JP6671591B2 - Short arc discharge lamp - Google Patents

Description

  The present invention relates to a short arc discharge lamp suitable for a light source such as an exposure device and a projection device.

  In such a short arc type discharge lamp, a pair of opposing electrodes are arranged in an arc tube, and a discharge gas is sealed. The discharge gas is a gas containing a rare gas such as xenon as a main component, and the brightness is increased by making the discharge gas pressure inside the arc tube extremely high. Since no mercury is sealed in the arc tube, the current supplied to the electrodes when the lamp is turned on also becomes large. Therefore, a pair of electrode core rods supporting a pair of electrodes are projected outside from the sealing tubes connected to both ends of the light emitting tube, and the stepped glass of the sealing tube and the electrode core rods inside the sealing tube. A stepped glass sealing structure that seals through is adopted. In general, the thermal expansion coefficient of a sealing tube made of quartz glass is smaller than the thermal expansion coefficient of an electrode core made of a metal material such as tungsten, so that the electrode core and the sealing tube are in direct contact. In addition, the sealing tube may be damaged due to thermal expansion of the electrode rod when the lamp is turned on (when electricity is supplied). However, by adopting the stepped glass sealing structure, the stepped glass buffers the difference in thermal expansion between the sealing tube and the electrode rod, and can properly seal the sealing tube and the electrode rod. .

  The step glass has a low heat resistance and has a property of being easily deformed at a high temperature. For this reason, in order to protect the stepped glass portion, the sealing tube includes an inner tubular portion surrounding the periphery of the electrode core rod outside the stepped glass in the lamp axial direction, and an outer tubular portion concentric with the inner tubular portion. And has a tubular gap between the electrode core rod and the inner tubular portion. Conventionally, an attempt has been made to cool a stepped glass portion by providing a ventilation port for actively introducing cooling air into the tubular gap in a lamp base connected to an electrode core rod (Patent Document 1).

JP 2003-059454 A

  A power supply line for supplying lamp lamp power is connected between the electrodes, and the power supply line is connected to a power supply terminal of the lighting device, to the pair of electrode core rods or the lamp bases electrically connected to the electrode core rods. Therefore, for example, in the process of mounting and transporting the lamp and in the lamp manufacturing process, a stress is applied to the power supply line directly or through a base. The applied stress (especially in the radial direction of the lamp) concentrates on the stepped glass that seals and holds the electrode via the electrode core rod, and there is a case where the stepped glass is broken. In particular, short arc type discharge lamps have become larger due to the demand for higher brightness, and with the enlargement of the electrode core rod and the sealing tube, and the enlargement of the tubular space between the electrode core rod and the sealing tube, The stress applied to the stepped glass tends to increase, and the risk of breakage of the stepped glass is increasing.

An object of the present invention is to provide a short arc type discharge lamp in which the step glass is less likely to be broken by stress applied through an electrode core rod based on the above problem awareness.
Another object of the present invention is to propose a structure in which the electrode core is suitably held at the end of the lamp regardless of the thermal expansion difference between the sealing tube (stepped glass) and the electrode core.

The present invention includes a light emitting tube having a pair of electrodes therein, a sealing tube connected to both ends of the light emitting tube, and a pair of electrode rods respectively connected to the pair of electrodes. In the short arc discharge lamp in which the sealing tube and the electrode core rod are sealed through the step glass, a position outside the step glass part in the lamp axis direction of the short arc discharge lamp. the method comprising, interposed the electrode rod supporting member having elasticity in the lamp radially a position between said sealing tube and said electrode rod facing with said lamp radially, the electrode rod The support member is characterized in that it has a gap for communicating a space inside the electrode core rod support member in the lamp axis direction and a space outside the electrode core rod support member in the lamp axis direction .

  In one aspect, the electrode core rod support member may include a gap that allows communication between a space inside the electrode core rod support member in the lamp axis direction and a space outside the electrode core rod support member in the lamp axis direction. .

  In another aspect, the electrode core rod support member can have air permeability.

  The electrode core rod support member is specifically made of, for example, a metal foil wound around the electrode core rod, and the gap can be formed between adjacent metal foils. A part of the metal foil can be welded to the electrode core rod.

The sealing tube has an outer tubular portion connected to the arc tube, a reduced diameter portion connected to the outer tubular portion, the outer diameter of which is reduced toward the outside in the lamp axial direction, and a reduced diameter portion. consecutively provided, an end wall portion along the ramp radially electrode rod side of said reduced diameter portion, and an inner tubular portion Ru Ren設Su the arc tube side of the end wall, continuously arranged in the inner tubular portion And the step glass to be sealed with the electrode core rod, and a part of the electrode core rod-facing inner peripheral surface of the end wall portion has an inner diameter of a lamp axial direction outer end surface of the end wall portion. The electrode core support member has a large-diameter concave portion that has a large inner diameter and expands inward in the lamp axial direction, and the electrode core support member is provided between the electrode core opposing inner peripheral surface having the large-diameter concave and the electrode core. May be interposed.

  In the short arc type discharge lamp of the present invention, since the electrode rod supporting member is interposed in the tubular space between the electrode rod and the sealing tube, the electrode rod swings around the step glass part. Possibility (room) can be reduced, and breakage of the step glass can be prevented. In addition, by providing a gap in the electrode core rod support member to allow communication between a space inside the electrode core rod support member in the lamp axis direction and a space outside the lamp axis direction, or by providing air permeability, the cooling property of the stepped glass portion is improved. Does not impair. Furthermore, since the electrode support member has elasticity in the lamp radial direction, it is possible to suppress the thermal expansion of the electrode core rod from being transmitted to the sealing tube, and prevent the sealing tube from being damaged.

1 is a longitudinal sectional view showing one embodiment of a light source device including a short arc discharge lamp and a reflector according to the present invention. It is an expanded sectional view of the inner tube part of a sealing tube, and an electrode core part. 3A is an enlarged plan view of an elastic electrode rod supporting member coupled to an end of the electrode rod, FIG. 3B is an enlarged sectional view taken along line III-III of FIG. 2, and FIG. FIG. 4 is an enlarged side view of an elastic electrode core support member. It is a perspective view which shows the aspect which forms the elastic electrode core rod support member couple | bonded with the edge part of an electrode core by the winding structure of a metal foil. FIG. 5A is an enlarged plan view corresponding to FIG. 3A, and FIG. 5B is an enlarged cross-sectional view corresponding to FIG. 3B, illustrating another embodiment of the present invention. It is an expanded sectional view corresponding to Drawing 3 (B) which shows another embodiment of the present invention. FIG. 3 is a sectional view corresponding to FIG. 2 and showing an embodiment in which the present invention is applied to a short arc discharge lamp proposed by the present applicant in Japanese Patent Application No. 2014-163543. FIG. 3 is a cross-sectional view corresponding to FIG. 2 and showing an embodiment in which the present invention is applied to a short arc type discharge lamp of another aspect proposed in Japanese Patent Application No. 2014-163543 by the present applicant.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. 1 to 4 show a first embodiment of a short arc discharge lamp (hereinafter, “lamp”) 100 according to the present invention.

  FIG. 1 shows an entire light source device having a lamp 100 and a concave reflecting mirror 1. The lamp 100 includes an arc tube 3 and sealing tubes 4 connected to both ends of the arc tube 3. The arc tube 3 and the sealing tube 4 are each made of quartz glass, and the arc tube 3 is filled with xenon gas as a discharge gas at atmospheric pressure or higher. A pair of electrodes 5 are arranged inside the arc tube 3, and electrode core bars 6 each having one end protruding outside from the end of the sealing tube 4 are connected to the pair of electrodes 5. The concave reflecting mirror 1 is usually an ellipsoidal mirror or a parabolic mirror, and the pair of electrodes 5 are arranged to face each other with the focal position of the concave reflecting mirror 1 as a center. In the illustrated example, a base 9 that is electrically connected to the electrode core bar 6 is provided at an end of the sealing tube 4, and the base 9 is provided with a plurality of air-cooling ventilation holes 9 a communicating inside and outside. The base 9 may be omitted.

  A reduced diameter portion 34 is formed between the arc tube 3 and the sealing tube 4 to reduce the diameter toward the electrode core 6. The sealing tube 4 includes an outer tubular portion 401 connected to the reduced diameter portion 34, A diameter-reduced portion 402 which is connected to the outer end of the outer tubular portion 401 and gradually reduces in diameter, an end wall portion 403 which is connected to the diameter-reduced portion 402 and extends in a direction perpendicular to the axis, and which is connected to the arc tube side from the end wall portion 403 , An inner tubular portion 404.

  Between the inner tubular portion 404 of the sealing tube 4 and the electrode core rod 6, a step glass 7 for sealing the electrode core rod 6 is interposed. In the example of FIG. 2, the sealing portion 7 a with the electrode core 6 is connected to the inner tubular portion 404. The sealing structure using such a stepped glass is known as a stepped glass sealing structure.

  An electrode core rod support member 10 is disposed between the end wall portion 403 or the inner tubular portion 404 of the sealing tube 4 and the electrode core bar 6, and the end portion of the sealing tube, the inner tubular portion 404, and the electrode core bar 6 are provided. Is at least partially in contact with the electrode core rod supporting member 10. A tubular (annular) space 8 exists inside the electrode core support member 10 in the lamp axial direction. The electrode core rod supporting member 10 is a metal member having elasticity in the radial direction, and preferably having air permeability for communicating the tubular space 8 with a space outside the electrode core rod supporting member 10 in the lamp axis direction.

Specifically, the electrode core rod support member 10 is formed by winding a metal foil (preferably molybdenum foil) loosely so as to form a gap (gap) between overlapping portions, and the length of the electrode core rod 6 (axial line). 3) are partially fixed to the electrode core bar 6 at a plurality of (two in the example of FIGS. 3A and 3C) fixed portions 11 separated in the direction. FIG. 4 schematically shows how the metal foil 10 a is wound around the electrode core 6. One end of the strip-shaped metal foil 10 a is fixed to the outer peripheral surface of the electrode core 6, and Is wound around the outer periphery of at least two times. The metal foil 10a is gently wound so as to form a gap 10b between the stacked portions. In FIG. 3 (B), but are drawn at equal intervals schematically gap 10b concentrically, actually more shape (deformation) or a winding state of the metal foil 10a, and non-uniform in at least a part Voids are formed at irregular intervals. Such a gap 10b simultaneously has elasticity in the radial direction and air permeability in the axial direction as a whole of the electrode core rod support member 10 wound around the outer periphery of the electrode core rod 6.

  If an embossed metal foil having an embossed portion (convex portion) 10c (see FIG. 4) is used as the metal foil 10a, a gap 10b is reliably secured between the metal foil 10a on the inner and outer circumferences and the embossed 10c. The gap 10b can be reliably formed between the gap and the emboss 10c.

  The electrode core rod supporting member 10 is partially spot-welded and fixed to the electrode core rod 6 at the fixing part 11. In the fixed portion 11, since the laminated metal foils 10a are in close contact with each other, no voids 10b exist between the metal foils 10a, and concave portions 11a are formed in the radial direction. The fixed portion 11 has less elasticity in the radial direction of the lamp than the portion having the gap 10b because the laminated metal foils 10a are in close contact with each other, but has the concave portion 11a so that the electrode rod supporting member 10 as a whole has elasticity in the radial direction. It does not hinder.

The above-described lamp 100 is provided between the outer peripheral surface of the electrode core 6 and the inner peripheral surface of the end wall portion 403 or the inner tubular portion 404 of the sealing tube 4, outside the step glass 7, in the electrode core support member. Because of the interposition of 10, the movement of the electrode core rod 6 (the swinging movement around the contact (sealing portion 7a) of the step glass 7) can be restricted. Therefore, it is possible to prevent the sealing tube 4 (the inner tubular portion 404) from being damaged due to the movement of the electrode core rod 6 in the sealing tube 4 (the inner tubular portion 404). Further, since the electrode core rod supporting member 10 has elasticity in the lamp radial direction, a difference in thermal expansion between the electrode core rod 6 and the sealing tube 4 at the time of lighting is buffered, and the thermal expansion of the electrode core rod 6 is reduced by the electrode core. By transmitting to the sealing tube 4 via the rod supporting member 10, the sealing tube 4 can be prevented from being damaged. (The fixed portion 11 has less elasticity in the radial direction of the lamp than the portion having the air gap 10b because the laminated metal foils 10a are in close contact with each other. The expansion is prevented from being transmitted to the sealing tube 4.)
Furthermore, since the air gap 10b exists between the metal foils 10a and 10a, outside air can be introduced into the tubular space 8 through the air gap 10b, and can be discharged from the tubular space 8, so that the stepped glass 7 Does not hinder cooling.

  FIGS. 5A and 5B show an example in which the fixed portion 11L of the electrode core rod supporting member 10 to the electrode core rod 6 is continuous (welded continuously) in a direction parallel to the axis of the electrode core rod 6. It is a form. The gap between the concave portion of the fixed portion 11L of the electrode core rod supporting member 10 and the inner peripheral surface of the sealing tube 4 is, together with the gap 10b between the metal foils 10a, an axial ventilation path 8a for communicating the tubular space 8 with the outside air. Is formed. In this embodiment, since the electrode core rod supporting member 10 has the air gap 10b and the ventilation path 8a, the cooling effect of the step glass 7 can be improved. From the viewpoint of improving the air cooling effect, a plurality of fixing portions 11L may be provided at different positions in the circumferential direction.

  The above-described winding operation of the metal foil 10a and fixing operation of the wound metal foil 10a to the electrode core rod 6 are performed before the electrode core rod 6 and the sealing tube 4 (step joint glass 7) are sealed. After that, the electrode core rod 6 and the sealing tube 4 (step joint glass 7) are sealed so as to have predetermined specifications. Such a sealing operation is well known. When this sealing operation is completed, the electrode core rod supporting member 10 is located between the outer periphery of the electrode core rod 6 and the inner peripheral surface of the end wall portion 403 or the inner tubular portion 404 of the sealing tube 4. At least a part of the metal foil 10a contacts the inner peripheral surface of the end wall portion 403 or the inner tubular portion 404 (the number of turns of the metal foil 10a is at least a part of the metal foil 10a and The end wall portion 403 or the inner peripheral surface of the inner tubular portion 404 is determined so as to be in contact with the inner wall surface.

  FIG. 6 is a schematic cross-sectional view showing an embodiment in which the electrode core rod supporting member 10 is formed of a metal sponge-like member or a metal swash-like member having air permeability. A large number of holes (gap, gap) 10 e of the electrode core rod support member 10 are connected in the axial direction, and form a ventilation path that communicates the tubular space 8 with a space outside the electrode core rod support member 10 in the lamp axis direction. ing. In this embodiment, a breakage preventing effect is obtained by the elasticity of the electrode core rod supporting member 10, and a cooling effect is obtained by the ventilation path formed by the large number of holes 10e of the electrode core rod supporting member 10.

  Next, an embodiment in which the present invention is applied to a short arc type discharge lamp proposed by the present applicant in Japanese Patent Application No. 2014-163543 (prior application) will be described with reference to FIGS. In this embodiment, in order to prevent (suppress) the illumination light propagating in the glass constituting the sealing tube and the arc tube from heating the electrode core bar 6 and the step glass 7, the sealing tube 4 The present invention is applied to a short arc type discharge lamp in which an enlarged-diameter concave portion 407 is formed in an inner tubular portion 404. The same functional members as those in the embodiment shown in FIGS. 1 and 2 are denoted by the same reference numerals.

  That is, in the short arc discharge lamp, part of the light emitted from the arc propagates inside the arc tube 3 and the sealed tube 4 by the optical fiber effect. At the same time, a part of the light radiated from the arc at a position out of the focus of the reflecting mirror 1 is radiated to the light emitting tube 3 and the sealing tube 4 by the reflecting mirror 1, and the light emitting tube 3 and the sealing tube 4 are caused by the optical fiber effect. Propagate inside. In addition, the step joint glass 7 is heated when the electrode 5 is heated by lighting, and the heat is transmitted from the electrode 5 via the electrode core rod 6. When the temperature of the part of the electrode core rod 6 irradiated with infrared rays rises, not only the electrode 5 but also the heat is transmitted from the part of the electrode core rod 6 irradiated with infrared rays, so that the step glass 7 is further heated, It gets hotter.

  Xenon is filled in the arc tube 3 as a discharge gas at a pressure higher than the atmospheric pressure. The step glass 7 in contact with the discharge gas always faces from the inside of the arc tube to the outside regardless of whether the lamp is on or off. Under pressure. Therefore, the stepped glass 7 is further heated by transmitting heat from the electrode core rod 6 irradiated with the infrared rays. When the temperature exceeds the strain point or the softening point, the stepped glass 7 expands to the outside of the arc tube. The position of the electrode core rod 6 held by the step glass 7 and the position of the electrode 5 supported by the electrode core rod 6 move. As a result, problems such as a change in the lighting power characteristics of the lamp 100 due to an increase in the distance between the electrodes, and a decrease in illuminance due to the arc generated between the pair of electrodes 5 being out of focus of the reflecting mirror 1 occur. Further, when the arc deviates from the focal point of the reflecting mirror 1, the amount of light applied to the sealing tube 4 by the reflecting mirror 1 increases, and the above-described problem may become more serious.

  In the prior application, in order to prevent the electrode core rod 6 and the step glass 7 from being heated by the optical fiber effect of the light emitting tube 3 and the sealing tube 4, the end wall portion 403 of the sealing tube 4 in the lamp axis direction is used. The outer end is used as a flat surface (first light emitting surface) 405 along the radial direction of the lamp, and a part of the inner peripheral surface 406 of the end wall portion 403 facing the electrode core 6 facing the electrode core 6 is enlarged in diameter. A (annular) recess 407 is provided. The diameter-increased concave portion 407 is gradually narrowed in the radial direction of the electrode core rod 6 and has an inner diameter R2 which is larger than the inner diameter R1 of the outer end surface of the end wall portion 403 in the lamp axis direction. The portion of the enlarged diameter concave portion 407 having the maximum inner diameter is located closer to the arc tube 3 than the center M1 in the lamp axial direction of the thickness of the end wall portion 403. The center M1 in the lamp axis direction is an intermediate portion in the lamp axis direction of the thinnest portion of the end wall portion 403 having the first light emitting surface 405.

  As described above, the diameter of the enlarged diameter concave portion 407 is maximized, that is, the portion having the largest inner diameter is provided on the arc tube side with respect to the center M1 of the end wall portion 403 in the lamp axis direction, so that the end wall portion 403 is located inward in the lamp radial direction. Most of the light L propagating toward the lamp can be internally reflected to the outside in the lamp axis direction by the large-diameter concave portion 407, and the temperature rise of the step glass 7 can be suppressed. As described above, in order to cause light to be internally reflected outward in the lamp axis direction without emitting light L to the electrode core rod 6 side, a cross section in the lamp axis direction of the electrode core opposing inner peripheral surface 406 having the enlarged diameter concave portion 407 is required. It is desirable that the shape be substantially V-shaped.

  In order to prevent light L propagating in the outer tubular portion 401 from being irradiated from the arc tube side end surface 410 of the end wall portion 403 to the inner tubular portion 404 and the stepped glass 7, the arc tube side end surface 410 is Desirably, the surface is curved. However, when it is necessary to provide a flat surface along the radial direction of the lamp also on the arc tube side end surface 410 in order to suppress the thickness difference of the end wall portion 403, the flat surface area is at least the first surface. Desirably, it is smaller than the light emitting surface 405.

  In the embodiment of FIG. 7, the electrode core rod supporting member 10 is interposed between the electrode core rod 6 and the inner peripheral surface 406 of the sealing tube 4 facing the electrode core, and at least a part of the metal foil 10a is provided. And the inner peripheral surface 406 facing the electrode core rod are in contact with each other, and the swing of the electrode core rod 6 is suppressed. A space exists between the electrode core 6 and the enlarged diameter concave portion 407. In the embodiment of FIG. 7, by providing the electrode core rod support member 10 at this location, it is possible to prevent the light propagating inside the glass of the sealing tube 4 from being irradiated to the electrode core rod support member 10. The advantage is obtained that the temperature rise of the support member 10 and the electrode core 6 can be prevented (suppressed).

  FIG. 8 shows the embodiment of FIG. 7 in which the end wall portion 403 is provided with a tubular light guiding portion 408 protruding on the opposite side (outside) from the inner tubular portion 404, and the light guiding portion 408 has an outer end surface in the lamp axial direction. The present invention is applied to the embodiment of the prior application provided with a flat surface 409 (second light emitting surface). Light L propagating inward in the lamp radial direction through the end wall portion 403 is internally reflected outward in the lamp axial direction by the enlarged diameter concave portion 407 which is a light reflecting surface, and propagates in the light guide portion 408. The light L propagated in the light guiding unit 408 is emitted from the second light emitting surface 409 to the outside.

  By propagating the light L in the light guiding section 408 and radiating the light L from the second light emitting surface 409 remote from the end wall section 403, it is possible to prevent the light radiated outside from irradiating the electrode core rod 6. Alternatively, it is possible to irradiate the electrode core rod 6 further outward in the lamp axis direction. Thereby, the temperature rise of the step glass 7 due to the light emitted from the sealing tube 4 can be suppressed.

  In this embodiment, the electrode core rod support member 10 fixed to the electrode core rod 6 faces (contacts) the electrode core opposing inner peripheral surface 406 and the tubular light guide 408, and the electrode core rod 6 is The swing movement around the step glass 7 is prevented. In the embodiment of FIG. 8, by providing the electrode core rod support member 10 at this location, light propagating inside the glass of the sealing tube 4 irradiates the electrode core rod support member 10 as in the embodiment of FIG. This is advantageous in that the temperature of the electrode core rod supporting member 10 and the electrode core rod 6 can be prevented (suppressed) from being raised.

DESCRIPTION OF SYMBOLS 1 Reflecting mirror 3 Light emitting tube 4 Sealing tube 401 Outer tubular part 402 Reduced diameter part 403 End wall part 404 Inner tubular part 405 Flat surface (first light emitting surface)
406 Electrode core opposing inner peripheral surface 407 Large diameter recess 408 Tubular light guide 409 Flat surface (second light emitting surface)
5 Electrode 6 Electrode core rod 7 Step glass 7a Contact part 8 Tubular space 8a Air passage 9 Cap 10 Electrode core rod support member 10a Metal foil 10b Void 10c Emboss 10e Hole 11 11L Fixed part 11a Recess 34 Reduced diameter part 100 Lamp M1 end Lamp axis center R1 of wall part Inner diameter R2 of end wall part

Claims (5)

An arc tube having a pair of electrodes inside,
A sealing tube connected to both ends of the arc tube,
A pair of electrode core rods respectively connected to the pair of electrodes,
Has,
In a short arc type discharge lamp for sealing the sealing tube and the electrode core rod through a step glass,
A position outside the stepped glass portion in the lamp axis direction of the short arc discharge lamp, and a position between the sealing tube and the electrode core rod facing each other in the lamp radial direction. That an electrode core rod supporting member having elasticity in the lamp radial direction is interposed,
The electrode core rod support member has a space that allows communication between a space inside the electrode core rod support member in the lamp axis direction and a space outside the electrode core rod support member in the lamp axis direction,
A short arc type discharge lamp characterized by the following. 2. The short arc discharge lamp according to claim 1, wherein said electrode core rod supporting member has air permeability. 2. The short arc discharge lamp according to claim 1, wherein said electrode core rod support member is made of a metal foil wound around said electrode core rod, and said gap is formed between adjacent metal foils. Type discharge lamp. In short arc type discharge lamp according to claim 3, wherein said metal foil is a short arc type discharge lamp in which a part is welded to the electrode rods. The short arc discharge lamp according to any one of claims 1 to 4,
The sealing tube has an outer tubular portion connected to the arc tube, a reduced diameter portion connected to the outer tubular portion, the outer diameter of which is reduced toward the outside in the lamp axial direction, and a reduced diameter portion. consecutively provided, an end wall portion along the ramp radially electrode rod side of said reduced diameter portion, and an inner tubular portion Ru Ren設Su the arc tube side of the end wall, continuously arranged in the inner tubular portion Having the step core glass to seal with the electrode core rod,
A part of the inner peripheral surface of the end wall portion facing the electrode core has an enlarged concave portion having an inner diameter larger than the inner diameter of the outer end surface in the lamp axial direction of the end wall portion, the inner diameter being enlarged inward in the lamp axial direction. ,
A short arc type discharge lamp in which the electrode core rod supporting member is interposed between the electrode core rod facing inner peripheral surface having the enlarged diameter concave portion and the electrode core rod.

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