Discharge lamp

Abstract

The invention provides a discharge lamp which is short in starting time. The discharge lamp is provided with: a light emitting tube in which mercury is sealed; the first electrode and the second electrode are oppositely arranged on the inner side of the light-emitting tube and are separated in the first direction; an electrode bar connected to a side opposite to the second electrode with respect to the first electrode and extending along the first direction; and a support part for supporting the electrode bar, the length D1 (mm) of the periphery of the electrode bar, the height H1 (mm) of the mercury from the support part, and the volume V1 (mm3) of the mercury sealed in the light emitting tube satisfy the following equation (1): D1 * H1 / V1 > = 0.079 (mm-1)... (1) when the first direction is set to be a direction approximately perpendicular to the horizontal plane and the first electrode is arranged in a state that the first electrode is closer to the lower side than the second electrode.

Description

Technical Field

[0001] The present invention relates to a discharge lamp having mercury sealed in a light-emitting tube. Background Art

[0002] A discharge lamp (hereinafter simply referred to as a “lamp”) using mercury as a light source is used as a light source for an exposure device or the like used in a manufacturing process of a flat panel display or the like.

[0003] In the above-mentioned lamp, when the lamp is lit in a state where the direction in which the pair of electrodes disposed in the light emitting tube face each other is the horizontal direction, the arc generated between the pair of electrodes may become uneven due to the convection of the mercury vapor in the light emitting tube. Therefore, the lamp is typically lit in a state where the direction in which the pair of electrodes face each other is the direction at right angles to the horizontal plane (hereinafter referred to as "vertical lighting").

[0004] Since mercury has a low melting point, mercury is in a condensed liquid state below the arc tube before the lamp is lit. That is, in a lamp arranged at right angles to the horizontal plane for vertical lighting, mercury condenses while in contact with an electrode rod connected to the lower electrode of a pair of electrodes.

[0005] In addition, a noble gas (also called "rare gas") is sealed in the light-emitting tube of the lamp to assist in starting the lamp. In this state, when a high voltage is applied between the electrodes via the joints located at both ends of the lamp, insulation breakdown occurs between the electrodes. By continuously inputting power, the lamp switches to arc discharge and lights up. After the lamp is lit, the pair of electrodes becomes hot due to the heating of the arc, and the liquid mercury is heated and evaporated mainly through the electrode rods. In the above-mentioned lamp, by evaporating the sealed mercury, the desired light can be obtained stably.

[0006] In recent years, for example, in exposure devices used in the manufacturing process of flat panel displays, longer lamp life is required in order to shorten downtime associated with lamp replacement and reduce operating costs. In conjunction with this, since the heat capacity of the lamp increases in most cases, the time required for evaporation of mercury during lighting increases. That is, after the power input is started for lighting the lamp, the time until the desired light is obtained from the lamp (hereinafter, for convenience, referred to as "start-up time") increases.

[0007] However, in the exposure device, the startup time of the lamp becomes the downtime. Therefore, even if the heat capacity is increased and the life of the lamp is extended, the startup time is required to be short.

[0008] Therefore, the applicant has developed a lamp that can efficiently supply heat to mercury when the lamp is lit in order to shorten the start-up time of the lamp. For example, in Patent Document 1, a heat transfer plate in contact with the electrode rod in contact with the condensed mercury is arranged. Patent Document 1 proposes that the heat of the electrode rod, which becomes high temperature when the lamp is lit, is efficiently transferred to mercury via the heat transfer plate.

[0009] Prior art literature

[0010] Patent Literature

[0011] Patent Document 1: Japanese Patent Application Publication No. 2001-15070 Summary of the invention

[0012] Problems to be solved by the invention

[0013] However, the lamp described in Patent Document 1 is manufactured by passing the electrode rod through a heat conducting plate having a hole, so the inner diameter of the hole of the heat conducting plate needs to be larger than the outer diameter of the electrode rod. Thus, when a gap is generated between the electrode rod and the heat conducting plate, it is difficult for heat from the electrode rod to be transferred to the heat conducting plate. Therefore, it takes time to heat the mercury in the lamp of Patent Document 1, and there is room for improvement in the start-up time of the lamp.

[0014] In view of the above situation, an object of the present invention is to provide a lamp with a short starting time.

[0015] Technical solutions to solve problems

[0016] The discharge lamp involved in the present invention is characterized in that it comprises: a light-emitting tube in which mercury is sealed; a first electrode and a second electrode, which are arranged to be separated and opposed to each other in a first direction inside the light-emitting tube; an electrode rod, which is connected to the first electrode on the side opposite to the second electrode and extends along the first direction; and a support portion, which supports the electrode rod, and when the first direction is set to be a direction substantially perpendicular to a horizontal plane and the first electrode is arranged below the second electrode, the length D1 (mm) of the outer circumference of the electrode rod, the height H1 (mm) of the mercury from the support portion, and the volume V1 (mm) of the mercury sealed in the light-emitting tube 3 ) satisfies the following formula (1): D1×H1 / V1≥0.079(mm -1 )…(1).

[0017] Here, the term “substantially at a right angle” means that the angle of the electrode rod relative to the horizontal plane is in the range of 90°±0.5°.

[0018] The process by which the inventor of the present invention obtained the structure of the above-mentioned discharge lamp is described. When the lamp is started, the electrode rod is mainly heated by the heat from the first electrode. Therefore, by increasing the area of ​​contact between the electrode rod and liquid mercury (hereinafter, for convenience, referred to as "contact area"), the mercury can be efficiently heated when the lamp is started. In addition, the lamp is stably lit by the evaporation of mercury in the light-emitting tube, so it is necessary to consider the amount of mercury sealed in. In view of these aspects, the inventor of the present invention believes that by increasing the contact area between the electrode rod and mercury relative to the volume of mercury sealed in the light-emitting tube, a lamp with a short starting time can be realized. In addition, the contact area corresponds to the product of the length D1 and the height H1.

[0019] The inventor of the present invention conducted intensive research and proposed the above structure. According to the above structure, mercury can be efficiently heated when the lamp is started, and a lamp with a short start-up time can be realized. As a result, the time required from the start of the lamp to the lighting is shortened, and the downtime of the exposure device, etc. is reduced. The details will be described later in the "Specific Implementation Method" section.

[0020] However, when the lamp is lit, the lamp voltage rises as mercury evaporates, and a long lamp startup time means that the voltage rises slowly. From a safety point of view, the lighting power supply of the lamp assembled in the exposure device is sometimes set so that if the lamp voltage does not reach a specified voltage within a certain period of time, it is judged that the lamp is abnormal and the voltage application is stopped. In this case, if the lamp startup time is long, the lamp lighting power supply stops the voltage application. As a result, there is a problem that the lamp is forced to be extinguished before stable lighting is achieved simply because the startup time is long, even though there is no problem with the characteristics of the lamp when it is stably lit.

[0021] In this regard, the lamp according to the present invention also has an effect that the lamp startup time is short, and therefore the problem of the lamp being forced to be extinguished due to the above-mentioned operation of lighting the power source is unlikely to occur.

[0022] In the above discharge lamp, the length D1 (mm), the height H1 (mm) of the mercury and the volume V1 (mm) of the mercury may be 3 ) further satisfies the following formula (2): D1×H1 / V1≤0.2(mm -1 )…(2).

[0023] Mercury in a liquid state condenses between the electrode rod and the inner wall surface of the arc tube. Here, in the above-mentioned lamp, if the separation distance L1 between the electrode rod and the arc tube in the direction orthogonal to the first direction is reduced, the height H1 of the mercury becomes higher. That is, reducing the separation distance L1 has the advantage of increasing the contact area between the electrode rod and the mercury without changing the amount of mercury.

[0024] As a method of reducing the separation distance L1, the outer diameter of the electrode rod may be increased to lengthen the above-mentioned length D1, or the inner diameter of the light-emitting tube may be reduced. However, if the separation distance L1 is reduced, the mechanical strength of the lamp may be reduced, and the light-emitting tube may be easily broken. In view of this, D1, H1 and V1 preferably satisfy the above-mentioned formula (2).

[0025] In addition, in the above discharge lamp, the volume V1 of the mercury may be 1480 (mm 3 )above.

[0026] In lamps with a large amount of mercury, the time required for the mercury to evaporate becomes longer, and the lamp startup time becomes longer. In this regard, according to the above structure, since the mercury can be efficiently heated, the amount of mercury enclosed can also be 20g or more. In addition, the volume of 20g of mercury at room temperature 25°C is about 1480mm 3 .

[0027] In the above discharge lamp, the first electrode may be a cathode.

[0028] In the arc formed between the pair of electrodes, the cathode is preferably disposed below the anode from the viewpoint of aligning the directions of thermal convection of the plasma gas flow generated by the cathode and the mercury vapor to stabilize the arc.

[0029] Here, the anode is heated by the inflow of electrons and tends to be hotter than the cathode. In other words, it can be said that the cathode is less likely to rise in temperature than the anode. That is, when the lamp is lit vertically, when the cathode is arranged at the lower side relative to the anode, it takes more time to heat the mercury, and the start-up time of the lamp becomes longer than when the anode is arranged at the lower side relative to the cathode. In contrast, according to the above structure, since mercury can be efficiently heated, it is possible to realize a lamp with a stable arc and a short start-up time by arranging the cathode at the lower side relative to the anode.

[0030] Effects of the Invention

[0031] According to the present invention, a lamp having a short starting time can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a cross-sectional view schematically showing one embodiment of the discharge lamp according to the present invention.

[0033] Figure 2A Yes Figure 1 An enlarged view of the cathode side of the discharge lamp in question.

[0034] Figure 2B yes Figure 2A BB section view in.

[0035] Figure 3This is a diagram schematically showing a state of measuring the height of mercury.

[0036] Figure 4 This is a graph showing the transition of the lamp voltage during verification.

[0037] Figure 5 It is a graph showing the relationship between the S1 / V1 ratio and the start-up time.

[0038] Figure 6 It is modeled after Figure 2A A cross-sectional view schematically showing a modified example of the lamp. DETAILED DESCRIPTION

[0039] The embodiments of the discharge lamp according to the present invention will be described with reference to the accompanying drawings as appropriate. In addition, the following drawings other than the diagrams are schematically illustrated, and the dimension ratios on the drawings may not be consistent with the actual dimension ratios. In addition, the dimension ratios between the drawings may not be consistent.

[0040] Figure 1 FIG. 1 is a cross-sectional view schematically showing an embodiment of a discharge lamp according to the present invention. Figure 1 As shown, the discharge lamp (hereinafter referred to as "lamp 1") includes a lamp having mercury 9 sealed therein (in Figure 1 Not shown in the figure. Figure 2A ) of the light-emitting tube 2, a cathode 3 and an anode 4 arranged opposite to each other, and a sealing portion (5, 6).

[0041] In the following figures, the description is made with reference to the XYZ coordinate system in which the direction in which the cathode 3 and the anode 4 are opposite to each other is defined as the Z direction and the plane perpendicular to the Z direction is defined as the XY plane. The Z direction is typically a direction perpendicular to the horizontal plane. In addition, the Z direction corresponds to the "first direction".

[0042] In the following description, when describing a direction, if the positive and negative directions are distinguished, the positive and negative signs are marked and recorded, such as "+X direction" and "-X direction". In addition, when describing a direction without distinguishing the positive and negative directions, it is simply recorded as "X direction". That is, in this specification, when it is simply recorded as "X direction", both "+X direction" and "-X direction" are included. The same applies to the Y direction and the Z direction.

[0043] The light emitting tube 2 has a light emitting portion 10 having a spherical or ellipsoidal shape, for example. In addition, the light emitting tube 2 has a first side tube 11 connected to the end of the light emitting portion 10 on the -Z side and a second side tube 12 connected to the end of the light emitting portion 10 on the +Z side. The light emitting portion 10, the first side tube 11, and the second side tube 12 constituting the light emitting tube 2 are integrally formed of a glass material such as quartz glass.

[0044] In addition, the arc tube 2 has an exhaust pipe residue 13 at a part of the part. When manufacturing the lamp 1, an exhaust pipe (not shown) for exhausting the gas in the arc tube 2 and sealing mercury 9 as a luminous material in the arc tube 2 is formed at a part of the arc tube 2. The exhaust pipe residue 13 is a trace left after the exhaust pipe is removed, and has a shape protruding from the arc tube 2.

[0045] The sealing parts (5, 6) seal both sides of the light emitting tube 2 in the Z direction. More specifically, the sealing part 5 seals the first side tube 11, and the sealing part 6 seals the second side tube 12. The both sides of the light emitting tube 2 in the Z direction are sealed, thereby forming a light emitting space E1 in the light emitting tube 2. In addition, in the light emitting space E1, a noble gas such as argon or xenon is sealed for the purpose of starting the auxiliary lamp 1.

[0046] In the light emitting space E1, the cathode 3 and the anode 4 are arranged opposite to each other. In the present embodiment, the cathode 3 corresponds to the "first electrode" and the anode 4 corresponds to the "second electrode". The lamp 1 is a short arc type discharge lamp in which the cathode 3 and the anode 4 are arranged opposite to each other at a distance of less than 40 mm (a value at room temperature without thermal expansion).

[0047] The cathode 3 is connected to the first electrode rod 7, and the anode 4 is connected to the second electrode rod 8. The first electrode rod 7 and the second electrode rod 8 extend in the Z direction. As an example, the outer diameters of the first electrode rod 7 and the second electrode rod 8 are 1 mm to 12 mm. In the present embodiment, the outer diameters of the first electrode rod 7 and the second electrode rod 8 are both 8 mm, but the outer diameters of the two may be different. In the present embodiment, the first electrode rod 7 corresponds to the "electrode rod".

[0048] The cathode 3, anode 4, first electrode rod 7 and second electrode rod 8 are made of a material containing tungsten, for example. In addition, as an example, the cathode 3, anode 4, first electrode rod 7 and second electrode rod 8 have a shape of a body of revolution around an axis A1 extending in the Z direction.

[0049] Figure 2A This is an enlarged view of the cathode 3 side of the lamp 1. Figure 2B yes Figure 2A BB section view in. Figure 2A As shown, a supporting cylinder 14, a metal foil 16, a metal plate 26, a glass member 18, and a metal foil 22 are arranged in the first side tube 11 of the lamp 1. The supporting cylinder 14 and the metal foil 16 constitute a first supporting portion 7a for supporting the first electrode rod 7. The first supporting portion 7a corresponds to the "supporting portion". The glass member 18 and the metal foil 22 constitute a sealing portion 5 for sealing the first side tube 11.

[0050] like Figure 2AAs shown, the first electrode rod 7 is inserted into the supporting cylinder 14. From the viewpoint of preventing the positional deviation of the first electrode rod 7 and the welding of the first electrode rod 7 and the supporting cylinder 14, the metal foil 16 is arranged between the supporting cylinder 14 and the first electrode rod 7. In addition, the outer peripheral surface of the supporting cylinder 14 is welded to the inner peripheral surface of the first side tube 11. Figure 2B , a distance L1 between the first side tube 11 and the first electrode rod 7 in a direction perpendicular to the Z direction on the +Z side of the supporting cylinder 14 is schematically shown.

[0051] The supporting cylinder 14 has a shape of a body of rotation centered on the axis A1. The supporting cylinder 14 is made of a glass material such as quartz glass. An example of the metal foil 16 is molybdenum foil.

[0052] A glass member 18 is arranged on the -Z side of the support cylinder 14 via a metal plate 26 to seal the first side tube 11. In addition, a metal foil 22 made of, for example, molybdenum is arranged around the glass member 18. For example, a plurality of metal foils 22 in a long strip shape are arranged to be separated from each other in the circumferential direction of the glass member 18. The outer peripheral surface of the glass member 18 is welded to the inner peripheral surface of the first side tube 11 via the metal foil 22 or directly. In this way, the sealing portion 5 seals the -Z side of the arc tube 2.

[0053] In addition, the glass member 18 has a hole that is recessed from the end on the -Z side to the +Z side. The external lead rod 20 is inserted into the hole. Moreover, a cylindrical body 21 made of, for example, quartz glass is arranged on the -Z side of the glass member 18 via a metal plate 27. The external lead rod 20 is inserted into the cylindrical body 21, and the outer peripheral surface of the cylindrical body 21 is welded to the inner peripheral surface of the first side tube 11.

[0054] The external lead rod 20 is connected to the first electrode rod 7 via the metal foil 22 and the metal plates ( 26 , 27 ).

[0055] A joint 23 covering the periphery of the first side tube 11 is disposed at the end portion on the −Z side of the first side tube 11 . The joint 23 is connected to the external lead bar 20 .

[0056] The structure of the +Z side of the light-emitting tube 2 is the same as that of the -Z side, so it is briefly described. The supporting cylinder 15, the metal foil 17, the glass member 19, and the metal foil 24 are arranged in the second side tube 12 of the lamp 1. In addition, as described for the first side tube 11, a metal plate (not shown) is arranged between the supporting cylinder 15 and the glass member 19. The second electrode rod 8 is inserted through the supporting cylinder 15, and the metal foil 17 is arranged between the supporting cylinder 15 and the second electrode rod 8. The supporting cylinder 15 and the metal foil 17 constitute the second supporting portion 8a that supports the second electrode rod 8. The outer peripheral surface of the glass member 19 is welded to the inner peripheral surface of the second side tube 12 via the metal foil 24 or directly. In this way, the sealing portion 6 seals the +Z side of the light-emitting tube 2.

[0057] The structure on the +Z side of the support cylinder 15 is the same as the structure on the -Z side of the support cylinder 14. Figure 1 In FIG. 1 , the +Z side of the supporting cylinder 15 is simplified. In the lamp 1 , voltage is applied between the cathode 3 and the anode 4 via a pair of terminals 23 .

[0058] Mercury 9 (see Figure 2A As an example, the amount of mercury 9 enclosed is 5 g to 100 g (volume at room temperature 25° C.: about 740 mm 3 ~Approximately 7390mm 3 ).

[0059] exist Figure 2A , the lamp 1 at room temperature is schematically illustrated. Since the melting point of mercury 9 is low, at room temperature, mercury 9 contacts the first electrode rod 7 and the first support portion 7a in the first side tube 11, condenses in a liquid state, and accumulates on the first support portion 7a. Figure 2A , a height H1 of the mercury 9 from the first supporting portion 7a is shown.

[0060] When the length of the outer circumference of the first electrode rod 7 is set to D1 (mm), the contact area S1 between the first electrode rod 7 and the mercury 9 is obtained by the product of the length D1 and the height H1. In the lamp 1, the contact area S1 is configured to be equal to the volume V1 (mm) of the mercury 9 at room temperature. 3 ) is 0.079mm -1 above.

[0061] Next, the operation of the lamp 1 when it is turned on will be described.

[0062] When the voltage starts to be applied to the lamp 1, the cathode 3 and the anode 4 are heated by arc discharge between the electrodes. Furthermore, the first electrode rod 7 is heated by heat conduction from the high-temperature cathode 3. Furthermore, the mercury 9 condensed in contact with the first electrode rod 7 is heated by heat conduction from the first electrode rod 7.

[0063] Mercury 9 is heated and evaporated, whereby the lamp voltage increases, and when this voltage reaches, for example, the rated voltage of the lamp 1 , desired light is obtained from the lamp 1 .

[0064] [verify]

[0065] A plurality of lamps having different ratios of the contact area S1 to the volume V1 of the mercury 9 (hereinafter referred to as "S1 / V1 ratio" for convenience) were produced, and the start-up time of each lamp was studied, as described below.

[0066] In this verification, the structure of the lamp 1 according to the above-described embodiment was adopted, and the lamp was vertically lit in a state where the cathode 3 was located below the anode 4 .

[0067] As described above, the mercury 9 is condensed in the first side tube 11 in contact with the first electrode rod 7. That is, under the premise of the same amount of mercury, if the separation distance L1 between the first side tube 11 and the first electrode rod 7 is reduced, the height H1 of the mercury 9 is increased, and the contact area S1 between the first electrode rod 7 and the mercury 9 is increased. In view of this, in this verification, the amount of mercury 9 sealed was set to the same amount and the separation distance L1 was changed to different, thereby producing lamps with different S1 / V1 ratios.

[0068] In addition, in the lighting power supply of the lamp, the voltage (hereinafter, for convenience, referred to as "reference voltage") that is judged to be the voltage that the lamp starts without abnormality after the lighting operation is typically set within the range of 70% to 80% relative to the design center value of the lamp voltage during stable lighting. In view of this, in this verification, the lamp starting time is defined as the time until the voltage reaches 75% of the above-mentioned design center value.

[0069] Next, a method for measuring the S1 / V1 ratio of each lamp is described. The S1 / V1 ratio is measured after measuring the start-up time of each lamp.

[0070] First, the remaining exhaust pipe portion 13 of the lamp at room temperature is cut off, and the arc tube 2 of the lamp is tilted so that the mercury 9 flows out from the cut portion and the amount of mercury 9 enclosed (g) is measured. The enclosed amount is divided by the density of mercury 9 at room temperature, 0.013534 g / mm 3 , and obtain the volume V1 of mercury 9.

[0071] Next, the arc tube 2 of the lamp is cut at a position between the cathode 3 and the anode 4, and the lamp is divided into the cathode 3 side and the anode 4 side. In this verification, the side where the mercury 9 is condensed is the cathode 3 side. Therefore, the part on the cathode 3 side is the object of measurement. The cathode 3 becomes an obstacle to the measurement of the height H1, so the connection part between the cathode 3 and the first electrode rod 7 is cut off, and the cathode 3 is removed from the object part.

[0072] Figure 3 Schematically shows the state of measuring the height H1 of mercury 9. Figure 3 As shown, the object part 30 is arranged on the platform 32 in a state where the first electrode rod 7 is substantially at right angles to the horizontal plane while being fixed by an arbitrary support member 31. In addition, the "substantially at right angles" mentioned here means that the angle of the first electrode rod 7 relative to the horizontal plane is in the range of 90°±0.5°.

[0073] Then, the measuring piece 34 of the altimeter 33 is brought into contact with the supporting cylinder 14 of the target part 30, and this state is set as the reference height of the altimeter 33. Next, the measuring piece 34 of the altimeter 33 is lifted, and the mercury 9 taken out in the previous operation is put into the target part 30. Then, the measuring piece 34 of the altimeter 33 is lowered, and the displacement from the reference at the time when the measuring piece 34 comes into contact with the mercury 9 is set as the height H1 of the mercury 9. In addition, the measuring piece 34 moves up and down in the XY plane at a position in the middle between the first electrode rod 7 and the inner wall surface of the first side tube 11.

[0074] In addition, any altimeter can be used as the altimeter 33 , but from the viewpoint of making the measurement of the height H1 easier, a rod-shaped member may be attached to the measuring tool 34 of the altimeter 33 .

[0075] The contact area S1 is obtained by multiplying the length D1 of the outer circumference of the first electrode rod 7 by the height H1 of the mercury 9. The ratio S1 / V1 is obtained by dividing the contact area S1 by the volume V1 obtained in the previous measurement.

[0076] In this verification, the separation distance L1 in each lamp is made different by making the diameter of the first side tube 11 different in the area closer to the +Z side than the first support portion 7a. In addition, by changing the diameter of the first side tube 11 in this area, the outer diameter of the +Z side of the support cylinder 14 is appropriately adjusted, but the structure of each lamp closer to the -Z side than the first support portion 7a is the same except for the manufacturing error. In addition, for the sake of caution, it is mentioned that since the wall surface of the first side tube 11 is a curved surface, the separation distance L1 changes at different positions in the Z direction. In this verification, "making the separation distance L1 in each lamp different" means making the average value of the separation distance L1 in each lamp different in consideration of the change of the separation distance L1 caused by the different positions in the Z direction. The verification results are described below as specifications 1 to 4 in order of the separation distance L1 from large to small.

[0077] Although details will be described later, from the viewpoint of considering the variation in the startup time of the lamps, the startup time of a total of ten lamps was measured under the same conditions as those of Standard 1 (hereinafter referred to as "equivalent to Standard 1").

[0078] [Verification results]

[0079] The verification results obtained in each specification are shown in the following Table 1. As shown in Table 1, in this verification, a plurality of lamps having different S1 / V1 ratios were produced.

[0080]

Table 1

[0081]

[0082] in addition, Figure 4 is a graph showing the change in lamp voltage when each lamp is lit. Figure 4 In FIG. 1 , the horizontal axis represents the time elapsed based on the time point when the voltage application is started, and the vertical axis represents the lamp voltage. Figure 4 In FIG. 8 , the reference voltage Vb is illustrated by a dotted line.

[0083] As described above, in this verification, the amount of mercury 9 enclosed in each lamp was the same when each lamp was manufactured. In this regard, according to Table 1, it was confirmed that the amount of mercury 9 enclosed in each lamp was the same by the above-mentioned method of measuring the enclosed amount. That is, it can be understood that according to the above-mentioned method of measuring the enclosed amount, the amount of mercury 9 enclosed can be measured even after the lamp is used for lighting.

[0084] According to Table 1, as the S1 / V1 ratio increases, the startup time of the lamp becomes shorter. This is also consistent with the specification that the larger the S1 / V1 ratio, Figure 4 The larger the slope of the rise of the lamp voltage in the lamp, the greater the increase. This is presumably because the contact area S1 is larger relative to the volume V1 of the mercury 9. That is, as the contact area S1 becomes larger, heat is efficiently transferred from the first electrode rod 7 to the mercury 9.

[0085] Figure 5 This is a graph where the horizontal axis represents the S1 / V1 ratio and the vertical axis represents the lamp start-up time. Figure 5 In FIG. 1 , an approximate straight line is shown when the start-up time of each lamp is approximated by the least square method. Figure 5 As described with reference to Table 1, it is clear that as the S1 / V1 ratio increases, the startup time becomes shorter.

[0086] In addition, in this verification, from the perspective of considering the deviation of the starting time of the lamp, under the same conditions as Specification 1, more specifically, under the conditions where the S1 / V1 ratio is the same as Specification 1, a total of ten lamps were produced, and the deviation of the starting time was confirmed. In addition, the so-called "same S1 / V1 ratio" means that the difference in the S1 / V1 ratio is within the range of ±5%. The results are shown in Table 2 below. If the starting time of the lamp follows a normal distribution, and the population mean and population standard deviation are respectively equal to the mean and standard deviation (σ) shown in Table 2, then at a significance level of 5%, for a lamp equivalent to Specification 1, it can be said that the range in which the starting time is short can be said to be a range that is 1.64σ or more lower than the mean value of the starting time of the lamp equivalent to Specification 1. That is, according to Table 2, if the starting time is 9.97 minutes or less, it can be said that the starting time is better than Specification 1.

[0087]

Table 2

[0088]

[0089] exist Figure 5The baseline startup time (9.97 minutes) obtained from Table 2 is shown by the dashed line. Figure 5 The approximate straight line of is derived as 0.079 as the S1 / V1 ratio for obtaining a lamp with a starting time better than 9.97 minutes. That is, it can be understood that if the S1 / V1 ratio is set to 0.079 or more, a lamp with a starting time better than at least specification 1 involved in this verification can be obtained. This also matches the fact that excellent starting times are obtained in specifications 3 and 4.

[0090] In addition, from the viewpoint of obtaining a lamp with a short start-up time, the S1 / V1 ratio may be 0.09 or more.

[0091] In this verification, about 50 g of mercury 9 is sealed, but this is just an example. Considering the contact area between mercury 9 and first electrode rod 7, the sealed amount of mercury 9 is preferably 20 g or more, and particularly preferably 40 g or more. In other words, the volume of mercury 9 at room temperature is preferably 1480 mm 3 Above, particularly preferably 2960mm 3 above.

[0092] In the above verification, the inner diameter of the region of the first side tube 11 closer to the +Z side than the first support portion 7a was changed, but the height H1 of the mercury 9 can also be increased by changing the outer diameter of the +Z side of the support cylinder 14 or increasing the outer diameter of the first electrode rod 7 while changing the inner diameter.

[0093] In view of the results of this verification, it can be understood that a lamp with a short start-up time can be realized by the structure described in the above embodiment.

[0094] [Modifications]

[0095] Hereinafter, a modified example of the lamp 1 will be described focusing on the parts different from the above-described embodiment.

[0096] <1> Figure 6 1 is a cross-sectional view schematically showing a modified example of the lamp 1. Figure 6 In, follow Figure 2A , the -Z side near the cathode 3 of the lamp 1 is enlarged and shown. Figure 6 As shown, the lamp 1 may also include a coil portion 25 formed by winding a metal wire around the first electrode rod 7. For example, by including the coil portion 25 formed of a metal wire such as tantalum or niobium, an effect of absorbing impurity gas in the light-emitting space E1 can be obtained. In addition, in order to align the position of the supporting cylinder 14, the coil portion 25 may also be formed of a tungsten wire and abut against the supporting cylinder 14.

[0097] Since the metal wire constituting the coil portion 25 is wound around the first electrode rod 7, there is a small gap between the first electrode rod 7 and the coil portion 25. The mercury 9, which is in a liquid state at room temperature, enters the gap and is in contact with the first electrode rod 7. Figure 6 As shown, even if the lamp 1 has the coil portion 25 around the first electrode rod 7, the coil portion 25 does not need to be considered in the S1 / V1 ratio. As discussed above, by setting the S1 / V1 ratio to 0.079 or more, the lamp starting time can be shortened.

[0098] <2> In the above description, the lamp 1 is lighted in a state where the cathode 3 is arranged below the anode 4. However, the lamp 1 may be lighted in a state where the anode 4 is arranged below the cathode 3. In this case, the second electrode rod 8 corresponds to the "electrode rod", and the first electrode rod 7 can be replaced by the second electrode rod 8 in the above discussion of the S1 / V1 ratio.

[0099] <3> The structure of the lamp 1 according to the present invention is not limited to the above-mentioned embodiment.

[0100] Description of symbols

[0101] 1: discharge lamp;

[0102] 2: Light-emitting tube;

[0103] 3: cathode;

[0104] 4: anode;

[0105] 5, 6: Sealing part;

[0106] 7: the first electrode rod;

[0107] 8: the second electrode rod;

[0108] 7a: first supporting portion;

[0109] 8a: second supporting portion;

[0110] 9: Mercury;

[0111] 10: light-emitting part;

[0112] 11: first side pipe;

[0113] 12: second side pipe;

[0114] 13: Exhaust pipe residue;

[0115] 14, 15: supporting cylinder;

[0116] 16, 17, 22, 24: Metal foil;

[0117] 18, 19: Glass components;

[0118] 20: external lead rod;

[0119] 21: cylinder;

[0120] 23: connector;

[0121] 25: coil part;

[0122] 26, 27: Metal plates;

[0123] 30: Object part;

[0124] 31: supporting member;

[0125] 32: Platform;

[0126] 33: Altimeter;

[0127] 34: Measurement piece.

Claims

1. A discharge lamp, characterized in that have: Light-emitting tube, sealed with mercury; The first electrode and the second electrode are disposed opposite to each other and separated in a first direction inside the light emitting tube; an electrode rod connected to a side of the first electrode opposite to the second electrode and extending along the first direction; and a supporting portion, supporting the electrode rod, When the first direction is set to be a direction substantially perpendicular to a horizontal plane and the first electrode is arranged below the second electrode, The length D1 (mm) of the outer circumference of the electrode rod, the height H1 (mm) of the mercury from the support portion, and the volume V1 (mm) of the mercury sealed in the arc tube 3 ) satisfies the following formula (1): D1×H1 / V1≥0.079(mm -1 )…(1)。 2. The discharge lamp according to claim 1, characterized in that In the above discharge lamp, the length D1 (mm), the height H1 (mm) of the mercury and the volume V1 (mm) of the mercury are 3 ) further satisfies the following formula (2): D1×H1 / V1≤0.2(mm -1 )…(2)。 3. The discharge lamp according to claim 1 or 2, characterized in that The volume V1 of the mercury is 1480 (mm 3 )above.

4. The discharge lamp according to claim 1 or 2, characterized in that The first electrode is a cathode.

Images