JP2733165B2 - Electrodeless lamp - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrodeless electrode in which a discharge gas is excited and emits light by applying a high-frequency electromagnetic field to the discharge gas inside the bulb from outside the bulb without having an electrode inside the bulb. It relates to a discharge lamp.

[0002]

2. Description of the Related Art Conventionally, this type of electrodeless discharge lamp has features such as small size, high output, and long life, and has been researched and developed in various places. The use to is considered. As an electrodeless discharge lamp,
As shown in FIG. 6, a bulb-shaped bulb 1 surrounding an induction coil 2 which is an air-core coil is provided, a high-frequency current is supplied to the induction coil 2, and a high-frequency electromagnetic field formed around the induction coil 2. Act on a discharge gas containing mercury vapor sealed in a bulb 1 to excite the discharge gas to emit light (Japanese Patent Application Laid-Open No. 57-78766).

The magnetic field formed around the air-core coil used as the induction coil 2 is
However, the above configuration has a problem that the efficiency is low because the high frequency magnetic field inside the induction coil 2 does not act on the discharge gas. On the other hand, as shown in FIG. 7, a spherical bulb 1 made of transparent quartz glass or the like and an induction coil 2 having a winding wound around the outer periphery of the bulb 1 are provided. An electrodeless discharge lamp in which a high-frequency magnetic field is applied to a discharge gas has been considered. In this configuration, a high-frequency magnetic field is applied to the discharge gas inside the induction coil 2.
The efficiency is higher than that of the configuration described above.

As a discharge gas of these electrodeless discharge lamps, a mixed gas of a luminescent substance such as mercury vapor and a rare gas is generally used. When a discharge gas containing mercury is used, the initial startup is relatively easy, but it is difficult to restart immediately after turning off the light. Further, since the vapor pressure of mercury changes exponentially with an increase in temperature, it is difficult to match with a high-frequency power supply for supplying a high-frequency current to the induction coil 2. And it cannot be stably lit. on the other hand,
If mercury is not contained in the discharge gas, the alignment becomes easier, but the initial startup becomes difficult. It is possible to forcibly start by applying a high voltage to the induction coil,
A high-frequency power supply capable of outputting a high voltage is required, which causes a problem that the high-frequency power supply as a lighting circuit becomes large.
That is, an electrodeless discharge lamp including an electrodeless discharge lamp and a high-frequency power supply is increased in size.

In order to solve the above-mentioned problem, as shown in FIG. 8, a winding of an induction coil 2 is wound around an outer periphery of a bulb 1 so that a high-frequency magnetic field acts on a discharge gas efficiently. On both sides of the bulb 1 in the axial direction of the induction coil 2, a pair of starting auxiliary electrodes 3a, 3b facing each other are provided.
An electrodeless discharge lamp has been proposed in which start-up is made relatively easy by disposing (see U.S. Pat.
No. 489,589, U.S. Pat. No. 4,902,937.
issue). In this electrodeless discharge lamp, prior to energization of the high-frequency current to the induction coil 2, depending on applying a high frequency voltage as pre備放electrodeposition occurs on both the starting auxiliary electrode 3a, 3b during, preliminary discharge A high-frequency current is supplied to the induction coil 2 in a state where the induction occurs, thereby facilitating the starting.

[0006]

When a high-frequency current is applied to the induction coil 2 to light it, a high-frequency magnetic field generates a toroidal induction electric field in the bulb 1, and the discharge gas is ionized by the induction electric field. Thus, a main discharge having a toroidal discharge path (a discharge state generally called an annular discharge or a high-frequency ring discharge) is generated. Since the induction electric field links with the high-frequency magnetic field, a discharge path is formed along the winding direction of the winding of the induction coil 2 at the time of lighting. On the other hand, the preliminary discharge is performed by starting auxiliary electrodes 3a and 3b.
Therefore, there is a problem that a high-frequency electric field generated between the starting auxiliary electrodes 3a and 3b prevents a transition from the preliminary discharge to the main discharge.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide an electrodeless discharge lamp which does not need to supply a large power to a starting auxiliary electrode and has a good startability.

[0008]

According to the first aspect of the present invention, in order to achieve the above object, the outer wall surface of the valve 1 is located on the intersection of a plane perpendicular to the central axis of the induction coil 2 and the outer wall surface of the valve 1. The two starting auxiliary electrodes 3a and 3b are arranged over substantially the entire circumference of the induction coil 2, and each starting auxiliary electrode 3a and 3b is connected to each end of the induction coil 2.

According to the second aspect of the present invention, two starting auxiliary electrodes are provided over substantially the entire circumference of the outer wall surface of the bulb 1 on the line of intersection of the plane perpendicular to the central axis of the induction coil 2 and the outer wall surface of the bulb 1. 3
a, 3b are arranged, one starting auxiliary electrode 3a is connected to one end of the induction coil 2 and the other starting auxiliary electrode 3b is connected.
Is connected to the other end of the induction coil 2 via the inductor L.

According to the third aspect of the present invention, two starting auxiliary electrodes are provided over substantially the entire circumference of the outer wall surface of the bulb 1 on the intersection of a plane perpendicular to the central axis of the induction coil 2 and the outer wall surface of the bulb 1. 3
a, 3b are arranged, one starting auxiliary electrode 3a is connected to one end of the induction coil 2 and the other starting auxiliary electrode 3b is connected.
Is connected to the other end of the induction coil 2 via the resonance circuit 5 including the inductor L and the capacitor C.

[0011]

According to the structure of the first aspect, when the induction coil 2 is energized from the high frequency power supply 4, the voltage between both ends of the induction coil 2 is applied to the starting auxiliary electrodes 3a, 3b. , A streamer-like preliminary discharge occurs. In other words, there is an advantage that it is not necessary to separately provide a power supply for generating the preliminary discharge. On the other hand, the high-frequency magnetic field around the induction coil 2 acts on the discharge gas in the bulb 1 to form a toroidal induced electric field in the bulb 1. The discharge gas shifts to a main discharge having a discharge path, and the discharge gas is ionized and excited to emit light with high luminance. Since the auxiliary starting electrodes 3a and 3b are arranged on the intersection of the plane perpendicular to the central axis of the induction coil 2 and the outer wall surface of the bulb 1, the preliminary discharge is formed along the electric field induced by the induction coil 2. Therefore, it is not necessary to change the direction of the discharge at the time of transition from the preliminary discharge to the main discharge, so that the energy supplied at the start can be reduced. The starting auxiliary electrodes 3a and 3b are arranged on the outer surface of the bulb 1 over substantially the entire circumference, and the distance between the adjacent starting auxiliary electrodes 3a and 3b may be relatively small. As a result, it is possible to increase the electric field intensity between the starting auxiliary electrodes 3a and 3b, which makes it easier to generate a preliminary discharge. In short, pre-discharge is easy to occur, and since the energy required for the transition from the pre-discharge to the main discharge is small, the startability is excellent,
In addition, since the supply energy at the time of starting is small, it is possible to reduce the size of the power supply, and it is possible to reduce the size as a whole.

According to the second aspect of the present invention, since the inductor L is interposed between one of the starting auxiliary electrodes 3a and one end of the induction coil 2, the voltage boosted by the inductor L is reduced. , 3b, the electric field strength of the electric field generated around the starting auxiliary electrodes 3a, 3b can be increased, and the starting is further facilitated.

According to the third aspect of the present invention, the resonance circuit 5 including the inductor L and the capacitor C is inserted between the one starting auxiliary electrode 3a and one end of the induction coil 2. Is added to the power supply voltage and applied to the starting auxiliary electrodes 3a and 3b, the electric field strength of the electric field generated around the starting auxiliary electrodes 3a and 3b can be increased, and starting can be further facilitated. It becomes.

[0014]

(Embodiment 1) As shown in FIG. 1, a bulb 1 is formed in a hermetically sealed cylindrical shape from a translucent material such as quartz glass, and is filled with, for example, 100 Torr xenon gas as a discharge gas. . An induction coil 2 is provided on the outer periphery of the valve 1.
Is wound so as to be substantially coaxial with the central axis of the valve 1. Here, the induction coil 2 is wound three turns, but the number of turns is not particularly limited as long as it is wound one or more turns. On the outer wall of the valve 1,
Two starting auxiliary electrodes 3 a and 3 b are arranged in close contact with the bulb 1 on a ring which is an intersection of a plane orthogonal to the central axis of the induction coil 2 and the outer wall surface of the bulb 1. As shown in FIG. 2, each of the starting auxiliary electrodes 3a and 3b is formed in a long and narrow strip having a sufficiently large vertical and horizontal dimension ratio, and the center of each of the starting auxiliary electrodes 3a and 3b is positioned in the direction of the central axis of the bulb 1. The terminal pieces 6a and 6b extend along the bottom of the bulb 1, and the distal ends of the terminal pieces 6a and 6b are bent along the bottom surface of the bulb 1.
In addition, a gap of, for example, 5 mm is formed between the ends of the starting auxiliary electrodes 3a and 3b. This gap is set to such a size that a discharge does not occur outside the bulb 1 when a high-frequency voltage is applied between the starting auxiliary electrodes 3a and 3b. Terminal strip 6 extended to each starting auxiliary electrode 3a, 3b
The tips of a and 6b are connected to one end of the induction coil 2, respectively.

The induction coil 2 is supplied with a high-frequency current from a high-frequency power supply 4 to generate a high-frequency magnetic field. The high-frequency magnetic field acts on a discharge gas inside the bulb 1 to generate a main discharge having a toroidal discharge path. The discharge gas is excited to emit light. That is, a toroidal induction electric field is generated in the bulb 1 along the winding direction of the winding of the induction coil 2 by the high frequency magnetic field, and the main discharge is maintained by the induction electric field. The high frequency power supply 4 includes a high frequency generator 4a for generating a high frequency, an amplifier 4b for amplifying an output of the high frequency generator 4a, and a matching circuit 4c inserted between the amplifier 4b and the induction coil 2 for matching impedance. Is done.

At the time of starting, when a high-frequency current is supplied to the induction coil 2 by the high-frequency power supply 4, a high-frequency voltage is applied between the auxiliary electrodes 3a and 3b by a voltage generated at both ends of the induction coil 2. At this time, the starting auxiliary electrodes 3a, 3b
When the electrons in the vicinity of 衝突 collide with the xenon atoms in the discharge gas to ionize the xenon atoms, when such a state is repeated, sufficient electrons are supplied to maintain the discharge. As shown in FIG.
Streamer-like preliminary discharges SP are generated along the lines a and 3b.

Since a high-frequency current is supplied from the high-frequency power supply 4 to the induction coil 2, a high-frequency magnetic field interlinking with the induction coil 2 is generated. It is formed in space. When the induced electric field acts on the preliminary discharge SP, the main discharge is shifted to the main discharge, and a strong light emission is generated by the excitation of the discharge gas to be turned on. Here, the high-frequency magnetic field generated by the induction coil 2 is linked to the preliminary discharge SP,
Generates an induced electric field in the same direction as that of the preliminary discharge SP, so that energy for changing the direction of the discharge is not required when shifting from the preliminary discharge SP to the main discharge.

By providing the starting auxiliary electrodes 3a and 3b as described above, the initial input for forming the main discharge can be greatly reduced. For example, in order to start discharge only by the induction coil 2 without providing the auxiliary starting electrodes 3a and 3b, power of 300 W or more is required.
Discharge can be started with power of about 0 W. As a result, the power supply can be reduced in size and can be easily started.

Here, as the discharge gas, other single gas or mixed gas may be used instead of xenon gas, and the gas pressure is not limited to 100 Torr. Further, the valve 1 is not limited to a cylindrical shape, but may be any other than a spherical shape. (Embodiment 2) In this embodiment, as shown in FIG. 4, an inductor L is inserted between one starting auxiliary electrode 3a and one end of the induction coil 2. The other starting auxiliary electrode 3b
Is connected to the other end of the induction coil 2 and grounded.

When the induction coil 2 is energized by the high-frequency power supply 4, the high-frequency magnetic field generated around the induction coil 2 is coupled to the starting auxiliary electrodes 3a and 3b so as to interlink. Then, a high voltage boosted by the inductor L is generated between the starting auxiliary electrodes 3a and 3b, and the electric field strength around the starting auxiliary electrodes 3a and 3b increases. As a result, the energy of the electrons near the starting auxiliary electrodes 3a and 3b increases,
Xenon atoms in the discharge gas are easily ionized. That is, the preliminary discharge is easily generated, and the starting is facilitated. Here, both starting auxiliary electrodes 3a,
Since the applied voltage to 3b increases as the number of turns of the inductor L increases, the inductor L can be designed as needed. Other configurations are the same as in the first embodiment.

(Embodiment 3) In this embodiment, as shown in FIG. 5, a resonance circuit 5 composed of a parallel circuit of an inductor L and a capacitor C is provided between one starting auxiliary electrode 3a and one end of an induction coil 2. Is inserted. The other starting auxiliary electrode 3b is connected to the other end of the induction coil 2 and is grounded. The resonance frequency of the resonance circuit 5 is set to match the output frequency of the high frequency power supply 4.

When the induction coil 2 is energized by the high-frequency power supply 4, the high-frequency magnetic field generated around the induction coil 2 is coupled to the starting auxiliary electrodes 3a and 3b so as to interlink. Then, a resonance current flows through the resonance circuit 5, a high voltage is generated between the starting auxiliary electrodes 3a and 3b, and the electric field intensity around the starting auxiliary electrodes 3a and 3b increases. As a result, the energy of the electrons near the starting auxiliary electrodes 3a and 3b increases,
Xenon atoms in the discharge gas are easily ionized. That is, the preliminary discharge is easily generated, and the starting is facilitated. Here, the voltage applied to both starting auxiliary electrodes 3a and 3b increases even when only the inductor L is used as in the second embodiment. However, by using the resonance circuit 5 including the inductor L and the capacitor C, the inductor L Even if the number of turns is small, it is possible to generate a voltage higher than or equal to the case of only the inductor L. Other configurations are the same as in the first embodiment.

(Embodiment 4) In this embodiment, a mixture of a rare gas and a metal or a metal halide is used as a discharge gas. The metal and the metal halide may be used alone or as a mixture. For example, NaI-TlI-InI or the like is mixed with a rare gas. When a discharge gas in which such a substance is mixed is used, excitation light emission of the rare gas occurs immediately after the main discharge occurs. If the rare gas is xenon, white light is generated. Thereafter, the vapor pressure of the mixed substance increases, and the mixed substance emits light. As described above, high emission luminance can be obtained from the initial state, and a high-intensity electrodeless discharge lamp with good startup can be provided. The technical idea of this embodiment can be applied to any of the above embodiments. The substance to be mixed with the rare gas as a component of the discharge gas is appropriately set according to the efficiency and light color.

[0024]

As described above, according to the first aspect of the present invention, two coils are provided over substantially the entire circumference of the outer wall surface of the valve on the intersection of the plane perpendicular to the central axis of the induction coil and the outer wall surface of the valve. When a high-frequency voltage is applied to the starting auxiliary electrode, a preliminary discharge is generated in the bulb along the starting auxiliary electrode. Since the preliminary discharge is generated along the induced electric field generated in the bulb, there is little energy for easily shifting from the preliminary discharge to the main discharge due to the induced electric field, and there is an advantage that the transition from the preliminary discharge to the annular discharge is facilitated. In addition, the starting auxiliary electrodes are arranged on substantially the entire outer surface of the bulb, and the distance between the adjacent starting auxiliary electrodes can be relatively small, so that the electric field strength between the starting auxiliary electrodes is increased. And thereby predischarge is likely to occur. As a result, there is an advantage that the power supply can be reduced in size because the supply energy at the time of starting is small, and the overall size can be reduced. In short, the predischarge is easy to occur, and the energy required for the transition from the predischarge to the main discharge is small, so that the startability is excellent. Moreover, since the supply energy at the time of the start is small, the power supply can be downsized. The overall size can be reduced. Further, since each starting auxiliary electrode is connected to each end of the induction coil, a voltage across the induction coil which is energized by the high frequency power supply is applied to the starting auxiliary electrode, thereby causing a preliminary discharge. Therefore, there is no need to provide a separate power supply.

According to the second aspect of the present invention, one starting auxiliary electrode is connected to one end of the induction coil and the other starting auxiliary electrode is connected to the other end of the induction coil via the inductor. The applied voltage is applied to the starting auxiliary electrode, so that the electric field intensity of the electric field generated around the starting auxiliary electrode can be increased, and there is an advantage that starting is further facilitated.

According to a third aspect of the present invention, one starting auxiliary electrode is connected to one end of the induction coil, and the other starting auxiliary electrode is connected to the other end of the induction coil via a resonance circuit including an inductor and a capacitor. Therefore, the voltage between both ends of the resonance circuit is added to the power supply voltage and applied to the starting auxiliary electrode, so that the electric field strength of the electric field generated around the starting auxiliary electrode can be increased, and the starting can be more easily performed. It has the effect of becoming.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a first embodiment.

FIG. 2 is a perspective view of a main part excluding an induction coil in the first embodiment.

FIG. 3 is an explanatory diagram of a preliminary discharge in Example 1.

FIG. 4 is a schematic configuration diagram of a second embodiment.

FIG. 5 is a schematic configuration diagram of a third embodiment.

FIG. 6 is a sectional view showing a conventional electrodeless discharge lamp.

FIG. 7 is a side view showing another conventional example of an electrodeless discharge lamp.

FIG. 8 is a side view showing still another conventional example of an electrodeless discharge lamp.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Valve 2 Induction coil 3a Starting auxiliary electrode 3b Starting auxiliary electrode 4 High frequency power supply 5 Resonance circuit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shingo Higashizaka 1048 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Works, Ltd. References JP-A-2-86049 (JP, A) JP-A-2-19098 (JP, A) JP-A-5-190156 (JP, A) JP-A-4-163385 (JP, A) JP-A-4 -292897 (JP, A) JP-A-5-89986 (JP, A)

Claims (3)

(57) [Claims] 1. A high-frequency current is supplied from a high-frequency power supply to an induction coil having a winding wound around the bulb made of a light-transmitting material, and a high-frequency electromagnetic wave is formed inside the winding in the radial direction of the induction coil. In an electrodeless discharge lamp that excites and emits a discharge gas by causing a field to act on a discharge gas sealed in the bulb, the outer wall surface of the bulb is located on the intersection of a plane perpendicular to the central axis of the induction coil and the outer wall surface of the bulb. An electrodeless discharge lamp characterized in that two starting auxiliary electrodes are arranged over substantially the entire circumference of the above-mentioned, and each starting auxiliary electrode is connected to each end of the induction coil. 2. A high-frequency current is supplied from a high-frequency power supply to an induction coil having a winding wound around an outer periphery of a valve made of a translucent material, and a high-frequency electromagnetic wave is formed inside the winding in the radial direction of the induction coil. In an electrodeless discharge lamp that excites and emits a discharge gas by causing a field to act on a discharge gas sealed in the bulb, the outer wall surface of the bulb is located on the intersection of a plane perpendicular to the central axis of the induction coil and the outer wall surface of the bulb. The two starting auxiliary electrodes are arranged over substantially the entire periphery of the starting coil, one starting auxiliary electrode is connected to one end of the induction coil, and the other starting auxiliary electrode is connected to the other end of the induction coil via the inductor. An electrodeless discharge lamp characterized in that: 3. A high-frequency current is supplied from a high-frequency power supply to an induction coil having a winding wound around the bulb made of a light-transmitting material, and a high-frequency electromagnetic wave is formed inside the winding in the radial direction of the induction coil. In an electrodeless discharge lamp that excites and emits a discharge gas by causing a field to act on a discharge gas sealed in the bulb, the outer wall surface of the bulb is located on the intersection of a plane perpendicular to the central axis of the induction coil and the outer wall surface of the bulb. , Two starting auxiliary electrodes are arranged over substantially the entire periphery of the starting coil, one starting auxiliary electrode is connected to one end of the induction coil, and the other starting auxiliary electrode is connected via a resonance circuit including an inductor and a capacitor. An electrodeless discharge lamp connected to the other end of an induction coil.