... cutting portion, e ... coil termination portion, R1 ... first region, R2 ... second region , T ... Cap terminal

Claims (4)

A translucent airtight container made of quartz glass provided with an enclosure part in which a discharge space is formed and a sealing part connected to an end part of the enclosure part;
A sealed metal foil hermetically embedded in the inside of the sealing part of the translucent airtight container;
An electrode having a base end connected to the sealing metal foil and an electrode main portion disposed at a tip end of the electrode shaft and facing the discharge space;
In the sealing part of the translucent airtight container, it is mounted around the electrode shaft part, one end is located on the discharge space side, and the other end is continuous toward the vicinity of the connection part between the sealing metal foil and the electrode shaft part. A first region consisting of the first coil portion extending and a cut portion and one end adjacent to the other end of the first coil portion are opposed to the other end of the first coil portion through the cut portion, and the other end is A subcoil provided with a second region composed of a second coil portion adjacent to the connection portion with the electrode shaft portion;
A current introduction conductor having a distal end connected to the sealing metal foil and a proximal end exposed to the outside from the sealing portion;
A discharge medium enclosed in a translucent airtight container so as to exhibit a pressure of 1 MPa or more when lit;
A high-pressure discharge lamp comprising: 2. The subcoil according to claim 1, wherein the ratio A / B satisfies the following expression 1 when the length of the second region is A and the length of the first and second regions is B: 2. High pressure discharge lamp.
[Formula 1]
2 <A / B <42   3. The high-pressure discharge lamp according to claim 1, wherein the discharge medium is mercury-free. A lighting device body;
A high-pressure discharge lamp according to any one of claims 1 to 3 disposed in a lighting device body;
A lighting device for lighting the high-pressure discharge lamp;
An illumination device comprising:

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