JPH11167900A - High pressure discharge lamp and lighting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high pressure discharge lamp with a prolonged life while retaining necessary lamp properties by suppressing cracks in small diameter cylindrical parts. SOLUTION: A glass seal material 6, electrode axes 3a, and electric current introducing bodies 2 are installed in a small diameter cylindrical part 1b of a discharge container 1. The electric current introducing bodies 2 supply electric current in the electrodes and support the electrodes and have a function of forming a small gap relative to the small diameter cylindrical parts of the discharge container 1. The sleeves 5 between the electric current introducing conductors and the small diameter cylindrical parts are made of a material containing a metal. The electric current introducing conductors 2 are preferably made of a material having similar thermal expansion coefficient to that of ceramic in order to be excellently joined to the ceramic.

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 Publication 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. Even if the glass seal is sufficiently performed, cracks may occur in the small-diameter cylindrical portion due to a difference in thermal expansion between the seal material, the ceramic material, the electrode shaft, and the niobium material. In particular, when tungsten is used for the electrode shaft, the difference in thermal expansion is significant.

SUMMARY OF THE INVENTION An object of the present invention is to provide a high-pressure discharge lamp in which cracks in a small-diameter cylindrical portion are suppressed and the 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; a shaft portion and an electrode main portion connected to the shaft portion, wherein the shaft portion is connected to the current-introducing and conducting portions and the small-diameter cylinder An electrode extending through a small gap in the portion; a sleeve made of substantially the same material as the current introduction body provided to cover a part of the current introduction body and the shaft portion in the small-diameter cylindrical portion; And a discharge medium containing an ionized metal compound and a rare gas.

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 to the outside. 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 space between the electrode and the small-diameter cylindrical portion of the discharge vessel. Further, the sleeve between the current introducing conductor and the small-diameter cylindrical portion is made of substantially the same material. 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 the sealing with ceramics. At least when the discharge vessel is mainly made of translucent alumina or YAG. , Niobium, tantalum, and platinum can be used. The sleeve made of niobium is good in that the electricity introducing body itself is made by sealing.

According to the above configuration, since a part of the electrode shaft is covered with the sleeve made of substantially the same material as the current introducing body, the sleeve absorbs a difference in thermal expansion between the electrode shaft and the sealing material, so that cracks in the discharge vessel are generated. Is suppressed.

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 temperature of the discharge vessel becomes high during lighting.
A material containing oxygen as a main component and dysprosium added thereto can be used.

The electrode includes 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 may be any as long as it contains at least an ionized luminescent metal and a rare gas. Further, the discharge medium may further contain mercury as a buffer metal.

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 seal material and the discharge medium.

In the high pressure discharge lamp according to the second aspect of the present invention, the sleeve is provided so as to cover a part of the current introducing body and the shaft in the small diameter cylindrical portion, and at least one of the materials constituting the shaft and the current introducing body is made of a material. It is characterized by containing.
Cermet is desirable as the sleeve. That is,
When the shaft is made of a tungsten or molybdenum alloy and the electric conductor is made of an alloy of tantalum or niobium, the sleeve should be made of a cermet of 1 to 4 of the above 4 metals and alumina or YAG. Can be.
In the small-diameter cylindrical portion, small gaps are formed around the sleeve, between the sleeve and the small-diameter cylindrical portion and between the sleeve and the electrode shaft. According to the above configuration, since a part of the electrode shaft is covered with the sleeve made of substantially the same material as the current introducing body, the sleeve absorbs the difference in thermal expansion between the electrode shaft and the sealing material, so that the occurrence of cracks in the discharge vessel is suppressed. .

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 metal 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 is:
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. 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 700.
It is characterized by being at least 0K. By setting the correlated color temperature of light emission at 7000 K or more, a more preferable high-pressure discharge lamp for a liquid crystal projector can be provided. Even more practical correlated color temperature is 7000K ~
It is in the range of 9000K. To increase the correlated color temperature,
As described above, this can be realized by reducing the amount of dysprosium enclosed. 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 containing silicon nitride as a main component on an inner surface. Silicon nitride has a temperature range of 70 ° C. on the tube wall during lamp operation.
At 0 to 900 ° C., the molecular bonding state is very stable, so that it does not react with the ionized product of the luminescent metal.
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. And Also in the case of the present invention, similarly to the fifth aspect, it is possible to effectively suppress the decrease in the discharge medium during the life. The modification such that the inner surface of the discharge vessel contains silicon nitride as a main component can be realized, for example, by heating the discharge vessel to 1200 to 1300 ° C. in an ammonia gas atmosphere.
The high-pressure discharge lamp according to the invention of claim 7 is the first to sixth aspects of the invention.
3. The high-pressure discharge lamp according to claim 1, wherein the discharge vessel is made of translucent alumina or YAG; and the sleeve is made of alumina.

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. Al10Y6O
24 or Al5Y3O12 (depending on the firing temperature). The high-pressure discharge lamp according to any one of claims 1 to 7, wherein the glass sealing material contains aluminum, silicon and oxygen as main components. And dysprosium added. Aluminum-Silicon-
The oxygen-based glass sealing 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.

[0027]

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 introduction 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. . The dimensions are as follows: the length of the discharge space la is 10 mm, the maximum inner diameter is 6.5 mm, and the volume is 1.4 c.
c, the length of the small-diameter cylindrical portion lb is 7 mm, and the inner diameter is 1.8 mm. The current introducing conductor 2 uses a 09 mm niobium wire. The anode 3 includes 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 also has an electrode shaft 4a.
And a main electrode group 4b, which was composed of a 0.7 mm thick thoriated tungsten rod. Anode 3 and cathode 4
One hundred chicks formed between the electrodes are 1.5 mm. The sleeve 5 is made of niobium and has an inner diameter of 3 mm and an outer diameter of 33 m.
m. The glass sealing material 6 has A120
3, Si02 and Dy203 were used as main components. The battery shaft 3a of the electrodes 3, 4 is attached to the tip of the current introduction conductor 2,
After connecting the base end of 4a and fitting the sleeve 5, these are inserted into the small-diameter tube portion lb, and the glass sealing material 6 is put on the end surface of the small-diameter tube portion 1b and heat-treated. As a result, the glass sealing material 6 is melted, and a small gap formed between the small-diameter cylindrical portion 1b and the sleeve 5 and an end portion near the booth formed between the sleeve 5 and the current introducing conductor 2 From the middle to solidify by cooling and airtightly seal them. The discharge medium was 1 mg of a halide containing dysprosium iodide, scandium bromide, and neodymium iodide as main components, 30 mg of mercury, and 6.7 K of argon.
Pa. 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 high-pressure discharge lamp of 250 W 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 second embodiment of the high-pressure discharge lamp of the present invention. In the present embodiment, a high-pressure discharge lamp with a reflecting mirror is constructed by 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 reflective film 7c that transmits visible light and infrared rays is applied to the inner surface of the reflecting mirror main portion 7b. Further, a through hole 7d is formed in the reflecting mirror main body 7b. The high-pressure discharge lamp 8 has its base 8a connected to the neck 7a.
Is fixed through a gold cement 9 therein. The power supply line 10 passes through the through hole 7d of the reflecting mirror 7 and is led out to the back 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, the same high-pressure discharge lamp as that of the first embodiment is further enclosed in an outer bulb, and the same parts as those in FIG. Reference numeral 12 denotes an outer tube, and reference numeral 13 denotes gold. 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. And then
Since this embodiment has an outer tube, it is suitable for use in general lighting.

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

The present embodiment is a 250 W long arc discharge type high pressure discharge lamp of an AC lighting type. In the figure, the same reference numerals are assigned to the same sound B as in FIG. 1 and the description is omitted. 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, and both ends of the discharge stroke 1a are tapered.
It is connected to the small-diameter cylindrical portion 1b having a length of 10 mm and has a volume of 8.4 cc. The current introduction conductor 2 has a current of 0.
A 9 mm niobium wire was used. The sleeve 5 is made of niobium and has a diameter of 2.5 mm and a length of 25 mm. Electrode 14
The electrode shaft 14a is formed by forming a tungsten tungsten rod having a diameter of 0.6 mm, and the electrode main portion 14b by winding a tungsten coil around the tip of the electrode shaft 14a. The distance between the electrodes is 35 mm. The discharge medium was 6 mg of a mixture of sodium iodide, thallium iodide and indium iodide, 40 mg of mercury and 67% of argon.
00 Pa was sealed in a discharge vessel. FIG. 5 is a conceptual diagram showing an image display device which is a first embodiment of the lighting device of the present invention. In the figure, 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 controller, 17 is an AC power supply, 18 is an optical system, 19 is a main body case, and 20 is a screen. is there. Liquid crystal display means 1
5 displays an image to be projected on a liquid crystal,
Light is irradiated from the back by a high-pressure discharge lamp 8 having 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. AC power supply 17
Supplies power to the image control means 16 and the ballast 11. The optical system 18 condenses the light transmitted through the liquid crystal display stage 15 and projects it on a screen 20. The body case 19
Each of the above components is housed. 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, a high-pressure discharge lamp 8 ′
The same high-pressure discharge lamp as the fourth embodiment of the present invention shown in FIG. 4 is sealed in an outer tube 12 to facilitate 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 apparatus which is a second embodiment of the lighting apparatus of the present invention. The present embodiment is a download line. In the figure, 21 is a lighting fixture main body, and 22 is a high-pressure discharge lamp. Lighting fixture body 21
Has a frame 21a embedded in the ceiling surface, a reflector 21b provided inside the frame 21a, and other components (not shown) such as a lamp socket terminal block.

[0033]

According to the first to eighth aspects of the present invention,
Since a sleeve made of substantially the same material as that of the current introducing conductor is used for the small-diameter cylindrical portion, the occurrence of cracks in the discharge vessel can be suppressed, and therefore, a high-pressure discharge lamp having an improved lamp life can be provided.

According to the second aspect of the present invention, it is possible to provide a high-pressure discharge lamp capable of satisfactorily sealing the current introducing conductor to the discharge vessel by using niobium as the ceramic sleeve.

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 evaporate during the operation and remains as a liquid phase without evaporating, 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 invention of claim 4, it is possible to provide a high-pressure discharge lamp having a correlated color temperature of light emission of 7000K or more.

According to the fifth aspect of the present invention, it is possible to provide a high-pressure discharge lamp in which the amount of discharge medium is reduced by reducing the amount of discharge medium by providing a coating containing silicon chamber as a main component on the inner surface of the discharge vessel. it can. 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 reducing the amount of discharge medium by one layer. According to the invention of claim 7, in addition, the discharge vessel is made of translucent alumina or YA.
A high-pressure discharge lamp comprising G can be provided.
According to the invention of claim 8, by using a glass sealing material containing aluminum, silicon and oxygen as main components and dysprosium added, a high pressure discharge lamp with good corrosion resistance of the glass sealing material can be provided. . According to the ninth aspect, 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 partially 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 sectional front view of a part of a high-pressure discharge lamp according to a fourth embodiment 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]

1 Discharge Vessel 1a Discharge Space 1b Small Diameter Cylindrical Part 2 Current Introducing Conductor 3 Anode 3a Electrode Shaft 3b Anode Main Part 4 Cathode 4a
Electrode shaft 4b cathode main part 0 sleeve 6 glass sealing material

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Atsushi Saita Toshiba Litec Co., Ltd. 4-3-1 Higashishinagawa, Shinagawa-ku, Tokyo

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 pair of electrodes located in the discharge space portion; a sleeve made of substantially the same material as the current introducer provided to cover a part of the current introducer and the shaft portion in the small-diameter cylindrical portion; and light emission sealed in the discharge vessel. A high-pressure discharge lamp comprising: a discharge medium containing an ionized metal and a rare gas. 2. A discharge vessel mainly composed of a radiation-transmissive ceramic 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 pair of electrodes located in the discharge space portion; a sleeve provided to cover a part of the current introducing body and the shaft portion in the small-diameter cylindrical portion and containing at least the shaft portion and any material constituting the current introducing body; A discharge medium containing an ionized luminescent metal and a rare gas enclosed in a container. 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.
The high-pressure discharge lamp according to any one of claims 1 to 6, 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.