JP4287780B2 - High pressure discharge lamp - Google Patents

Description

  The present invention relates to a high-pressure discharge lamp used for general illumination or a light source for a projector, and more particularly to a high-pressure discharge lamp with a reduced starting voltage.

  In recent years, image projectors such as liquid crystal projectors and DMD projectors have been widely used as systems for realizing large screen images, and such image projectors include an ultra-high pressure mercury lamp that exhibits high brightness among high-pressure discharge lamps. Generally used widely.

  This projector device is a large development point in terms of brightness, size, and weight, and a smaller, lighter and brighter projector device is being developed.

  Among them, as one means for realizing a reduction in size and weight, there is a reduction in the starting voltage of the high-pressure discharge lamp. If the starting voltage can be reduced, the lighting circuit can be reduced in size, weight, and cost. Further, if the starting voltage can be reduced, the safety against the voltage can be improved, and simpler wiring and connectors can be used, so that the cost can be saved. In addition, since the influence of noise on the other electronic circuits due to the starting voltage can be reduced, there is a merit that the possibility of malfunction and failure is reduced.

  In such a background, in order to reduce the starting voltage of the high-pressure discharge lamp, a method of winding a trigger line is generally known (for example, Patent Document 1 and Patent Document 2). The invention described in Patent Document 1 or Patent Document 2 is an invention in which a trigger line laying method is improved and a demerit when the trigger line is laid is improved. This will be described in detail below.

  The invention described in Patent Document 1 is a horizontally lit, direct current lighting type metal halide lamp having a configuration in which one end of the trigger wire is connected to the cathode and the middle portion of the trigger wire is separated from the outer wall of the arc tube. is doing. It is described that this configuration can reduce damage to quartz, which is the arc tube material, caused by positive ions attracted to the trigger wire.

The invention described in Patent Document 2 is a DC-lighted short arc mixed metal vapor discharge lamp having a bulb composed of a bulging portion and a pair of branch pipe portions, and one end of a trigger wire is connected to the cathode side. The other end is stretched over a position 3 mm or more away from the rising end of the bulb of the branch pipe portion of the anode portion. It is described that this configuration can reduce damage to quartz that is an arc tube material due to positive ions attracted to the trigger wire, as in Patent Document 1.
Japanese Patent Laid-Open No. 9-265947 (see, for example, FIG. 1) JP-A-8-87984 (see, for example, paragraph number 0005)

  In recent years, development competition for downsizing projectors has intensified, and a reduction in starting voltage is required to achieve further downsizing. However, simply laying the trigger wire on the high-pressure discharge lamp cannot sufficiently reduce the starting voltage.

  This invention is made | formed in view of the said subject, The place made into the objective is to provide the high voltage | pressure discharge lamp by which the trigger wire which reduced the starting voltage was wound.

  The high-pressure discharge lamp of the present invention includes an arc tube in which a luminescent material is sealed in a tube, a side tube portion that maintains airtightness of the arc tube, and a trigger wire wound around the side tube portion. The tube portion includes a first glass portion extending from the arc tube, and a second glass portion provided on at least a part of the inside of the first glass portion, and the second glass portion The glass portion contains at least one selected from the group consisting of Li, Na, and K in an amount of 0.001 wt% or more and 1.0 wt% or less, and a pair of electrodes is provided in the arc tube. Each of the pair of electrodes is electrically connected to a metal foil, the metal foil is buried in the side tube portion, and at least a part of the metal foil is disposed The second glass part is covered, and the side pipe part is applied with compressive stress. It has a site there.

The compressive stress is 10 kgf / cm ² or more and 50 kgf / cm ² or less in a region corresponding to the second glass portion when the side tube portion is measured using a sensitive color plate method using a photoelastic effect. Preferably there is.

  In one embodiment, a part of the electrode is buried in the side tube part, and a metal coil is wound around at least a part of the part buried in the side tube part of the electrode.

  In one embodiment, there are a pair of the side tube portions, the metal foils connected to the pair of electrodes are buried in different side tube portions, and the trigger wire includes a first and a second Two trigger wires, the first trigger wire is electrically connected to one of the electrodes, and is wound around the side tube portion on which the other electrode is disposed, The trigger wire is electrically connected to the other electrode, and is wound around the side tube portion on which the one electrode is disposed. Here, even when a conductive member is interposed between the trigger wire and the electrode, it can be said that the trigger wire and the electrode are electrically connected.

Wherein the tube of the arc tube, bromine and which is mercury is enclosed as the luminous substance, the amount of the enclosed bromine, in terms of per the arc tube volume 10 ^-4 μmol / cm ³ or more 10 .mu.mol / cm ³ The following is preferable.

The first glass part includes 99% by weight or more of SiO _2, and the second glass part includes at least one of 15% by weight or less of Al ₂ O ₃ and 4% by weight or less of B ₂ O _3. , Preferably less than 99% by weight of SiO ₂ .

  The softening point of the second glass part is lower than the softening point temperature of the first glass part.

  In one embodiment, the end of the metal foil on the side close to the arc tube is etched.

In one embodiment, mercury is enclosed as the luminescent material, and the amount of mercury enclosed is 160 mg / cm ³ or more in terms of the volume of the arc tube.

In one embodiment, mercury is enclosed as the luminescent material, and the amount of mercury enclosed is 300 mg / cm ³ or more in terms of the volume of the arc tube.

  The invention of the present application is a high pressure discharge lamp including a trigger wire wound around a side tube portion, wherein the side tube portion extends from the arc tube to at least a part of the inside of the first glass portion. A second glass part provided, and the second glass part contains at least one substance of Li, Na, and K in an amount of 0.001% by weight to 1.0% by weight. A metal foil electrically connecting the external lead and the electrode is buried in the side tube portion, and at least a part of the metal foil is covered with the second glass portion; The part has a structure to which compressive stress is applied, so that a high-pressure discharge lamp with dramatically reduced starting voltage can be provided, and the lighting circuit can be reduced in size, weight, and cost. Can be planned. In addition, safety can be improved by a high voltage from the lighting circuit, and an insulating member such as a lamp lead-in wire can have a simpler structure, so that a light source set (for example, a projector) can be realized at a lower cost. . In addition, noise to other electric circuits can be reduced, and malfunctions can be reduced. In addition, the pressure strength can be improved.

  Embodiments according to the present invention will be described below with reference to the drawings. In the following drawings, components having substantially the same function are denoted by the same reference numerals for the sake of simplicity. The present invention is not limited to the following embodiment.

(Embodiment 1)
FIG. 1 is a schematic diagram of a high-pressure discharge lamp 1000 according to Embodiment 1 of the present invention. The high-pressure discharge lamp 1000 includes an arc tube 101 in which a luminescent substance is sealed in a tube, and a side tube portion (or generally referred to as a “sealing portion”) 109 that maintains the hermeticity of the arc tube 101. A pair of side tube portions 109, 109 exist and extend in opposite directions from both ends of the arc tube 101. The side tube portion 109 has a first glass portion 101 ′ extending from the arc tube 101 and a second glass portion 106 provided at least in part inside the first glass portion 101 ′. ing. First glass portion 101 'is intended to include SiO ₂ 99 wt% or more. In the present embodiment, the first glass portion 101 ′ is made of quartz glass. The outer diameter (maximum diameter) of the arc tube 101 is about 10 mm, the inner diameter is about 5 mm, the glass thickness (wall thickness) is about 3 mm, and the inner volume of the arc tube 101 is about 0.1 ml.

  A pair of electrodes 102, 102 are arranged in the tube of the arc tube 101, and a part of each electrode 102 is buried in a separate side tube portion 109. That is, a part of the electrode 102 is surrounded by the glass constituting the side tube portion 109. The electrode 102 is made of tungsten. The distance between the tips of the electrodes 102 is about 1.0 mm. In addition, the distance between electrodes is suitably selected from about 0.8-1.5 mm according to the use of the high pressure discharge lamp to be used.

  A metal foil 103 is electrically connected (welded) to the end of the electrode 102 opposite to the end existing in the arc tube 101. Further, the metal foil 103 is buried in the side tube portion 109. That is, the periphery of the metal foil 103 is surrounded and sealed by the glass constituting the side tube portion 109. In other words, the metal foil 103 is in close contact with the glass constituting the side tube portion 109 on the entire surface. In the present embodiment, the entire surface of the metal foil 103 is covered with the second glass portion 106. The second glass part and the metal foil 103 are in close contact with each other, and the hermeticity of the arc tube 101 is ensured. It suffices that at least a part of the metal foil 103 is covered with the second glass portion 106. That is, in the present embodiment, as shown in FIG. 8, in the cross section of the side tube portion 109 (cross section orthogonal to the longitudinal direction of the side tube portion 109), the entire periphery of the metal foil 103 is covered by the second glass portion 106. In other words, at least a part of the metal foil 103 is covered by the second glass part 106 in the entire width direction, and the edge part of the metal foil 103 is the second part in this part. It is surrounded by the glass part 106 of this, and this ensures sufficient airtightness.

The glass constituting the second glass portion 106 contains at least one of 15 wt% or less of Al ₂ O ₃ and 4 wt% or less of B ₂ O ₃ and less than 99 wt% of SiO ₂ , and Li Further, at least one element selected from the group consisting of Na and K is further added, and the total addition amount is 1% by weight or less. When Al ₂ O ₃ or B ₂ O ₃ is added to SiO ₂ , the softening point of the glass is lowered. Therefore, the softening point of the second glass portion 106 is lower than the softening point of the first glass portion 101 ′. In the present embodiment, Vycor Glass (trademark registration No. 1657152) is used as the glass constituting the second glass portion 106. Vycor glass is made by adding an additive to quartz glass and has a softening point lower than that of quartz, so that workability is improved. The composition of Vycor glass is, for example, SiO ₂ : 96.5%, Al ₂ O ₃ : 0.5%, B ₂ O ₃ : 3%, and in addition, it contains 0.04% of Na ₂ O although it is a trace It is out. In the present embodiment, the first glass portion has a softening point of 1680 ° C. and a strain point of 1120 ° C., and the second glass portion (Vycor) has a softening point of 1530 ° C. and a strain point of 890 ° C.

  In the present embodiment, the side tube portion 109 has a portion to which a compressive stress is applied. The portion to which the compressive stress is applied is a portion corresponding to the second glass portion 106. The second glass part 106 is located at the center of the side tube part 109, and the outer periphery of the second glass part 106 is covered with the first glass part 101 '.

  When the strain measurement by the sensitive color plate method using the photoelastic effect is performed on the high-pressure discharge lamp 1000 of this embodiment and the side tube portion 109 is observed, the portion is compressed to a portion corresponding to the second glass portion 106. The presence of stress is confirmed. This observation was performed from a direction (so-called lateral direction) perpendicular to the direction (longitudinal direction) in which the side tube portion 109 extends. In the strain measurement by the sensitive color plate method, it is impossible to observe the strain (stress) in the cross section in which the side tube portion 109 is cut into a circular shape while maintaining the shape of the high-pressure discharge lamp 1000. The fact that compressive stress was observed in the portion corresponding to the glass portion 106 means that the second glass portion 106 and the first glass portion are in addition to the case where the compressive stress is applied to all or most of the second glass portion 106. When compressive stress is applied to the boundary portion with the glass portion 101 ′, the portion of the second glass portion 106 on the first glass portion 101 ′ side or the second portion of the first glass portion 101 ′. That is, the compressive stress is applied to a part of the side tube portion 109 in the case where the compressive stress is applied to the portion on the glass portion 106 side or a combination thereof. In this measurement, the stress (or strain) compressing in the longitudinal direction of the side tube portion 109 is observed as an integral value.

In this embodiment, Vycor glass is used as the glass constituting the second glass portion 106, but SiO ₂ : 62% by weight, Al ₂ O ₃ : 13.8% by weight, CuO: 23.7% by weight. Glass having% as a component may be used.

The compressive stress applied to a part of the side tube portion 109 only needs to exceed substantially zero (that is, 0 kgf / cm ² ). The value of the compressive stress is a value in a state where the high pressure discharge lamp is not lit. Due to the presence of this compressive stress, the pressure strength can be improved as compared with the conventional structure. This compressive stress is preferably about 10 kgf / cm ² or more (about 9.8 × 10 ⁵ N / m ² or more). And it is preferable that it is about 50 kgf / cm < ² > or less (about 4.9 * 10 < ⁶ > N / m < ² > or less). This is because if it is less than 10 kgf / cm ² , the compressive strain is weak and the pressure strength of the lamp cannot be sufficiently increased. And, in order to achieve a configuration exceeding 50 kgf / cm ² , there is no practical glass material for realizing it. However, even if it is less than 10 kgf / cm ² , if the value exceeds substantially 0, the breakdown voltage can be increased as compared with the conventional structure, and a configuration that can exceed 50 kgf / cm ² can be realized. If a new material has been developed, the second glass portion 106 may have a compressive stress exceeding 50 kgf / cm ² .

Assuming from the result of observing the high-pressure discharge lamp 1000 with a strain tester, the boundary between the first glass portion 101 ′ and the second glass portion 106 is a strain boundary caused by the difference in compressive stress between the two. An area seems to exist. This means that the compressive stress is exclusively present in the second glass portion 106 (or the vicinity of the outer periphery of the second glass portion 106), and the entire first glass portion 101 ′ has the second This is considered to mean that the compression stress of the glass part 106 is not transmitted so much (or almost). The difference in compressive stress between the two (106, 101 ′) can be, for example, in the range of about 10 kgf / cm ² to about 50 kgf / cm ² .

  In the present embodiment, the measuring instrument used for quantifying the distortion is a distortion inspector (Toshiba: SVP-200), and when this distortion inspector is used, the compression strain of the side pipe portion 109 is reduced. The magnitude can be obtained as an average value of the stress applied to the side tube portion 109.

  The principle of strain measurement by the sensitive color plate method using the photoelastic effect will be briefly described with reference to FIG. FIGS. 9A and 9B schematically show a state where linearly polarized light transmitted through the polarizing plate is incident on the glass. Here, if the incident linearly polarized light is u, u can be regarded as a combination of two orthogonal linearly polarized light u1 and u2.

As shown in FIG. 9 (a), when the glass is not distorted, u1 and u2 pass through it at the same speed, so that there is a deviation between u1 and u2 after passing through the glass. Absent. On the other hand, as shown in FIG. 9 (b), when the glass is distorted and the stress F is applied, u1 and u2 do not pass through the glass at the same speed. And u2 are displaced. That is, one of u1 and u2 is delayed from the other. This delayed distance is called the optical path difference. Since the optical path difference R is proportional to the stress F and the glass passage distance L, if the proportionality constant is C,
R = C ・ F ・ L
Can be expressed as Here, the unit of each symbol is R (nm), F (kgf / cm ² ), L (cm), and C ({nm / cm} / {kgf / cm ² }), respectively. C is a constant determined by a material such as glass and is called a photoelastic constant. As can be seen from the above equation, if C is known, F can be obtained by measuring L and R.

  The inventor of the present application measures the light transmission distance L in the side tube portion 109, that is, the outer diameter L of the side tube portion 109, and uses the distortion standard to determine the optical path from the color of the side tube portion 109 at the time of measurement. The difference R was read. As the photoelastic constant C, the photoelastic constant 3.5 of quartz glass was used. These were substituted into the above formula, and the compressive strain in the longitudinal direction of the metal foil 103 was quantified from the result of the calculated stress value.

  In this measurement, the stress in the longitudinal direction of the side tube portion 109 (the direction in which the axis of the electrode 102 extends) was observed, but this does not mean that there is no compressive stress in the other direction. Absent. Measure whether compressive stress is present in the radial direction of the side tube portion 109 (the direction from the central axis toward the outer periphery or vice versa) or in the circumferential direction of the side tube portion 109 (eg, clockwise direction). In this case, it is necessary to cut the arc tube 101 and the side tube portion 109. As soon as such cutting is performed, the compressive stress of the second glass portion 106 is relaxed. Therefore, since it is the compressive stress in the longitudinal direction of the side tube portion 109 that can be measured without cutting the lamp 1000, the inventors of the present application at least quantify the compressive stress in that direction. It was.

In the lamp 1000 of the present embodiment, the second glass portion 106 provided at least in part inside the first glass portion 101 ′ has a compressive strain (at least a compressive strain in the longitudinal direction). The pressure strength of the high pressure discharge lamp 1000 can be improved. In other words, the pressure strength can be made higher than that in which the second glass portion 106 has no compressive strain. The discharge lamp 1000 of the present embodiment shown in FIG. 1 exceeds 30 MPa (corresponding to a mercury filling amount of 300 mg / cm ³ ), which exceeds the conventional maximum operating pressure of 20 MPa (corresponding to a mercury filling amount of 200 mg / cm ³ ). ) It is possible to operate with the above operating pressure. Moreover, when the amount of mercury can be increased to 300 mg / cm ³ or more, the arc width (thickness) is reduced, and the arc luminance can be remarkably increased.

  The metal foil 103 is made of molybdenum. Although not shown, the tip of the metal foil 103 on the arc tube 101 side is etched. In the etching process, the metal foil 103 is deburred by applying a current to the metal foil 103 by placing the metal foil 103 in an alkaline solution such as NaOH to melt the tip of the metal foil 103. The cross-sectional shape on the short and long side at the tip of the metal foil 103 on the arc tube 101 side has a wedge shape (a shape obtained by smoothing the angle of a rhombus). By using the metal foil 103 that has been subjected to the etching process in this manner, the breakdown voltage can be improved as compared with the case where the etching process is not performed.

  An external lead wire 104 is electrically connected (welded) to the metal foil 103 on the side opposite to the side to which the electrode 102 is connected. The external lead wire 104 is made of molybdenum.

  A tungsten coil 107 is wound around a portion of the electrode 102 embedded in the side tube portion 109. The wire diameter of the coil 107 of this embodiment is 0.06 mm. The wire diameter of the coil 107 is not limited to 0.06 mm, and is appropriately selected from 0.01 to 0.3 mm. Note that the coil 107 may be at least part of the portion embedded in the side tube portion 109 of the electrode 102, and the coil 107 may exist in the tube of the arc tube 101. However, if the coil 107 exists in the tube of the arc tube 101, root discharge is likely to occur at the start of lighting from the coil 107. Therefore, it is preferable that the coil 107 is not exposed in the tube of the arc tube 101.

In the tube of the arc tube 101, bromine (not shown), a rare gas (for example, argon), and mercury 108 as a luminescent substance are sealed. Bromine is enclosed to prevent blackening of the arc tube 101 and is enclosed at about 10 ⁻¹ μmol / cm ³ in terms of the inner volume in the arc tube 101. Further, a rare gas (argon) is sealed so as to have a partial pressure of 0.03 MPa at 25 ° C. Further, mercury is enclosed in an amount represented by 300 mg / cm ³ in terms of the inner volume in the arc tube 101. Note that other halogen such as iodine other than bromine may be enclosed in the arc tube 101. However, since the optimum amount varies depending on the halogen species, an appropriately adjusted amount may be enclosed. The amount of the enclosed mercury may be in the range of content in terms of per product 160mg / cm ³ ~400mg / cm ³ in the arc tube 101, but the lamp in this embodiment, corresponds to up to 600mg / cm ³ (600MPa ) Up to mercury. And if mercury enclosed amount is 160 mg / cm < ³ > or more, it is suitable as a high pressure mercury lamp, and if it is 300 mg / cm < ³ > or more, a brightness can be improved more and it is preferable. Further, the rare gas may be selected from at least one of argon, xenon, neon, and krypton, and may be sealed so as to have a partial pressure of 0.001 to 0.1 MPa at 20 ° C.

  For reference, a method for manufacturing a high-pressure discharge lamp using the second glass portion will be briefly described.

  In a state where an electrode structure composed of the electrode 102, the metal foil 103, and the external lead wire 104 is put in a tube made of Vycor glass constituting the second glass portion 106, the arc tube 101 and the first glass portion 101. Insert into the bulb made of quartz glass that constitutes'. The first glass portion 101 ′ is heated by a heating means such as a burner while the arc tube 101 is in a reduced pressure state, and the first glass 101 ′ portion and the second glass portion 106 are softened to form the metal foil 103. Seal the part. As a result, a structure in which the second glass portion 106 exists between the electrode 102 and the first glass portion 101 'is completed.

  Next, a mechanism for applying compressive stress to the second glass portion 106 will be described.

In general, compression stress (compression strain) often exists when there is a difference in the thermal expansion coefficient between materials in contact with each other. That is, the reason why compressive stress is applied to the second glass portion 106 provided in the side tube portion 109 is generally considered that there is a difference in the coefficient of thermal expansion between the two materials in contact with each other. Is. However, in the case of this embodiment, actually, there is no big difference in both thermal expansion coefficients, and it can be said that it is substantially equal. More specifically, the thermal expansion coefficients of tungsten and molybdenum, which are metals used for the electrode 102 and the metal foil 103, are about 46 × 10 ⁻⁷ / ° C. and about 37 to 53 × 10 ⁻⁷ / ° C., respectively. Somehow, the thermal expansion coefficient of the quartz glass constituting the first glass part 101 ′ is about 5.5 × 10 ⁻⁷ / ° C., and the thermal expansion coefficient of the Vycor glass of the second glass part 106 is It is about 7 × 10 ⁻⁷ / ° C. which can be regarded as the same level as the thermal expansion coefficient of quartz glass. It is unlikely that a compressive stress of about 10 kgf / cm ² or more is generated between the two due to such a slight difference in thermal expansion coefficient. The difference between the two properties lies in the softening point or the strain point rather than the thermal expansion coefficient. From this point of view, it can be explained that compressive stress is applied by the following mechanism. The softening point and strain point of quartz glass are 1650 ° C. and 1070 ° C. (annealing point is 1150 ° C.), respectively, while the softening point and strain point of Vycor glass are 1530 ° C. and 890 ° C., respectively. (Annealing point is 1020 ° C.).

  In the sealing process of the high-pressure discharge lamp 1000, when the first glass part 101 ′ (side tube part 109) is heated and shrunk from the outside, first, the first glass part 101 ′ and the second glass part 106 The gap between them is filled and both touch. After shrinking, the first glass portion 101 ′ having a high softening point and a large area in contact with the outside air is located on the inner side even when the first glass portion 101 ′ is released from the softened state first (that is, when it hardens). In addition, the second glass portion 106 having a low softening point is still softened (ie, in a molten state). The second glass portion 106 at this time has fluidity as compared with the first glass portion 101 ′, and the thermal expansion coefficients of both at the normal time (when not softened) are almost the same. Even so, the properties (for example, elastic modulus, viscosity, density, etc.) of the two at this point are considered to be greatly different. And when time passes further and the 2nd glass part 106 which had fluidity cools, and the temperature of the 2nd glass part 106 falls below a softening point, the 2nd glass part 106 will also be 1st. It will harden in the same way as the glass part 101 ′. Here, if the softening points of the first glass part 101 ′ and the second glass part 106 are the same, both glass parts will be hardened so that they gradually cool from the outside and no compressive strain remains. However, in the case of the configuration of the present embodiment, the first glass portion 101 ′ located on the outside hardens early, and after a while, the second glass portion 106 on the inside hardens. It seems that compressive strain remains in the glass part 106.

  Next, the reason why the pressure strength of the lamp 1000 is increased by compressive strain in the second glass portion 106 will be described with reference to FIG. FIG. 10A is an enlarged view of the main part of the side tube portion 109 of the lamp 1000 according to the present embodiment, while FIG. 10B shows the first glass portion without the second glass portion for comparison. It is a principal part enlarged view of the side pipe | tube part 109 which consists only of glass part 101 '.

  The mechanism of increasing the pressure strength of the lamp 1000 is not clearly understood in practice, but the present inventors have inferred as follows.

  First, as a premise, since the metal foil 103 in the side tube portion 109 is heated and expanded during the lamp operation, stress from the metal foil 103 is applied to the glass portion of the side tube portion 109. More specifically, in addition to the fact that the coefficient of thermal expansion of metal is larger than that of glass, the metal foil 103 that is thermally connected to the electrode 102 and through which an electric current passes is formed on the side tube. Since it is easier to heat than the glass part of the part 109, stress is easily applied to the glass part from the metal foil 103 (particularly, from the side of the foil having a small area).

  Here, as shown in FIG. 10A, when compressive stress 15 is applied in the longitudinal direction of the second glass portion 106 (portion 20 to which compressive stress is applied), stress 16 from the metal foil 103 is applied. It is considered that the occurrence of the occurrence can be suppressed. In other words, it is considered that the large stress 16 can be prevented from being generated from the metal foil 103 due to the compressive stress 15 of the second glass portion 106. As a result, for example, the occurrence of cracks in the glass portion of the side tube portion 109 and the occurrence of leakage (peeling) between the glass portion of the side tube portion 109 and the metal foil 103 are reduced, and the strength of the side tube portion 109 is reduced. Will be improved.

  On the other hand, as shown in FIG. 10B, in the case of the structure without the second glass portion 106, the stress 17 from the metal foil 103 is larger than that in the configuration shown in FIG. I think. That is, since there is no region where compressive stress is applied around the metal foil 103, the stress 17 from the metal foil 103 is considered to be larger than the stress 16 shown in FIG. Therefore, it is inferred that the pressure resistance strength can be improved in the configuration shown in FIG. 10A than in the configuration shown in FIG. This idea seems to be compatible with the general property of glass that it is easy to break if the glass has tensile strain (tensile stress) and that it is difficult to break if it has compressive strain (compressive stress).

  However, it cannot be inferred that the side tube portion 109 of the lamp 1000 has a high pressure resistance because of the general property of the glass that it is difficult to break if the glass has compressive stress. Because, even if the strength of the glass in the region where the compressive strain is increased, the load is generated compared to the case where there is no strain when viewed from the side tube portion 109 as a whole. This is because the idea that the strength of the entire side pipe portion 109 is rather lowered can also hold. The result that the pressure strength of the lamp 1000 has been improved is the first time the inventors of the present application have made a prototype of the lamp 1000 and experimented with it, and could not be derived from theory alone. If a larger compressive stress than necessary is left in the second glass portion 106 (or its peripheral peripheral region), the side tube portion 109 is actually damaged when the lamp is turned on, and the life of the lamp is reduced. It may be shortened. Considering such a situation, it is considered that the structure of the lamp 1000 having the second glass portion 106 exhibits its high pressure strength under an exquisite balance. If the portion of the arc tube 101 is cut, it is assumed that the stress strain of the second glass portion 106 is relieved. Therefore, the load due to the stress strain of the second glass portion 106 is well received by the entire arc tube 101. It may be.

  In addition, the structure which shows the high compressive strength is also brought about by the site | part 20 to which the compressive stress produced by the difference of the compressive stress of 1st glass part 101 'and the 2nd glass part 106 is applied. Conceivable. In other words, the second glass portion 106 (or the periphery of the outer periphery thereof) located on the center side of the portion 20 to which the compressive stress is not applied to the first glass portion 101 ′ is substantially not applied. ) That the compression strain can be well confined in the region, it can be concluded that it has succeeded in exhibiting excellent pressure resistance characteristics. As a result of the stress values being discretely indicated due to the principle of strain measurement by the sensitive color plate method, the portion 20 to which compressive stress is applied is clearly shown in FIG. However, even if the actual stress value can be shown continuously, it is considered that the stress value is changing steeply in the portion 20 to which the compressive stress is applied. It is considered that the portion 20 to which a compressive stress is applied can be defined.

Further, in order to apply a compressive stress of about 10 kgf / cm ² or more to the second glass portion 106, the second glass portion is applied to the high-pressure discharge lamp 1000 (lamp completed body) completed by the above-described manufacturing method. It has been found necessary to heat at a temperature higher than the strain point temperature of 106. It was also found that heating at 1030 ° C. for 2 hours or more is preferable. Specifically, the sealed lamp 1000 may be placed in a furnace at 1030 ° C. and annealed (for example, vacuum baking or reduced pressure baking). In addition, the temperature of 1030 degreeC is an illustration, and should just be a temperature higher than the strain point temperature of the 2nd glass part (Vycor glass) 106. FIG. That is, it should be higher than the strain point temperature of Vycor 890 ° C. A preferred range is a temperature that is higher than the strain point temperature of Vycor 890 ° C. and lower than the strain point temperature of the first glass part (quartz glass) 101 ′ (the strain point temperature of SiO ₂ is 1070 ° C.), but is 1080 ° C. In some cases, the present inventors conducted an experiment at a temperature of about 1200 ° C.

For comparison, the high pressure discharge lamp not annealed was measured by the sensitive color plate method, and the second glass portion 106 was provided on the side tube portion 109 of the high pressure discharge lamp. Nevertheless, a compressive stress of about 10 kgf / cm ² or more was not observed in the sealed portion.

In the above description, the example in which the second glass portion 106 is made of Vycor glass has been described. However, SiO ₂ : 62 wt%, Al ₂ O ₃ : 13.8 wt%, and CuO: 23.7 wt% are constituents. It was also found that even when the second glass portion 106 is made of glass (trade name: SCY2, manufactured by SEMCOM, strain point: 520 ° C.), a compressive stress is applied at least in the longitudinal direction.

  Next, a mechanism inferred by the inventors of the present application that a compressive stress is applied to the second glass portion 106 of the lamp when the lamp complete body is annealed at a predetermined temperature for a predetermined time or more with reference to FIG. While explaining.

  First, as shown in FIG. 11A, a completed lamp is prepared. The method for manufacturing the finished lamp is as described above.

  Next, when the lamp complete body is heated, as shown in FIG. 11B, mercury (Hg) 108 starts to evaporate. As a result, pressure is also applied to the inside of the arc tube 101 and the second glass portion 106. . The arrow in the figure represents the pressure (for example, 100 atmospheres or more) due to the vapor of mercury 108. The reason why the vapor pressure of mercury 108 is applied not only to the inside of the arc tube 101 but also to the second glass portion 106 is that there is a gap 13 in the sealing portion of the electrode 102 that is invisible.

  When the heating temperature is further raised and the heating is continued at a temperature exceeding the strain point of the second glass portion 106 (for example, 1030 ° C.), the second glass portion 106 is in a soft state and the vapor pressure of mercury becomes the second. Therefore, compressive stress is generated in the second glass portion 106. The time for generating the compressive stress is estimated to be about 4 hours when heated at the strain point and about 15 minutes when heated at the annealing point, for example. This time is derived from the definitions of strain point and annealing point. That is, the strain point means a temperature at which internal strain can be substantially removed if kept at this temperature for 4 hours, and the annealing point means a temperature at which internal stress can be substantially removed if kept at this temperature for 15 minutes. From the point of view, the above time is estimated.

  Next, the heating is stopped and the finished lamp is cooled. Even after the heating is stopped, as shown in FIG. 11C, the mercury remains evaporated, so that the temperature of the second glass portion 106 becomes lower than the strain point while continuing to receive the pressure due to the mercury vapor. As shown in FIGS. 12A and 12B, the compressive stress remains in the second glass portion 106 not only in the longitudinal direction of the metal foil but also in the radial direction, etc. Only the longitudinal compressive stress can be confirmed).

Finally, when the cooling proceeds to about room temperature, a lamp 1000 having a compressive stress of about 10 kgf / cm ² or more in the second glass portion 106 is obtained as shown in FIG. As shown in FIGS. 11 (b) and 11 (c), the vapor pressure of mercury applies pressure to both second glass portions 106, and according to this technique, about 10 kgf is applied to both side tube portions 109. A compressive stress of / cm ² or more can be applied reliably.

This heating profile is schematically shown in FIG. First, when heating is started (time O), the temperature of the strain point (T ₂ ) of the second glass portion 106 is reached (time A). Next, at a temperature between the strain point of the second glass portion 106 (T ₂₎ and the strain point of the first glass portion 101 '(T _1), holding the lamp a predetermined time. This temperature region can basically be regarded as a range in which only the second glass portion 106 can be deformed. During this holding, as shown in the schematic diagram of FIG. 14, a compressive stress enters the second glass portion 106 due to mercury vapor pressure (for example, 100 atm or more).

Note that applying the pressure to the second glass portion 106 by the mercury vapor pressure seems to be the most effective method of using the annealing treatment, but the lamp is held in the temperature range of T _{2 to} T ₁ in FIG. If any force can be applied to the second glass portion 106, not only the mercury vapor pressure but also the force (for example, by pressing the external lead 104) can be applied to the second glass portion 106. It is assumed that compressive stress can be applied.

Next, when the heating is stopped, the lamp is cooled, and after time B, the temperature of the second glass portion 106 is lower than the strain point (T ₂ ). Below the strain point (T ₂ ), the compressive stress of the second glass portion 106 remains. In this embodiment, after holding at 1030 ° C. for 150 hours, cooling (natural cooling) is performed to apply the compressive stress of the second glass portion 106 and leave it.

  With the mechanism described above, compressive stress is generated by the mercury vapor pressure. Therefore, the magnitude of the compressive stress depends on the mercury vapor pressure (in other words, the amount of enclosed mercury).

  In general, as the amount of mercury increases, the lamp easily bursts. However, when the sealing structure of this embodiment is used, the compressive stress increases as the amount of mercury increases, and the breakdown voltage improves. That is, according to the configuration of the present embodiment, as the amount of mercury is increased, a high withstand voltage structure can be realized. Therefore, stable lighting at an extremely high withstand voltage that cannot be realized with the current technology is enabled. .

  Next, the trigger line 105 will be described.

  A trigger wire 105 is electrically connected to the external lead wire 104. The trigger wire 105 is electrically connected to the electrode 102 via the external lead wire 104 and the metal foil 103. That is, the trigger wire 105 is electrically connected to the electrode 102, the metal foil 103, and the external lead wire 104 on the side where the trigger wire 105 is electrically connected. The end of the trigger wire 105 opposite to that connected to the external lead wire 104 is a side tube on the side where a part of the electrode 102 to which the k trigger wire 105 is electrically connected is embedded. It is wound around the portion 109. The trigger wire 105 is made of Kanthal (Fe alloy containing 22% Cr and 5% to 6% Al), and has a wire diameter of about 0.3 mm. The trigger wire 105 is preferably made of Kanthal so that it can withstand the heat generated by the high-pressure discharge lamp 1000. The wire diameter is preferably about φ0.1 to 0.8 mm. If the thickness is smaller than 0.1 mm, the trigger wire 105 may be corroded before the lamp life is reached due to the heat of the lamp. Further, if the thickness is larger than 0.8 mm, there is a problem that processing is difficult and impractical.

  Subsequently, the results of the startability test of the high-pressure discharge lamp of this embodiment will be shown.

  Using the high-pressure discharge lamp 1000 of this embodiment, the lamp was turned on by a lighting circuit capable of generating a starting pulse, and the starting voltage was measured. The starting pulse used for the measurement has a waveform as shown in FIG. 2, and the peak voltage is about 13 kV. The time width of the pulse is about 280 nsec at the GND level.

  Here, for comparison, a comparison was made with a high-pressure discharge lamp 3000 having a conventional configuration that does not have the second glass portion. A schematic diagram of a conventional high-pressure discharge lamp 3000 is shown in FIG. The high pressure discharge lamp 3000 shown in FIG. 3 differs from the high pressure discharge lamp 1000 of FIG. 1 only in that the second glass portion 106 does not exist in the side tube portion 109. The other configuration of the high-pressure discharge lamp 3000 is the same as that of the high-pressure discharge lamp 1000.

  The startability test was performed as follows.

  The high-pressure discharge lamp 1000 and the high-pressure discharge lamp 3000 were turned on and off at 160 W in a cycle of 3.5 hours ON and 0.5 hours OFF, and the transition of lighting voltage lighting time was measured. The high-pressure discharge lamps 1000 and 3000 were measured with 10 each and compared with the average value of the starting voltage.

  The results of starting voltage measurement are shown in FIG. From FIG. 4, the high-pressure discharge lamp 1000 of the present embodiment has a very low starting voltage after lighting as compared with the conventional high-pressure discharge lamp 3000. For example, it is about 4.5 kV lower after 100 hours (h) of lighting, and the starting voltage can be reduced by at least 2 kV (in the case of 500 hours after lighting) even when the lamp is lit longer than 100 hours of lighting. The effect of reducing the startability is very great, the safety can be improved by the high voltage from the lighting circuit, and the insulating member such as the lead wire to the high-pressure discharge lamp 1000 can have a simpler structure. Thereby, a lower-cost light source set (for example, a projector) can be realized. In addition, since the starting voltage is reduced, noise to other electric circuits can be reduced, and malfunctions can be reduced.

  Although the reason why the starting voltage is greatly reduced by the configuration of the high-pressure discharge lamp 1000 of the present embodiment is not known in detail, the high voltage generated by the trigger wire 105 and Na contained in the second glass portion 106 have some reaction. Thus, it is considered that there is an action that assists starting in the arc tube 101.

  The surprising and prominent effect that the starting voltage is lowered by Na present in the side tube portion 109 is that the trigger wire 105 and the structure including the second glass portion 106 in the side tube portion 109 are combined. It is a unique phenomenon that occurs. Such an effect is a new discovery that could not be considered by extending the conventional technology.

In the present embodiment, the second glass portion 106 contains Na. However, if at least one selected from Li, Na, and K is present, the same effect can be obtained. Moreover, it is preferable that the total content in the 2nd glass part 106 of Li, Na, and K is 0.001 weight% or more and 1.0 weight% or less. If these contents are less than 0.001% by weight (10 ppm), the effect of reducing the starting voltage cannot be obtained. On the other hand, when the amount is more than 1.0% by weight, the softening point of the second glass portion 106 may be excessively lowered to cause devitrification. Further, when it is more than 1.0% by weight, the expansion coefficient of the second glass portion 106 is greatly changed as compared with the first glass portion 101 ′, and the sealing strength is lowered. For this reason, when 160 mg / cm ³ (equivalent to 160 MPa) of mercury is sealed in the arc tube 101, the reliability of airtightness may be impaired, which is not preferable. Further, when the mercury amount is 160 mg / cm ³ or more, it is suitable as a light source used in a projector or the like in combination with a reflecting mirror or the like. Furthermore, by setting the distance between the electrode tips to 2 mm or less, it becomes more suitable as a projector light source.

The amount of bromine sealed in the arc tube 101 is preferably 10 ⁻⁴ μmol / cm ³ or more and 10 μmol / cm ³ or less in terms of the inner volume of the arc tube 101. In the case of a high-pressure discharge lamp containing halogen such as bromine in the arc tube 101, it has been found that there is a correlation between the starting voltage and the amount of halogen. As the amount of halogen increases, the starting voltage increases. For this reason, the halogen amount to be sealed may be designed in conformity with the starting voltage of the lighting circuit. Further, since the degree varies depending on the halogen species, the amount of encapsulated halogen may be changed depending on the halogen species. For example, in order to set the starting voltage to 10 kV or less, if bromine is included, it is necessary to be about 10 μmol / cm ³ or less per unit internal volume of the arc tube 101. Further, bromine has an effect of suppressing the blackening of the arc tube 101 by rotating the halogen cycle in the arc tube 101 during lighting. In order to suppress this blackening, bromine is preferably 10 ⁻⁴ μmol / cm ³ or more.

  Further, a coil 107 is preferably wound around the portion of the electrode 102 embedded in the side tube portion 109 as in the present embodiment. For comparison, the starting voltage was measured with a high-pressure discharge lamp around which the coil 107 was not wound. When the coil 107 was not present, the average value of the starting voltage was higher by about 0.5 kV in the measurement after 100 hours from the lighting than when the coil 107 was wound. Here, the difference in the starting voltage of 0.5 KV is significant. This is because there is a strong demand for users of high-pressure discharge lamps to use wiring with as low a breakdown voltage as possible, aiming for a small set. The fact that the starting voltage is reduced by about 0.5 KV has the potential to realize such downsizing of the user set.

  Further, the second glass portion 106 does not necessarily need to cover the entire surface of the metal foil 103. Only the arc tube 101 side of the metal foil 103 may be covered, or only the connection portion with the electrode 102 may be covered. From the viewpoint of startability, the trigger wire 105 is preferably wound around the outside of the portion where the second glass portion 106 exists (around the side tube portion 109). It has been confirmed that a lamp having a lower starting voltage can be obtained with this configuration. In order to improve the pressure resistance of the high-pressure discharge lamp 1000, it is preferable that the second glass portion 106 covers at least the side of the metal foil 103 close to the arc tube 101.

Further, considering that the first glass portion 101 ′ (including the light emitter 101) is used for a high-pressure discharge lamp, it is preferable that 99% or more of SiO ₂ is contained in view of devitrification and the like. This is because when the component of SiO ₂ is reduced, the softening point of the first glass portion 101 ′ is lowered and the possibility of causing devitrification is increased.

(Embodiment 2)
A schematic diagram of a high-pressure discharge lamp 5000 of Embodiment 2 is shown in FIG. The high-pressure discharge lamp 5000 differs from the high-pressure discharge lamp 1000 of the first embodiment only in that two trigger lines 501a and 501b exist. Since other configurations are the same as those of the high-pressure discharge lamp 1000, the same reference numerals are used and description thereof is omitted.

  In the tube of the arc tube 101, a pair of electrodes 102a and 102b are disposed facing each other. A trigger line 501a (first trigger line) electrically connected to one electrode 102a (left side in the figure) is wound around a side tube portion 109b on which the other electrode 102b (right side in the figure) is arranged. Yes. The trigger wire 501b (second trigger wire) electrically connected to the other electrode 102b is wound around the side tube portion 109a where the one electrode 102a is disposed.

  FIG. 6 shows the result of measuring the starting voltage of the high-pressure discharge lamp 5000 by the same method as in the first embodiment. For reference, FIG. 6 shows results of starting voltages of the high-pressure discharge lamp 1000 and the high-pressure discharge lamp 3000. Each high-pressure discharge lamp is measured with 10 lamps and described as an average value. With the configuration of the high-pressure discharge lamp 5000, that is, by using the two trigger wires 501a and 501b, it is possible to start with a starting voltage lower by about 1 kV to 2 kV than the high-pressure discharge lamp 1000 using one trigger wire 105. I understood. In all ten high-pressure discharge lamps 5000, the starting voltage during the lighting test was 10 kV or less.

  Here, a high-pressure discharge lamp that can be lit at a starting voltage of 10 kV or less during lighting, including production variations, is a very useful high-pressure discharge lamp. This is because if it is 10 kV or less, the connector and connection wiring that are generally used to connect a high-pressure discharge lamp and a lighting circuit can be changed to a smaller, lighter, and lower cost, so the device is also smaller. This is because it can be reduced in weight, weight, and cost. The high-pressure discharge lamp 5000 of this embodiment is all 10 KV or less including variations, and has a great advantage that the apparatus can be miniaturized.

  As the laying method of these trigger lines 501a and 501b, an optimum method may be selected according to the application.

  In addition, since the second glass portions 106a and 106b exist, there are portions where compressive stress is applied to the side tube portions 109a and 109b in the present embodiment as in the first embodiment. The pressure strength of the lamp 5000 is high.

(Embodiment 3)
FIG. 7 schematically shows the configuration of the high-pressure discharge lamp 7000 according to the present embodiment. The configuration of the high-pressure discharge lamp 7000 of the present embodiment is different from the high-pressure discharge lamp 1000 of the first embodiment only in that the coil 107 is not present and the metal foil 103 is not etched. Other components are the same as those of the high-pressure discharge lamp 1000, and are denoted by the same reference numerals and description thereof is omitted.

As in the first embodiment, mercury 108 is sealed in the arc tube 101. When operating the high-pressure discharge lamp 7000 as an ultra-high pressure discharge lamp, for example, about 200 mg / cm ³ or more (220 mg / cm ³ or more, 230 mg / cm ³ or more, or 250 mg / cm ³ or more), preferably 300 mg / cm ³ or more. cm ^3, or more (e.g., 300 mg / cm ³ to 500 mg / cm ³⁾ and mercury, a rare gas (e.g., argon), if necessary, and a small amount of halogen are enclosed in the arc tube 101 Yes.

  In this embodiment, no coil is wound around the buried portion of the electrode 102 in the side tube portion 109, and the tip of the metal foil 103 is not etched, so the pressure resistance strength is not improved as much as in the first and second embodiments. However, the pressure strength can be improved as compared with the conventional high pressure discharge lamp that does not have the second glass portion 106 and does not have a portion to which compressive stress is applied. Moreover, since Na is contained in the second glass portion 106, the same effect as that of the first embodiment can be obtained in the starting characteristics.

(Other embodiments)
The above embodiment can be similarly applied to a mercury-free high-pressure discharge lamp that does not contain mercury (a lamp that uses a halide as a light-emitting substance).

  It was also found that the pulse width and the starting voltage have a correlation. When the pulse width is increased (longer in time), the starting voltage decreases. Specifically, when the starting pulse width of the above embodiment is reduced, the starting voltage tends to increase. Conversely, when the pulse width was increased, the starting voltage tended to decrease slightly. From this result, it can be said that it is preferable that the starting voltage is larger than the pulse width of the above embodiment in order to make the starting voltage 10 kV or less.

  As described above, the high-pressure discharge lamp according to the present invention is useful as a general illumination or a light source for a projector because the starting voltage is reduced and the pressure resistance is improved.

It is a figure which shows typically the high pressure mercury lamp 1000 of Embodiment 1. FIG. It is a starting voltage pulse waveform figure in the case of measuring a starting voltage. It is a figure which shows the conventional high pressure mercury lamp 3000 typically. It is a figure which shows the relationship between the starting voltage in the high pressure discharge lamp 1000, and lighting time. It is a figure which shows typically the high pressure mercury lamp 5000 of Embodiment 2. FIG. It is a figure which shows the relationship between the starting voltage in the high voltage | pressure discharge lamp 5000, and lighting time. It is a figure which shows typically the high pressure mercury lamp 7000 of Embodiment 3. FIG. FIG. 2 is a cross-sectional view taken along line A-A ′ of FIG. 1. (A) And (b) is a figure for demonstrating the principle of the distortion measurement by the sensitive color plate method using a photoelastic effect. (A) And (b) is a principal part enlarged view for demonstrating the reason why the pressure strength of the lamp | ramp 1000 goes up by the compressive strain having entered into the 2nd glass part. (A) to (d) are cross-sectional views for explaining a mechanism in which compressive stress is applied by annealing. (A) is a figure which shows typically the compressive stress of the longitudinal direction which exists in a 2nd glass part, (b) is the B-B 'sectional view taken on the line of (a). It is a graph which shows typically the profile of a heating process (annealing process). It is the schematic for demonstrating the mechanism in which compressive stress enters into the 2nd glass part by mercury vapor.

Explanation of symbols

101 arc tube 101 ′ first glass portion 102, 102a, 102b electrode 103 metal foil 104 external lead wire 105, 501a, 501b trigger wire 106 second glass portion 107 coil 108 mercury 109, 109a, 109b side tube portion

Claims (10)

A luminous tube in which a luminescent material is enclosed, and
A side tube portion that maintains the airtightness of the arc tube;
A trigger wire wound around the side pipe portion,
The side tube portion includes a first glass portion extending from the arc tube, and a second glass portion provided on at least a part of the inside of the first glass portion,
In the second glass part, at least one selected from the group consisting of Li, Na, and K is contained in an amount of 0.001% by weight to 1.0% by weight,
In the tube of the arc tube, a pair of electrodes are arranged facing each other,
Each of the pair of electrodes is electrically connected to a metal foil,
The metal foil is buried in the side tube portion, and at least a part of the metal foil is covered with the second glass portion,
The side tube portion is a high pressure discharge lamp having a portion to which a compressive stress is applied. The compressive stress is 10 kgf / cm ² or more and 50 kgf / cm ² or less in a region corresponding to the second glass portion when the side tube portion is measured using a sensitive color plate method using a photoelastic effect. The high-pressure discharge lamp according to claim 1. A part of the electrode is buried in the side tube part,
The high pressure discharge lamp according to claim 1 or 2, wherein a metal coil is wound around at least a part of the electrode buried in the side tube portion. A pair of the side pipe portions exist,
The metal foils connected to the pair of electrodes are buried in different side tube parts,
The trigger line includes first and second trigger lines,
The first trigger wire is electrically connected to one of the electrodes, and is wound around the side tube portion on which the other electrode is disposed,
The second trigger wire is electrically connected to the other electrode, and is wound around the side tube portion on which the one electrode is disposed. High-pressure discharge lamp described in 1. In the tube of the arc tube, bromine and mercury as the luminescent material are enclosed,
5. The high-pressure discharge lamp according to claim 1, wherein the bromine filling amount is 10 ⁻⁴ μmol / cm ³ or more and 10 μmol / cm ³ or less in terms of the inner volume of the arc tube. The first glass part contains 99% by weight or more of SiO ₂ ;
6. The second glass portion includes at least one of 15 wt% or less of Al ₂ O ₃ and 4 wt% or less of B ₂ O ₃ and less than 99 wt% of SiO _2. A high-pressure discharge lamp according to any one of the above.   6. The high-pressure discharge lamp according to claim 1, wherein a softening point of the second glass part is lower than a softening point temperature of the first glass part.   The high-pressure discharge lamp according to any one of claims 1 to 7, wherein an end of the metal foil on the side close to the arc tube is etched. Mercury is enclosed as the luminescent material,
The high-pressure discharge lamp according to any one of claims 1 to 8, wherein the amount of mercury enclosed is 160 mg / cm ³ or more in terms of the volume of the arc tube. Mercury is enclosed as the luminescent material,
The high-pressure discharge lamp according to any one of claims 1 to 8, wherein the amount of mercury enclosed is 300 mg / cm ³ or more in terms of the volume of the arc tube.

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