JP2006114240A - Short arc type extra high pressure discharge lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a discharge lamp having a superior pressure resistance structure. <P>SOLUTION: The discharge lamp is consisting of a light emitting part 2 in which a pair of electrodes 4, 5 are arranged opposed to each other and mercury of 0.15 mg/mm<SP>3</SP>or more is sealed and a sealing part 2 of which on both sides extended pre-sealing bodies 6 are embedded. The pre-sealing body 6 has a mount of the electrode 4 and a metal foil 7, and a cavity 10 is formed at the welding position of the electrode 4 and the metal foil 7. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a short arc type discharge lamp in which the mercury vapor pressure during lighting is 150 atmospheres or more, and in particular, the back of a projector device such as a liquid crystal display device or a DLP (digital light processor) using a DMD (digital mirror device). The present invention relates to a short arc type discharge lamp used as a light.

  Projection-type projector devices are required to illuminate images with a uniform and sufficient color rendering on a rectangular screen. For this reason, a metal halide lamp in which mercury or a metal halide is enclosed is used as the light source. I have been.

Recently, instead of a metal halide lamp, a discharge lamp having a high mercury vapor pressure, for example, 150 atm has been proposed. By increasing the mercury vapor pressure, the spread of the arc is suppressed (narrowed) and the light output is further improved.
This discharge lamp is disclosed in, for example, JP-A-2-148561 and JP-A-6-52830.

In such a discharge lamp having a high pressure at the time of lighting, the sealing structure of the electrode and the metal foil is more important. For this reason, for example, Japanese Patent Application Laid-Open No. 2000-311610 proposes a technique using pre-seal glass. In this technology, a metal foil, electrode, and external lead integrated mount is sealed in advance with pre-seal glass, and then the discharge lamp is sealed in the sealing process by fusing the inner surface of the sealing part and the outer surface of the pre-seal glass. To be integrated.
This technique can achieve a sealing structure with an excellent breakdown voltage because the pre-seal is fused compared to sealing the mount in the discharge lamp sealing process.
However, the sealing structure using the pre-seal may be able to withstand a gas pressure of about several tens of atmospheres at the most, but it cannot be said that the gas pressure is as high as 150 atmospheres or more.
Japanese Patent Laid-Open No. 2-148561 JP-A-6-52830 JP 2000-311610 A

The problem to be solved by the present invention is to provide a sealing structure with a higher withstand pressure in a short arc type discharge lamp in which mercury of 0.15 mg / mm ³ or more is enclosed and has a vapor pressure at the time of lighting of 150 atmospheres or more. That is.

In order to solve the above-mentioned problems, a short arc type ultra-high pressure discharge lamp according to the present invention comprises a light emitting part in which a pair of electrodes are opposed to each other and 0.15 mg / mm ³ or more of mercury is enclosed, and both sides thereof It consists of the sealing part which embedded the pre-seal body extended in this.
The pre-seal body has a mount of the electrode and metal foil, and a cavity is formed at a welding position of the electrode and metal foil.

  By adopting the above configuration, a high pressure is accumulated in the cavity of the pre-seal body through a minute gap formed by the electrode and the metal foil, thereby improving the adhesion between the metal foil and the quartz glass.

FIG. 1 shows the overall configuration of a short arc type ultra-high pressure discharge lamp (hereinafter also simply referred to as “discharge lamp”) according to the present invention.
In the discharge lamp 1, a substantially spherical light emitting portion 2 formed by a discharge vessel made of quartz glass, and a sealing portion 3 are formed so as to extend from both ends of the light emitting portion 2. The cathode 4 and the anode 5 are disposed opposite to each other inside the light emitting unit 2. A pre-seal body 6 is embedded in the sealing portion 3. In the pre-seal body 6, a cathode 4 or an anode 5, a metal foil 7, and an external lead 8 mount are embedded. A cavity 10 to be described later is formed in the pre-seal body 6.
The cathode 6 and the anode 7 may be expressed by distinguishing the rod-shaped portion joined to the metal foil. However, in the present invention, the term including the rod-shaped portion is used unless otherwise specified.

The light emitting unit 2 is filled with mercury, rare gas, and halogen gas.
Mercury is used to obtain a necessary visible light wavelength, for example, radiated light having a wavelength of 360 to 780 nm, and 0.15 mg / mm ³ or more is enclosed. Although the amount of sealing varies depending on the temperature condition, the vapor pressure becomes extremely high at 150 atm or higher when the lamp is turned on. Also, by enclosing more mercury, it is possible to make a discharge lamp with a high mercury vapor pressure of 200 atm or higher and 300 atm or higher when the lamp is turned on. Can be realized.
As the rare gas, for example, argon gas is sealed at about 13 kPa, and the lighting startability is improved.
As for halogen, iodine, bromine, chlorine and the like are enclosed in the form of a compound with mercury or other metals. The amount of enclosed halogen can be selected from the range of, for example, 10 ⁻⁶ to 10 ⁻² μmol / mm ³ , and its function is to extend the life using the halogen cycle. As described above, it is considered that such a halogen having a high internal pressure has an effect of preventing breakage of the discharge vessel and prevention of devitrification.

As an example of the numerical value of such a discharge lamp, for example, the outer diameter of the light emitting portion is selected from the range of φ6.0 to 15.0 mm, and the distance between the electrodes is, for example, 9.5 mm and 0.5 to 2.0 mm. is selected from a range with for example 1.5 mm, the arc tube volume is 75 mm ^3, for example, selected from a range of 40~200mm ^3. The lighting conditions are, for example, a tube wall load of 1.5 W / mm ² , a rated voltage of 80 V, and a rated power of 150 W.
The discharge lamp is mounted on a presentation device such as a projector device or an overhead projector, and provides emitted light having good color rendering properties.

  FIG. 2 shows a pre-seal body of a discharge lamp according to the present invention, wherein (a) shows a pre-seal body without a groove 10 ′ for convenience of explanation, and (b) and (c) show a discharge lamp of the present invention with a groove 10 ′. Represents a pre-seal body. (B) and (c) show the same structure as different cross-sectional views. (B) is a cross-sectional view taken along the line B-B in (c), and (c) is (b). ) Shows a cross-sectional view taken along the line AA of FIG. Further, since the cavity 10 is not formed in the state of the pre-seal body, the expression “groove 10 ′” is used, but this groove 10 ′ becomes the cavity 10 through the sealing process.

FIG. 3 is a drawing for explaining a discharge lamp according to the present invention, and shows an enlarged view of a pre-seal body for explaining the occurrence of cracks in the case of not having a cavity (groove) according to the present invention.
(A) shows the structure of the electrode side tip of the pre-seal body without a groove, (b) shows a cross-sectional view taken along the line CC in (a), and (c) shows a cross-sectional view taken along the line DD in (a). .
In the pre-seal body 6, a minimal space X is formed at the electrode end portion at the joint between the electrode 4 and the metal foil 7. Further, as shown in (b), there is a minimal space X2 also in the electrode 4 and the pre-seal body 6, and as shown in (c), there is a minimal space X3 between the electrode 4, the pre-seal body 6 and the metal foil 7. Exists. These spaces are inevitably formed because it is impossible to completely contact them. The high pressure in the discharge space during lamp lighting strongly affects the minimal space X at the end of the electrode, and the wedge-shaped contact X1 and the like are the starting points of crack generation.

FIG. 4 shows a pre-seal body of a discharge lamp according to the present invention, which is compared with FIG.
As shown in the figure, since the groove 10 'is formed at the end of the electrode 4 where the electrode 4 and the metal foil 7 are joined, wedge-shaped contacts X4 and X5 tapering inward are formed. The Therefore, the wedge-shaped contact X1 tapering outward as shown in FIG. 3 is not formed.
Here, the groove 10 ′ is formed by a grinder after the pre-seal body 6 is formed.
The groove 10 'may be formed so as to leave the end of the metal foil 4 as shown in (a), but considering the simplification of the manufacturing process, the tip 4 of the metal foil 4 as shown in (b). 'May be cut off.
As described above, the groove 10 'exists as a cavity 10 when it becomes a discharge lamp. In the cavity 10, a pressure equivalent to the pressure generated in the discharge space, for example, 150 atm or more is generated. This high pressure acts to press the metal foil 7 against the quartz glass (pre-seal body), and thus has an effect of improving the adhesion between them. In the case of the structure (a), it also acts in the direction in which the electrode 4 and the metal foil 7 are in close contact. On the other hand, as shown in FIG. 3, there is no wedge-shaped contact X1 that tapers outward, so that no crack is generated from the contact X1.

  The groove 10 ′ must include at least the end of the electrode 4. This is to prevent the generation of the cavity X and the wedge-shaped contact X1 shown in FIG. The width L10 of the groove 10 'is selected from the range of 0.2 to 1.0 mm and is, for example, 0.4 mm. If the width L10 is too large, as indicated by 100 in FIG. 4B, the quartz glass outside the pre-seal body will fall into the groove 10 ′ in the sealing step, and a wedge-shaped contact may be formed. .

FIG. 5 shows another embodiment of the pre-seal body according to the present invention.
The groove 10 ′ is not formed until the metal foil 7 is reached (until the surface of the metal foil is exposed), but is formed so as to leave quartz glass on the surface of the metal foil 7. In this case, since the metal foil 7 is sandwiched between quartz glasses and the high pressure of the cavity acts, the adhesion can be further improved.
In this case, even if the gap X or the wedge-shaped contact X1 shown in FIG. 3A is generated at the end of the electrode 4, the force in the direction shown by the arrow acts, so that the generation of cracks can be prevented.
The supply of high pressure to the cavity 10 can be achieved by a minimal space formed around the electrode 4.

As a numerical example, the pre-seal body is selected from a range of φ1.9 to 3.0 mm, for example, φ2.5 mm, and the total length of the metal foil is selected from a range of 8.0 to 30.0 mm, for example, 11.0 mm. And the width direction is selected from the range of 1.0 to 4.0 mm, for example, 1.5 mm. The electrode diameter is selected from a range of φ0.3 to 1.0 mm, for example, φ1.0 mm. Moreover, the thickness of metal foil is chosen from the range of 10-40 micrometers, for example, is 20 micrometers.
In the case of the groove structure shown in FIG. 5, the thickness of the quartz glass remaining on the surface of the metal foil is selected from the range of 0.05 to 1.0 mm, for example 0.3 mm.

FIG. 6 shows another embodiment of the metal foil.
As shown to (a), metal foil can employ | adopt cross-sectional omega shape, without being limited to flat form. In this case, the electrode or the external lead can be adapted to the groove, and undesired eccentricity of the electrode or the external lead can be prevented.
As shown in (b), the metal foil is not limited to a perfect rectangular shape, and the joint with the electrode can be made narrow. In this case, the gap X3 shown in FIG. 3C can be reduced.
It is also possible to employ a combination of the omega shape shown in (a) and the narrow tip shape shown in (b).

  As described above, the discharge lamp according to the present invention has a pre-seal body including a mount of an electrode and a metal foil, and a cavity is formed at a joint portion between the electrode and the metal foil. By utilizing this, the adhesion of the pre-seal and the pressure-resistant structure can be improved.

1 shows an overall view of a short arc type ultra-high pressure discharge lamp of the present invention. The metal foil, electrode, and external lead of the short arc type ultra high pressure discharge lamp of the present invention are shown. 1 shows a structure for explaining the present invention. The elements on larger scale of the pre seal body of the present invention are shown. The elements on larger scale of the pre seal body of the present invention are shown. The other form of the metal foil of this invention is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Discharge lamp 2 Light emission part 3 Sealing part 4 Cathode 5 Anode 6 Pre seal body 7 Metal foil 8 External lead 10 Cavity 10 'Groove

Claims (1)

A short arc type ultra-high pressure discharge comprising a light emitting part in which a pair of electrodes are arranged facing each other and 0.15 mg / mm ³ or more of mercury is sealed, and a sealing part in which a pre-seal body extending on both sides is embedded. In the ramp,
The pre-seal body has a mount of the electrode and metal foil,
A short arc type ultra-high pressure discharge lamp characterized in that a cavity is formed at the joining position of the electrode and metal foil.

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