JP4561351B2 - Metal halide lamp and lighting device using the same - Google Patents

Description

  The present invention relates to a metal halide lamp and an illumination device using the metal halide lamp.

  Metal halide lamps, especially metal halide lamps (hereinafter simply referred to as “ceramic metal halide lamps”), which are composed of ceramics, are used for indoor lighting in stores and outdoor lighting in stadiums. in use.

Among these types of ceramic metal halide lamps, in order to obtain extremely high luminous efficiency, cerium iodide (CeI ₃ ) and sodium iodide (NaI) are enclosed in the arc tube, and the shape of the arc tube is elongated (the arc tube There has been proposed a ceramic metal halide lamp in which L _d / D _i > 5) where D _{i is} the inner diameter and L _d is the distance between the electrodes (see, for example, Patent Document 1).

Moreover, this ceramic metal halide lamp has an elongated arc tube shape, so that the amount of metal mercury contained in the liquid is smaller than usual, for example, 0.7 [mg] (<1.6) when the rated lamp power is 150 [W]. [Mg / cm ³ ]), a lamp voltage of 80V to 100V can be obtained, which has the advantage of being environmentally friendly.

  By the way, the arc tube used in this kind of ceramic metal halide lamp has an electrode introduction body arranged in the envelope in addition to the envelope, and has a metal halide, mercury and rare earth inside. Each gas is sealed. The envelope is composed of a main pipe part and narrow pipe parts formed at both ends of the main pipe part. The electrode introduction body includes an electrode rod, an electrode coil attached to one end of the electrode rod, one end connected to the other end of the electrode rod, and the other end led out to the outside of the thin tube portion. And an internal lead portion. The electrode coil and a part of the electrode rod form an electrode part. Such an electrode introduction body is inserted into the narrow tube portion so that the electrode portion is located in the main tube portion, and the end portion of the thin tube portion opposite to the main tube portion is sealed with a sealing material or the like. Sealed. That is, the sealing material enters only the gap between the narrow tube portion and the internal lead portion so as to fill the entire gap. Therefore, a gap is mainly formed between the electrode rod and the thin tube portion. When such a gap is formed, the halide sealed in the arc tube gradually sinks and deposits in the liquid state in the gap and cannot contribute to light emission, and the color temperature changes with the elapsed lighting time. The problem of end up occurs.

  Therefore, conventionally, in order to fill such a gap as much as possible and suppress the sinking of the halide, a molybdenum coil (tubular body) is tightly wound around the electrode rod located in the narrow tube portion. It has been proposed (see, for example, Patent Document 2).

In particular, while reducing the above-described change in color temperature, it is possible to suppress an arc (hereinafter simply referred to as “back arc”) from occurring between this coil and an electrode portion having a polarity different from that of the coil during startup. Therefore, the distance X [mm] from the end surface on the discharge space side of the end surface of the thin tube portion to the end surface on the thin tube portion side of the end surface of the electrode coil, and a part of the cylindrical body are defined as the discharge space of the thin tube portion. It has been proposed to define the length L [mm] of the extending portion from the side end face (see, for example, Patent Document 3).
JP 2000-501563 A JP 2003-272560 A JP 2003-317661 A

First, in order to increase the efficiency of a ceramic metal halide lamp, the inventors of the present invention have a long and narrow arc tube described in Patent Document 1 such as an inner diameter D _i of 4.0 [mm] and a distance L between electrode portions L. An arc tube having _d of 8.0 [mm] was produced. In the arc tube, a total amount of halide composed of praseodymium iodide and sodium iodide is 12 [mg], mercury is 0.8 [mg] (1.84 [mg / cm < ³ >]), and xenon gas is several dozen. Each kPa was enclosed. In addition, in order to reduce the change in color temperature and suppress the occurrence of back arc, a cylindrical body made of a closely wound coil made of molybdenum is attached to the electrode rod, and the positional relationship between the cylindrical body and the narrow tube portion is determined. The distance X to be represented and the length L representing the positional relationship between the electrode coil and the thin tube portion were set so as to satisfy predetermined relational expressions described in Patent Document 3, respectively.

  Then, when the produced arc tube was evaluated, the inner surface of the boundary portion between the main tube portion and the thin tube portion where the back arc was generated and the cylindrical body was located particularly at the time of restart immediately after the lamp was turned off. Unexpected problems such as blackening or cracking.

  The present invention has been made in order to solve such a problem, and particularly at the time of restart, a back arc is generated between the cylindrical body and the electrode portion having a different polarity from the cylindrical body. It aims at providing the metal halide lamp which can suppress this, and an illuminating device using the same.

The present inventors have various reasons for the occurrence of a back arc at the restart even though the distance X and the length L satisfy the predetermined relational expression described in Patent Document 3. Upon examination, it was found that the amount of mercury present in the arc tube is related. As a result of further studies, the occurrence of a back arc at the time of restart is a specific problem that can occur in metal halide lamps in which the amount of mercury present in the arc tube is 4.0 [mg / cm ³ ] or less. I found a new thing.

Here, mercury-free metal halide lamps in which the amount of mercury present in the arc tube is 0 [mg / cm ³ ] (excluding those inevitably mixed such as impurities) are also included. .

The metal halide lamp of the present invention is made on the basis of such new knowledge, and is made of a ceramic envelope comprising a main pipe part and narrow pipe parts formed at both ends of the main pipe part. An electrode introduction body having an electrode portion formed at an end thereof, and an arc tube having an amount of mercury present in the interior of 4.0 [mg / cm ³ ] or less, the electrode introduction body Is inserted in the narrow tube portion so that the electrode portion is located in the main tube portion, and is sealed at an end portion of the narrow tube portion opposite to the main tube portion, In the narrow tube portion, a metal tubular body is interposed between the electrode introduction body and the narrow tube portion, and the tubular body from the opening surface on the main tube side of the opening surface of the narrow tube portion. when the shortest distance to was L _i [mm], a _{0 [mm] <L i ≦} 0.5 [mm] relational expression Together plus the shortest distance from the opening of the main pipe portion to the tip of the electrode portion closer to the opening plane L _e [mm], tube of the light emitting tube of the opening surface of the narrow tube portion When the wall load is W _e [W / cm ² ], the configuration satisfies the relational expression of 1.3 [mm] ≦ L _e and L _e ≦ W _e / 11.

  Moreover, the illuminating device of this invention has the structure that the said metal halide lamp is integrated in the lighting fixture.

  The present invention relates to a metal halide lamp capable of suppressing the occurrence of a back arc between a cylindrical body and an electrode portion having a polarity different from that of the cylindrical body, particularly at restart, and an illumination device using the same Can be realized.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  As shown in FIG. 1, a metal halide lamp (ceramic metal halide lamp) 1 having a rated power (input power) of 150 W according to the first embodiment of the present invention is closed at one end and a stem glass 2 at the other end. Are sealed with a straight tubular outer tube 3, and two power supply lines 4 partially sealed with the stem glass 2 and with one end drawn from the stem glass 2 into the outer tube 3. 5, an arc tube 6 supported by these power supply lines 4, 5 in the outer tube 3, and a screw-in (E-shaped) base 7 fixed to the other end of the outer tube 3. .

  The central axis X in the longitudinal direction of the outer tube 3 and the central axis Y in the longitudinal direction of the arc tube 6 are substantially on the same axis.

The outer tube 3 is made of, for example, hard glass and the inside thereof is in a vacuum state of about 1 × 10 ⁻¹ [Pa] at 300 [K]. Of course, instead of vacuum, nitrogen gas or the like may be sealed as necessary. The shape of the outer tube 3 is not limited to the straight tube type shown in FIG. 1, and various known shapes such as a drop type can be used.

  The power supply lines 4 and 5 are made of nickel or mild steel, for example. The other end of one power supply line 4 is electrically connected to the eyelet portion 8 of the base 7, and the other end of the other power supply line 5 is electrically connected to the shell portion 9 of the base 7. One power supply line 4 is electrically connected via a resistor 11 to a proximity conductor 10 attached to the arc tube 6 in order to assist the start of the lamp at the start and restart. In addition, a getter 12 for capturing gas impurities in the outer tube 3 is attached to a portion of the one power supply line 4 that is drawn into the outer tube 3.

  The power supply lines 4 and 5 shown in FIG. 1 are formed by connecting and integrating a plurality of metal wires. However, a single metal wire may be appropriately processed and used as the power supply lines 4 and 5.

As shown in FIG. 2, the arc tube 6 includes a substantially cylindrical cylindrical portion 13 having an outer diameter D _o of 6.4 [mm] and an inner diameter D _i of 4.0 [mm], and both end portions of the cylindrical portion 13. And a main pipe portion 15 formed of a substantially hemispherical hemispherical portion 14 formed continuously with the outer periphery, and an outer diameter _ro (3.2 [mm]) formed on both ends of the main pipe portion 15. Has an envelope 17 made of polycrystalline alumina composed of a substantially cylindrical thin tube portion 16 having a diameter smaller than the maximum outer diameter D _o (6.4 [mm]) of the main tube portion 15. Yes. The envelope 17 is formed by integral molding in which the cylindrical portion 13, the hemispherical portion 14 and the thin tube portion 16 are separately formed and are not integrated by shrink fitting later, but each member is simultaneously formed. Is. Thus, when the main pipe part 15 and the thin pipe part 16 are formed by integral molding, the inner surface of the main pipe part 15 and the inner surface of the thin pipe part 16 have a predetermined radius of curvature R as shown in FIG. _It is often formed so as to be connected through a curved surface having _b . As an example, the inner surface of the hemispherical portion 14 having a radius of curvature R _h of 2.0 [mm] among the inner surfaces of the arc tube 6 in a cross section obtained by cutting the arc tube 6 along an arbitrary plane including the central axis Y in the longitudinal direction. The radius of curvature R _b of the boundary portion that changes from a straight inner surface (inner surface of the straight portion) of the narrow tube portion 16 having an inner diameter r _i of 1.0 [mm] to 0.1 [mm].

  In FIG. 3, only the structure of one end of the arc tube 6 is shown, but the other end also has the same structure.

Here, in this way, the inner surface of the main tube portion 15 and the inner surface of the narrow tube portion 16 are connected via a convex curved surface having a predetermined radius of curvature R _b . When the inner diameter is r _i [mm], the portion where the opening diameter d [mm] at the boundary between the main pipe portion 15 and the thin tube portion 16 is (r _i × 1.05) [mm] is referred to as “the narrow tube portion 16. Are defined as “opening surfaces on the main pipe part 15 side”. If the inner surface of the hemispherical portion 14 and the inner surface of the straight portion of the thin tube portion 16 are connected via a tapered curved surface whose diameter decreases toward the thin tube portion 16, or the inner surface of the hemispherical portion 14 and the thin tube portion 16. Even when the inner surface of the straight portion is connected via a complex curved surface, the “opening surface on the main tube portion 15 side among the opening surfaces of the thin tube portion 16” is defined in accordance with this. However, when the inner surface of the hemispherical portion 14 and the inner surface of the straight portion of the thin tube portion 16 are directly connected without passing through the above-described convex curved surface or tapered curved surface having the predetermined radius of curvature R _b , The end (or start end) of the straight portion of the thin tube portion 16 is “the open surface on the main tube portion 15 side of the open surface of the thin tube portion 16”. And when the main pipe part 15 and the thin pipe part 16 are formed by integral molding, the main pipe part 15 and the thin pipe part 16 can be divided on the plane containing this opening surface for convenience.

  As a material constituting the envelope 17, a light-transmitting ceramic such as yttrium-aluminum-garnet (YAG), aluminum nitride, yttria, or zirconia can be used in addition to polycrystalline alumina.

The arc tube 6, for example, sodium iodide as a light-emitting substance (NaI), metal halide comprising at least one of iodide praseodymium (PrI ₃₎ and cerium iodide (CeI _3), as a buffer gas Mercury and a predetermined amount of, for example, xenon gas (Xe) as a starting auxiliary gas are enclosed.

As the metal halides to be sealed, and sodium iodide (NaI), in addition to the metal halide comprising at least one of iodide praseodymium (PrI ₃₎ and cerium iodide (CeI _3), high color rendering type ceramic metal halide lamp iodide dysprosium which are commonly used (DyI _3), iodide thulium (TmI _3), and an iodide of a rare earth metal such as iodide, holmium (HoI _3), thallium iodide ( Various known metal halides can be used depending on the desired color temperature and color rendering properties, such as a combination of TlI) and sodium iodide. However, in the above example, only iodides are listed, but all or part of these iodides can be used instead of bromide.

Mercury may be sealed as pure mercury or as a compound in any state, but the amount present in the arc tube 6 is 4.0 [mg / cm ³ ] or less. Of course, the enclosed amount of mercury is appropriately adjusted so as to obtain a desired lamp voltage at the time of lighting within a range of 4.0 [mg / cm ³ ] or less, but various enclosures may be adjusted depending on circumstances. Then, it may be made anhydrous silver (0 [mg / cm ³ ]) using a known means. In the case of not using mercury-free, the lamp tube 6 has a long and narrow shape, for example, the lamp tube 6 satisfying the relational expression L _d / D _i > 4.0 described later, and a lamp voltage of 80 [V] to 100 [V] In order to obtain it, it is preferable that the amount of mercury enclosed be at least 0.8 [mg / cm ³ ].

  As the rare gas, argon gas alone, xenon gas alone, or a mixed gas thereof is enclosed. The enclosed amount is preferably set as appropriate in the range of 10 [kPa] to 50 [kPa] regardless of the components and ratios.

The tube wall load W _e [W / cm ² ] of the arc tube 6 is expressed by a value obtained by dividing the input power [W] by the inner area [cm ² ] of the arc tube 6 (excluding the narrow tube portion 16). The In the present embodiment, the input power 150 [W] is represented by a value obtained by dividing the inner area [cm ² ] of the main pipe portion 15 (excluding the opening portion).

As shown in FIGS. 2 and 3, a pair of electrode portions 18 to be described later are arranged in the main tube portion 15 so as to be substantially opposed on substantially the same axis (Y axis), thereby forming a discharge space 19. Has been. The distance L _d between the electrode portions 18 is 32.2 [mm]. Here, L _d / D _i that is a parameter representing the shape of the arc tube 6 is 8.05. However, the “inner diameter D _i ” is defined as the average value of the inner diameters of the portions of the arc tube 6 existing between the pair of electrode portions 18. In the case where the entire corresponding portion has a cylindrical shape and a simple shape as in the present embodiment, for example, an arbitrary portion in the range of the corresponding portion is simply set to the value of the inner diameter of the central portion of the main pipe portion 15 Can be used as they are.

  In each narrow tube portion 16, as described above, the electrode portion 18 formed at the distal end portion is located in the main tube portion 15, and the opposite end portion (a part of an internal lead portion 20 described later and an external portion) Electrode introduction bodies 22 are respectively inserted so that the lead portions 21) lead out to the outside of the narrow tube portion 16. The inserted electrode introduction body 22 is composed of the thin tube portion 16 and the electrode introduction body 22 so as to cover the entire internal lead portion 20 only at the end portion of the thin tube portion 16 opposite to the main tube portion 15. It is sealed with a sealing material 23 made of glass frit poured into the gap formed. The sealing material 23 exists not only in the gap formed by the narrow tube portion 16 and the electrode introduction body 22 but also outside the narrow tube portion 16 so as to cover the joint portion between the internal lead portion 20 and the external lead portion 21. Yes.

The electrode introduction body 22 is a conductive material obtained by sintering a mixture of, for example, aluminum oxide (Al ₂ O ₃ ) and molybdenum (Mo) having an electrode portion 18 formed at a tip portion and one end portion connected to the electrode portion 18. An internal lead portion 20 having a diameter of, for example, 0.9 [mm] and a length of, for example, 3.1 [mm], and an external lead portion made of, for example, niobium having one end connected to the internal lead portion 20. 21. The other end portion of the external lead portion 21 is led out of the narrow tube portion 16 and is electrically connected to the power supply lines 4 and 5, respectively.

  The electrode portion 18 has a tungsten electrode rod 24a having a diameter of, for example, 0.5 [mm] and a length of, for example, 16.5 [mm], and an outer diameter provided at the tip of the electrode rod 24a is, for example, 0.1 mm. And an electrode coil 24b made of tungsten of 9 [mm].

In addition to the conductive cermet obtained by sintering a mixture of aluminum oxide (Al ₂ O ₃ ) and molybdenum (Mo) as the internal lead portion 20, a mixture of aluminum oxide (Al ₂ O ₃ ) and tungsten (W). Various known halogen-resistant materials such as a conductive cermet obtained by sintering and a simple metal molybdenum rod can be used in place of these conductive cermets.

  Further, the structure of the electrode introduction body 22 is shown as comprising the electrode part 18, the internal lead part 20 and the external lead part 21, but not limited to this, for example, the internal lead part and the external lead part consist of one thing. Using various known electrode introduction bodies such as one end connected to the electrode rod 24a and the other end led out to the outside of the thin tube portion 16 and directly connected to the power supply lines 4 and 5 Can do. As a result of using various electrode introduction bodies, a known metallized seal can be used as a sealing method within the narrow tube portion 16 of the electrode introduction body in addition to the sealing method using the sealing material 23 described above. .

Here, as shown in FIG. 3, the shortest distance from the opening surface on the main tube portion 15 side of the opening surface of the thin tube portion 16 to the tip of the electrode portion 18 closer to the opening surface is _Le [mm]. When the tube wall load of the arc tube 6 is W _e [W / cm ² ], the relational expression 1.3 [mm] ≦ L _e and L _e ≦ W _e / 11 is satisfied for the reason described later. Is set to

  Further, in the narrow tube portion 16, a metallic cylindrical body 25 is interposed between the narrow tube portion 16 and the electrode introduction body 22, specifically, the electrode rod 24a. This cylindrical body 25 is for filling the gap 26 formed between the narrow tube portion 16 and the electrode rod 24a as much as possible and reducing the amount of metal halide that sinks into the narrow tube portion 16. is there. Here, as the cylindrical body 25, a coil in which molybdenum wire having a wire diameter of 0.2 [mm] is closely wound is used from the viewpoint of easy manufacture and easy attachment to the electrode rod 24a. The wire diameter of the molybdenum wire may be appropriately determined according to the size of the gap 26 formed between the narrow tube portion 16 and the electrode rod 24a. Further, in the case of using this coil-shaped cylindrical body 25, a closely wound coil in which the turns are in close contact from the viewpoint of filling as much as possible the gap 26 formed between the narrow tube portion 16 and the electrode rod 24a. Is preferably used.

  The electrode rod 24a and the cylindrical body 25 attached to the electrode rod 24a are electrically connected and have the same potential. Therefore, since a pair of electrode part 18 differs in polarity at the time of electric power supply, one cylindrical body 25 and the other cylindrical body 25 also mutually differ in polarity.

Thus, in order to eliminate the gap between the thin tube portion 16 and the electrode rod 24a, the cylindrical body 25 is in close contact with both the thin tube portion 16 and the electrode introduction body 22, and the gap 26 is completely filled. preferable. However, in practice, the inner diameter of the narrow tube portion 16 and the size of the cylindrical body 25 vary due to manufacturing variations and the like, and the electrode introduction body 22 to which the cylindrical body 25 is attached as described above is used as the narrow tube. Considering the tolerance when inserted into the portion 16, it is difficult to completely fill the gap 26 with the cylindrical body 25. Therefore, normally, even if the cylindrical body 25 is interposed between the thin tube portion 16 and the electrode introduction body 22, for example, a maximum of 0.05 [mm] is provided between the thin tube portion 16 and the cylindrical body 25. ] To 0.10 [mm]. In the present embodiment, the inner diameter r _i of the narrow tube portion 16 is 1.0 [mm], the diameter of the electrode rod 24a is 0.5 [mm], and the electrode introduction body 22 is attached with the cylindrical body 25 attached. In consideration of the tolerance when inserting the wire into the narrow tube portion 16, a molybdenum wire having a wire diameter of 0.2 [mm] is used. Therefore, a gap 26 of 0.05 [mm] exists between the narrow tube portion 16 and the cylindrical body 25. However, when the electrode introduction body 22 is inserted and sealed in the narrow tube portion 16, the electrode introduction body 22 may be eccentrically sealed in the narrow tube portion 16. In that case, a gap 26 of 0.1 [mm] at the maximum exists between the thin tube portion 16 and the cylindrical body 25.

  In addition to molybdenum, as the constituent material of the cylindrical body 25, various known halogen-resistant materials such as tungsten and platinum can be used.

Here, when the shortest distance from the opening surface on the main tube portion 15 side of the opening surface of the narrow tube portion 16 to the cylindrical body 25 is L _i [mm], 0 [mm] <L _i ≦ 0.5 [mm] is set so as to satisfy the relational expression.

  And such a metal halide lamp 1 is lighted using the following electronic ballasts (not shown). That is, as an example, when starting and restarting, the lamp is started or restarted by applying a high-frequency pulse voltage with a frequency of 240 [kHz] to 390 [kHz] and a maximum value of 4.0 [kV] by LC resonance, The lamp is steadily lit by a rectangular wave voltage having a frequency of 400 [Hz].

Next, when the shortest distance from the opening surface on the main tube portion 15 side of the opening surface of the narrow tube portion 16 to the cylindrical body 25 is L _i [mm], 0 [mm] <L _i ≦ 0.5 It fulfills [mm] relational expression, the shortest distance from the aperture plane to the tip of the electrode portion 18 nearer to the opening plane L _e [mm], the wall loading of the arc tube 6 W _e [W / The reason why it is defined to satisfy the relational expression 1.3 [mm] ≦ L _e and _Le ≦ W _e / 11 when cm ² ] is described.

First, in the rated power (input power) halide lamp 1 of 150W which is a first embodiment of the present invention described above, the wall loading W _e is kept constant at 33 [W / cm ^2], the shortest distance L _i within the scope of -0.3 [mm] ~0.9 [mm] , while varying as indicating the shortest distance L _e in table 1, respectively in the range of 1.2 [mm] ~3.3 [mm] 20 pieces of each were prepared. Then, 10 of each of the produced lamps are horizontally lit at the rated power using the electronic ballast described above, and the number and the color temperature at which blackening occurs on the inner surface of the arc tube 6 after 1000 hours of lighting. When the change ΔT _C [K] was examined, the results as shown in Table 1 were obtained. Further, the remaining 10 are vertically lit at the rated power using the electronic ballast described above, and similarly, the number of blackenings that have occurred on the inner surface of the arc tube 6 and the change in color temperature ΔT after 1000 hours of lighting. _{When C} [K] was examined, the results shown in Table 1 were obtained.

  As a lighting method, after continuously lighting for 5 hours, it was once turned off (power off), restarted after 2 minutes (power on), and again continuously lighting for 5 hours. “Lighting elapsed time” indicates the cumulative lighting time.

Further, the value indicated by “− (minus)” at the shortest distance L _i indicates that the cylindrical body 25 projects from the opening surface on the main tube portion 15 side to the main tube portion 15 side among the opening surfaces of the thin tube portion 16. , Showing its protruding length. Therefore, the shortest distance L _i of 0.0 [mm] indicates that the end surface of the cylindrical body 25 and the opening surface of the narrow tube portion 16 on the main tube portion 15 side are flush with each other. The shortest distance L _e was adjusted by changing the length of the tubular member 25 as appropriate. On the other hand, the shortest distance L _i was adjusted by appropriately changing the length of the electrode rod 24a. As a result, in each sample, the distance L _d between the electrode portions 18 has a value as shown in Table 1 as the shortest distance L _i is adjusted.

Also, in the “blackening occurrence state” column in Table 1, the denominator indicates the total number of samples, and the numerator indicates the number of blackenings observed on the inner surface of the arc tube 6. Here, the presence or absence of blackening is confirmed visually. In Table 1, the value in the “color temperature change ΔT _C ” column is the absolute value of the difference between the color temperature [K] after 100 hours of lighting and the color temperature [K] after 1000 hours of lighting. The average value of all samples is shown. As an evaluation standard of “color temperature change ΔT _C ”, 300 [K], in which a person hardly feels a change in color temperature by visual observation, is set as a standard. It was. Further, “Lamp Efficiency”, “Color Temperature”, and “Average Color Rendering Evaluation Index” in Table 1 indicate the average values of the samples at the initial stage of lighting (lighting elapsed time 100 hours). Among them, the symbol “-” indicates unevaluated.

Further, in each sample, the main pipe portion 15 has an outer diameter D _o of 6.4 [mm], an inner diameter D _i of 4.0 [mm], and an inner area of 4.54 [cm ² ]. The thin tube portion 16 has an outer diameter r _o of 3.2 [mm] and an inner diameter r _i of 1.0 [mm]. The electrode rod 24a has a diameter of 0.5 [mm]. The outer diameter φ (see FIG. 2) of the electrode coil 24b is 0.9 [mm]. The wire diameter of the coil constituting the cylindrical body 25 is 0.2 [mm]. The amount of the enclosed material enclosed in the arc tube 6 is as follows. Sodium iodide (NaI) and praseodymium iodide (PrI ₃ ) as a luminescent material have a molar composition ratio (NaI / PrI ₃ ) of 6.2 and a total amount of 12 [mg]. Mercury as a buffer gas is 0.8 [mg] (1.84 [mg / cm ³ ]). Xenon gas (Xe) as a starting auxiliary gas is enclosed so that its enclosure pressure is 10 [kPa] to 30 [kPa] at 300 [K].

As is clear from Table 1, while satisfying the relational expression of 0 [mm] <L _i ≦ 0.5 [mm], the relational expression of 1.3 [mm] ≦ L _e and L _e ≦ W _e / 11 For example, in the case of sample 12, sample 13, sample 14, sample 17, sample 18, sample 19, sample 22, sample 23, and sample 24, the lighting direction of either the horizontal lighting or the vertical lighting for all samples. is also not intended to blackening occurs on the inner surface of the arc tube 6 at the time of lighting lapse of 1000 hours, the change [Delta] T _C of the color temperature satisfied the criteria described above.

On the other hand, 0 [mm] <but satisfy L _i ≦ 0.5 [mm] relational expression, when satisfying L _e <1.3 [mm] relational expression, for example, a sample 11, sample 16, and sample 21 If, even in operating position in either the horizontal lighting or vertical lighting for all samples, although the change [Delta] T _C of the color temperature satisfied the criteria described above, the lighting direction is in the horizontal lighting at least in ten If one or more of the lamps are vertically lit, at least one of the ten lamps is lit for 1000 hours. Of the inner surfaces of the arc tube 6, the inner surface of the boundary between both the main tube portion 15 and the narrow tube portion 16 is used. Blackening occurred.

Further, 0 [mm] <but satisfy L _i ≦ 0.5 [mm] relational expression, L _e> if it meets W _e / 11 relational expression, for example, a sample 15, for sample 20, and sample 25, No blackening occurred on the inner surface of the arc tube 6 after 1000 hours of lighting, regardless of whether the lighting direction is horizontal lighting or vertical lighting for all samples. Although the change ΔT _{C in} color temperature satisfied the above-mentioned evaluation criteria, the change ΔT _{C in} color temperature did not satisfy the above-described evaluation criteria for all samples in vertical lighting.

Further, when satisfying the relational expression L _i ≦ 0 [mm], for example, in the case of Sample 1, Sample 2, Sample 3, Sample 4, Sample 5, Sample 6, Sample 7, Sample 8, Sample 9, and Sample 10, It is horizontal lighting and vertical lighting any of the lighting direction for all samples, although the change [Delta] T _C of the color temperature satisfied the criteria described above, at least two of ten lighting direction is in the horizontal lighting In the case of vertical lighting, blackening occurs on the inner surface of the boundary between the main tube portion and the narrow tube portion of the inner surface of the arc tube 6 when at least three of the ten lamps are lit for 1000 hours. Was. Especially, L _i [mm] = - In the vertical lighting in the case of (0.3), cracks occurred in those one in ten and one of the boundary portion.

Further, when the relational expression L _i > 0.5 [mm] is satisfied, for example, sample 26, sample 27, sample 28, sample 29, sample 30, sample 31, sample 32, sample 33, sample 34, and sample 35 In some cases, except for some samples (sample 26, sample 31), no blackening occurred on the inner surface of the arc tube 6 after 1000 hours of lighting, regardless of the lighting direction of horizontal lighting or vertical lighting. , in operating position is only horizontally operated although the change [Delta] T _C of the color temperature for all samples satisfied the criteria described above, in the vertical lighting change [Delta] T _C of the color temperature for all samples was the evaluation The standard was not satisfied.

  Next, the reason why the relational expression is derived based on such results will be described.

First, in the case where the relational expression L _i ≦ 0 [mm] is satisfied, a sample of the inner surface of the arc tube 6 that was blackened was analyzed. There was a black deposit adhering to the ingredients. The reason for this blackening is that the discharge does not start between the pair of electrode portions 18 when the lamp is restarted, but the discharge between the cylindrical body 25 and the electrode portion 18 having a different polarity from the cylindrical body 25 ( This is probably because the discharge has shifted between the pair of electrode portions 18 after the back arc) has started. Actually, when the state at the time of restart of the lamp is observed using a high-speed video camera, the main tube portion 15 and the narrow tube portion 16 in which the end portion on the electrode portion 18 side of the end portion of the cylindrical body 25 is located. At the boundary with, light emission considered to be the bright spot of the arc was confirmed. Therefore, when a back arc occurs between the cylindrical body 25 and the electrode part 18 having a different polarity from the cylindrical body 25, molybdenum as a component of the cylindrical body 25 is scattered by the thermal shock at that time, It is thought that it adhered to the inner surface of the arc tube 6 in the vicinity thereof. However, in a conventional metal halide lamp (described in Patent Document 3), it is said that such a phenomenon of back arc hardly occurs when the relational expression L _i ≦ 0 [mm] is satisfied. Nevertheless, it was considered that the occurrence of such a phenomenon was caused by the amount of mercury present in the arc tube 6. That is, the conventional one has a large amount of mercury enclosed, for example, 6.0 [mg / cm ³ ] or more. Therefore, especially at the time of restart, it is considered that the back arc is difficult to occur because the mercury vapor pressure in the arc tube 6 is high and discharge is unlikely to occur. However, the amount of mercury enclosed is small as in the case of the elongated arc tube 6 having L _d / D _i exceeding 4.0, and the amount of mercury present in the arc tube 6 is 4.0 [mg / cm ^3. In the following, at the time of restart, the mercury vapor pressure in the arc tube 6 becomes remarkably low, and discharge is more likely to occur than when the amount of mercury is large (for example, 6.0 [mg / cm ³ ]). It is thought that a back arc has occurred.

Therefore, when the amount of mercury present in the arc tube 6 is 4.0 [mg / cm ³ ] or less, the relational expression L _i > 0 [mm] is satisfied in order to suppress the occurrence of back arc. I found it necessary.

However, even if satisfying L _i> 0 [mm] relational expression, sample 11, when satisfying L _e <1.3 [mm] relational expression as the sample 16 and sample 21, main tube Blackening has occurred on the inner surface of the boundary portion between both of 15 and the narrow tube portion 16. However, regarding these samples, when the state at the time of restarting the lamp is observed using a high-speed video camera, the main tube portion 15 where the end portion on the electrode portion 18 side of the end portion of the cylindrical body 25 is located. The light emission that seems to be the bright spot of the arc could not be confirmed at the boundary between the thin tube portion 16 and the thin tube portion 16. That is, in the case of these samples, it is considered that the back arc as described above does not occur at the time of restart. However, the analysis of the black deposits which is the cause of its blackened, given that the component was molybdenum, for these samples, meet the L _e <1.3 [mm] relational expression As a result, it is considered that the tubular body 25 is too close to the electrode portion 18 and the temperature thereof is excessively increased, and molybdenum as a component thereof is scattered and adhered to the inner surface of the arc tube 6.

Therefore, as a result, the occurrence of back arc is suppressed, and the cylindrical body 25 is excessively heated by the heat of the electrode portion 18 to reduce the evaporation of the components, and the inner surface of the arc tube 6 is black. It was found that the relational expression of 0 [mm] <L _i and 1.3 [mm] ≦ L _e should be satisfied (hereinafter referred to as “first condition”).

Next, when the relational expression L _i ≦ 0 [mm] is satisfied, the cylindrical body 25 is interposed between the thin tube portion 16 and the electrode rod 24a. It is considered that the metal halide hardly sinks into the gap formed between them, so that the change in color temperature ΔT _c after 1000 hours of lighting has been reduced. However, as described above 0 [mm] <fulfills L _i ≦ 0.5 [mm] relational expression, when satisfying L _e ≦ W _e / 11 relational expression, in narrow tube portion 16, capillary Although there is a portion where the cylindrical body 25 is not interposed between the portion 16 and the electrode rod 24a, and there is room for the metal halide to sink there, the color temperature at the time of lighting for 1000 hours The change ΔT _c satisfies the above evaluation criteria. This can be attributed to the following factors. First, since there is a small portion where the cylindrical body 25 is not interposed between the thin tube portion 16 and the electrode rod 24a, the amount of metal halide permeating into that portion is small. Second, as a result of satisfying the relational expression L _e ≦ W _e / 11, the electrode portion 18 approaches the cylindrical body 25 and the temperature of the cylindrical body 25 is increased, so that the cylindrical body 25 is interposed. Even if the metal halide has infiltrated into the unexposed portion, most of the metal halide evaporates immediately by touching the high temperature cylindrical body 25 before sinking deeply into the narrow tube portion 16. That is, it is considered that the metal halide is constantly invading and evaporating into the narrow tube portion 16. As a result, it is considered that the metal halide does not sink deeply into the narrow tube portion 16 and does not deposit, and the color temperature change ΔT _c is reduced. However, when the relational expression L _i > 0.5 [mm] is satisfied as in the case of the sample 26, the sample 27, the sample 28, the sample 29, the sample 31, the sample 32, the sample 33, and the sample 34, for example, L _e ≦ W _{Even if the} relational expression _e / 11 is satisfied, the change ΔT _c in color temperature after 1000 hours of lighting does not satisfy the above-described evaluation criteria. This is because when the relational expression L _i > 0.5 [mm] is satisfied, the portion where the cylindrical body 25 is not interposed between the narrow tube portion 16 and the electrode rod 24a is too large, and the portion penetrates accordingly. Since the amount of the coming metal halide is increased, the invading metal halide cannot be sufficiently evaporated by the cylindrical body 25, and the metal halide that has not evaporated sinks deep inside the narrow tube portion 16 as it is. It is thought that this is because it no longer contributes to light emission.

Therefore, 0 [mm] <L _i ≦ 0.5 [mm] in order to suppress the metal halide from sinking into the narrow tube portion 16 and prevent the color temperature from changing with the passage of lighting time. It was found that when the relational expression was satisfied, the relational expression L _e ≦ W _e / 11 should be satisfied (hereinafter referred to as “second condition”).

In addition to this, it has been newly found that the phenomenon that the metal halide as described above permeates into the narrow tube portion 16 and repeats evaporation constantly improves the lamp efficiency. For example, as shown in Table 1, in the sample 18 in which the shortest distance L _i is 0.2 [mm] and the shortest distance _Le is 2.0 [mm], the lamp efficiency is 136.3 [lm / W] when horizontally lit. In the case of Sample 5 with the shortest distance L _i being −0.3 [mm] and the shortest distance L _e being 3.3 [mm], the lamp efficiency was 134.7 [lm / W] at the time of vertical lighting. 129.0 [lm / W] is a time horizontal lighting is at the time of normal lighting 127.3 [lm / W], also the shortest distance L _i is 0.9 [mm], the shortest distance L _e 3.3 In the sample 35 of [mm], the lamp efficiency was 125.0 [lm / W] when horizontally lit and 117.2 [lm / W] when vertically lit. Usually, the amount of the metal halide to be encapsulated is not completely evaporated even during stable lighting, but is excessively encapsulated so that a part thereof exists in a liquid state. Most of the excess metal halide is present at the lowest temperature on the inner surface of the arc tube 6, that is, at the coldest spot, and repeats evaporation and liquefaction. Therefore, it is this excess metal halide that enters the narrow tube portion 16. However, the excess metal halide that enters the narrow tube portion 16 is immediately evaporated by the cylindrical body 25 as described above. Therefore, most of the liquid excess metal halide is a portion having the next lowest temperature of the coldest spot in the narrow tube portion 16, or the narrow tube portion of the inner surface of each hemispherical portion 14 in the case of horizontal lighting. In the vicinity of 16 and in the case of vertical lighting, it is considered that the vicinity of the narrow tube portion 16 in the inner surface of the hemispherical portion 14 located on the lower side corresponds to this. Generally, the vapor pressure of the luminescent metal, which is one factor that determines the luminous efficiency of the lamp, is determined by the temperature of the portion where the excess metal halide exists.

Therefore, by satisfying the relational expression L _e ≦ W _e / 11, liquid excess metal halide can be present on the inner surface of the hemispherical portion 14 having a higher temperature than the inner surface of the thin tube portion 16. It has been found that the vapor pressure of the luminescent metal determined by the temperature of the portion can be increased, and the lamp efficiency can be improved (hereinafter referred to as “third condition”).

To summarize the above results, from the first condition, the second condition, and the third condition described above, the shortest distance from the opening surface on the main tube portion 15 side to the cylindrical body 25 among the opening surfaces of the thin tube portion 16. When the distance is L _i [mm], the relational expression of 0 [mm] <L _i ≦ 0.5 [mm] is satisfied, and from the opening surface on the main tube portion 15 side among the opening surfaces of the thin tube portion 16. the shortest distance to the tip of the opening face to the closer electrode portions 18 L _e [mm], when the tube wall loading of the arc tube 6 was ^{_{W e [W / cm 2]}} , 1.3 [mm] ≦ L _e, and by satisfying L _e ≦ W _e / 11 relational expression, together with the back arc can be prevented from occurring, the tubular body 25 becomes excessively high temperature by the heat of the electrode portion 18, the It is possible to reduce the evaporation of the components, and as a result, the inner surface of the arc tube 6 is not blackened. In addition, since it is possible to suppress the metal halide from sinking into the narrow tube portion 16, it is possible to prevent the color temperature from changing as the lighting time elapses, and the vapor of the luminescent metal. It has been found that the pressure can be increased and the lamp efficiency can be improved.

Therefore, according to the configuration of the metal halide lamp 1 according to the first embodiment of the present invention described above, the position of the end portion on the electrode portion 18 side in the end portion of the cylindrical body 25 is the mercury existing inside. Can be optimized to a specific position in the metal halide lamp 1 provided with the arc tube 6 of 4.0 [mg / cm ³ ] or less, so that the cylindrical body 25 and the cylindrical body 25 have polarities. Back arcs generated between different electrode portions 18 can be suppressed, and the tubular body 25 is too close to the electrode portions 18 to become excessively hot due to the heat, thereby reducing evaporation of the components. As a result, blackening of the inner surface of the arc tube 6 can be prevented. In addition, the amount of metal halide itself entering the narrow tube portion 16 can be reduced, and the metal halide that has entered the narrow tube portion 16 can be evaporated again into the main tube portion 15 by the cylindrical body 25. Therefore, it is possible to suppress the surplus metal halide from sinking into the narrow tube portion 16, and it is possible to prevent the color temperature from changing as the lighting time elapses due to this. Moreover, as a result of suppressing the surplus metal halide from sinking into the narrow tube portion 16, the surplus metal halide can be present in the vicinity of the narrow tube portion 16 on the inner surface of the hemispherical portion 14. Therefore, the vapor pressure of the luminescent metal can be increased, and the lamp efficiency can be improved.

  Next, as shown in FIG. 4, the lighting device according to the second embodiment of the present invention is used for, for example, ceiling lighting, and an umbrella-shaped reflection lamp 28 incorporated in the ceiling 27. And a lighting fixture 31 having a plate-like base portion 29 attached to the bottom of the reflecting lamp 28 and a socket portion 30 provided at the bottom of the reflecting lamp 28, and attached to the socket portion 30 in the lighting fixture 31. The metal halide lamp 1 having a rated power of 150 W, which is the first embodiment of the present invention, and the electronic ballast 32 attached at a position away from the reflection lamp 28 of the base portion 29 are provided.

  As mentioned above, according to the structure concerning the illuminating device which is 2nd Embodiment of this invention, since the metal halide lamp 1 which is 1st Embodiment of this invention mentioned above is used, a back arc generate | occur | produces. Therefore, it is difficult to blacken the inner surface of the arc tube 6, and it is possible to realize a lighting device that is small in change in color temperature with the passage of lighting time and high in efficiency.

  In the second embodiment, ceiling lighting is given as an example of the use of the lighting device, but it can also be used for other indoor lighting, store lighting, street lamp lighting, etc. It is not limited. Moreover, various well-known lighting fixtures and electronic ballasts can be used according to the use.

In each of the above-described embodiments, the case where the envelope 17 is configured using the main pipe portion 15 including the cylindrical portion 13 and the hemispherical portion 14 and the thin tube portion 16 has been described. Not only this but also when using an envelope instead of a substantially tapered portion (not shown) whose diameter decreases as the hemispherical portion 14 of the main tube portion 15 moves toward the thin tube portion 16 side, An effect can be obtained. Of course, the cylindrical portion 13, the tapered portion, and the narrow tube portion 16 are formed by integral molding. As described above, even when an envelope formed by any of various known integral moldings is used, the same effect as described above can be obtained. Even in these cases, when the inner diameter of the straight portion of the thin tube portion 16 is r _i [mm] as described above, the opening diameter d [mm] of the boundary portion between the main tube portion 15 and the thin tube portion 16 is (r _i × 1.05) [mm] can be defined as “the opening surface of the narrow tube portion 16 on the main tube portion 15 side”.

  Further, as shown in FIG. 5, the envelope 33 is constituted by a main pipe comprising a substantially cylindrical cylindrical portion 34 and substantially ring-shaped ring portions 35 provided inside both ends of the cylindrical portion 34. Even in the case of using the portion 36 and the substantially cylindrical thin tube portion 37 formed at both ends of the main pipe portion 36, that is, one end portion is fitted in the center portion of the ring portion 35. The same effect as described above can be obtained. In the envelope 33, the cylindrical portion 34, the ring portion 35, and the thin tube portion 37 are integrated by shrink fitting. In this case, the location of the straight portion of the narrow tube portion 37 on the main tube portion 36 side (the portion indicated by A in FIG. 5) is “the open surface of the thin tube portion 37 on the main tube portion 36 side”. It becomes. However, although FIG. 5 shows only one end of the arc tube, the other end also has the same configuration.

  Further, as shown in FIG. 6, the envelope 38 has a substantially cylindrical first cylindrical portion 39 and a first cylindrical portion 39 formed through a tapered portion 40 and having an outer diameter of the first cylindrical portion 39. From the main pipe part 42 composed of a substantially cylindrical second cylindrical part 41 having a smaller diameter than the outer diameter of one cylindrical part 39, and a narrow pipe part 43 formed at the end of the second cylindrical part 41 Even when what is comprised is used, the effect similar to the above can be acquired. For example, the first cylindrical portion 39, the tapered portion 40, and the second cylindrical portion 41 are formed by integral molding, and the narrow tube portion 43 is baked after one end portion thereof is fitted into the second cylindrical portion 41. Integrated by fit. In this case, the location of the straight portion of the narrow tube portion 43 on the main tube portion 42 side (the portion indicated by B in FIG. 6) is “the open surface of the thin tube portion 43 on the main tube portion 42 side”. It becomes. However, in FIG. 6, only one end of the arc tube is shown, but the other end also has the same configuration.

  Furthermore, in any of the cases described above, the case where the cylindrical portions 13, 34, 39 of the main pipe portions 15, 36, 42 are substantially cylindrical has been described. Even when a spindle-shaped one having a diameter gradually decreasing toward both ends is used, the same effect as described above can be obtained.

  In each of the above embodiments, the case where the coiled cylindrical body 25 made of molybdenum has been described. However, as the cylindrical body, a cylindrical body in which the core of a metal rod is cut through, or a metal sheet is cylindrical. Even in the case of using the one rounded, the same effect as above can be obtained.

In each of the above embodiments, the arc tube 6 having L _d / D _i larger than 4.0, and the amount of mercury present inside is 4.0 [mg / cm ³ ] or less. Although the case where it is used has been described, the shape or the like is not particularly limited as long as the amount of mercury present inside is 4.0 [mg / cm ³ ] or less. For example, L _d Even when various known arc tubes having / D _i of 4.0 or less are used, the same effect as described above can be obtained.

  In each of the above embodiments, the case where the metal halide lamp 1 having a rated power (input power) of 150 W is used has been described. However, the present invention may be applied to a metal halide lamp having a rated power (input power) of, for example, 100 W to 250 W. it can.

  The present invention can also be applied to applications that need to suppress the occurrence of a back arc between a cylindrical body and an electrode portion having a polarity different from that of the cylindrical body, particularly at the time of restart. .

1 is a partially cutaway front view of a metal halide lamp according to a first embodiment of the present invention. Front sectional view of arc tube used in metal halide lamp An enlarged cross-sectional view of the main part of the arc tube used in the same metal halide lamp The figure which showed typically the illuminating device which is the 2nd Embodiment of this invention. The principal part expanded sectional view of another arc_tube | light_emitting_tube which can be used for the metal halide lamp of this invention. The principal part expanded sectional view of another arc tube which can be similarly used for a metal halide lamp

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Metal halide lamp 2 Stem glass 3 Outer tube 4,5 Power supply line 6 Light emission tube 7 Base 8 Eyelet part 9 Shell part 10 Proximity conductor 11 Resistor 12 Getter 13, 34 Cylindrical part 14 Hemisphere part 15, 36, 42 Main part 16, 37, 43 Narrow tube portion 17, 33, 38 Enclosure 18 Electrode portion 19 Discharge space 20 Internal lead portion 21 External lead portion 22 Electrode introduction body 23 Sealing material 24a Electrode rod 24b Electrode coil 25 Cylindrical body 26 Gap 27 Ceiling 28 reflective lamp 29 base part 30 socket part 31 lighting fixture 32 electronic ballast 35 ring part 39 first cylindrical part 40 taper part 41 second cylindrical part

Claims (2)

It has a ceramic envelope consisting of a main pipe part and narrow pipe parts formed at both ends of the main pipe part, and an electrode introduction body in which an electrode part is formed at the end part. An arc tube in which the amount of mercury present is 4.0 [mg / cm ³ ] or less,
The electrode introduction body is inserted into the narrow tube portion so that the electrode portion is located in the main tube portion, and is sealed at an end portion of the thin tube portion opposite to the main tube portion. In the narrow tube portion, a metal cylindrical body is interposed between the electrode introduction body and the narrow tube portion, and from the opening surface on the main tube side of the opening surface of the narrow tube portion. When the shortest distance to the cylindrical body is L _i [mm], the relational expression 0 [mm] <L _i ≦ 0.5 [mm] is satisfied, and the book in the opening surface of the narrow tube portion the shortest distance from the opening surface of the tube portion to the tip of the electrode portion closer to the opening plane L _e [mm], when the tube wall loading of the arc tube was ^{_{W e [W / cm 2]}} , A metal halide lamp characterized by satisfying a relational expression of 1.3 [mm] ≦ L _e and _Le ≦ W _e / 11. A lighting device comprising the metal halide lamp according to claim 1 incorporated in a lighting fixture.

Images