JPH1022086A - Electrodeless discharge lamp device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a stable starting characteristic and to reduce stresses on a switching element used in a high frequency generating circuit. SOLUTION: In an electrodeless discharge lamp device, which includes an electrodeless discharge lamp 1 comprising a translucent bulb 1b with a discharge gas sealed therein, an induction coil 2 placed in proximity to the translucent bulb 1b, and a high frequency generating circuit 7 supplying high frequency power to the induction coil 2, and which allows the electrodeless discharge lamp 1 to stably turn on by causing excited emission of the discharge gas by means of a high frequency electromagnetic field produced in the induction coil 2, a recess 1a is provided in the translucent bulb 1b, and an auxiliary induction coil fitted with an iron core 8a causing a leading discharge inside the translucent bulb 1b by the application of high frequency voltage, at least during the start of the electrodeless discharge lamp 1, is placed in the recess 1a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrodeless discharge lamp device and, more particularly, to an external electrodeless discharge lamp having no electrodes therein, which externally applies a high-frequency electromagnetic field to excite a discharge gas enclosed therein. The present invention relates to an electrodeless discharge lamp device that emits light.

[0002]

2. Description of the Related Art Conventionally, a high-frequency electromagnetic field is externally applied to a discharge gas sealed in a light-transmitting bulb to generate an annular discharge in the light-transmitting bulb, thereby exciting the discharge gas to emit light. Electrodeless discharge lamps are known. Since this electrodeless discharge lamp has features such as small size, high output, and long life, it has been researched and developed in various places.

[0003] Such an electrodeless discharge lamp is provided with a light-bulb-shaped translucent bulb surrounding an induction coil, such as an electrodeless discharge lamp disclosed in Japanese Patent Application Laid-Open No. 57-78766. It is known that a discharge gas containing mercury vapor is sealed in the light-transmitting bulb and a high-frequency current is supplied to the induction coil to excite the discharge gas sealed in the light-transmitting bulb to emit light. ing.

FIG. 7 shows a conventional electrodeless discharge lamp device including such an electrodeless discharge lamp. This electrodeless discharge lamp device includes an electrodeless discharge lamp 1, an induction coil 2,
The lighting device 3 is provided.

[0005] The electrodeless discharge lamp 1 has a substantially spherical shape.
Translucent bulb 1 having a recess 1a formed on one side
b, a discharge gas containing an inert gas or metal vapor is sealed therein, and the induction coil 2 is provided with a light-transmitting bulb 1
b is accommodated in the concave portion 1a. The lighting device 3 includes a smoothing circuit 4 for rectifying the AC power supply AC, a high-frequency generating circuit 7 including a chopper smoothing circuit 5 and a matching circuit 6, and supplies a high-frequency current to the induction coil 2. Have been able to.

[0006]

However, in the conventional electrodeless discharge lamp device configured as described above,
When the induction coil 2 is air-core, as shown in FIG. 2, the combined capacitance C of the resonance capacitor C2 of the high-frequency generation circuit 7 and the capacitors C3, C4 and C5 of the matching circuit 6 is used.
The relationship between the starting voltage V and the starting voltage V becomes considerably steeper than the curve b using the induction coil 2 containing the iron core, as shown by a curve a in FIG. It is necessary to operate at a steep point of the resonance voltage curve. For this reason, the circuit current for obtaining the starting voltage increases, and the stress on the MOSFETs, which are the switching elements Q1 and Q2 of the high-frequency generating circuit 7, increases at the time of starting. In addition, the high-frequency generating circuit 7, the induction coil 2, and the lamp load If the matching state changes sensitively to obtain a stable operation, the L and C elements used in the high-frequency generation circuit 7 including the matching circuit 6 do not change at all with time or with time. It is necessary to use such an unrealistic element. Otherwise, there is a problem that a stable operation cannot be obtained, for example, a starting voltage is lowered due to a change in the matching state.

The present invention has been made in view of the above problems, and has as its object to obtain a stable starting characteristic and reduce the stress of a switching element used in a high-frequency generating circuit. It is to provide a device.

[0008]

According to the present invention, there is provided an electrodeless discharge lamp in which a discharge gas is sealed in a light-transmitting bulb 1b. A lamp 1, an induction coil 2 disposed close to the light-transmitting bulb 1b, and a high-frequency generation circuit 7 for supplying high-frequency power to the induction coil 2;
In the electrodeless discharge lamp device that excites and discharges the discharge gas by the high-frequency electromagnetic field generated in the electrodeless lamp 1 to stably turn on the electrodeless discharge lamp 1, the light-transmitting bulb 1b is provided with a concave portion 1a, and at least the concave portion 1a has At the time of starting the electrodeless discharge lamp 1, an auxiliary induction coil for applying a high-frequency voltage to generate a preliminary discharge in the light-transmitting bulb 1b is provided.

According to the second aspect of the present invention, the first aspect is provided.
In the electrodeless discharge lamp device described above, the auxiliary induction coil 8 is provided with an iron core 8a.

According to the third aspect of the present invention, in the electrodeless discharge lamp device according to the first or second aspect,
The auxiliary induction coil 8 is provided with a shut-off means 9 for detecting that the electrodeless discharge lamp 1 is turned on and cutting off the power supply to the auxiliary induction coil 8.

According to a fourth aspect of the present invention, in the electrodeless discharge lamp device according to any one of the first to third aspects, the induction coil 2 and the auxiliary induction coil 8 are connected to each other. It is characterized by being arranged in close proximity.

According to a fifth aspect of the present invention, in the electrodeless discharge lamp device according to any one of the first to third aspects, the one end of the induction coil 2 and the one end of the auxiliary induction coil 8 are connected to each other. The one end is electrically connected.

According to a sixth aspect of the present invention, in the electrodeless discharge lamp device according to any one of the first to fifth aspects, the high frequency generating circuit 7 is connected to a power supply side of the high frequency generating circuit 7. A chopper smoothing circuit 5 for supplying DC power to the circuit 7 is provided, and power is supplied to the auxiliary induction coil 8 from the chopper smoothing circuit 5.

According to the seventh aspect of the present invention, there is provided the sixth aspect.
In the electrodeless discharge lamp device described above, the operating frequency of the chopper smoothing circuit 5 is set to 10 MHz or less, and the operating frequency of the high frequency generating circuit 7 is set to 10 MHz or more.

According to the invention described in claim 8, claim 7 is provided.
In the electrodeless discharge lamp device described above, the operating frequency of the chopper smoothing circuit 5 is set to 2.65 MHz, and the operating frequency of the high frequency generating circuit 7 is set to 13.65 MHz or more.

According to a ninth aspect of the present invention, in the electrodeless discharge lamp device according to any one of the first to fifth aspects, the high-frequency generation circuit 7 has a resonance at a first frequency. A first resonance circuit 7a that resonates at a second frequency and a second resonance circuit 7b that resonates at a second frequency.
Is connected to the first resonance circuit 7a, the auxiliary induction coil 8 is connected to the second resonance circuit 7b, and the high-frequency generation circuit 7 is operated at a first frequency, and the electrodeless lamp is operated. 1 is operated at the second frequency after the preceding discharge.

[0017]

1 and 2 show a first embodiment of an electrodeless discharge lamp device according to the present invention. This electrodeless discharge lamp device comprises an electrodeless discharge lamp 1 and It comprises an induction coil 2, a lighting device 3, and an auxiliary induction coil 8.

The electrodeless discharge lamp 1 has a light-transmitting bulb 1b formed by a light-transmitting member so as to be airtight and substantially spherical.
A substantially cylindrical concave portion 1a is formed on one side of the light transmitting valve 1b, and a discharge gas containing an inert gas or a metal vapor is sealed in the light-transmitting bulb 1b. The number of turns is not particularly limited around the circumference, but the induction coil 2 having three turns is provided with a winding center axis having a concave portion 1.
The auxiliary induction coil 8 wound around an iron core 8a such as a ferrite core is wound in the concave portion 1a in a direction substantially parallel to the central axis of the induction coil 2. , Or are accommodated so as to substantially match. Note that the center axis of the winding of the induction coil 2 is not parallel to the center axis of the concave portion 1a, and the center axis of the auxiliary induction coil 8 does not have to coincide with the center axis.

The lighting device 3 is a first high-frequency generation circuit (high-frequency generation circuit) for supplying a high-frequency current to the induction coil 2.
7 and a second for passing a high-frequency current through the auxiliary induction coil 8.
And a high-frequency generation circuit 10 of FIG.

The induction coil 2 generates a high-frequency magnetic field when a high-frequency current is supplied from the first high-frequency generation circuit 7, and the high-frequency magnetic field acts on the discharge gas inside the electrodeless discharge lamp 1. Generates an annular discharge, and emits light by exciting the discharge gas.
In other words, a ring-shaped induction electric field is generated inside the electrodeless discharge lamp 1 by the high-frequency magnetic field, and the discharge gas inside the electrodeless discharge lamp 1 is ionized by this induction electric field to generate an annular discharge. The auxiliary induction coil 8 is configured to generate a high-frequency magnetic field around the same as the induction coil 2 when a high-frequency current is supplied from the second high-frequency generation circuit 10. An annular discharge is generated as a discharge. Here, the auxiliary induction coil 8 has a smaller diameter than the induction coil 2 and the annular discharge generated as the preliminary discharge is
The diameter becomes smaller than that of the annular discharge caused by the discharge.

Therefore, the energy supplied from the second high-frequency generation circuit 10 to the auxiliary induction coil 8 can be made smaller than the energy supplied from the first high-frequency generation circuit 7 to the induction coil 2. Can be generated more easily than the annular discharge caused by the induction coil 2. Further, since the auxiliary induction coil 8 has the iron core 8a made of a ferrite core or the like, the current for generating a high-frequency magnetic field can be reduced, and the current from the second high-frequency generation circuit 10 can be reduced. The high-frequency generation circuit 10 can be reduced in size with a simple configuration.

Hereinafter, the operation of the electrodeless discharge lamp device according to the present embodiment will be described in detail.
A high-frequency voltage is applied by the high-frequency generation circuit 10 described above, and a preliminary discharge is generated inside the electrodeless discharge lamp 1 by the auxiliary induction coil 8. In other words, the electrons accelerated by the high-frequency magnetic field generated around the auxiliary induction coil 8 collide with the atoms of the discharge gas and ionize, so that the streamer advances from the auxiliary induction coil 8, and in the vicinity of the auxiliary induction coil 8. An annular discharge, which is a preceding discharge, occurs. At this time, when a high-frequency current is applied to the induction coil 2 from the first high-frequency generation circuit (high-frequency generation circuit) 7, a high-frequency magnetic field interlinking the induction coil 2 is generated, and the high-frequency magnetic field is formed by the induction coil 2. When the supply power from the first high-frequency generation circuit 7 is increased, the annular discharge is maintained in the vicinity of the induction coil 2 and the annular discharge is maintained. Strong light emission is generated by the excitation of the gas, and the light is turned on.

After shifting to the lighting state, the light emitting state is maintained without applying a high-frequency voltage to the auxiliary induction coil 8. For this reason, after shifting to the lighting state, the space between the auxiliary induction coil 8 and the second high-frequency generation circuit 10 is opened,
The high-frequency voltage to the auxiliary induction coil 8 may be stopped.

With such a configuration, in the electrodeless discharge lamp device according to the present embodiment, the electrodeless discharge lamp 1 can be pre-discharged with a simple structure using the auxiliary induction coil 8 and , Electrodeless discharge lamp 1
Is pre-discharged by the auxiliary induction coil 8, the induction coil 2 for maintaining the lighting state of the electrodeless discharge lamp 1
It is not necessary to apply a high voltage to the power supply, and sufficient power can be supplied even with an air core, and the stress of the switching element used in the high frequency generation circuit 7 can be reduced.

FIG. 3 shows a second embodiment of the electrodeless discharge lamp device according to the present invention.
This embodiment is different from the first embodiment in that the electrodeless discharge lamp 1 has a different concave portion 1c on the side opposite to the concave portion 1a formed on the light-transmitting bulb 1b. The lighting device 3 is provided with a chopper smoothing circuit 5 connected to an AC power supply AC via a rectifier circuit 4, and is formed by accommodating the induction coil 2 in the different concave portion 1c. The power supply is supplied from the circuit 5 to the high-frequency generation circuit 7, the high-frequency generation circuit 7 is used as a first high-frequency generation circuit, and the chopper smoothing circuit 5 is used as a second high-frequency generation circuit 10. The configuration is substantially the same as that of the first embodiment.

The high-frequency generation circuit 7 serving as the first high-frequency generation circuit supplies a direct current to the electrodeless discharge lamp 1 using the induction coil 2.
In order to facilitate supply of power to the induction coil 2, a high-frequency voltage of 13.56 MHz, which is equal to or higher than 10 MHz, is converted, and the high-frequency voltage can be applied to the induction coil 2 via the matching circuit 6. The induction coil 2 includes a light-transmitting bulb 1b.
Is formed by being wound several turns in a concave portion 1c having a different shape. When this high-frequency current is applied, the discharge gas in the light-transmitting bulb 1b is excited, and the annular discharge is coupled with the induction coil 2 in a timely manner. (Plasma ring) is formed.
Thus, high-frequency power is supplied from the induction coil 2 to the magnetically coupled plasma ring in the translucent bulb 1b, and the electrodeless discharge lamp 1 is turned on. The high-frequency generation circuit 7 is composed of, for example, a class D amplifier circuit, and the switching elements Q1 and Q2 are driven by a transmission circuit and a drive circuit via a transformer T1.

The chopper smoothing circuit 5 obtains a smoothed DC voltage with a small low-frequency ripple component at the same time as reducing the high-frequency distortion factor of the input current, and reduces the switching loss of the switching element Q3. The operating frequency of the chopper section is set to, for example, 2.56 MHz, which is 10 MHz or less. The secondary winding n2 of the inductor L1 of the chopper smoothing circuit 5 is connected to the auxiliary induction coil 8 via the cut-off means 9, and this chopper serves as a second high-frequency generation circuit 10.

Hereinafter, the operation of the electrodeless discharge lamp device according to the present embodiment will be described in detail. First, from the secondary winding n2 of the inductor L1 of the chopper smoothing circuit 5 to the auxiliary induction coil 8 via the cutoff means 9. A high-frequency voltage is applied to cause a preliminary discharge in the vicinity of the auxiliary induction coil 8 of the electrodeless discharge lamp 1. Then, a high-frequency voltage is applied to the induction coil 2 from the high-frequency generation circuit 7 to cause the induction coil 2 to cause the electrodeless discharge lamp 1 to perform a main discharge to be turned on. After that, the disconnection means 9 opens the gap between the secondary winding n2 of the inductor L1 and the auxiliary induction coil 8 to cut off the supply of the high-frequency voltage to the auxiliary induction coil 8. Here,
The operating frequency 13.56 MHz of the high-frequency generation circuit 7 is a frequency assigned as a high-frequency device so as not to cause a communication failure.

With such a configuration, in the electrodeless discharge lamp device according to the present embodiment, in addition to the effect of the first embodiment, since the advance discharge by the auxiliary induction coil 8 may be minute, The power supply from the chopper smoothing circuit 5 operating at a lower frequency than the high frequency generation circuit 7 is sufficient, and the power can be supplied to the auxiliary induction coil 8 with a simple structure.

In the present embodiment, as in the first embodiment, after a transition to the lighting state, the switch between the auxiliary induction coil 8 and the second high-frequency generation circuit 10 is turned off by the switch as the disconnection means 9. It may be opened to stop the high-frequency voltage to the auxiliary induction coil 8, and the auxiliary induction coil 8 may be air-core as long as it generates a small advance discharge that can shift to the main discharge. good.

FIG. 4 shows a third embodiment of the electrodeless discharge lamp device according to the present invention.
This embodiment is different from the second embodiment in that the light-transmissive bulb 1b of the electrodeless discharge lamp 1 is provided with one recess 1a as in the first embodiment. The point is that the induction coil 2 and the auxiliary induction coil 8 are accommodated in the recess 1a in close proximity to each other, and that the chopper smoothing circuit 5 of the lighting device 3 uses a step-down chopper smoothing circuit. The configuration is substantially the same as that of the embodiment. With such a configuration, the same effect as in the second embodiment can be obtained.

FIG. 5 shows a fourth embodiment of the electrodeless discharge lamp device according to the present invention.
The present embodiment is different from the third embodiment in that one end of the induction coil 2 and one end of the auxiliary induction coil 8 are electrically connected. The configuration is substantially the same as that of the embodiment. The induction coil 2
Since a current for the main discharge must be supplied, a wire having a large wire diameter is used, and the auxiliary induction coil 8 is wound by a wire having a small wire diameter because it is only necessary to make a small discharge by the preceding discharge.
Also, the secondary winding n3 of the inductor L1 requires a relatively high voltage, and thus has a relatively large number of turns. Even with such a configuration, the same effect as in the third embodiment can be obtained.

FIG. 6 shows a fifth embodiment of the electrodeless discharge lamp device according to the present invention.
This embodiment is different from the third embodiment in that a smoothing capacitor C0 is connected to the power supply side of the high frequency generation circuit 7 of the lighting device 3 instead of the chopper smoothing circuit, and the high frequency generation circuit 7 switching elements Q1, Q
2 is provided with a second resonance circuit 7b in addition to the first resonance circuit 7a on the output side, and the output of the second resonance circuit 7b is connected to the auxiliary induction coil 8; The configuration is substantially the same as that of the third embodiment.

That is, the induction coil 2 is connected to the switching element Q of the high-frequency generation circuit 7 through the first resonance circuit 7a.
1, Q2, and the resonance frequency of the first resonance circuit 7a is the first resonance frequency, for example, approximately 13.56 MHz, and the second resonance circuit 7b
Has its resonance frequency set to a second resonance frequency, for example, approximately 2.65 MHz.

When the electrodeless discharge lamp 1 is started, first, the switching elements Q1 and Q2 are controlled by the control circuit.
, The operating frequency is set to the second resonance frequency, a resonance current is supplied to the auxiliary induction coil 8, and the electrodeless discharge lamp 1 is controlled.
Causes a pre-discharge. Next, the operating frequency is switched to the first resonance frequency by the control circuit, and a resonance current is caused to flow through the induction coil 2 to cause a main discharge to be brought into a lighting state. At this time, the first resonance circuit 7a and the second resonance circuit 7b are configured so that when one resonance current is flowing, the impedance of the other resonance circuit becomes high and the resonance current does not flow. Set. Even with such a configuration, the same effects as in the third embodiment can be obtained.

In the second to fourth embodiments, the auxiliary induction coil 8 is formed separately from the secondary winding n3 of the inductor L1 of the chopper smoothing circuit 5. The invention is not limited to this, and the secondary winding itself of the inductor of the chopper smoothing circuit may be an auxiliary induction coil. Further, in each of the above embodiments, the auxiliary induction coil 8 is housed in the concave portion 1a formed in the light-transmitting bulb 1b. However, the present invention is not limited to this. The auxiliary induction coil may be wound around the projection.

[0037]

As described above, according to the present invention, the electrodeless discharge lamp has a simple structure using an auxiliary induction coil. Since the discharge can be performed and the electrodeless discharge lamp is pre-discharged by the auxiliary induction coil, it is not necessary to apply a high voltage to the induction coil for maintaining the lighting state of the electrodeless discharge lamp, and the core is empty. However, it is possible to sufficiently supply power, and it is possible to reduce the stress of the switching element used in the high-frequency generation circuit.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a configuration of an electrodeless discharge lamp according to a first embodiment of the present invention.

FIG. 2 is a perspective view of the electrodeless discharge lamp of FIG.

FIG. 3 shows a second embodiment of the electrodeless discharge lamp device of the present invention, and is a schematic configuration diagram including a circuit thereof.

FIG. 4 is a schematic configuration diagram showing a third embodiment of the electrodeless discharge lamp device of the present invention, including a circuit thereof.

FIG. 5 shows a fourth embodiment of the electrodeless discharge lamp device of the present invention, and is a schematic configuration diagram including a circuit thereof.

FIG. 6 shows a fifth embodiment of the electrodeless discharge lamp device of the present invention, and is a schematic configuration diagram including a circuit thereof.

FIG. 7 shows a conventional electrodeless discharge lamp device, and is a schematic configuration diagram including a circuit thereof.

FIG. 8 is an explanatory diagram showing characteristics of the above.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 electrodeless discharge lamp 1 a recess 1 b translucent bulb 2 induction coil 5 chopper smoothing circuit 7 high frequency generation circuit 7 a first resonance circuit 7 b second resonance circuit 8 auxiliary induction coil 8 a iron core 9 blocking means

Claims (9)

[Claims] An electrodeless discharge lamp in which a discharge gas is sealed in a light-transmitting bulb, an induction coil disposed in close proximity to the light-transmitting bulb, and a high-frequency power supply to the induction coil An electrode discharge lamp device that excites and discharges the discharge gas by a high-frequency electromagnetic field generated in the induction coil to stably turn on the electrodeless discharge lamp. At the same time, at the time of starting the electrodeless discharge lamp,
An electrodeless discharge lamp device comprising an auxiliary induction coil for applying a high-frequency voltage to generate a preliminary discharge in the light-transmitting bulb. 2. The electrodeless discharge lamp device according to claim 1, wherein an iron core is mounted on the auxiliary induction coil. 3. The auxiliary induction coil is provided with a cut-off means for detecting that the electrodeless discharge lamp is turned on and cutting off the power supply to the auxiliary induction coil. Item 3. An electrodeless discharge lamp device according to Item 2. 4. The electrodeless discharge lamp device according to claim 1, wherein said induction coil and said auxiliary induction coil are arranged close to each other. 5. The electrodeless discharge lamp according to claim 1, wherein one end of the induction coil and one end of the auxiliary induction coil are electrically connected. apparatus. 6. A chopper smoothing circuit for supplying DC power to the high frequency generating circuit is provided on a power supply side of the high frequency generating circuit, and power is supplied to the auxiliary induction coil from the chopper smoothing circuit. Claim 1,
The electrodeless discharge lamp device according to any one of claims 1 to 5. 7. The operating frequency of the chopper smoothing circuit is set to 1
7. The electrodeless discharge lamp device according to claim 6, wherein the operating frequency of the high frequency generating circuit is set to 10 MHz or more while being set to 0 MHz or less. 8. The electrodeless discharge lamp device according to claim 7, wherein the operating frequency of the chopper smoothing circuit is 2.65 MHz, and the operating frequency of the high frequency generating circuit is 13.65 MHz or more. 9. A high frequency generating circuit comprising a first resonance circuit resonating at a first frequency and a second resonance circuit resonating at a second frequency, wherein the induction coil is connected to the first resonance circuit. After connecting the auxiliary induction coil to the second resonance circuit and operating the high-frequency generation circuit at a first frequency to discharge the electrodeless lamp in advance, a second frequency The electrodeless discharge lamp device according to any one of claims 1 to 5, wherein the electrodeless discharge lamp device is operated by: