WO2011148681A1 - Discharge lamp, discharge lamp unit, and method of manufacturing thereof - Google Patents

Abstract

Disclosed is a configuration of a discharge lamp, wherein cracks at sealing sections caused by temperature rise in external leads are prevented from occurring. A method of manufacturing a discharge lamp is provided with: (A) a process for manufacturing electrode structures each of which is comprised of an electrode, a metal foil connected to the electrode, and an external lead connected to the metal foil; and (B) a process for arranging the electrodes within a light-emitting section, and sealing prescribed sections of the external leads with light-emitting tube sealing sections. Process (A) comprises a process, before process (B), for oxidizing the surface of sections corresponding to at least the prescribed sections of the external leads.

Description

Discharge lamp, discharge lamp unit, and manufacturing method thereof

The present invention generally relates to a discharge lamp, a discharge lamp unit, and a method for manufacturing the same, and more particularly to a configuration that prevents cracks in the arc tube sealing portion of the discharge lamp.

FIG. 4 shows a configuration of a general discharge lamp 4. The discharge lamp 4 includes an arc tube 20 and a pair of electrode structures 40. The arc tube 20 includes a light emitting portion 21 and a sealing portion 22, and the electrode structure 40 includes an electrode 41, a metal foil 42 connected to the electrode 41, and an external lead 43 connected to the metal foil 42. The arc tube 20 is made of quartz glass, the electrode 41 is made of tungsten, the metal foil 42 and the external lead 43 are made of molybdenum.

In manufacturing a discharge lamp, first, a pair of electrode structures 40 are manufactured. Then, the metal foil side portion of the electrode 41, the metal foil 42, and the metal foil side portion of the external lead 43 are sealed with the sealing portion 22 in a state where the tip portion of the electrode 41 is disposed in the light emitting portion 21. By this sealing, gas of the light emitting unit 21 and airtightness of the light emitting substance are formed.

Here, the upper limit of the use temperature of the joint between the external lead 43 and the metal foil 42 is about 350 ° C. When this temperature is exceeded, the external lead 43 is oxidized at the close contact portion between the external lead 43 (having a smaller heat capacity than the metal foil 42) and the sealing portion tip 22a, and the tip of the sealing portion from the oxide layer formed on the surface The stress applied to the portion 22a may cause a crack in the sealing portion distal end portion 22a, thereby causing the sealing portion 22 to be damaged. For this reason, the said upper limit use temperature is about 350 degreeC.

Various measures have been disclosed to prevent cracks at the tip of the sealing portion. Patent Documents 1 to 6 aim to prevent oxidation of external leads.
Patent Document 1 discloses a configuration in which oxidation is prevented by forming a two-layer protective film on an external lead.
Patent Document 2 discloses a configuration in which oxidation is prevented by forming a two-layer protective film on the surface of a metal foil and an external lead.
Patent Document 3 discloses a configuration in which a coating film is formed on the entire surface of the metal foil to reduce the influence of stress on the sealing portion.
Patent Document 4 discloses a configuration in which irregularities are formed on the surface of the sealing portion, and a heat sink is provided at the tip of the sealing portion to suppress the temperature rise (that is, oxidation) of the external leads.
Patent Document 5 discloses a configuration in which a slit extending in a direction perpendicular to the longitudinal direction of the sealing portion is provided at the front end portion of the sealing portion to suppress a temperature rise (that is, oxidation) in the vicinity of the external lead.
Patent Document 6 discloses a configuration in which an external lead is filled with a filler to prevent oxidation.

Patent Documents 7 and 8 disclose crack prevention measures based on the assumption that external leads are oxidized.
Patent Document 7 discloses a configuration in which cracks are formed in advance around the external leads and the metal foil in the sealing portion to reduce the stress in the sealing portion.
Patent Document 8 discloses a configuration in which the external lead and the periphery of the metal foil in the sealing portion are used as non-sealing portions so that the external leads and the sealing portion do not interfere with each other.

JP 2005-228665 A JP 2006-501618 A Japanese Patent No. 3687582 JP 2004-227984 A Japanese Patent Laid-Open No. 2007-200230 JP 2008-66308 A JP 2006-216311 A JP 2006-294269 A

However, as described in Patent Documents 1-3 above, the configuration in which the coating is provided on the external lead or the like has a problem that the productivity is poor because the number of work steps for producing the electrode structure increases. In addition, Patent Document 4 also has a problem in that productivity is deteriorated due to an increase in work steps for manufacturing the arc tube, and the temperature of the light emitting section is also lowered.
As in Patent Document 5, when a slit is formed in the sealing portion, there is a problem that mechanical strength is lowered.
As in Patent Document 6, the configuration in which the filler is injected requires steps such as injection and drying, which has a problem of poor productivity.
In addition, as in Patent Documents 7 and 8, the configuration in which cracks, spaces, and the like are previously provided in the sealing portion has a problem in that the configuration for securing the sealing capability of the sealing portion is complicated and productivity is deteriorated. is there.

Therefore, an object of the present invention is to provide a crack prevention measure with a reliable and simple configuration and mode.

The first aspect of the present invention is a method for manufacturing a discharge lamp, wherein (A) a step of producing an electrode structure comprising an electrode, a metal foil connected to the electrode, and an external lead connected to the metal foil, and (B) including a step of disposing an electrode in the light-emitting portion and sealing a predetermined portion of the external lead with the arc tube sealing portion, and the step (A) includes at least a predetermined portion of the external lead before the step (B). It is a manufacturing method including the process of oxidizing the surface of the part corresponding to this.

A second aspect of the present invention is a discharge lamp, wherein an electrode structure (10) comprising an electrode, a metal foil connected to the electrode, and an external lead connected to the metal foil, and the electrode are disposed in the light emitting portion. A discharge lamp having an arc tube (20) for sealing a predetermined portion of the external lead with a sealing portion, and the external lead having an oxidized surface portion (13a) whose surface is previously oxidized at a portion corresponding to the predetermined portion. It is.

In the first and second aspects, the external lead is preferably oxidized by laser irradiation.

The third aspect of the present invention is a discharge lamp unit including the discharge lamp of the second aspect and a reflecting mirror having the discharge lamp mounted in the concave surface.

It is a figure which shows the discharge lamp of this invention. It is a figure explaining the manufacturing method of the discharge lamp of this invention. It is a figure which shows the discharge lamp unit of this invention. It is a figure which shows the conventional discharge lamp.

FIG. 1 shows the configuration of the discharge lamp 1 of the present invention. The discharge lamp 1 includes an arc tube 20 and a pair of electrode structures 10, and the arc tube 20 is the same as that shown in FIG. The electrode structure 10 includes an electrode 11, a metal foil 12 connected to the electrode 11, and an external lead 13 connected to the metal foil 12. The electrode 11 is made of tungsten (melting point: 3422 degrees), and the metal foil 12 and the external lead 13 are made of molybdenum (melting point: 2623 degrees).

The discharge lamp of the present embodiment is assumed to be a projector ultra-high pressure discharge lamp, but the disclosed technology is a general ultra-high pressure discharge lamp, high-pressure discharge lamp, low-pressure mercury lamp, halogen lamp having similar components. Etc.

The electrode structure 10 in FIG. 1 and the electrode structure 40 in FIG. 4 have different external leads. The external lead 13 of the present embodiment has an oxidized surface portion 13 a that has been oxidized in the vicinity of the joint portion with the metal foil 12. The presence of the oxidized surface portion 13a prevents the portion and the inside thereof from being further oxidized during lamp operation (that is, at a high temperature). As a result, a new oxide film is not formed even at a high temperature, and the oxide layer formed on the surface of the external lead during the lighting of the lamp, as in the prior art, applies stress to the tip 22a of the sealing portion to cause cracks. Can be prevented.

In manufacturing a discharge lamp, first, a pair of electrode structures 10 is manufactured. Here, as described above, the surface of a predetermined portion of the external lead 13 (near the joint with the metal foil 12) is oxidized in advance to form the oxidized surface portion 13a. This predetermined portion includes at least a range sealed by the sealing portion distal end portion 22a.

In this oxidation step, specifically, as shown in FIG. 2, a predetermined portion of the electrode structure 10 is irradiated with laser from the laser irradiation device 30 in the atmosphere to form an oxidized surface portion 13a. The length (L) of the oxidized surface portion 13a is about 3 mm to 5 mm, but this length may vary depending on the use of the lamp. Further, not only the external lead 13 but also the metal foil 12 may be oxidized.

As described above, this oxidation step is preferably performed by laser irradiation. The first advantage of laser irradiation is that there is little variation in oxidation. That is, since positioning of laser irradiation is easy, it is possible to oxidize only a desired place, and it is possible to suppress positional variation in oxidation at that time. Secondly, embrittlement of the external lead 13 can be prevented. That is, since oxidation can be performed in a very short time, polycrystallization inside the external lead can be suppressed, thereby preventing embrittlement of the external lead. Third, since the irradiation intensity of the laser can be set, the oxidation depth can be easily controlled. That is, heating up to the inside of the external lead can be prevented.

In FIG. 2, the oxidation process is shown after the external lead 13 is connected to the metal foil 12. However, after the oxidation in the state of the single external lead before the connection to the metal foil 12, the oxidation process is performed. You may make it connect to the metal foil 12. FIG. In any case, it is necessary to perform the oxidation step before the arc tube 20 sealing step.

Thereafter, the metal foil side portion of the electrode 11, the metal foil 12, and the oxidized surface 13 a of the external lead 13 are sealed with the sealing portion 22 in a state where the tip portion of the electrode 11 is disposed on the light emitting portion 21. By this sealing, gas of the light emitting portion 21 and airtightness of the luminescent material are formed, and the discharge lamp 1 is completed.

From the above, it is possible to reliably prevent cracks in the arc tube sealing portion without losing productivity by simply adding a simple process of laser irradiation to the external lead.
In addition, since oxidation due to the temperature rise of the external lead is prevented, the upper limit temperature of use of the joint portion of the external lead with the metal foil can be made higher than the conventional 350 ° C., and the degree of freedom in lamp design is increased. .

Furthermore, a discharge lamp unit is completed by attaching a reflecting mirror to the discharge lamp 1 described above. As shown in FIG. 3, the discharge lamp unit 3 includes the above-described discharge lamp 1 and a reflecting mirror 2 in which the discharge lamp 1 is attached to the concave surface portion.
Since the discharge lamp unit 3 includes a discharge lamp in which crack prevention measures are taken, the discharge lamp unit 3 can be a highly reliable discharge lamp unit. In addition, since a discharge lamp having a high degree of freedom in designing the temperature around the arc tube sealing portion is attached, the degree of freedom in designing the configuration of the attachment portion of the discharge lamp and the reflecting mirror (heat radiation structure, bonding method) is also increased. .

1. 1. Discharge lamp Reflector 3. Discharge lamp unit 10. Electrode structure 11. Electrode 12. Metal foil 13. External lead 13a. Oxidized surface
20. Arc tube 21. Light emitting unit 22. Sealing part 22a. Seal portion tip 30. Laser irradiation device

Claims (5)

A method for manufacturing a discharge lamp, comprising:
(A) producing an electrode structure comprising an electrode, a metal foil connected to the electrode, and an external lead connected to the metal foil; and (B) arranging the electrode in a light emitting part of an arc tube, and A step of sealing a predetermined portion of the external lead with a sealing portion of the arc tube,
The manufacturing method, wherein the step (A) includes a step of oxidizing at least a surface of a portion corresponding to the predetermined portion of the external lead before the step (B). 2. The manufacturing method according to claim 1, wherein the oxidizing step is performed by laser irradiation. A discharge lamp,
An electrode structure comprising an electrode, a metal foil connected to the electrode and an external lead connected to the metal foil, and the electrode is disposed in a light emitting portion, and a predetermined portion of the external lead is sealed with a sealing portion With arc tube,
A discharge lamp in which the external lead has an oxidized surface portion whose surface is previously oxidized at a portion corresponding to the predetermined portion. 4. The discharge lamp according to claim 3, wherein the oxidized surface portion is oxidized by laser irradiation. A discharge lamp unit comprising: the discharge lamp according to claim 3; and a reflecting mirror having the discharge lamp attached to a concave surface portion.

Images