KR20230127125A - Discharge lamp - Google Patents

Abstract

[Problem] In an electrode of a discharge lamp, generation of cracks or the like is suppressed with respect to a rectifying body or the like disposed in an airtight space enclosing a heat transfer body.
[Solution] A closed space 50 is formed in the anode 30 of the discharge lamp 10, and the heat transfer body M melted when the lamp is turned on is sealed. In addition, a rectifying body 40 in which the first and second plate-like members 40A and 40B are stacked is disposed in the closed space 50 . The thicknesses T1 and T2 of the first and second plate-like members 40A and 40B are different, and the first plate-like member 40A is made thicker than the second plate-like member 40B.

Description

Discharge lamp {DISCHARGE LAMP}

The present invention relates to discharge lamps such as short arc type discharge lamps, and particularly to heat dissipation of electrodes.

In the discharge lamp, the tip of the electrode becomes hot during lighting, the electrode material such as tungsten melts and evaporates, and the discharge tube blackens, resulting in a decrease in lamp illumination. In order to prevent overheating of the electrode including the tip of the electrode, a structure in which a heat transfer body such as metal is sealed inside the electrode is known (see Patent Document 1). There, a heat transfer element made of a metal having a high thermal conductivity and a relatively low melting point, such as silver, is sealed inside the anode. As the temperature of the electrode rises due to lighting of the lamp, the heat transfer body melts and liquefies. As a result, heat convection occurs in the closed space, and the heat from the tip of the electrode is transported to the opposite side of the electrode support bar.

In addition, in order to promote heat convection, a configuration in which a plate-like member (rectifying body) forming a flow path along the electrode axis is disposed in the closed space (see Patent Document 2), or a heat transfer body In order to prevent high-temperature creep deformation due to the temperature difference in the closed space due to heat convection from occurring, a plate-like member (restrictor) that regulates the flow of the molten heat transfer body in the circumferential direction is installed in the sealed space. A configuration disposed inside is known (see Patent Document 3).

[Patent Document 1] Japanese Unexamined Patent Publication No. 2004-006246 [Patent Document 2] Japanese Patent No. 6259450 [Patent Document 3] Japanese Unexamined Patent Publication No. 2012-028168

When the lamp is turned on, a force is applied to the rectifying body or the like according to the flow of the molten heat transfer body, and in some cases it is inclined. When the rectifying body or the like is inclined, the amount of thermal expansion of the rectifying body or the like is different depending on the axial direction of the electrode because there is a temperature difference between the bottom surface side and the ceiling surface side of the closed space. Therefore, deformation such as warping occurs, and there is a possibility that cracks or damage may occur in the rectifying body or the like.

Therefore, in an electrode, it is required to suppress generation of cracks and the like with respect to a rectifying body or the like disposed in an airtight space that encloses the heat transfer body.

A discharge lamp, which is an aspect of the present invention, has a discharge tube and a pair of electrodes arranged oppositely in the discharge tube, and at least one electrode forms an airtight space in which a heat transfer body that melts when the lamp is turned on is sealed, and has a plate shape. The rectifying body of the (板狀) is arrange|positioned in the closed space.

The "rectifying body" here is constituted as a member capable of adjusting the flow of the heat transfer body in an enclosed space, such as forming a flow path, guiding the flow direction, and promoting the flow. The rectifying body is constituted by a plurality of members, and can be configured by laminating a plurality of plate-like members, for example. In addition, "plate-shaped" means that the outer shape can be configured as a plate-shaped rectifying body as a whole, and a rectifying body having an external shape in which a plurality of plate-shaped members such as T-shaped and cross-shaped are combined. It is also possible to configure. A plurality of plate-like members can be configured by solid-phase bonding to each other.

In the present invention, in the rectifying body, a plate-like member constituting one side surface (herein referred to as a 'first plate-like member') is a plate-like member constituting the other side surface (herein referred to as a 'second plate-like member'). ) has a thickness compared to Here, "one side surface" denotes a side surface facing the electrode tip side when the rectifying body is inclined in the closed space when the lamp is turned on, and "the other side surface" refers to the side surface on the opposite side or the electrode tip side. Side refers to the side facing the opposite side. The first plate-like member and the second plate-like member respectively constitute these side surfaces.

Further, in the discharge lamp as another aspect of the present invention, in the rectifying body, the first plate-like member constituting one side surface is configured to have a smaller thermal expansion coefficient than the second plate-like member constituting the other side surface. .

In the discharge lamp that is another aspect of the present invention, the plate-shaped rectifying body is constituted by one member or a plurality of members. For example, an integrated member having an external shape such as a T shape or a cross shape by cutting or the like is also included as a plate-shaped rectifying body. And it has become a structure in which the difference between the amount of thermal expansion along one side surface and the amount of thermal expansion along the other side surface is suppressed in a state where the rectifier is inclined in the closed space at the time of lamp lighting.

ADVANTAGE OF THE INVENTION According to this invention, in an electrode, generation|occurrence|production of a crack etc. can be suppressed with respect to the rectifying body etc. which are arrange|positioned in the airtight space which encloses a heat transfer body.

[Fig. 1] It is a plan view of the discharge lamp of this embodiment.
[Fig. 2] A schematic cross-sectional view of an anode.
[Fig. 3] A schematic cross-sectional view taken along the line (III-III) in Fig. 2. [Fig.
[Fig. 4] It is a sectional view along the longitudinal direction of the rectifying body.
[Fig. 5] It is a diagram showing a state in which a rectifying body is inclined.
[Fig. 6] A schematic cross-sectional view of a rectifying body of a discharge lamp as a second embodiment.

The short arc type discharge lamp 10 is a large discharge lamp capable of outputting light with high luminance, and has a substantially spherical discharge tube (light emitting tube) 12 made of transparent quartz glass, and in the discharge tube 12, A pair of electrodes 20 and 30 made of tungsten are disposed opposite (coaxially). On both sides of the discharge tube 12, sealed tubes 13A and 13B made of quartz glass are formed integrally with the discharge tube 12 in continuous communication. In the discharge space DS in the discharge tube 12, rare gases such as mercury, halogen, and argon gas are sealed.

The electrode 20 serving as a cathode is supported by an electrode support rod 17A. In the sealing tube 13A, a glass tube (not shown) through which the electrode support rod 17A is inserted, a lead rod 15A connected to an external power supply, and a metal foil connecting the electrode support rod 17A and the lead rod 15A (16A) etc. are sealed. Mounting parts such as a glass tube (not shown) through which the electrode support bar 17B is inserted, a metal foil 16B, and a lead bar 15B are similarly sealed for the electrode 30 serving as the anode. Further, mouthpieces 19A and 19B are attached to the ends of the sealing tubes 13A and 13B, respectively.

When a voltage is applied to the pair of electrodes 20 and 30, an arc discharge occurs between the electrodes 20 and 30, and light is emitted toward the outside of the discharge tube 12. Here, power of 1 kW or more is applied. Light emitted from the discharge tube 12 is guided in a predetermined direction by a reflector (not shown).

2 is a schematic cross-sectional view of the electrode (anode) 30 . FIG. 3 is a schematic cross-sectional view taken along line III-III in FIG. 2 .

As shown in FIG. 2 , the anode 30 is composed of a cylindrical body portion 34 and a conical tip portion 32 having an electrode tip end face 30S. The body portion 34 has a structure in which the sealing lid 60 to which the electrode support rod 17B is attached is bonded, and here, the body portion 34 and the front end portion 32 excluding the sealing lid 60 are tungsten. It is molded from the same metal material as However, it is okay to mold it with a separate material. In addition, the airtight lid 60 may also be molded from the same metal material such as tungsten.

In the body portion 34, a cylindrical closed space 50 is formed coaxially with respect to the electrode axis E at the center of the inside. And in the closed space 50, the heat transfer body M is sealed. The heat transfer element M is made of a metal (for example, silver) having a lower melting point than that of the fuselage 34 and the sealing lid 60, and melts to become a liquid when the lamp is turned on. convection in In FIG. 2, the state in which the molten heat transfer body M is convective is shown. Here, the heat transfer body M is sealed so that the entire rectifying body 40 is submerged in a melted state (when the lamp is lit).

In the closed space 50, the rectifying body 40 is arrange|positioned. The rectifying element 40 is made of a high melting point metal (eg, tungsten, molybdenum, tantalum, etc.) or an alloy with a potassium additive, and has a function of promoting convection of the heat transfer element M (structure ) is constituted as a plate-like member having

Specifically, the rectifying body 40 does not have a size or shape that restricts convection in the vertical direction, left-right direction, and circumferential direction (whole circumference) of the sealed space 50 . A distance interval D1 between the upper end 40T of the rectifier 40 and the ceiling surface 50T of the closed space 50, a distance D2 between the lower end 40D and the bottom face 50B, and the closed space ( The distance interval D3 from the closed space side surface 50S along the vertical direction of the electrode axis of 50) is the flow of the heat transfer element M along the side surfaces 40S1 and 40S2 of the rectifying element 40, the rectifying element 40 The distance interval is ensured so that the flow of the heat transfer body M beyond the upper end 40T and the lower end 40D of ) occurs. In addition, the rectifying body 40 may be mounted in the closed space 50, and in this case, there is substantially no distance D2.

Further, the rectifying body 40 is arranged such that its central axis is along the vicinity of the electrode axis E. However, in the state in which the heat transfer body M is melting (lamp lighting state), the position of the rectifying body 40 is not fixed. In this regard, in FIG. 2, the rectifying body 40 is not illustrated by hatching for convenience.

4 is a cross-sectional view of the rectifying body 40 along the longitudinal direction. 5 is a diagram showing a state in which the rectifying body 40 is inclined. The structure of the rectifying body 40 in this embodiment is demonstrated using FIGS. 4 and 5. FIG. However, in FIG. 5, the inclination of the rectifying body 40 is exaggerated and drawn.

The rectangular rectifying body 40 overlaps two plate-like members 40A and 40B (hereinafter referred to as "first plate-like member" and "second plate-like member") and joins them (welding). , solid-state junction, etc.). The first and second plate-like members 40A and 40B are configured to have the same size (area), for example, the length L in the longitudinal direction is about 30 mm and the total thickness T is about 1 mm. It is possible. In addition, the first and second plate-like members 40A and 40B are made of the same material (here, tungsten).

On the other hand, the thicknesses T1 and T2 of the first and second plate-like members 40A and 40B are different, and the first plate-like member 40A is thicker than the second plate-like member 40B (T1> T2). Here, the thickness T1 of the first plate-like member 40A is set within the range of 1.1 to 2.0 of the thickness T2 of the second plate-like member.

In this way, by the rectifying body 40 having a structure in which the first and second plate-like members 40A and 40B having different thicknesses are laminated, as described below, in the case where the rectifying body is tilted when the lamp is turned on. The generation of cracks in (40) can be suppressed.

During lamp lighting, when the rectifier 40 inclines the side surface 40S1 of the first plate-like member 40A toward the tip side of the electrode where the temperature is relatively high, the first plate-like member 40A moves to the closed space. Since it is close to the bottom face 50B side of the 50, the amount of heat received is large compared to the second plate-like member 40B close to the ceiling face 50T of the sealed space 50. If it is considered that the temperature of the entire rectifying body 40 rises, a temperature difference occurs between the first plate-like member 40A and the second plate-like member 40B.

However, the heat capacity between the first plate-like member 40A and the second plate-like member 40B of the rectifying body 40 differs due to the difference between the thicknesses T1 and T2. Therefore, the amount by which the first plate-like member 40A increases along the side surface 40S1 (longitudinal direction) due to thermal expansion (hereinafter, the amount of thermal expansion) increases along the side surface 40S2 of the second plate-like member 40B. It is approximately equal to the amount of thermal expansion. Alternatively, the difference in thermal expansion amount is suppressed. This is recognized regardless of the joining method between the first plate-like member 40A and the second plate-like member 40B.

Therefore, when the rectifier 40 is tilted, the rectifier 40 is deformed to be bent due to the difference between the amount of thermal expansion along the side surface of the electrode tip side and the amount of thermal expansion along the side surface of the electrode support bar, thereby suppressing the generation of cracks. can do. As a result, the rectifier 40 exhibits its function until the end of the lamp life, and the lamp temperature can be suppressed.

In addition, when the rectifying body 40 is inclined, the relatively heavy first plate-like member 40A is inclined towards the electrode tip side, but the thickness of the second plate-like member 40B of the rectifying body 40 is ensured so as to be inclined ( T2) may be configured to be thin on the ceiling surface side of the closed space 50.

Next, a discharge lamp as a second embodiment will be described with reference to FIG. 6 . In the second embodiment, a rectifying body is formed by laminating materials having different thermal expansion coefficients.

6 is a schematic cross-sectional view of a rectifying body of a discharge lamp that is a second embodiment. The rectifying body 240 has a structure in which a first plate-like member 240A and a second plate-like member 240B are overlapped and bonded. The thicknesses T1 and T2 of the first plate-like member 240A and the second plate-like member 240B are the same, and the lengths L along the side are also the same.

On the other hand, the first plate-like member 240A is made of a material different from that of the second plate-like member 240B and is made of a material having a smaller coefficient of thermal expansion than that of the second plate-like member 240B. For example, the first plate-like member 240A is made of tungsten and the second plate-like member 240B is made of molybdenum. Alternatively, the first plate-like member 240A may be made of tantalum, and the second plate-like member 240B may be made of titanium. When the rectifying body 240 is tilted, the first plate-like member 240A is tilted toward the tip of the electrode.

Thus, by configuring the rectifying body 240 with the first plate-like member 240A and the second plate-like member 240B having different coefficients of thermal expansion, the same effect as in the first embodiment can be obtained. Incidentally, even if the rectifying body 240 is inclined, the arrangement of the rectifying body 240 or the weight of the constituent material may be adjusted so that the first plate-like member 240A is inclined toward the tip side of the electrode.

In the first and second embodiments, the rectifying body is constituted by two plate-like members, but the rectifying body may be constituted by overlapping three or four or more plate-like members. For example, in the case of the first embodiment, it may be configured in which plate-like members having different thicknesses are laminated, or the same thickness may be set for several plate-like members, and the thickness may be gradually reduced.

Further, in the case of the second embodiment, the plate-like members may be laminated so that the thermal expansion coefficient increases in stages, or several plate-like members having the same thermal expansion coefficient may be stacked to increase the thermal expansion coefficient in stages. Regarding a rectifying body that becomes inclined while the lamp is on, the amount of thermal expansion along one of the opposing side surfaces (surfaces) along the side surface is substantially the same as the amount of thermal expansion along the side surface on the other side surface, or Alternatively, it may be configured so that the difference in thermal expansion amount is suppressed.

As mentioned above, although the rectifying body which promotes the convection of the heat exchanger M was demonstrated, the member which restricts the flow partially, for example, which restricts the flow in the circumferential direction of the heat exchanger M, is used as a rectifying body. It is free to configure For example, as a plate-shaped rectifying body, it is possible to configure a cross-section cross-section or a T-shaped rectifying body. Then, it may be configured so that the difference in thermal expansion amount with respect to the other part is suppressed by adjusting the thickness and thermal expansion coefficient of the part inclined toward the tip side of the electrode where the temperature becomes relatively high.

For example, in the case of constructing a T-shaped rectifier in cross section, the first plate-like member corresponding to the T-shaped vertical bar portion and the second plate-like member corresponding to the T-shaped horizontal bar portion are constituted. In this case, the first plate-like member constitutes one side surface of the cross-sectional T-shaped rectifying body, and the second plate-like member constitutes one side surface of the cross-sectional T-shaped rectifying body.

Then, in consideration of the state in which the rectifier is inclined in the closed space, the first plate-like member is made thicker than the second plate-like member, or the coefficient of thermal expansion of the first plate-like member is made smaller than the coefficient of thermal expansion of the second plate-like member. It is possible. Incidentally, with respect to the rectifying body having a T-shaped cross section, it is possible to have a structure in which the first plate-like member and the second plate-like member are fitted to each other or a structure in which they are joined, but while changing the thickness by cutting or the like, It is also possible to set it as cross-sectional shape or T-shape.

10: discharge lamp
30: electrode (anode)
40: rectifier
40A: first plate-like member
40B: second plate member
50: confined space

Claims (5)

discharge tube,
A pair of electrodes disposed opposite to each other in the discharge tube
equipped with,
In at least one electrode, an airtight space in which a heat transfer body that melts when a lamp is turned on is sealed, and a plate-shaped rectifying body is disposed in the airtight space,
A discharge lamp characterized in that in the rectifying body, a first plate-like member constituting one side surface is thicker than a second plate-like member constituting the other side surface. discharge tube,
A pair of electrodes disposed opposite to each other in the discharge tube
equipped with,
In at least one electrode, an airtight space in which a heat transfer body that melts when a lamp is turned on is sealed, and a plate-shaped rectifying body is disposed in the airtight space,
A discharge lamp characterized in that in the rectifying body, a first plate-like member constituting one side surface has a smaller thermal expansion coefficient than a second plate-like member constituting the other side surface. According to claim 1 or 2,
The discharge lamp characterized in that the rectifying body is formed by laminating a plurality of plate-like members. According to claim 3,
The discharge lamp characterized in that the plurality of plate-like members are solid-phase bonded to each other. discharge tube,
A pair of electrodes disposed opposite to each other in the discharge tube
equipped with,
In at least one electrode, an airtight space in which a heat transfer body that melts when a lamp is turned on is sealed, and a plate-shaped rectifying body is disposed in the airtight space,
A discharge lamp characterized in that, when the lamp is turned on, a difference between an amount of thermal expansion along one side surface and an amount of thermal expansion along the other side surface is suppressed in a state where the rectifying body is inclined in the sealed space.

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