JPH08212980A - Electrodeless fluorescent lamp - Google Patents

Abstract

PURPOSE: To provide a high efficient electrodeless lamp by operating the electrodeless fluorescent lamp, with a fluorescent material emitting light by an ultraviolet ray excitation radiated by a discharge, to make a total surface become luminous except a part necessary for supplying power, in a discharge vessel lighted by high frequency power. CONSTITUTION: A lamp, when lighted, is connected to a commercial power supply, to supply high frequency power to an excitation coil 20 from a lighting circuit 12. Normally, since the excitation coil 20 is placed in a resonance condition between itself and a resonance capacitor provided in the lighting circuit 12, voltage across both ends of the excitation coil 20 becomes high voltage, to generate intensive electric field in a coil axial direction in the vicinity of the coil. By this electric field, a discharge breakdown is generated to start a discharge. Thereafter by a high frequency electromagnetic field generated around the coil, ring-shaped high frequency plasma concentrical to the coil is generated around the coil. An ultraviolet ray generated from this high frequency plasma, irradiating a phosphor 2, is converted into visible light and taken out to outside a discharge vessel 1. Here is excepted an ordinary base part for introducing commercial power, to cover a total unit with a luminous surface, so as to realize high efficiency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrodeless fluorescent lamp having no electrode and having a long life. In particular, the present invention relates to an electrodeless fluorescent lamp having high efficiency and excellent interior quality.

[0002]

2. Description of the Related Art As a light source for illumination, a fluorescent lamp which is turned on at a commercial frequency or a frequency of about several tens of kHz is widely used. These fluorescent lamps are usually tubular or curved and have electrodes at both ends. A voltage is applied between the electrodes to generate a commercial frequency or a discharge having a frequency of about several tens of kHz, and ultraviolet rays generated by the discharge are converted into visible light by a phosphor coated on the inner surface of the glass container and taken out to the outside. The electrodes are coated with an electron emitting substance that easily emits electrons into the discharge space. This electron emission material is scattered and reduced by sputtering due to ions and evaporation due to a rise in temperature. If the electron emission material is exhausted, it becomes difficult for electrons to be emitted from the electrodes, and discharge cannot be maintained. Therefore, the life of the lamp having such an electrode is determined by the consumption of the electron emitting material applied to the electrode.

Recently, a long-life electrodeless fluorescent lamp has been studied. For example, Japanese Patent Laid-Open No. 63-310.
550 and so on. Electrodeless fluorescent lamps generate high-frequency induction by applying a high-frequency current to an induction coil placed close to the discharge vessel containing the discharge gas or by applying a high-frequency voltage to a pair of counter electrodes placed close to the discharge vessel. The discharge gas in the discharge vessel is discharged and emitted by an electromagnetic field. The frequency of the high frequency is about several MHz to several tens of MHz. Since this electrodeless fluorescent lamp has no electrode inside the discharge vessel, it has a long life regardless of the consumption of the electron emitting material.

[0004]

The above-mentioned conventional electrodeless fluorescent lamp has a bulb base and is of a lighting circuit integrated type.
The circuit compartment is covered with a container such as plastic or metal,
That part did not emit light. Further, even if the lighting circuit is provided separately, a part of the lamp does not emit light because of a matching circuit or the like.

An object of the present invention is to provide an inexpensive electrodeless fluorescent lamp which is highly efficient and excellent in interior quality.

[0006]

The above-mentioned object can be achieved by constructing such that the entire surface is emitting light except for the part required for supplying electric power.

[0007]

[Operation] By using the above electrodeless discharge lamp,
The phosphor coating area, that is, the light emitting area can be maximized, and high efficiency can be realized.

Further, since the entire surface emits light, an electrodeless discharge lamp excellent in interior quality can be realized.

[0009]

FIG. 1 is a diagram showing an electrodeless fluorescent lamp which is an embodiment of the present invention. The discharge container 1 is made of a glass container similar to an ordinary fluorescent lamp. The appearance is substantially spherical, and is a cylindrical recess from the bottom to the inside. The discharge vessel 1 is filled with a gas such as argon and mercury. The phosphor 2 is applied to the inner surface of the discharge container 1. A light-transmissive conductive film 3 is applied to the outer surface of the discharge container 1. At the lower part of the discharge vessel 1, a normal base 10 for connecting to a commercial power source is provided.
A lighting circuit 12 is installed from the inside of the cylindrical concave portion inside the discharge container 1 to the inside of the base 10. The lighting circuit 12 generates a high frequency of several MHz from a commercial power source.
The high frequency output of the lighting circuit 12 is connected to the excitation coil 20 provided inside the cylindrical recess. The operation at the time of lighting is as follows. High frequency power is supplied from the lighting circuit 12 to the excitation coil 20 by being connected to a commercial power source. Normally, since it is in resonance with the resonance capacitor in the lighting circuit 12, the voltage across the excitation coil 20 is high, and a strong electric field is generated near the coil in the axial direction of the coil. This electric field causes discharge breakdown and starts discharge. After this, a ring-shaped high-frequency plasma concentric with the coil is generated around the coil by the high-frequency electromagnetic field generated around the coil. Ultraviolet rays generated from the high-frequency plasma are applied to the phosphor 2 and converted into visible light, and the discharge container 1
Taken out of. In this embodiment, the excitation coil 20
Is an air core, but a ferrite core may be installed in the center if necessary. In this embodiment, the entire surface is covered by the light emitting surface except for the usual base part for introducing commercial power, so that high efficiency can be realized and an electrodeless discharge lamp excellent in interior quality can be realized.

Another embodiment of the present invention is shown in FIG. In this embodiment, discharge lamps 4 and 5 each having a substantially hemispherical shape are combined into one lamp. A phosphor is applied to the inner walls of the discharge vessels 4 and 5 as in the embodiment of FIG. Each of the discharge vessels has a cylindrical recess facing inward, in which the lighting circuit 12 and the excitation coils 21 and 2 are arranged.
2 are installed. The excitation coils 21 and 22 are configured to be wound around the ferrite cores 23 and 24, respectively. Further, an electric wire 13 for introducing commercial power from the outside is installed between the two discharge vessels. The lighting circuit 12 converts the electric power from the commercial power source into a high frequency electric power of several MHz and applies it to the excitation coils 21 and 22. Mercury and argon gas are enclosed in the discharge vessels 4 and 5 for several torr. These functions are exactly the same as those in the above-mentioned embodiment. In this embodiment, the entire surface is covered with the light emitting surface except for the electric wires for introducing the commercial power, so that high efficiency can be realized and an electrodeless discharge lamp excellent in interior property can be realized.

FIG. 3 shows another embodiment of the present invention. In the present embodiment, the lighting circuit 12 is installed at a position apart from the discharge container 1, and a high frequency cable 6 is connected between them. For example, the lighting circuit 12 is fixed to a ceiling or the like, and the discharge container 1 which is a light emitting unit is suspended by a high frequency cable 6 which also serves to introduce high frequency power. The discharge vessel 1 has a cylindrical concave portion facing inward, and only the excitation coil 20 is installed inside the concave portion. A metal fixture 7 is provided on the top of the discharge vessel 1 and is connected to the outer conductor of the high frequency cable 6, and is further connected to one end of the excitation coil 20. As in the embodiment of FIGS. 1 and 2, the entire surface is covered by the light emitting surface except for the cable portion for introducing the high frequency power, so that high efficiency can be realized and an electrodeless discharge lamp excellent in interior design is obtained. realizable.

In the above embodiment, mercury and argon gas were used as the materials to be enclosed in the discharge vessel 1. However, the present invention is not limited to these. For example, various amalgams can be used instead of mercury. In this case, the amalgam with the highest luminous efficiency is selected according to the temperature of the lamp when it is operating. This makes it possible to cope with various operating conditions of the lamp. Further, xenon gas or neon gas can be used instead of the argon gas. Alternatively, no mercury may be used and only a rare gas such as xenon may be used. In this case, it is possible to realize a lamp that has stable temperature characteristics regardless of the ambient temperature and that has a quick start-up at the time of starting.

[0013]

According to the present invention, it is possible to realize an electrodeless fluorescent lamp having a long life, high efficiency and excellent interior quality.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of an electrodeless fluorescent lamp of the present invention.

FIG. 2 is a diagram showing another embodiment of the electrodeless fluorescent lamp of the present invention.

FIG. 3 is a diagram showing another embodiment of the electrodeless fluorescent lamp of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Discharge container, 2 ... Phosphor, 3 ... Light-transmissive conductive film,
4, 5 ... Discharge container, 6 ... High frequency cable, 12 ... Lighting circuit, 20, 21, 22 ... Excitation coil.

Front Page Continuation (72) Inventor Toshiyuki Moriya 1-280 Higashi Koigakubo, Kokubunji City, Tokyo Inside Hitachi Design Laboratory

Claims (3)

[Claims] 1. A light-transmissive discharge vessel in which a gas filling capable of being excited into a discharge state is enclosed, and inside or near the discharge vessel for converting ultraviolet rays generated by the discharge into visible light. A fluorescent substance provided, a coil for generating a high frequency electromagnetic field in close contact with the discharge container to generate the discharge, and a high frequency electromagnetic field surrounding the discharge and the coil to prevent leakage of the high frequency electromagnetic field to the outside. In the electrodeless fluorescent lamp, which is composed of a shielding means for supplying the high frequency power to the coil and a high frequency power source for supplying the high frequency power to the coil, it is confirmed that the entire surface is emitting light except for the part necessary for supplying the power. Characteristic electrodeless fluorescent lamp. 2. The electrodeless fluorescent lamp according to claim 1, wherein the electric power supplied to the light emitting portion from the outside is commercial frequency electric power. 3. The electrodeless fluorescent lamp according to claim 1, wherein the electric power externally supplied to the light emitting portion is the high frequency electric power.