JP2006318796A - High-pressure discharge lamp, electrode therefor, and lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode for a high-pressure discharge lamp by which mixing is suppressed with impurities such as impure gases when halide is enclosed in an airtight envelope, and to provide the high-pressure discharge lamp and a lighting device which are configured using the electrode. <P>SOLUTION: The electrode E for the high-pressure discharge lamp consists of an electrode base body 1 and the halide 2 as a discharge medium adhered in a film shape to an external surface on the tip side of the electrode base body 1. The electrode E for the high-pressure discharge lamp is mounted hermetically in the airtight envelope SE. After that, for example, the electrode E for the high-pressure discharge lamp is heated. Consequently, the halide 2 secedes from the electrode base body 1, and consequently the halide 2 is enclosed in the inside of the airtight envelope SE. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electrode for a high-pressure discharge lamp, and a high-pressure discharge lamp and an illumination device configured using the same.

When using a halide as a discharge medium in a high-pressure discharge lamp such as a metal halide lamp, it is generally solidified, formed into a required amount of pellets, and then introduced into an airtight container through a sealing part before sealing. (For example, refer to Patent Document 1).
Japanese Patent Laid-Open No. 10-154484

  In recent years, high-pressure discharge lamps such as metal halide lamps have been downsized and sealed. Along with this, the temperature of the arc tube is increased, and accordingly, defects such as blackening and cloudiness are likely to occur. In addition, the influence of slight blackening and cloudiness on the lamp characteristics is increasing. In particular, the factors that affect these are adsorption and contained gas in the in-pipe use member.

In the case where the halide of the discharge medium is used as one of the members used in the tube, the impure gas contained in the halide becomes a problem. That is, the halide is pelletized as described above and enclosed in the arc tube, but moisture and the like are easily occluded in the manufacturing process of the pellet. Then, when this pellet is sealed inside the high-pressure discharge lamp, it is dissociated and becomes impure gas such as O ₂ and H ₂ .

  An object of the present invention is to provide an electrode for a high-pressure discharge lamp that makes it difficult for impurities such as impure gas to be mixed when a halide is sealed in an airtight container, and a high-pressure discharge lamp and an illumination device configured using the electrode. And

    An electrode for a high-pressure discharge lamp according to the present invention is characterized by comprising: an electrode main body; and a discharge medium halide deposited in a film shape on the outer surface of the electrode main body on the tip end side.

  According to the present invention, the high pressure discharge lamp is deposited in the form of a film on the outer surface on the tip side of the electrode body by using means such as vapor deposition in an atmosphere in which impurities used as the encapsulating medium are difficult for impurities to enter. An electrode can be obtained.

  Therefore, if the electrode for a high-pressure discharge lamp of the present invention is sealed in an airtight container by, for example, a conventional method and incorporated in the high-pressure discharge lamp, the halide can be easily enclosed in the airtight container while preventing impurities from entering. Can do. If the high-pressure discharge lamp is heated by an appropriate means after enclosing the halide, the halide is detached from the electrode body and moves into the hermetic container, and can act as a discharge medium.

  As can be understood from the above, by manufacturing a high-pressure discharge lamp using the electrode for a high-pressure discharge lamp of the present invention, impurities such as impure gas are hardly mixed when a halide is sealed in an airtight container. The occurrence of problems such as turbidity and cloudiness can be effectively suppressed.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a front view of a high pressure discharge lamp according to an embodiment of the present invention sealed in a high pressure discharge lamp. In the figure, a high-pressure discharge lamp electrode E includes an electrode body 1 and a halide 2. In the figure, symbol SE is an airtight container, 11 is an enclosing portion, 11a is a discharge space, 12 is a sealing portion, and 12a is a sealing metal foil, all of which are part of a high-pressure discharge lamp.

  The electrode main body 1 includes an electrode shaft portion 1a and an electrode main portion 1b.

  The electrode shaft portion 1a is sealed on the base end side of the hermetic container 11 of the high-pressure discharge lamp as will be described later. Further, the electrode shaft portion 1a is designed to have a predetermined cross-sectional area in consideration of the lamp current at the start and at the time of stability. Furthermore, when the airtight container SE is made of quartz glass, the electrode shaft portion 1a is loosely supported in the long and narrow sealing portion 12, but a holding coil can be wound around the portion if desired. . The holding coil is wound around a portion supported by a sealing portion at an intermediate portion of the electrode shaft portion 1a with a thin wire such as tungsten at an appropriate pitch.

  The electrode main portion 1b is disposed on the tip end side of the electrode shaft portion 1a and serves as a starting point and an ending point of a discharge arc during lighting of the high-pressure discharge lamp. When a pair of high-pressure discharge lamp electrodes 1 are sealed in a high-pressure discharge lamp, as is well known, one of them becomes a cathode and the other becomes an anode. The structure of a pair of high-pressure discharge lamp electrodes is different.

  That is, in the case of AC lighting, the pair of high-pressure discharge lamp electrodes 1 has the same structure. In the case of direct current lighting, the structure differs between the cathode and the anode. A relatively small ion current flows into the cathode to emit electrons, and becomes the starting point of the discharge arc. For this reason, the electrode main part 1b of the cathode is formed relatively thin.

  On the other hand, in the anode, an electron current constituted by most of the lamp current flows from there and becomes the end point of the discharge arc. For this reason, the electrode main portion 1b of the anode is formed so as to have a larger diameter and a larger heat capacity than the electrode shaft portion 1a, so that heat dissipation is facilitated. As a configuration in the case of a large diameter, a known large-diameter portion structure such as a cut-out structure or a closely wound coil can be employed. In the case of the large-diameter portion of the machined structure, if desired, a groove can be formed on the peripheral surface of the large-diameter portion to increase the surface area contributing to heat dissipation.

  The electrode body 1 generally uses a refractory metal as a constituent material. As the refractory metal, tungsten (W), molybdenum (Mo), rhenium (Re), and alloys between these metals, such as rhenium-tungsten (Re-W), are used. As tungsten, pure tungsten (W), triated tungsten, doped tungsten, or the like can be selectively used as appropriate.

  Furthermore, in the present invention, the halide 2 is deposited in the form of a film on the outer surface of the electrode body 1 on the distal end side as schematically shown by the dotted line in the figure. It is not essential that the surface of the portion to which the halide 2 is applied facilitates special treatment and structure.

  However, a rough surface can be formed on the outer surface of the part if desired. In this case, the rough surface can be easily formed by performing an etching process. When the rough surface is formed in this manner, the amount of halide deposited is increased or it is difficult to drop off. In addition, in the case of such a configuration that forms a rough surface, it is easy to increase the deposition amount of the halide 2, but the halide does not necessarily have to be deposited in a film form.

  Further, the halide 2 is used as a halide in the discharge medium of the high-pressure discharge lamp by releasing the electrode E for the high-pressure discharge lamp into the hermetic vessel SE after being sealed in the high-pressure discharge lamp. It becomes easy.

  Furthermore, in order to deposit the halide 2 on the outer surface of the electrode body 1 on the tip end side, various known deposition means can be appropriately selected and used. For example, the halide can be deposited on the electrode body 1 while avoiding the intrusion of impurities by depositing the halide using a vapor deposition means such as PVD method or CVD method.

  The portion of the electrode body 1 to which the halide 2 is deposited must be a portion that does not come into contact with the hermetic vessel 11 when the high pressure discharge lamp electrode E is sealed in the high pressure discharge lamp. It is preferable that the portion on the tip side of 1a and the electrode main portion 1b, and hence the portion exposed to the inside of the airtight container 11 are used. In addition, if the halide 2 is attached to a portion that is loosely supported by the base end portion or the intermediate sealing portion that becomes the sealing portion of the electrode body 1, the high-pressure discharge lamp electrode is sealed in the hermetic vessel SE. In doing so, the halide 2 may be detached from the electrode body 1 or cause a sealing failure, so care should be taken so that the halide does not adhere to such positions.

  Further, the halide 2 allows various configurations in order to realize desired light emission characteristics in the high pressure discharge lamp. For example, when mercury is used as the lamp voltage forming medium, the halide can be composed only of a light emitting metal halide mainly responsible for light emission as a lamp. Further, when mercury is not used, it is allowed to be composed of a metal halide mainly responsible for light emission as a lamp, and a mercury substitute material that mainly acts as a lamp voltage generator. . As the light emitting metal and the halide mainly acting for forming the lamp voltage, various known metals and halides can be selected and used as desired.

  Then, when the high pressure discharge lamp electrode 1 of the present invention is sealed in the high pressure discharge lamp, the halide 2 deposited on the electrode body 1 is easily evaporated from the electrode body 1 by turning on the high pressure discharge lamp, for example. Thus, the airtight container 1 can be sealed.

    FIG. 2 is a front view of a projection metal halide lamp which is an embodiment of the high-pressure discharge lamp of the present invention. In the figure, the metal halide lamp for projection includes an arc tube IT, a reflecting mirror M, a base B, a connection conductor CC, and power supply lines W1 and W2.

  The arc tube IT includes an airtight container SE, a pair of high-pressure discharge lamp electrodes E and E, an introduction conductor OL, and a discharge medium.

  The hermetic vessel SE is a means for hermetically shielding a discharge arc occurring inside thereof from the outside. The hermetic vessel SE is translucent and has a discharge space 11a to be described later. And it has the fire resistance which can fully endure the normal high temperature operating temperature in a high pressure discharge lamp. Further, the translucency of the hermetic vessel SE may be any as long as visible light in a desired wavelength region generated by discharge can be led out from at least a part.

  Therefore, in the present invention, the hermetic vessel SE may be made of any material as long as the above conditions are satisfied, but preferably quartz glass, polycrystalline or single crystal translucent ceramics, etc. Can be formed. If necessary, it is allowed to form a halogen-resistant or halogenated-resistant transparent film on the inner surface of the hermetic container SE or to modify the inner surface of the hermetic container SE.

  In the figure, the hermetic vessel SE is made of quartz glass, and is constituted by the surrounding portion 11 and the pair of sealing portions 12 and 12, and the discharge space 11 a is formed inside the surrounding portion 11. The discharge space 11a is hermetically sealed against the outside air, and a pair of electrodes E and E face the discharge space 11a so as to face each other at a predetermined interval as will be described later. . The discharge space 11a is allowed to have an appropriate shape, but can be formed in a shape such as a sphere, a spheroidal sphere, or a cylinder.

  The pair of sealing portions 12, 12 enclose the discharge space 11 a in an airtight manner to the outside by the surrounding portion 11, seal the high-pressure discharge lamp electrode E at a predetermined position, and supply power to the electrode E. Is formed for. In the illustrated embodiment, the sealing portion 12 is formed to face both ends of the surrounding portion 11 in the tube axis direction.

  In addition, the pair of sealing portions 12 and 12 respectively support the electrode shaft portion 1a loosely in order to seal the electrode E, and seal both ends of the enclosure portion 11 of the airtight container SE. The introduction conductor OL is connected to the electrode shaft portion 1a through the sealing metal foil 12a. The sealing metal foil 12a is embedded in the middle of the sealing portion 12 in an airtight manner.

  The sealing metal foil 12a is interposed between the electrode shaft portion 1a and the introduction conductor OL, and these members are connected by welding or the like, and the quartz glass of the sealing portion 12 is hermetically sealed to the sealing metal foil 12a. It contributes to sealing and sealing the airtight container SE. In this case, the pressure resistance of the hermetic container SE can be increased by using a reduced pressure sealing method.

  A pair of electrodes E and E is shown in FIG. In this embodiment, the distance between the tips of the pair of electrodes E, E of the high-pressure discharge lamp, that is, the distance between the electrodes, is sealed so that, for example, a short arc type discharge occurs. The short arc type has a structural feature that the distance between the electrodes formed in the hermetic container is small, and therefore the arc discharge region forming the light emitting portion can be reduced. For this reason, since the light emission of the high-pressure discharge lamp can be as close as possible to the point light source, it is possible to efficiently collect light by an optical system such as a reflecting mirror M described later or a lens (not shown).

  Accordingly, a short arc type high-pressure discharge lamp is used for projection such as a liquid crystal projector, and the distance between the electrodes is preferably 3 mm or less, for example, about 1 to 2 mm. If desired, an interelectrode distance of 1 mm or less is allowed. When the distance between the electrodes exceeds 4 mm, it is separated from the point light source, the focal characteristic of the optical system is deteriorated, and the screen illuminance is lowered when used as the light source of the liquid crystal projector. The optimum thickness is 0.5 to 2.0 mm. However, in the present invention, a so-called long arc type high-pressure discharge lamp may be used.

  The leading end of the introduction conductor OL is connected to the sealing metal foil 12a by welding or the like in the sealing portion 12 of the hermetic container SE, and the base end is exposed to the outside from the end face portion of the sealing portion 12.

  The discharge medium includes a halide, a rare gas, and a buffer medium.

  The halide includes at least a metal halide that mainly functions as a luminescent metal. In the present invention, at least a part of the halide is made of a halide deposited on the electrode body of the high-pressure discharge lamp electrode. If desired, a part of the halide may be enclosed in the form of a pellet. Even in such a case, the amount of impure gas entering the inside of the hermetic vessel 1 through the halide can be clearly reduced by the halide deposited on the electrode body of the electrode for the high-pressure discharge lamp. . However, most, preferably all, of the halide is composed of halide deposited on the electrode body of the high-pressure discharge lamp electrode.

  The noble gas also functions as a starting gas and a buffer medium. The buffer medium functions to form a lamp voltage to a desired level, and mercury or a halide for mainly forming a lamp voltage is used.

  In the case of high-pressure discharge lamps for projection, headlamps and general illumination, metal halides mainly functioning as luminescent metals are rare earth metals such as dysprosium (Dy) and thulium (Tm), and thallium (Tl). Alkali metals such as sodium (Na), metal halides selected from the group such as scandium (Sc), yttrium (Y) and indium (In) can be used. As an example, sodium (Na), thallium (Tl), and dysprosium (Dy) can be used, and a combination of holmium (Ho), thulium (Tm), and indium (In) can be employed as accessory components. As another example, thulium may be used as a main component.

  As the rare gas, one kind or a mixture of plural kinds such as argon (Ar), krypton (Kr), and xenon (Xe) can be used.

  When mercury is used as the buffering medium, a required amount of mercury can be enclosed so that the mercury vapor pressure is at least 10 MPa or more, preferably 15 MPa or more during stable lighting.

  When a lamp voltage forming halide is mainly used as a buffer medium, for example, magnesium (Mg), iron (Fe), cobalt (Co), chromium (Cr), zinc (Zn), nickel (Ni), manganese Selected from the group consisting of (Mn), aluminum (Al), antimony (Sb), beryllium (Be), rhenium (R), gallium (Ga), titanium (Ti), zirconium (Zr) and hafnium (Hf) One or more of the halides used can be used. Among the above groups, one or more halides selected from the group consisting of iron (Fe), zinc (Zn), manganese (Mn), aluminum (Al) and gallium (Ga) are particularly suitable. It is.

  The above-described halide is characterized in that, in the presence of a metal halide that mainly functions as a luminescent metal, the amount of light emitted in the visible region is less than that emitted by a metal that mainly functions as a luminescent metal.

  The reflecting mirror M has a bowl shape with a rotating quadratic curved surface, a reflecting surface is formed on the inner surface of the glass substrate, supports the arc tube IT along the central axis, and the front opening is closed with a transparent glass plate. Has been. The reflection surface is made of an infrared light transmission / visible light type dichroic reflection film. In the reflecting mirror M, the arc tube IT is supported on the central axis via a base B which will be described later.

  One end of the connection conductor CC is connected to the external lead wire OL led out from the arc tube IT located on the opening end side of the reflector M, and the other end penetrates the reflector M and is fixed to the outer surface thereof. It is connected to the terminal t.

  The base B is attached to one end of the arc tube IT, connected to a lead conductor (not shown) led out from the arc tube IT to the top side of the reflector M, and fixed to the outer surface of the top of the reflector M. The arc tube IT is supported as described above.

  The power supply lines W1 and W2 are made of a wire harness or the like, and the power supply line W1 is connected to the relay terminal t, and the power supply line W2 is connected to the base B so that the connection between the lighting circuit (not shown) and the high-pressure discharge lamp HDL is established. Connecting.

  Next, examples will be described.

The embodiment is a projection metal halide lamp of the present invention shown in FIG. 2, which is a lamp having a rated lamp power of 400 W in which an electrode for a high-pressure discharge lamp in which 0.5 mg of ScI ₃ -NaI is vapor-deposited as a halide is deposited on the electrode body. About the high-pressure discharge lamp of an Example, the lighting test was implemented with the following comparative example.

  The comparative example is a high-pressure discharge lamp having the same specifications as the examples except that the halide is pelletized and sealed in an airtight container.

  The results of the lighting test are shown in Table 1.

[Table 1]
Sample lamp 500 hours luminous flux maintenance rate (%)
Example 91
Comparative Example 83

As can be seen from Table 1, according to the high-pressure discharge lamp of the present invention, the luminous flux maintenance rate is clearly superior to that of the comparative example. Since the embodiment is different from the comparative example only in the manner in which the halide is enclosed, the results shown in Table 1 indicate that impurities are intruded by encapsulating the halide using the high-pressure discharge lamp electrode of the present invention. It can be said that it means that it is reduced.

    The illuminating device of this invention is equipped with the illuminating device main body and the high-pressure discharge lamp arrange | positioned at the illuminating device main body. The above-described high-pressure discharge lamp is manufactured using the electrode for high-pressure discharge lamps of the present invention, and is therefore composed of a halide in which at least a main part of the halide of the discharge medium is attached to the electrode body.

  In the present invention, the lighting device includes any device that utilizes light emission of a high-pressure discharge lamp. For example, light projectors such as liquid crystal projectors and overhead projectors, automotive headlamps, lighting fixtures, display devices, and optical fiber lighting devices. Of course, the lighting apparatus may be for indoor use or for outdoor use.

    FIG. 3 is a conceptual cross-sectional view of a liquid crystal projector which is an embodiment of the illumination device of the present invention. In the figure, 21 is a high-pressure discharge lamp, 22 is a liquid crystal display means, 23 is an image control means, 24 is an optical system, 25 is a lighting circuit, 26 is a main body case, and 27 is a screen.

  The high-pressure discharge lamp 21 is an embodiment of the high-pressure discharge lamp of the present invention shown in FIG.

  The liquid crystal display means 22 displays an image to be projected by liquid crystal, and is illuminated by a high-pressure discharge lamp 21 from the back side.

  The image control means 23 drives and controls the liquid crystal display means 22, and can be provided with a television reception function if necessary.

  The optical system 24 projects the light that has passed through the liquid crystal display means 22 onto the screen 27.

  The lighting circuit unit 25 lights the high-pressure discharge lamp 21.

  The main body case 26 accommodates the above elements 21 to 26.

The front view of the state which sealed one Embodiment of the electrode for high pressure discharge lamps of this invention to the high pressure discharge lamp The front view of the metal halide lamp for projections which is one Embodiment of the high pressure discharge lamp of this invention 1 is a conceptual cross-sectional view of a liquid crystal projector that is an embodiment of a lighting device of the present invention

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Electrode main body, 1a ... Electrode axial part, 1b ... Electrode main part, 11 ... Surrounding part, 11a ... Discharge space, 12 ... Sealing part, 12a ... Sealing metal foil, 2 ... Halide

Claims (4)

An electrode body;
A discharge medium halide deposited in the form of a film on the outer surface of the electrode body on the tip side;
An electrode for a high-pressure discharge lamp, comprising: An electrode body having a rough surface formed on the surface on the tip side;
A halide deposited on the rough surface of the electrode body;
An electrode for a high-pressure discharge lamp, comprising: An airtight container having a discharge space formed therein;
An electrode for a high-pressure discharge lamp according to claim 1 or 2 sealed in an airtight container;
A discharge medium containing a halide and a noble gas separated from the electrode for the high-pressure discharge lamp and enclosed in an airtight container;
A high-pressure discharge lamp comprising: A lighting device body;
A high-pressure discharge lamp according to claim 3 disposed in the illuminating device body;
A lighting circuit for lighting the high-pressure discharge lamp;
An illumination device comprising:

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