JPH10172516A - High pressure discharge lamp and lighting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lengthen the life of a lamp by arranging a pair of electrodes in which an electrode main part locates in a discharge space part and a discharge medium containing an ionized material of light emitting metal sealed so as to evaporate the whole during lighting and a noble gas. SOLUTION: A spindle-shaped discharge space part 1a in the center and a cylindrical small diameter cylinder part 1b at both ends of the discharge space part 1a are integrally formed in a discharge container 1. The base ends of electrode axes 3a, 4a of tip anode and cathode 3, 4 of a current introducing conductor 2 are connected, a sleeve 5 is fit, then they are inserted into the small diameter cylinder part 1b, glass seal 6 is placed on the edge surface of the small diameter cylinder part 1b and heated. The glass seal 6 is melted, penetrates into a small gap formed between the small diameter cylinder part 1b and the sleeve 5 and into between the sleeve 5 and the current introducing conductor 2, and airtightly seals there by being cooled. A discharge medium is a halide mainly comprising dysprosium iodide, scandium bromide, and neodymium iodide, mercury, and argon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-pressure discharge lamp provided with a discharge vessel mainly made of ceramics, and a lighting apparatus using the same.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. 53-56875 discloses that an electrode is sealed with a glass seal leaving a small gap at the end of an arc tube made of ceramics, and an excessive amount of ionized material is turned inside during lighting. Are described.

In the above prior art, the life of a high-pressure discharge lamp is determined by the hermeticity of a glass seal provided at the end of the arc tube. That is, while the lamp is turned on, the glass seal reacts strongly with various components of the ionized substance sealed in the light tube, thereby impairing its airtightness. As a result, there is a problem that a component of the ionized material partially escapes from the arc tube to adversely affect lamp characteristics or cause a defect.

On the other hand, Japanese Patent Publication No. Hei 3-1777 discloses that a glass seal is made to penetrate a part of the small gap as described above, and the surface temperature of the glass seal in the small gap is set in the small gap. 5 higher than the maximum temperature of the ionized material remaining in the phase state
A technique is disclosed in which the airtightness of a glass seal is ensured for a long period of time by lowering the temperature by 0K.

[0005]

However, as in a small metal halide lamp having a ceramic discharge vessel for a liquid crystal projector, which is expected to be put to practical use in recent years, a high-pressure lamp having a distance between electrodes of about 1 to 3 mm is used. In a discharge lamp, it is necessary to increase the required vapor pressure of mercury in order to secure a predetermined lamp voltage. In order to maintain this, it is necessary to increase the temperature of the coldest part.

As a result, the surface temperature of the glass seal cannot always be lowered due to restrictions on the lamp power and the heat capacity of the arc tube. Therefore, the latter prior art can be applied to some high pressure discharge lamps. There is a problem that is limited to.

SUMMARY OF THE INVENTION An object of the present invention is to provide a high-pressure discharge lamp in which a reaction between an ionized material and a glass sealing material is suppressed and a life is improved while securing necessary lamp characteristics.

[0008]

According to a first aspect of the present invention, there is provided a high-pressure discharge lamp comprising a discharge space portion and a small-diameter cylindrical portion connected to the discharge space portion, the discharge vessel being mainly made of radiation-transmissive ceramics. A current-introducing conductor sealed to the small-diameter cylindrical portion of the discharge vessel with a glass sealing material; and a shaft portion and an electrode main portion connected to the shaft portion, wherein the shaft portion is connected to the current-introducing conductor and inside the small-diameter cylindrical portion. A pair of electrodes extending through a small gap and having a main electrode portion located in a discharge space portion; and a discharge medium containing a luminescent metal ionized substance and a rare gas sealed so that all of them evaporate during lighting. ; Characterized by having;

In the present invention and the following inventions, the definitions and technical meanings of terms are as follows unless otherwise specified.

[0010] The discharge vessel may be air-tight and radiation-transmissive, and may be of any shape, size and material. For example, the shape of the discharge space is spindle-shaped, spheroidal,
Various shapes such as an oval sphere and a sphere are allowed.
The small-diameter cylindrical portion means that the inner diameter is smaller than the maximum diameter of the discharge space portion, and the outer diameter does not matter. The term “radiation transmissive” means that radiation in a desired wavelength range among radiations generated by discharge can be led out from at least a part of the discharge vessel. The transmission of radiation in the desired wavelength range may be either transparent or diffuse transmission. Further, “mainly made of ceramics” means that a part of the discharge vessel may have a part having no radiation transmissivity, for example, a part made of a refractory metal.

The term “radiation” in the present invention refers to ultraviolet, visible, and infrared rays radiated by high-pressure vapor discharge of a luminescent metal.

The ceramic in the present invention includes a single crystal of a metal oxide, for example, a single crystal alumina.

The mode of the discharge may be either AC discharge or DC discharge. Therefore, the electrodes may have a configuration corresponding to the above-described discharge mode.

The current introducing conductor has a function of supplying a current to the electrode, supporting the electrode, and forming a small gap between the electrode and the small-diameter cylindrical portion of the discharge vessel. When a ceramic sleeve is interposed between the current introducing conductor and the small-diameter cylindrical portion, a small gap is formed between the current introducing conductor and the sleeve. The current introducing conductor is preferably made of a material having a coefficient of thermal expansion similar to that of ceramics in order to improve sealing with ceramics, and at least when the discharge vessel is mainly made of translucent alumina or YAG. May be one or more selected from the group consisting of niobium, tantalum and platinum.

The glass sealing material is applied to the end surface of the small-diameter cylindrical portion, melts during the heat treatment, enters the small gap, solidifies with cooling, and hermetically seals the small gap. As the material of the glass sealing material, a high-temperature type is preferable in consideration of the fact that the discharge vessel becomes hot during lighting, and aluminum-silicon-
A material containing oxygen as a main component and dysprosium added thereto can be used.

The electrode is configured to include an electrode shaft and an electrode main portion disposed at the tip of the electrode shaft, and the base end of the electrode shaft is connected to the current introducing conductor. A part or most of the electrode shaft may be made of the same metal as the current introducing conductor. Therefore, the current introducing conductor may extend integrally in the small-diameter cylindrical portion to serve also as the electrode shaft. The electrode main portion is a portion that acts as an electrode with respect to discharge.

The discharge medium contains at least an ionized metal of the light emitting metal and a rare gas. The ionized metal of the light emitting metal is a substance capable of contributing to the light emission by the light emitting metal being ionized at the time of lighting. Means The ionized metal of the light emitting metal can take the form of a halide. Further, the ionized substance of the light emitting metal is sealed in such an amount that all of the light emitting metal evaporates during lighting. Further, the discharge medium may further contain mercury as a buffer metal.

In the present invention, since the ionized metal of the luminescent metal is entirely evaporated during lighting, the surface of the glass sealing material in the small gap of the small-diameter cylindrical portion comes into contact with the ionized metal of the luminescent metal as a liquid phase. Therefore, the ionization of the luminescent metal rarely reacts with the glass sealing material.
Therefore, good airtightness can be maintained over a long period of time. Therefore, lamp life is greatly improved.

Further, since the small gap has an appropriate length, the high temperature of the discharge space is not transmitted to the glass sealing material as it is, but rather contributes to the temperature reduction of the glass sealing material. This also effectively prevents the reaction between the glass sealing material and the discharge medium.

According to a second aspect of the present invention, there is provided the high-pressure discharge lamp according to the first aspect, wherein a ceramic sleeve is interposed between the small-diameter cylindrical portion and the electrode shaft, and a small gap is formed between the electrode shaft and the sleeve. It is characterized in that it is formed between the sleeve and between the sleeve and the small-diameter cylindrical portion.

The ceramic sleeve may be made of the same material as the ceramic constituting the discharge vessel, or may be made of a different material.
As an example, high-purity alumina with high strength can be used. Then, small gaps are respectively formed between the sleeve and the small-diameter cylindrical portion and between the sleeve and the electrode shaft centering on the sleeve.

The sleeve has an effect of reducing the high temperature of the electrode shaft from being directly transmitted to the discharge vessel. This prevents the discharge vessel from being damaged by the heat of the electrode shaft.

According to a third aspect of the present invention, there is provided the high-pressure discharge lamp according to the first or second aspect, wherein the luminous metal ionized material is a halide and a part thereof does not evaporate during operation. And contains mercury encapsulated in such a quantity as to remain in the small gap in a liquid phase.

The high-pressure discharge lamp obtained according to the present invention comprises:
This is a so-called metal halide lamp. Various metals known for metal halide lamps can be enclosed as the luminescent metal. For example, for a liquid crystal projector, a light emitting metal mainly composed of dysprosium, cesium and neodymium can be enclosed in a discharge vessel as iodide and / or bromide. in this case,
Dysprosium has the effect of whitening the emission color and lowering the correlated color temperature of the emission color. However, according to the present invention, the color temperature is increased to a desired level by encapsulating a small amount so that the entirety evaporates during lighting. be able to.

Further, thulium, indium, thallium, sodium and the like can also be used as the luminescent metal.

A high pressure discharge lamp according to a fourth aspect of the present invention is the high pressure discharge lamp according to any one of the first to third aspects, wherein the correlated color temperature of light emission is 7000K or more.

By setting the correlated color temperature of light emission to 7000 K or more, a high-pressure discharge lamp more preferable for a liquid crystal projector can be provided. Even more practical correlated color temperatures range from 7000K to 9000K.

The correlated color temperature can be increased by reducing the amount of dysprosium as described above.

A high pressure discharge lamp according to a fifth aspect of the present invention is the high pressure discharge lamp according to any one of the first to fourth aspects, wherein the discharge vessel is provided with a coating mainly composed of silicon nitride on an inner surface thereof. Features.

In the temperature range of 700 to 900 ° C., which is the temperature of the tube wall during operation of the lamp, silicon nitride does not react with the ionized product of the luminescent metal because its molecular bonding state is very stable. Therefore, by forming a coating containing silicon nitride as the main component on the inner surface of the discharge vessel, the decrease in the discharge medium during the life is very small, and the color temperature is reduced by the decrease in the luminescent metal during the operation of the lamp. Changes can be suppressed. In the present invention in which the excess ionized metal of the light emitting metal is not encapsulated during lighting, the effect of forming the above-mentioned coating is extremely large.

The coating containing silicon nitride as a main component is formed by thermally decomposing polysilazane, which is a silazane polymer having (-Si-N-) as a main chain, in an inert atmosphere such as nitrogen or vacuum. Can be obtained by converting into ceramics.

A high pressure discharge lamp according to a sixth aspect of the present invention is the high pressure discharge lamp according to any one of the first to fourth aspects, wherein the inner surface of the discharge vessel is modified so that silicon nitride is a main component. It is characterized by:

Also in the case of the present invention, it is possible to effectively suppress the decrease of the discharge medium during the life as in the case of the fifth aspect.

The modification such that the inner surface of the discharge vessel contains silicon nitride as a main component can be achieved by, for example, heating the discharge vessel to 1200 to 1300 ° C. in an ammonia gas atmosphere.

According to a seventh aspect of the present invention, in the high-pressure discharge lamp according to any one of the first to sixth aspects, the discharge vessel is made of translucent alumina or YAG; and the sleeve is made of alumina; It is characterized by:

Both translucent alumina and YAG have good radiation transmittance and good moldability.
Of course, there is no problem with fire resistance. In addition, YAG is yttrium-alumina-garnet-based ceramics, and the chemical symbols are as follows. Al ₁₀ Y ₆ O ₂₄
Or Al ₅ Y ₃ O ₁₂ (varies depending on the firing temperature.) High-pressure discharge lamp of the invention of claim 8, in the high pressure discharge lamp according to any one of claims 1 to 7, glass sealant, aluminum, silicon and It is characterized by containing oxygen as a main component and adding dysprosium.

The aluminum-silicon-oxygen-based glass seal material to which dysprosium is added has a high melting point and relatively good corrosion resistance to ionized luminescent metals.

According to a ninth aspect of the present invention, there is provided a lighting device, comprising: a lighting device main body; and the high-pressure discharge lamp according to any one of the first to ninth aspects, supported by the lighting device main body.

The lighting device of the present invention is applicable to any device that uses a high-pressure discharge lamp for some kind of lighting. For example, the present invention can be applied to a lighting fixture, a display device, a signal lamp device, an image projection device, and the like. The lighting fixtures include various indoor lighting fixtures and various indoor lighting fixtures. As the image projection device, a liquid crystal projector,
It can be applied to an overhead projector and the like.

[0040]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing a first embodiment of the high-pressure discharge lamp of the present invention.

This embodiment is a 150 W short arc discharge type high pressure discharge lamp.

In the figure, 1 is a discharge vessel, 2 is a current introducing conductor, 3 is an anode, 4 is a cathode, 5 is a sleeve, and 6 is a glass seal.

The discharge vessel 1 is made of translucent alumina. A spindle-shaped discharge space 1a is formed in the center, and a cylindrical small-diameter tube 1b is formed integrally at both ends of the discharge space 1a. I have. The dimensions are as follows: the length of the discharge space 1a is 10 mm, the maximum inner diameter is 6.5 mm, the volume is 1.4 cc,
The length of the small-diameter cylindrical portion 1b is 7 mm, and the inner diameter is 1.8 mm.

The current introducing conductor 2 uses a 0.9 mm niobium wire.

The anode 3 comprises an electrode shaft 3a and an electrode main portion 3b.
, And was constituted by a solid bar cut out of tungsten having a maximum diameter of 2.4 mm.

The cathode 4 is also composed of an electrode shaft 4a and an electrode main part 4b, and is constituted by a 0.7 mm thoriated tungsten rod.

The distance between the electrodes formed between the anode 3 and the cathode 4 is 1.5 mm.

The sleeve 5 is made of high-purity alumina.

Al ₂ O ₃ , SiO _2
2 , a material containing Dy ₂ O ₃ as a main component was used. The bases of the electrode shafts 3a, 4a of the electrodes 3, 4 are connected to the distal end of the current introducing conductor 2, and the sleeve 5 is fitted.
b, and a glass sealing material 6 is attached to the end surface of the small-diameter cylindrical portion 1b.
And heat-treat. Thereby, the glass sealing material 6
Melts and penetrates from the end side of the small gap formed between the small-diameter cylindrical portion 1b and the sleeve 5 and the small gap formed between the sleeve 5 and the current introducing conductor 2 to the middle,
They are solidified by cooling and they are hermetically sealed.

The discharge medium was composed of 1 mg of a halide mainly composed of dysprosium iodide, scandium bromide and neodymium iodide, 30 mg of mercury, and 6.7 K of argon.
Pa.

The above high-pressure discharge lamp was operated at a lamp current of 2.5
A, when the lamp was turned on at a lamp voltage of 60 V and a lamp power of 150 W, the correlated color temperature was 7,500 K.

In the case of a 250 W high-pressure discharge lamp having the same structure as in FIG. 1, the discharge vessel 1 has a discharge space 1a having a length of 12
mm, maximum inner diameter 8 mm, volume 2.0 cc, small diameter cylinder 1
The length of b was 9 mm and the inner diameter was 2.6 mm. The discharge medium was composed of a luminescent metal halide 2 mg and mercury 30 mg.
And argon 6.7 KPa.

FIG. 2 is a sectional view showing a high-pressure discharge lamp according to a second embodiment of the present invention.

In this embodiment, a high-pressure discharge lamp with a reflecting mirror is constructed using the high-pressure discharge lamp of the first embodiment of the present invention shown in FIG.

In the figure, the same parts as those in FIG.

The reflecting mirror 7 is formed by glass molding, but has a neck portion 7a at the top and a reflecting mirror main portion 7b.
Is coated with a reflective film 7c that reflects visible light and infrared light. The reflecting mirror main part 7b has a through hole 7d.
Are formed. The high-pressure discharge lamp 8 has its base 8 a fixed to the neck 7 a via the base cement 9. In addition, the power supply line 10 is a through hole 7d
And is led out to the rear side of the reflecting mirror 7.

Reference numeral 11 denotes a ballast, which may be operated electronically or may be composed of an iron core and a coil.

FIG. 3 is a front view showing a third embodiment of the high-pressure discharge lamp of the present invention.

In this embodiment, a high-pressure discharge lamp similar to that of the first embodiment is further sealed in an outer tube.

In the figure, the same parts as those in FIG. 12 is an outer tube, 13 is a base.

The outer tube 12 is evacuated and filled with nitrogen at an appropriate pressure.

The base 13 is attached to the outer tube 12 at one end.

Since the present embodiment has an outer tube, it is suitable for general lighting.

FIG. 4 is a partially sectional front view showing a fourth embodiment of the high-pressure discharge lamp of the present invention.

This embodiment is a 250 W long arc discharge type high pressure discharge lamp of an AC lighting type.

In the figure, the same parts as those in FIG.

The discharge vessel 1 is made of translucent alumina and has an outer diameter of 15 mm, a total length of 80 mm, and a discharge space 1a having a thickness of 0.8 mm.
mm, and both ends of the discharge space 1a are tapered and connected to a small-diameter cylindrical portion 1b having a length of 10 mm, and have a volume of 8.4 cc.

Current The current introducing conductor 2 used was a 0.9 mm niobium wire.

The sleeve 5 is made of high-purity alumina and has a diameter of 2.5 mm and a length of 25 mm.

The electrode 14 is formed by a thoriated tungsten rod having an electrode shaft 14a of 0.6 mm, and a main electrode portion 14b having a tungsten coil wound around the tip of the electrode shaft 14a.

The distance between the electrodes is 35 mm.

The discharge medium was a mixture of sodium iodide, thallium iodide and indium iodide (6 mg), mercury (4).
0 mg and 6700 Pa of argon were sealed in the discharge vessel.

FIG. 5 is a conceptual diagram showing an image display device which is a first embodiment of the illumination device of the present invention.

In the drawing, 7 is a reflecting mirror, 8 is a high-pressure discharge lamp, 11 is a ballast, 15 is a liquid crystal display, 16 is an image control means, 17 is an AC power supply, 18 is an optical system, 19 is a main body case, 20 Is the screen.

The liquid crystal display means 15 displays an image to be projected by liquid crystal, and is illuminated from behind by a high-pressure discharge lamp 8 provided with a reflecting mirror 7.

The image control means 16 drives and controls the liquid crystal display means 15, and can have a television receiving function if necessary.

The AC power supply 17 supplies power to the image control means 16 and the stabilizer 11.

The optical system 18 condenses the light transmitted through the liquid crystal display means 15 and projects it on a screen 20.

The main body case 19 houses each of the above components.

FIG. 6 is a circuit block diagram of a discharge lamp lighting device for lighting a high pressure discharge lamp according to the present invention.

In the figure, the high pressure discharge lamp 8 ′ is
The same high-pressure discharge lamp as the fourth embodiment of the present invention shown in FIG. 1 is sealed in an outer tube 12 to facilitate its use for general lighting.

The ballast 11 receives power from the AC power supply 17 and turns on the high-pressure discharge lamp 8 ′.

FIG. 7 is a conceptual diagram showing a lighting fixture which is a second embodiment of the lighting device of the present invention.

This embodiment is a downlight. In the figure, 21 is a lighting fixture main body, and 22 is a high-pressure discharge lamp.

The lighting fixture body 21 includes a frame 21a embedded in the ceiling surface and a reflector 21b provided inside the frame 21a.
And other components (not shown) such as a lamp socket and a terminal block.

[0087]

According to each of the first to eighth aspects of the present invention, since the ionized metal of the light emitting metal is sealed so as to evaporate during lighting, a ceramic discharge vessel is provided to secure necessary lamp characteristics. However, it is possible to provide a high-pressure discharge lamp in which the reaction between the ionized material and the glass seal can be suppressed, and thus the life of the lamp is improved.

According to the second aspect of the present invention, in addition, the ceramic sleeve is interposed between the small-diameter cylindrical portion and the current-introducing conductor, so that the current-introducing conductor can be well sealed to the discharge vessel. Can be provided.

According to the third aspect of the present invention, in addition, the ionization of the luminescent metal is a halide, and the mercury does not partially evaporate during operation and remains in a liquid phase, thereby further increasing the temperature of the glass sealing material. It is possible to provide a high-pressure discharge lamp in which the reaction with the discharge medium is surely reduced to reduce the reaction.

According to the fourth aspect of the present invention, it is possible to provide a high-pressure discharge lamp having a correlated color temperature of light emission of 7000 K or more.

According to the fifth aspect of the present invention, in addition, by providing a coating containing silicon nitride as a main component on the inner surface of the discharge vessel, it is possible to provide a high-pressure discharge lamp with a further reduced discharge medium.

According to the sixth aspect of the present invention, it is possible to provide a high-pressure discharge lamp in which the inner surface of the discharge vessel is modified so that silicon nitride is a main component, thereby further reducing the discharge medium. it can.

According to the seventh aspect of the present invention, it is possible to provide a high-pressure discharge lamp in which the discharge vessel is made of translucent alumina or YAG.

According to the eighth aspect of the present invention, a high-pressure discharge lamp having good corrosion resistance of the glass sealing material is provided by using a glass sealing material containing aluminum, silicon and oxygen as main components and dysprosium. be able to.

According to the ninth aspect of the present invention, it is possible to provide a lighting device having the effects of the first to eighth aspects.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of a high-pressure discharge lamp of the present invention.

FIG. 2 is a partial sectional front view showing a second embodiment of the high-pressure discharge lamp of the present invention.

FIG. 3 is a front view showing a third embodiment of the high-pressure discharge lamp of the present invention.

FIG. 4 is a partial sectional front view showing a fourth embodiment of the high-pressure discharge lamp of the present invention.

FIG. 5 is a conceptual diagram showing an image display device according to a first embodiment of the lighting device of the present invention.

FIG. 6 is a circuit block diagram of a discharge lamp lighting device for lighting a high pressure discharge lamp according to the present invention.

FIG. 7 is a conceptual diagram showing a lighting apparatus according to a second embodiment of the lighting apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Discharge container 1a ... Discharge space part 1b ... Small diameter cylinder part 2 ... Current introduction conductor 3 ... Anode 3a ... Electrode shaft 3b ... Anode main part 4 ... Cathode 4a ... Electrode shaft 4b ... Cathode main part 5 ... Sleeve 6 ... Glass seal Lumber

Claims (9)

[Claims] 1. A discharge vessel mainly composed of radiation-transmissive ceramics and having a discharge space portion and a small-diameter tube portion connected to the discharge space portion; and a discharge vessel sealed to the small-diameter tube portion of the discharge vessel with a glass sealing material. A shaft portion and an electrode main portion connected to the shaft portion, wherein the shaft portion is connected to the current introducing conductor, extends through the small-diameter cylindrical portion through a small gap, and the electrode main portion is A high-pressure discharge lamp comprising: a pair of electrodes located in a discharge space; and a discharge medium containing a luminescent metal ionized substance and a rare gas sealed so that all of the electrodes evaporate during operation. 2. A ceramic sleeve is interposed between the small-diameter cylindrical portion and the electrode shaft, and a small gap is formed between the electrode shaft and the sleeve and between the sleeve and the small-diameter cylindrical portion. The high-pressure discharge lamp according to claim 1. 3. The discharge medium contains an amount of mercury in which the ionized metal of the luminescent metal is made of a halide and a part thereof is not evaporated during lighting and remains in a small gap in a liquid phase state. 3. The high-pressure discharge lamp according to claim 1, wherein: 4. The high-pressure discharge lamp according to claim 1, wherein a correlated color temperature of light emission is 7000 K or more. 5. The discharge vessel according to claim 1, wherein the inner surface of the discharge vessel is provided with a coating containing silicon nitride as a main component.
A high-pressure discharge lamp according to any one of the preceding claims. 6. The high-pressure discharge lamp according to claim 1, wherein the inner surface of the discharge vessel is modified so that silicon nitride is a main component. 7. The discharge vessel is made of translucent alumina or YAG.
7. The high-pressure discharge lamp according to claim 1, wherein the tube is made of alumina. 8. The high-pressure discharge lamp according to claim 1, wherein the glass sealing material contains aluminum, silicon and oxygen as main components and dysprosium added. 9. A lighting device comprising: a lighting device main body; and the high-pressure discharge lamp according to claim 1 supported by the lighting device main body.