CN101924009B - High-pressure discharge lamp - Google Patents

Abstract

A long-life high-pressure discharge lamp according to the present invention does not cause cracks or the like near the sealing portion and does not cause cracks due to stress concentration near the sealing portion in a high-pressure discharge lamp driven at high pressure. Consisting of a luminous tube made of quartz glass and a sealing portion protruding from both ends of the luminous tube, a rare gas, mercury of 0.15 mg/mm ³ or more, 1×10 ^-6 to 1×10 ^{- 2} μmol/mm ³ halogen, with a pair of oppositely arranged electrodes, the electrode core wire connected to the electrodes is welded to the metal foil, a part of the electrode core wire and the metal foil are buried in the sealing part, and the electrode core wire In the long side direction of the electrode core wire, a groove is formed on the periphery of the section perpendicular to the long side direction. range.

Description

high pressure discharge lamp

technical field

The present invention relates to a high-pressure discharge lamp widely used as a projector light source. In particular, it is a high-pressure discharge lamp having a characteristic shape of an electrode core wire connected to electrodes disposed opposite to each other in a luminous tube.

Background technique

Conventionally, as a light source for an image projection apparatus used in an image projection apparatus such as a projector, a high-pressure discharge lamp in which a rare gas and mercury are sealed in an arc tube has been widely used. This high-pressure discharge lamp has, for example, sealed mercury of 0.15 mg/mm ³ or more inside the arc tube, and has the characteristic of efficiently emitting light in the entire visible light range by utilizing the high pressure during lighting.

As shown in FIG. 9 , this high-pressure discharge lamp 101 is composed of an arc tube 102 made of quartz glass and sealing portions 103 protruding from both ends of the arc tube 102 . In addition, inside the luminous tube 102, a pair of opposing electrodes 105 and an electrode core wire 106 connected to the electrodes 105 are arranged. An external lead 108 connected to the metal foil 107 to supply electric power from the outside is buried in the quartz glass constituting the sealing portion 103 . In addition, mercury of, for example, 0.15 mg/mm ³ or more, and a rare gas, such as halogen of 1×10 ^-6 to 1×10 ^-2 μmol/mm ³ are sealed in the arc tube 102 .

When the high-pressure discharge lamp 101 having such a structure is turned on, for example, when it is turned on at a high pressure of 150 atmospheres or more, the tip of the electrode 105 made of tungsten, which is a high-melting point material, becomes a high temperature of a melting degree, and the electrode 105 And the electrode core wire 106 thermally expands in the axial direction of the lamp. On the other hand, the sealing portion 103 in which the electrode core wire 106 is embedded is made of quartz glass having a very small coefficient of thermal expansion. Since the high-pressure discharge lamp 101 is repeatedly turned on and off, a large stress is generated between the electrode core wire 106 and the seal portion 103 due to the difference in thermal expansion coefficient between the electrode core wire 106 and the seal portion 103, and the high-pressure discharge lamp 101 breaks itself, and this problem has been known from the past.

Various countermeasures have been taken in order to solve the crack caused by the high stress of the sealing portion 103 generated in the high pressure discharge lamp 101 . As a technique for alleviating this stress, Japanese Patent Publication No. 2008-529252 and the like are known, for example. According to this publication, as shown in FIG. 10, it is described that the main part of the electrode core wire 116 of the connection electrode 110, that is, the portion in contact with the quartz glass of the sealing part (not shown) is provided with a groove 114 in the longitudinal direction. . The groove 114 substantially reduces the area where the quartz glass is in close contact with the electrode core wire 116 in the sealing portion (not shown), and has the effect of alleviating the stress generated in the sealing portion (not shown).

However, in the high-pressure discharge lamp 101 shown in FIG. 9, even if the groove 114 shown in FIG. Stress may cause cracks to cause damage to the lamp itself, and there is a problem that the high pressure discharge lamp 101 cannot be sufficiently prevented from being broken only by providing the groove 114 .

Patent Document 1 Japanese PCT Publication No. 2008-529252

Contents of the invention

The problem to be solved by the present invention is to provide a long-life high-pressure discharge lamp that does not cause cracks or the like near the sealing portion and does not cause stress concentration near the sealing portion in the high-pressure discharge lamp driven at high pressure. of rupture.

The high-pressure discharge lamp described in this invention is composed of a luminous tube made of quartz glass and sealing parts protruding from both ends of the luminous tube, and a rare gas, mercury of 0.15 mg/ ^mm3 or more, 1× 10 ^-6 ~ 1×10 ^-2 μmol/mm ³ halogen, with a pair of electrodes arranged oppositely, the electrode core wire connected to the electrodes is welded to the metal foil, and a part of the electrode core wire and the metal foil are embedded in the In the sealing part, it is characterized in that, in the electrode core wire, in the longitudinal direction of the electrode core wire, a groove is formed on the entire periphery of the section perpendicular to the longitudinal direction, and the sealing part side end of the groove The part is set in the range where the metal foil overlaps with the electrode core wire.

In addition, the high-pressure discharge lamp described in this invention is characterized in that, in addition to the above-mentioned structure, a portion without a groove is provided between the end of the groove on the sealing portion side and the end of the electrode core wire.

Furthermore, the high-pressure discharge lamp described in the present invention is characterized in that, in addition to the above-mentioned structure, the discharge space-side end of the groove is arranged at a portion of the glass material embedded in the sealing portion.

In the high-pressure discharge lamp of the present invention, in the long-side direction of the electrode core wire, a groove is provided on the surface of the electrode core wire as a whole on the periphery of the cross-section perpendicular to the long-side direction, and the sealing portion side end of the groove is provided with In the range where the metal foil and the electrode core wire overlap, the electrode core wire and the glass material are in close contact with each other in the sealing portion, so that even if the electrode core wire and the glass material thermally expand due to turning on and off It has the advantage of being able to suppress the generation of cracks and the like without accumulating a large stress in the sealing portion.

In addition, by forming a portion without a groove between the end of the groove on the sealing portion side and the end of the electrode core wire, the stress generated on the sealing portion can be reduced, and the stress generated on the sealing portion can be further suppressed. The effect of cracks, etc. This point can be considered for the following reasons. There is a minute space formed at the end of the electrode core wire where the glass material does not enter during sealing. In this minute space, the mercury enclosed in the arc tube is transferred to the tank after the high-pressure discharge lamp is turned off, and is transported in large quantities. The transported mercury vaporizes rapidly when the high-pressure discharge lamp is re-lit, and the pressure in the tiny space rises. In addition to the difference in thermal expansion between the electrode core wire and the glass material, this pressure tends to move the electrode core wire toward the discharge space side, thereby applying additional stress. This additional stress is reduced by being formed in the portion not having the groove, and the amount of mercury transported through the groove is suppressed, resulting in suppressing the occurrence of cracks.

Furthermore, since there is no groove when the electrode core wire and the metal foil are welded by using the portion without the groove, reliable welding can be performed, the welding strength can be improved, and the problem of peeling off of the electrode core wire from the metal foil can be suppressed. Additional effects.

Furthermore, the end portion of the groove on the discharge space side is disposed at a portion embedded in the glass material constituting the sealing portion, whereby the occurrence of cracks can be further suppressed. This is because, when the lamp is started, the unstable arc discharge is not fixed near the root of the electrode core wire (from the part of the electrode buried in the glass material to the discharge space side), and the glass material near the root Being excessively heated, a local thermal expansion coefficient difference occurs, so cracks and the like will not occur.

Description of drawings

Fig. 1 is a schematic cross-sectional view showing the outline of a high-pressure discharge lamp of the present invention.

Fig. 2 is a detailed enlarged view showing electrodes and electrode core wires arranged in the high-pressure discharge lamp of the present invention.

3 is a cross-sectional view of the electrode core wire of the present invention cut in a direction perpendicular to the long-axis direction.

Fig. 4 is a detailed view showing the formation range of grooves formed on the electrode core wire of the present invention.

5 is a schematic cross-sectional view showing the shape of a sample in which the formation range of grooves in the high-pressure discharge lamp of the present invention was confirmed.

Fig. 6 is a table showing the effects of groove formation positions in the high pressure discharge lamp of the present invention.

Fig. 7 is a schematic sectional view showing another embodiment of the present invention.

Fig. 8 is a schematic explanatory view showing cracks generated in a conventional high-pressure discharge lamp.

Fig. 9 is a schematic cross-sectional view showing the outline of a conventional high-pressure discharge lamp.

FIG. 10 is a diagram showing a conventional electrode and an electrode core wire disclosed in a known document.

Detailed ways

The high-pressure discharge lamp of the present invention is characterized in that a groove is formed on the electrode core wire to which the electrodes are connected, and the range where the groove is provided is formed in the glass material embedded in the sealing part protruding to both ends of the arc tube of the high-pressure discharge lamp. range, and one end of the groove is formed in a range where the electrode core wire overlaps with the metal foil. With such a configuration, stress generated in the sealing portion is suppressed, and there is an effect that a long-lived high-pressure discharge lamp free from cracks and the like can be provided.

Example 1

Fig. 1 shows the outline of a high-pressure discharge lamp 1 of the present invention. This high-pressure discharge lamp 1 is composed of an arc tube 2 and sealing portions 3 protruding toward both ends of the arc tube 2 . In addition, there is a pair of electrodes 5 disposed opposite to each other inside the luminous tube 2 , and the sealing portion 3 is provided with: an electrode core wire 6 connected to the electrodes 5 , and an electrode core wire 6 welded to one end of the electrode core wire 6 . The metal foil 7 and the external lead bar 8 welded to the other end of the metal foil 7 . In addition, on the electrode core wire 6 , grooves 4 parallel to the long-axis direction of the electrode core wire 6 are provided on the outer peripheral surface of the electrode core wire 6 . The groove 4 moderately relieves the close contact between the electrode core wire 6 and the glass material of the sealing part 3 , and can prevent the sealing part 3 from contacting the electrode when the electrode core wire 6 strongly adheres to the sealing part 3 . Cracks are generated due to the stress caused by the difference in thermal expansion rate of the core wire 6 .

FIG. 2 shows an enlarged view of electrodes 5 and electrode core wires 6 disposed on the high-pressure discharge lamp 1 . In the case of this embodiment, the electrode 5 and the electrode core wire 6 are cut from the same material by cutting. Micro protrusions 11 are formed on the front end side of the electrode 5 facing the arc tube 2 , and the outer diameter of the main body of the electrode 5 is formed to be thicker than the electrode core wire 6 connected to the electrode 5 . In addition, on the electrode core wire 6 , grooves 4 formed along the long axis direction of the electrode core wire 6 are formed on the surface. In addition, in this embodiment, a portion where the groove 4 is not formed is provided on one end portion 12 of the electrode core wire 6 . In addition, in the arrow A-A shown in the electrode core wire 6 in FIG. 2 , a cross-sectional view cut along a cross section perpendicular to the axis in the long axis direction of the electrode core wire 6 is shown in FIG. 3 .

Fig. 3 shows the section A-A in Fig. 2 . FIG. 3( a ) is a cross-sectional view showing the entire outer peripheral edge of the electrode core wire 6 in an axial cross-section. The groove 4 is integrally formed on the outer periphery of the electrode core wire 6 . In addition, FIG. 3(b) is an enlarged view of FIG. 3(a). The groove 4 is formed by minute valleys 16 formed between minute peaks 15 . The pitch P formed by the mountain portion 15 and the depth D of the valley portion 16 are, for example, a pitch P=40 μm and a depth D=6 μm. The grooves 4 are formed with such fine pitches and depths, so the glass material of the sealing portion 3 shown in FIG. The effect of suppressing the occurrence of cracks and the like.

Fig. 4 is a partial cross-sectional view showing only one electrode side of the high pressure discharge lamp 1 of the present invention. On the sealing portion 3 of the high-pressure discharge lamp 1 shown in FIG. 4, the metal foil 7 sealed by the glass material (quartz glass) forming the sealing portion 3; and the electrode core wire welded to the metal foil 7 are arranged. 6. In addition, the electrode 5 connected to the electrode core wire 6 is disposed inside the arc tube 2 following the sealing portion 3 . In addition, the groove 4 along the long axis direction is formed in the electrode core wire 6 . The formation range of the groove 4 will be described below. One end portion 21 of the groove 4 is formed in the range of the overlapping portion B of the electrode core wire 6 and the metal foil 7 . In addition, the other end 22 of the groove 4 is arranged in the range of the part C formed on the side of the metal foil 7 from the border between the sealing portion 3 and the arc tube 2 so that the end portion 22 does not protrude into the arc tube. 2 interior. The ends 21 and 22 of the groove 4 are formed in this range, so there will be no cracks caused by the stress caused by the thermal expansion difference between the electrode core wire 6 and the glass material of the sealing part 3, and it is possible to provide Advantages of long-life high-pressure discharge lamps.

FIG. 5 shows the sample shape of an experiment conducted to study the formation range of the groove 4 . 5( a ) to ( f ) are partial sectional views of the high pressure discharge lamp 1 shown in FIG. 4 , and the formation ranges of the grooves 4 are different.

In (a), the end portion 22 of the groove 4 on the arc tube 2 side is provided at a position buried by the glass material on the sealing portion 3 side. In addition, the end portion 21 on the side of the metal foil 7 is provided outside the range where the metal foil 7 and the electrode core wire 6 overlap (on the arc tube 2 side).

Next, in (b), the end portion 22 on the arc tube 2 side is the same as in (a) above, but the position of the end portion 21 on the metal foil 7 side is different. The end portion 21 is provided in a range where the metal foil 7 and the electrode core wire 6 overlap, and there is a portion of the end portion 12 of the electrode core wire 6 where the groove 4 is not formed.

The end portion 22 of the groove 4 on the arc tube 2 side in (c) is the same as in (a) and (b). The end portion 21 on the metal foil 7 side is provided to the end portion 12 of the electrode core wire 6 .

(d) is different in that the end portion 22 of the groove 4 on the arc tube 2 side penetrates into the arc tube 2 . The end portion 21 on the side of the metal foil 7 is the same as the case of (a) above.

(e) Similar to (d), the point that the end portion 22 of the arc tube 2 side of the groove 4 enters into the interior of the arc tube 2 is different, and the end portion 21 of the metal foil 7 side is the same as that of the above (b) same situation.

(f) Similar to (d) and (e), the difference is that the end portion 22 of the groove 4 on the arc tube 2 side enters the interior of the arc tube 2, and the end portion 21 on the metal foil 7 side is the same as The same case as (c) above.

FIG. 6 is a table showing the results of examining the formation range of the groove 4 in each sample shape shown in FIG. 5 . Ten high-pressure discharge lamps 1 of each sample shape shown in FIG. 5 were manufactured, and a lighting test was performed. In addition, the high-pressure discharge lamp 1 used was a 230W type with a lamp voltage of 65V and a lamp current of 3.5A, and AC lighting was performed with a rated input. In addition, the high-pressure discharge lamp 1 is started using a lighting device that generates high-voltage alternating current. As a lighting-off test of this test, under the condition of lighting on for 45 minutes and turning off the light for 30 minutes, cracks generated in the sealing portion 3 after lighting for 1000 hours were observed. In addition, in order to observe the crack, the vicinity of the sealing portion 3 was enlarged and observed at a magnification of about 5 times using an optical microscope. When cracks were observed in this observation, it was judged as impossibility and represented by x. In addition, when no cracks were observed, it was judged to be good and represented by ◯ or ⊚. In addition, as an example of the crack, for example, as shown in FIG. 8 , in the sealing portion 3 connected to the arc tube 2 , the metal foil 7 embedded in the glass material is welded to the electrode core wire 5 and occurs near the portion. Multiple tiny cracks85.

In the sample (sample a) shown in FIG. 5( a ), the range of the groove 4 formed in the electrode core wire 6 is set so that the end portion 22 on the side of the arc tube 2 is buried by the glass material on the side of the sealing portion 3 The end portion 21 on the side of the metal foil 7 is disposed outside the range where the metal foil 7 overlaps with the electrode core wire 6 (on the side of the arc tube 2 ). Thus, since the groove is not formed in the area where the metal foil 7 and the electrode core wire 6 overlap, a space for appropriately absorbing the difference in thermal expansion with the glass cannot be formed, and cracks are generated. Therefore, as the judgment, it is not possible, and is indicated by x in FIG. 6 .

The sample (sample b) shown in FIG. 5(b) is the shape of the present invention, and the groove 4 formed on the electrode core wire 6 is formed to the electrode core wire 6 where the metal foil 7 overlaps the electrode core wire 6. up to the connection. In this sample, the cracks observed in this sample a did not occur. Therefore, as the judgment, it is the best result, which is indicated by ⊚ in FIG. 6 .

The sample (sample c) shown in FIG. 5( c ) is a case where the groove 4 formed in the electrode core wire 6 is formed to the end 12 of the electrode core wire 6 . Due to the groove 4, an appropriate space is formed between the glass material forming the sealing portion 3, and the thermal expansion difference between the glass material and the electrode core wire 6 can be appropriately absorbed without forming cracks. However, since the groove 4 is formed up to the end of the electrode core wire 6, a part of the mercury inside the arc tube 2 condenses in the tiny space formed at the end of the electrode core wire 6, and the high-pressure discharge lamp 1 In the case of a problem that the self-luminescence becomes unstable. In addition, when the high pressure discharge lamp 1 is re-lit, the condensed mercury may generate unnecessary stress. Therefore, it was judged to be good, and is indicated by ◯ in FIG. 6 .

In the samples (sample d, sample e, and sample f) shown in FIGS. The point that the end portion 22 of the groove 4 on the side of the arc tube 2 protrudes toward the inside of the arc tube 2 is different. When performing a lighting test on each of the above-mentioned samples, during lighting, a local arc discharge was fixed to the end 22 of the groove 4 of the electrode core wire 6 protruding toward the luminous tube 2 side, and the area near the end 22 was locally heated. Cracks were generated in either case of the glass material or the like. Therefore, as a judgment, it is not possible, and it is indicated by X in FIG. 6 .

Fig. 7 shows another embodiment of the high pressure discharge lamp 1 of the present invention. The high-pressure discharge lamp 1 is composed of a discharge tube 2 and sealing portions 3 protruding toward both ends of the discharge tube 2 as in FIG. 1 . In addition, other configurations are basically the same, except that a pair of electrodes 55 disposed opposite to each other inside the arc tube 2 has a coil 56 arranged at the tip of the electrode core wire 6, and the tip portion is formed as a molten electrode that melts. . The groove 4 is formed on the electrode core wire 6 in the same manner as in the case of FIG. 1 , and has the same effect of suppressing the occurrence of cracks due to stress caused by the difference in thermal expansion coefficient between the sealing portion 3 and the electrode core wire 6 . . And, in the present embodiment, the electrode 55 is shown as a melting electrode, and what is shown in FIG. This is self-explanatory.

Claims (1)

1. A high-pressure discharge lamp comprising a luminous tube made of quartz glass and a sealing portion protruding from both ends of the luminous tube, in which a rare gas, 0.15 mg/mm or ^more of mercury, 1 ×10 ^-6 ~ 1×10 ^-2 μmol/mm ³ halogen, with a pair of oppositely arranged electrodes, each of the electrodes and the electrode core wire is cut out of the same material by cutting, and the same material is cut by cutting The electrode core wire connected to the electrode is welded to the metal foil, and a part of the electrode core wire and the metal foil are buried in the sealing part, wherein, In the electrode core wire, in the longitudinal direction of the electrode core wire, a groove is formed on the entire periphery of the section perpendicular to the longitudinal direction, and the end of the groove on the sealing part side is provided between the metal foil and the metal foil. In the range where the electrode core wires overlap, and a portion without a groove is formed between the sealing part side end of the above groove and the end of the electrode core wire, the discharge space side end of the above groove is arranged in the Part of the glass material.