JPH10275599A - Ceramic discharge lamps and lighting devices - Google Patents

Abstract

(57) Abstract: A ceramic discharge lamp having a high light-collecting property is provided by providing a lens portion that can be easily manufactured on the outer surface of a ceramic discharge vessel. A discharge vessel made of ceramic is a cylindrical vessel having a hollow, and has a lens portion formed on an outer periphery opposed to a discharge space portion. The lens unit 5 maximizes the thickness of the discharge vessel 2 near the center of the outer surface of the discharge space 3 and maximizes the discharge vessel 2.
The thickness is reduced as approaching both ends. Since the discharge vessel 2 is cylindrical, the lens portion 5 can be easily manufactured by pouring and solidifying molten ceramic between the inner frame forming the hollow and the outer frame forming the lens portion 5. The lens unit 5 adjusts the emission direction of most light rays emitted in the discharge space 3 of the discharge vessel 2 to the lens unit 5.
Change to the center side of and focus. The light emitted from the lamp 1 is controlled by an optical system such as a reflecting mirror.

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 of a discharge vessel constituted by a ceramic bulb and a lighting device using the same.

[0002]

2. Description of the Related Art Discharge lamps composed of a light-transmitting ceramic bulb are less susceptible to reaction between the bulb and impurities such as impurities or a metal halide in the lamp than those composed of a quartz bulb. . For this reason, the lamp is not likely to have a short life mainly due to devitrification, and its use as a long life lamp is widely expected.

[0003] However, the ceramic bulb has a problem that the transmittance of visible light is lower than that of a quartz glass bulb and the light output is reduced. For this reason, it is conceivable to increase the luminous efficiency by increasing the temperature of the coldest part, or to form a lens on the bulb to collect light.

Japanese Patent Publication No. 4-32497 discloses a lamp (conventional lamp) technology in which a quartz glass arc tube has a lens function. In this lamp, the thickness near the center of the arc tube is maximized, and the thickness is continuously reduced as it approaches the end portion of the arc tube. FIG. 3 shows this conventional lamp.

[0005]

However, it is very difficult to make the structure of a conventional lamp using ceramics because it requires a minute adjustment to give a lens action to the wall thickness. An object of the present invention is to provide a ceramic discharge lamp and a lighting device which are easy to manufacture and have high light-collecting properties.

[0006]

The high-pressure discharge lamp according to the present invention comprises a light-transmitting ceramic bulb, has a cylindrical discharge space portion, and has a lens portion on the outer periphery opposed to the discharge space portion. A discharge vessel; and a pair of electrodes composed of an electrode shaft and an electrode main portion formed at an end of the electrode shaft, the electrode main portion being disposed in the discharge space within a range of 0.5 to 9 mm. A pair of current introduction conductors electrically connected to the electrode assembly; a pair of closing means provided so that the inside of the discharge container is hermetically sealed at both ends of the discharge container; A discharge medium containing a metal halide sealed in a container.

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

The ceramic includes a single crystal of a metal oxide, for example, a single crystal alumina.

The discharge vessel is airtight and translucent,
What is necessary is just to have a cylindrical discharge space portion such as a cylindrical shape.
The dimensions are not limited.

The electrode assembly includes an electrode shaft and an electrode main body disposed at the tip of the electrode shaft, and the base end of the electrode shaft is connected to a current introducing conductor. A part or most of the electrode shaft may be the same metal as the current introducing conductor,
Therefore, the electrode shaft may also serve as the current introducing conductor.
When a ceramic sleeve is interposed between the electrode assembly and the sealing portion of the discharge vessel, a small gap is formed between the electrode assembly and the sleeve. I do. The electrode main portion is a portion that acts as an electrode against discharge.

The current introducing conductor has a function of supplying a current to the electrode assembly to support the electrode assembly and forming a small gap between the current introduction conductor and the sealing portion of the discharge vessel. 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. Further, the current introducing conductor may be a lead wire such as a nickel wire.

The closing means is not limited as long as it is a member that supports the electrode assembly and the current introducing conductor and keeps the discharge vessel airtight. The closing member can be used as a mounting portion for the high-pressure discharge lamp itself. In the present invention, the closing means also includes a glass sealing material. The glass sealing material is applied to the end face of the sealing portion of the discharge vessel, melts during the heat treatment, enters the small gap of the sealing portion, 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 metal halide may be a metal halide of a metal such as sodium, thallium, indium, thulium and a halogen.

The discharge medium contains at least an ionized substance of a light emitting metal and a rare gas. The ionized substance of the light emitting metal is a substance capable of contributing to light emission when the light emitting metal is ionized at the time of lighting. Means The ionized metal of the light emitting metal can take the form of a halide. Further, the discharge medium may further contain mercury as a buffer metal.

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 discharge vessel is a hollow cylindrical vessel having a lens portion formed on the outer periphery facing the discharge space. The lens section has a maximum thickness near the center of the outer surface of the discharge space of the discharge vessel, and has a smaller thickness as it approaches both ends of the discharge vessel. Since the discharge vessel is cylindrical, the lens portion can be easily manufactured by pouring and solidifying molten ceramic between the inner frame forming the hollow and the outer frame forming the lens portion.

When a discharge occurs between the electrode main portions, light is emitted in the discharge space of the discharge vessel. The emitted light is condensed by a lens formed on the outer periphery of the discharge vessel facing the discharge space, and is emitted from the discharge vessel. Light distribution of light emitted from the discharge vessel is controlled by an optical system such as a reflecting mirror.

According to a second aspect of the present invention, there is provided a lighting device comprising: a lighting device main body; and a high-pressure discharge lamp according to the first aspect disposed in the lighting device main body.

In the lighting device of the present invention, since the ceramic discharge lamp has a lens portion to provide light condensing properties, light distribution control can be easily performed by combination with an optical system such as a reflecting mirror. The lighting device of the present invention is applicable to all devices that use a ceramic 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 outdoor lighting fixtures. The image projection device can be applied to a liquid crystal projector, an overhead projector, and the like.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of the high-pressure discharge lamp of the present invention. The lamp power of the present embodiment is 150W.

In FIG. 1, 1 is a ceramic discharge lamp, 2 is a discharge vessel, 3 is a discharge space portion, 4 is a sealing portion, 5 is a lens portion, 6 is an electrode assembly, 7 is an electrode shaft, and 8 is an electrode main portion. , 9 are current conducting conductors, 10 is a sleeve, 11 is a closing means, 12 is a closing member, and 13 is a glass sealing material.

The discharge vessel 2 is made of translucent alumina.
A cylindrical discharge space portion 3 is formed at the center, sealing portions 4 and 4 are formed at both ends of the discharge space portion 3, and a lens portion 5 is formed on the outer periphery facing the discharge space portion 3. The length of the discharge vessel 2 is 40 mm, the inner diameter is 10 mm, and the outer diameter excluding the lens portion 5 is 12 mm.

The lens portion 5 has a maximum thickness from the outer surface of the discharge vessel 2 of 2 mm, and is formed gradually thinner as it approaches the sealing portions 4 and 4 of the discharge vessel 2. The width of the lens unit 5 is 12 mm
Circumscribes the outer surface of the discharge vessel 2 facing the discharge space 3.

In the discharge vessel 2, a pair of electrode assemblies 6, 6 are disposed facing each other, and the electrode assemblies 6, 6 have electrode shafts 7, 7 and an electrode main body made of tungsten at the tips of the electrode shafts 7, 7. Parts 8,8 are formed. The electrode shafts 7, 7 have an outer diameter φ0.
A 5 mm tungsten solid bar is used.
The distance L between the pair of electrode main portions 8 is 2.5 mm.

The electrode structures 6, 6 are electrically connected to the current introducing conductors 9, 9. The current introducing conductors 9, 9 are made of niobium having an outer diameter of 0.5 mm.

The electrode shafts 7, 7 of the sealing portions 4, 4 of the discharge vessel 2
, Sleeves 10 and 10 are fitted. The sleeves 10, 10 were made of high-purity alumina and had a cylindrical shape, a length of 15 mm, and an inner diameter of 0.6 mm. A gap of 0.1 mm is formed between the inner surface of the discharge vessel 2 and the outer surfaces of the sleeves 10, 10.

The ends of the discharge vessel 2 are closed by closing means 11, 11.
Is kept airtight by Closing means 11, 11
Are closing members 12 and 12 and glass sealing materials 13 and 1
3. The closing members 12 and 12 are made of ceramics, and the glass sealing materials 13 and 13 are made of Al2O3,
A material containing SiO2 and Dy2O3 as main components was used. The electrode shafts 7, 7 of the electrode assemblies 6, 6 are attached to the tips of the current introduction conductors 9, 9, respectively.
After connecting the base ends of the sleeves and fitting the sleeves 10, 10,
These are inserted through the sealing portions 4 and 4 of the discharge vessel 2, and glass sealing materials 13 and 13 are provided on the end surfaces of the sealing portions 4 and 4, and heat treatment is performed. As a result, the glass sealing materials 13 are melted and formed between the sealing portions 4 and 4 and the sleeves 10 and between the sleeves 10 and the electrode shafts 7. The small gap enters from the end side of the small gap partway and solidifies by cooling to seal them tightly.

The discharge medium was composed of 0.5 mg of a halide mainly composed of dysprosium iodide, neodymium bromide and cesium iodide, 30 mg of mercury and 26.6 KP of argon.
a.

Thus, the ceramics discharge lamp 1 is constituted. The lens portion 5 has a maximum thickness near the center of the outer surface of the discharge space 3 of the discharge vessel 2, and has a smaller thickness as approaching the sealing portion 4 of the discharge vessel 2. In the case of the quartz glass bulb of the conventional lamp shown in FIG. 3, while melting the quartz glass with a gas burner, the molten glass meat is gradually moved, so that a gradually different thickness can be formed.
However, in the case of a ceramic valve, it is difficult to form a thick wall by this method. Therefore, in the present invention, the discharge space 2 is formed by using a cylindrical container having a hollow as the discharge container 2.
The thickness which becomes the lens part 5 was formed in the outer periphery facing. Since the discharge vessel 2 is cylindrical, the lens portion 5 can be easily manufactured by pouring and solidifying molten ceramic between the inner frame forming the hollow and the outer frame forming the outer surface forming the lens portion 5. Can be. Note that the thickness and width of the lens portion 5 may be appropriately determined according to the distance L between the electrode main portions 8 and 8, the size of the discharge space portion 3, the degree of condensing, the consistency in combination with a lighting fixture, and the like. As is well known, since the transmittance of ceramics decreases exponentially with respect to the thickness, it is not preferable that the thickness is large. In the present invention, the distance L between the electrode main portions 8, 8 is set to 0.5 in consideration of the light collecting property.
９9 mm. If the distance L between the electrode main portions 8 and 8 is shorter than 0.5 mm, a short circuit may occur between the electrode main portions 8 and 8. Is low.

When power is supplied to the current introducing conductors 9, 9, discharge occurs between the electrode main portions 8, 8, and light is emitted in the discharge space 3 of the discharge vessel 2. The emitted light beam a is refracted by the discharge space 3 and the inner surface of the discharge vessel 2 and changes the path to the center of the lens unit 5. Then, the light ray a travels straight in the discharge vessel 2, is refracted at the boundary between the lens 5 and the outside air, and further changes its path to the center side of the lens unit 5 and is emitted to the outside air. Since the outer surface of the discharge vessel 2 facing the discharge space portion 3 is formed by the lens portion 5,
Most of the light rays emitted in the discharge space 3 are changed in the path toward the center of the lens 5, that is, condensed and emitted from the lamp 1 to the outside air. The light beam emitted from the lamp 1 is used by being controlled in light distribution by an optical system such as a reflecting mirror.

FIG. 2 is a cross-sectional view showing one embodiment of the lighting device of the present invention. In the present embodiment, a high-pressure discharge lamp 20 with a reflecting mirror is configured as a lighting device body using the high-pressure discharge lamp according to the embodiment of the present invention shown in FIG. It can be used for a backlight of a liquid crystal projector and the like.

In FIG. 2, the same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. In FIG. 2, 1 is a ceramic discharge lamp, 20 is a high-pressure discharge lamp with a reflecting mirror,
21 is a reflecting mirror, 22 is a neck portion, 23 is a reflecting mirror main portion,
24 is a reflection film, 25 is a through hole, 26 is a base, 27 is cement, 28 is a power supply line, and 29 is a ballast.

The reflecting mirror 21 is formed by glass molding.
A reflective film 24 that reflects visible light and transmits infrared light is adhered to the inner surface of 3. In addition, the through hole 2 is
5 are formed. The ceramic discharge lamp 1 has the base 26 in the neck 22 and the base cement 2.
7 is fixed. A power supply line 28 passes through the through-hole 25 of the reflecting mirror 21 and is led out to the rear side of the reflecting mirror 21.

The ballast 29 may be operated electronically or may consist of a core and a coil.

The condensing light a emitted from the ceramic discharge lamp 1 is reflected by the reflecting mirror 21 of the high-pressure discharge lamp 20 with a reflecting mirror to illuminate an object (not shown) or a surface to be irradiated. Since the emitted light from the ceramics discharge lamp 1 has a condensing property, it is easy to control the light distribution by an optical system such as the reflecting mirror 21. As a result, a desired illumination distribution can be easily obtained, and the illuminance can be increased.

[0035]

According to the first aspect of the present invention, since the ceramic discharge lamp uses a cylindrical discharge vessel, a lens portion can be easily formed on the outer periphery of the discharge vessel. If the light condensed by the lens portion is used effectively, it can be used to compensate for the decrease in the visible light transmittance of the ceramics.

According to the second aspect of the present invention, since a lens portion is formed on a ceramic discharge lamp, which can be expected to have a long life, and light is condensed, a desired light distribution can be obtained by combining the lens with an optical system such as a reflector. Can be obtained, and the illuminance can be increased.

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view illustrating an embodiment of the lighting device of the present invention.

FIG. 3 is a sectional view of a conventional lamp.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ceramic discharge lamp, 2 Discharge container 3 Discharge space part 5 Lens part 6 Electrode structure 7 Electrode shaft 8 Electrode main part 9 Current introduction conductor 11 Closing means 20 Illumination device main body

Claims (2)

[Claims] A discharge vessel having a cylindrical discharge space portion formed of a translucent ceramic bulb and having a lens portion on an outer periphery opposed to the discharge space portion; and an electrode shaft and formed at an end of the electrode shaft. A pair of electrode assemblies, each of which is composed of a plurality of electrode main portions and is disposed in the discharge space portion so as to be separated from each other within a range of 0.5 to 9 mm; and a pair of electrode assemblies electrically connected to the electrode assembly. A pair of closing means provided so that the inside of the discharge vessel is airtight at both ends of the discharge vessel; and a discharge medium containing a metal halide sealed in the discharge vessel; A high-pressure discharge lamp comprising: 2. A lighting device comprising: a lighting device main body; and the high-pressure discharge lamp according to claim 1 disposed in the lighting device main body.