JP2011154863A - High-pressure discharge lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide, in a high-pressure discharge lamp in which a metal foil within a sealed tube is constituted of a broad body portion and a narrow portion at the front end thereof, a recessed groove is formed in the metal foil, and an electrode shaft and an external lead are fitted and connected to the recessed groove, a lamp structure capable of eliminating the warpage of the metal foil at a middle flat portion thereof by residual distortions in the processing of the recessed groove. <P>SOLUTION: The metal foil in the inside of the sealed tube has a backward recessed groove formed from an end of the broad body portion, a forward recessed groove formed extending from the narrow portion toward the body portion, and an opening formed at an intermediate flat portion between the recessed grooves. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a high-pressure discharge lamp, and more particularly to a high-pressure discharge lamp used for a backlight of a projection type projector device such as a liquid crystal display device or a digital light processor (DLP: registered trademark).

In a high-pressure discharge lamp used as a backlight of a projector device, it is required to illuminate an image with a uniform color rendering property with respect to a screen. Therefore, as a light source, a large amount of mercury, for example, There is a demand for a lamp that contains 0.15 mg / mm ³ or more and realizes a high mercury vapor pressure of 150 atm or more when lit.

In such a high-pressure discharge lamp, as described above, the mercury vapor pressure when the lamp is lit becomes extremely high, so that the high adhesion between the metal foil and the glass of the sealing tube for maintaining the high pressure is very high. It will be important. If this high adhesion is not realized, the metal foil peels off at the end of the sealing tube on the arc tube side (foil float), cracks may occur, and the lamp may eventually burst. .
At the same time, in this type of lamp, the distance between the electrodes is particularly small, for example, 1.5 mm. Therefore, even if the electrode axis is slightly shifted in the sealing process, the front end position of the electrode is greatly affected. The discharge distance will change greatly.
As described above, in the sealing portion of this type of high-pressure discharge lamp, it is required that the position of the electrode axis is securely arranged on the central axis of the arc tube while having pressure resistance.

By the way, in manufacturing such a discharge lamp, in the sealing process, a mount in which an electrode, a metal foil, and an external lead bar are integrated is inserted into a sealing tube material made of cylindrical quartz glass. A so-called shrink seal method is employed in which the outer periphery of the sealing tube is heated and melted and sealed while rotating the glass tube for sealing tube around its tube axis.
In such a lamp, in order to accurately position the electrode shaft described above, in Patent Document 1 (Patent No. 3570414), a concave groove is formed over the entire length of the metal foil, and the electrode shaft and the outside are formed in the groove. It has been proposed to place and seal the leads.

  FIG. 4 shows such a conventional high-pressure discharge lamp. A discharge vessel 1 is composed of an arc tube 2 and sealing tubes 3 provided at both ends of the arc tube 2. 4 are arranged facing each other. A metal foil 5 is embedded in each sealing tube 3, and an electrode shaft 6 of the electrode 4 and an external lead 7 are connected to both ends thereof.

FIG. 5 shows the metal foil 5, where (a) is a plan view of the entire metal foil, and (b) is a cross-sectional view taken along the lines AA and BB of (a). The metal foil 5 is composed of a wide body portion 5a and a small width portion 5b continuously provided at the front end thereof, and a concave groove 8 is formed over the entire length thereof.
That is, in the small width portion 5b, the entire small width portion 5b has a curved surface shape as shown in the AA sectional view, and the wide main body portion 5a has an omega shape in cross section as shown in the BB sectional view ( Ω shape). The electrode shaft 6 is disposed in the narrow width portion 5 b of the metal foil 5, and the external lead 7 is disposed in the concave groove 8 of the wide body portion 5 a and sealed in the sealing tube 3.

By using such a metal foil 5, it is possible to prevent a gap from being generated in a welded portion between the metal foil 5 and the electrode shaft 6, and the electrode shaft 6 and the external lead 7 are not eccentric from each other. Thus, it can be connected to each end of the metal foil 5.
However, in the metal foil having the above structure, it is possible to sufficiently suppress the occurrence of voids in the welded portion between the metal foil and the electrode shaft, but the electrode shaft and the external lead connected to each end in the longitudinal direction of the metal foil. Another problem has arisen when trying to prevent the eccentricity of and from being eccentric.

That is, in the operation of shrink-sealing the electrode mount composed of the electrode, the metal foil, and the external lead into the sealing tube, the electrode axis of the electrode in the electrode mount inserted into the sealing tube and the central axis of each of the external leads Are not necessarily inserted in a matched state, and are often arranged in an inclined state with respect to the central axis of the sealing tube. In such a case, the center axis of each of the electrode shaft and the external lead is not on the same axis, and they are in an eccentric state.
If the electrode shaft and the external lead are forcibly arranged on the same shaft during shrink sealing in an attempt to eliminate the eccentric state of the electrode shaft and the external lead, the wide body portion of the metal foil is Since the mechanical strength is strengthened by forming an omega (Ω) -shaped cross section, a narrow portion of the metal foil having a relatively weak mechanical strength is bent. As a result, the metal foil and the quartz are bent. In some cases, the adhesion strength with the glass is lowered, and a crack is generated in the sealing portion.

In order to solve such a problem, in Patent Document 2 (Japanese Patent Application Laid-Open No. 2007-329044), a flat portion that does not form a groove is formed at a substantially intermediate position of the wide body portion of the metal foil, and the above-mentioned narrow portion is formed. A structure has been proposed in which bending is avoided to prevent eccentricity between the electrode shaft and the external lead.
This structure is shown in FIG. 6, (A) is a plan view, (B) is an AA sectional view, a BB sectional view, and a CC sectional view of (A), (C ) Is a longitudinal sectional view of (A).
As shown in FIG. 6 (A), concave grooves 8 a and 8 b are formed at both ends of the metal foil 5. That is, a concave groove 8a is formed from the rear end of the body portion 5a of the metal foil 5 and a concave groove 8b is formed from the small width portion 5b at the front end to the wide main body portion 5, respectively, as shown in FIGS. 6 (B) and 6 (C). As shown in the figure, the depth of the groove gradually decreases, and a flat portion 9 in which no groove is formed is formed in the middle portion of the main body portion 5a of the metal foil 5. The electrode shaft 6 and the external lead 7 are respectively disposed in the concave grooves 8a and 8b as in the case of FIG.

  According to the prior art, since the concave portion is not formed in the flat portion 9, the mechanical strength is weaker than the portion where the concave groove 8 of the wide body portion 5a is formed. It is expected that the situation where stress concentrates on 5b and bends at the relevant part, and the electrode shaft and the external lead are eccentric can be solved.

However, the metal foil 5 shown in the prior art is for forming a groove on the wide body portion 5a and the small width portion 5b by pressing a flat foil-like metal foil. Sometimes, as shown in FIG. 7, the metal foil 5 may be warped 10 at the intermediate flat portion 9 due to residual strain.
When the metal foil is warped, the electrode shaft and the external lead are naturally decentered, and the metal foil contacts the inner wall of the sealing tube when the electrode mount is inserted into the sealing tube made of quartz glass. There is a problem that the eccentricity of the electrode shaft and the external lead is further promoted.
Thus, in the prior art, since the intermediate flat portion is formed in the wide portion of the metal foil, the metal foil having the structure of Patent Document 1 described above is bent at the small width portion during shrink sealing. Although the problem of the eccentricity of the electrode and the external lead can be alleviated to some extent, the intermediate flat part may be warped separately from this, so the state where the electrode and the external lead are eccentric is completely eliminated. It was difficult to eliminate it.

Japanese Patent No. 3570414 JP 2007-329044 A

  The problem to be solved by the present invention is a high pressure formed by forming a concave groove in a metal foil composed of a wide main body portion and a small width portion connected thereto, and fitting an electrode shaft and an external lead into the concave groove. In the discharge lamp, the electrode and the external lead are connected to each end of the metal foil in the longitudinal direction while preventing bending at the small width portion and suppressing warping at the flat portion formed in the main body portion. It is to propose a lamp structure that can be arranged on the same axis without being decentered in a connected state.

  In order to solve the above problems, a high-pressure discharge lamp according to the present invention includes an arc tube in which a pair of electrodes are disposed to face each other, a sealing tube continuously provided at both ends of the arc tube, and an inside of the sealing tube. A metal foil embedded in the metal foil, the metal foil comprising a wide body portion and a small width portion connected to the front end thereof, the electrode axis of the electrode being connected to the small width portion of the metal foil, In the high pressure discharge lamp in which the lead is connected to the rear end of the wide main body portion, the metal foil has a front concave groove formed from the small width portion to the wide main body portion, and a rear concave groove from the rear end of the main body portion. The electrode shaft and the external lead are fitted in the both concave grooves, respectively, the intermediate flat portion located between the two concave grooves is formed in the main body portion, and the double concave portions are formed in the intermediate flat portion. An opening is formed between the grooves.

  Further, the opening is formed across the both concave grooves.

According to the high-pressure discharge lamp of the present invention, since the opening is formed in the intermediate flat portion between the grooves formed in the main body portion and the narrow portion of the metal foil, the residual when the groove is formed in the metal foil. Since the strain is released by the opening, the metal foil is not warped at the intermediate flat portion, and the electrode shaft and the external lead can be arranged on the same axis without decentering.
Then, the mechanical strength is partially weakened at the flat portion, and when the electrode mount is sealed in the sealing tube, the narrow portion of the metal foil is not bent, and the electrode shaft and the external lead are not bent. Kept on the same axis.
In addition, since the electrode shaft and the external lead are arranged in the front concave groove of the small width portion of the metal foil and the rear concave groove of the main body portion, respectively, the electrode shaft and the external lead are further kept on the same axis. No gap is generated between the electrode shaft connected to the portion and the metal foil.

Explanatory drawing of the metal foil in the high pressure discharge lamp of this invention. The manufacturing method of the metal foil of this invention. The other manufacturing method of the metal foil of this invention. 1 is an overall cross-sectional view of a conventional high-pressure discharge lamp. Explanatory drawing of a prior art example. Explanatory drawing of another prior art example. Explanatory drawing of the malfunction of the prior art example of FIG.

FIG. 1 shows a metal foil in a high-pressure discharge lamp of the present invention, (A) is a plan view, and (B) is a sectional view thereof.
The metal foil 5 is composed of a wide main body portion 5a and a small width portion 5b connected to the front end thereof, and a rear concave groove 8a is formed to a predetermined length from the rear end of the main body portion 5a. A front concave groove 8b having a predetermined length is formed from the small width portion 5b to the main body portion 5a.
The connecting manner of the electrode shaft and the external lead to these concave grooves 8a and 8b is the same as that shown in FIG. 4, and the electrode shaft 6 of the electrode 4 is disposed and connected to the front concave groove 8b, and the rear concave groove 8a. The external lead 7 is arranged in the case.

An intermediate flat portion 9 in which no groove is formed is formed between the both concave grooves 8a and 8b of the wide body portion 5a. The intermediate flat portion 9 has an opening 11 between the both concave grooves. It has been drilled.
The opening 11 may extend to the vicinity of the ends of the both concave grooves 8a and 8b, or may be formed so as to straddle both the concave grooves 8a and 8b.

The manufacturing method of the metal foil which concerns on this invention is demonstrated based on FIG. 2 and FIG.
In FIG. 2, the front end of the rectangular metal foil material 5 (A) is cut to form the front end narrow portion 5b (B). Next, the groove 8 is formed over the entire foil by pressing (C). And the opening part 11 is formed in the substantially intermediate part of the main-body part 5a by laser processing (D).
As a result, a rear concave groove 8a is formed in the main body portion 5a of the metal foil 5, a front concave groove 8b is formed from the small width portion 5b to the main body portion 5a, and a flat portion provided with an opening 11 in the middle thereof. 9 is formed.

Another method is shown in FIG.
In FIG. 3, the front end of the metal foil material 5 (A) is cut to form the front end narrow portion 5b (B). Subsequently, the opening part 11 is formed in the main-body part 5a (C). Then, the front concave groove 8b and the rear concave groove 8a are formed on the rear end of the main body portion 5a from the small width portion 5b to the main body portion 5a by pressing (D).
In addition, when employ | adopting this method, you may shape | mold the back ditch | groove 8a and the front ditch | groove 8b in the surface which is not the same surface of the metal foil 5, but each.

  In this specification, the front refers to the arc tube side or the electrode side with respect to the tube axis of the lamp, and the rear refers to the external end side of the external lead opposite to that.

  As described above, in the present invention, by providing an opening in the intermediate flat portion of the main body portion of the metal foil composed of the narrow width portion and the wide main body portion, residual strain due to the formation of the concave groove on the metal foil is reduced. Since it is released at the opening, there is no warping of the metal foil due to residual strain at the part, and the electrode shaft and the external lead are arranged without being eccentric on the same time axis. .

DESCRIPTION OF SYMBOLS 1 Discharge vessel 2 Light emission tube 3 Sealing tube 4 Electrode 5 Metal foil 5a Wide body part 5b Narrow part 6 Electrode axis 7 External lead 8 Groove 8a Back groove 8b Front groove 9 Middle flat part 11 Opening

Claims (2)

An arc tube in which a pair of electrodes are opposed to each other, a sealing tube connected to both ends of the arc tube, and a metal foil embedded in the sealing tube, the metal foil having a wide body A high-pressure discharge lamp comprising a portion and a small width portion connected to the front end thereof, wherein the electrode axis of the electrode is connected to the small width portion of the metal foil, and the external lead is connected to the rear end of the wide body portion ,
The metal foil has a front groove formed from the small width part to the wide body part, and a rear groove formed from the rear end of the body part, and the electrode shaft and the external lead are fitted to the both groove grooves, respectively. And
The main body is formed with an intermediate flat portion located between the both concave grooves,
The high-pressure discharge lamp is characterized in that an opening is formed between the both concave grooves in the intermediate flat portion. The high-pressure discharge lamp according to claim 1, wherein the opening is formed across the both concave grooves.

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