JPH0945488A - Electrodeless discharge lamp lighting device - Google Patents

Abstract

(57) Abstract: An electrodeless discharge lamp lighting device that can be miniaturized, reduces stress on circuit elements, improves circuit efficiency, and enables stable lighting of an electrodeless discharge lamp. SOLUTION: An AC power supply Vac is rectified and smoothed by a rectifier DB and an electrolytic capacitor Co via a switch SW to obtain a DC voltage E, and a self-excited half-bridge type inverter circuit INV1 supplies an AC high frequency through a starting circuit 1. Converted to electric power, resonance circuit 3, capacitor C4, resistor R4, coil 4
Power is supplied to the electrodeless discharge lamp La via. Then, the output terminal Tb of the lighting unit U1 is separated into an output terminal Tb1 provided at one end of the primary winding n1 of the transformer T1 and an output terminal Tb2 provided at the ground, and the output terminal Ta and the cable terminal Ka are separated. The lighting unit U by connecting the output terminals Tb1 and Tb2 to the cable terminal Kb
1 and the lamp unit U2 are connected.

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 lighting device.

[0002]

2. Description of the Related Art A circuit diagram of a conventional example according to the present invention is shown in FIG.

This circuit uses an AC power supply Vac as a switch SW.
A self-excited half-bridge composed of a rectifier DB and an electrolytic capacitor Co for rectifying and smoothing to obtain a DC voltage E via a starting circuit 1 and a switching circuit Q1, Q2 and a driving circuit 2 for driving the switching elements Q1, Q2 via a starting circuit 1. The inverter circuit INV1 of the formula converts the power into AC high frequency power and supplies the power to the electrodeless discharge lamp La through the resonance circuit 3, the capacitor C4, the resistor R4 and the coil 4. The resistor R4 is for assisting in starting the inverter circuit INV1.

A starting circuit 1 for starting the inverter circuit INV1, that is, the switching element Q1 is connected to both ends of the electrolytic capacitor Co. The starting circuit 1 includes a series connection of resistors R1 and R2 connected to both ends of an electric field capacitor Co, and a capacitor C1 inserted between a connection point A1 of the resistors R1 and R2 and a connection point A2 of the switching elements Q1 and Q2. , A series connection of a resistor R3 and a diode D2 connected in parallel to both ends of the capacitor C1, and a series connection of a trigger element Q3 (eg PUT) and a diode D1 connected between the connection point A1 and the gate terminal of the switching element Q1; A resistor R5 and a capacitor C5 connected between the anode and gate of the trigger element Q3, and a Zener diode ZD connected between the cathode and gate of the trigger element Q3.
1 and 1.

The resonance circuit 3 is a series circuit of an inductance element L1 and a capacitor C3 connected between the drain and source of a switching element Q2 via a primary winding n1 of a transformer T1 having secondary windings n2 and n3. Consists of. The coil 4 is a high-frequency power supply coil (hereinafter, referred to as an induction coil) that is closely arranged along the outer circumference of the electrodeless discharge lamp La.

The inverter circuit INV1, that is, the switching elements Q1 and Q2 are driven by the drive circuit 2 after starting, and the drive circuit 2 is the secondary windings n2 and n3 of the transformer T1.
And a capacitor C2 connected to both ends of the secondary winding n3 of the transformer T1.

This device uses a coaxial cable K to connect a rectifier DB, a starting circuit 1, an inverter circuit INV1, a resonance circuit 3, a lighting unit U1 including a resistor R4 and a capacitor C4, an induction coil 4, and an electrodeless discharge lamp La. It is separated into a lamp unit U2 including the lamp unit U2. This is to prevent thermal influence on the lighting unit U1 due to lighting of the electrodeless discharge lamp La. The output terminals Ta and Tb of the lighting unit U1,
This device is configured by connecting the cable terminals (hereinafter, referred to as connection terminals) Ka and Kb of the coaxial cable K.

Next, the operation will be briefly described. Switch SW
When the power is turned on by turning on, the DC voltage E is obtained as described above, and the electrolytic capacitor Co → resistor R1 → capacitor C
1 → inductance element L1 → resistor R4 → induction coil 4
→ A current flows in the closed loop composed of the electrolytic capacitor Co, and the capacitor C1 is charged. The voltage across the capacitor C1 (hereinafter referred to as voltage) Vc1 gradually rises, and when the voltage Vc1 exceeds the Zener voltage of the Zener diode ZD1, the trigger element Q3 turns on, and the capacitor C1 → trigger element Q3 → diode D1 → transformer. The current flows in the closed loop composed of the secondary winding n2 of T1 → the capacitor C1,
A voltage is generated between the gate and the source of the switching element Q1 to turn on the switching element Q1. When the switching element Q1 is turned on, the electrolytic capacitor Co → the switching element Q1 → the inductance element L1 → the capacitor C3.
→ Primary winding n1 of the transformer T1 → Current flows in the closed loop of the electrolytic capacitor Co. This current causes the transformer T1
Since the secondary voltage is generated in the secondary windings n2 and n3, the switching elements Q1 and Q2 are alternately turned on and off thereafter.

Therefore, an oscillating current flows through the resonance circuit 3 and the inverter circuit INV1 oscillates by itself to generate high frequency power. Then, a high-frequency current of several MHz to several hundreds of MHz is passed from the inverter circuit INV1 to the induction coil 4 to generate a high-frequency electromagnetic field in the induction coil 4 to supply high-frequency power to the electrodeless discharge lamp La to generate an electrodeless discharge lamp. A high-frequency plasma current is generated in La to generate ultraviolet rays or visible light.

When the inverter circuit INV1 oscillates, when the switching element Q1 is turned on, a current flows in a closed loop of the electrolytic capacitor Co → switching element Q1 → diode D2 → resistor R3 → resistor R2 → electrolytic capacitor Co. Stop.

[0011]

However, the above-mentioned conventional example has the following first problem.

When at least one of the connection terminal Ka and the output terminal Ta or the connection terminal Kb and the output terminal Tb is disconnected when the electrodeless discharge lamp La is lit, a no-load state occurs, which causes a problem in the resonance state. Switching element Q1,
An overcurrent flows in Q2, which causes great stress.

In order to solve such a first problem, there is a method of adding a protection circuit for stopping the oscillation of the inverter circuit INV1 by detecting an overvoltage or an overcurrent, but the apparatus becomes complicated. The second problem is that it will occur.

The present invention has been made in view of the above first and second problems, and an object thereof is miniaturization, reduction of stress applied to a circuit element, improvement of circuit efficiency, and An electrodeless discharge lamp lighting device capable of stably lighting an electrodeless discharge lamp.

When the electrodeless discharge lamp La is not lit, the starting circuit 1 does not operate even if the lighting unit U1 and the lamp unit U2 are disconnected, so the inverter circuit INV is used.
Oscillation of 1 does not occur. Therefore, in the following, the case where the electrodeless discharge lamp La is lit will be described.

[0016]

In order to solve the above problems, according to the invention of claim 1, an electrodeless discharge lamp,
It has an induction coil that is placed close to the electrodeless discharge lamp, supplies high-frequency power to the electrodeless discharge lamp by passing a high-frequency current, and has at least one switching element, and converts the DC power supply into AC high-frequency power. And an inverter circuit for supplying to the induction coil, and a resonance circuit connected to the output end of the inverter circuit, and at least an electrodeless discharge lamp and an induction coil constitute a lamp unit, and at least the inverter circuit lights up. In the electrodeless discharge lamp lighting device that constitutes the unit, the resonance circuit is opened by opening the connection between the lamp unit and the lighting unit.

According to the second aspect of the present invention, the resonance is achieved by opening the connection between the lamp unit and the lighting unit, and instead of opening the resonance circuit, opening the connection between the lamp unit and the lighting unit. An impedance element is added to the circuit.

According to the invention of claim 3, an electrodeless discharge lamp, and an induction coil which is disposed in the vicinity of the electrodeless discharge lamp and supplies high-frequency power to the electrodeless discharge lamp by supplying a high-frequency current. And an inverter circuit that has at least one switching element, converts a DC power supply into AC high-frequency power and supplies the AC power to an induction coil, and a resonance circuit connected to an output end of the inverter circuit. In an electrodeless discharge lamp lighting device in which a lamp unit is composed of an electrode discharge lamp and an induction coil, and a lighting unit is composed of at least an inverter circuit, by opening the connection between the lamp unit and the lighting unit, It is characterized by less vibration.

According to the invention described in claim 4, the lamp unit has two connection terminals, the lighting unit has at least three output terminals, and the lamp unit and the lighting unit are connected. At the time of opening, at least the first output terminal connected to the ground is opened first.

According to a fifth aspect of the invention, the connection terminal connected to the first output terminal is shorter than the other connection terminals.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) FIG. 1 shows a circuit diagram of a first embodiment according to the present invention.

The difference from the conventional example shown in FIG. 18 is that the output terminal Tb is a second output terminal (hereinafter referred to as the output terminal) Tb1 provided at one end of the primary winding n1 of the transformer T1.
And a first output terminal (hereinafter, referred to as an output terminal) Tb2 provided on the ground, the output terminal Ta and the connection terminal Ka are connected, and the output terminal Tb1, the output terminal Tb2, and the connection terminal Kb are connected. The lighting unit U1 and the lamp unit U2 are configured to be connected to each other by connecting them. The same configurations as those of the other conventional examples are denoted by the same reference numerals and the description thereof will be omitted.

In the present embodiment, when the lighting unit U1 and the lamp unit U2 are disconnected when the electrodeless discharge lamp La is lit, the connection terminal Kb is disconnected to cause the output terminal Tb.
Since both 1 and Tb2 are opened and the resonance circuit 3 is also opened, the oscillation of the inverter circuit INV1 is stopped. Therefore, overcurrent and overvoltage are not applied to the inverter circuit INV1, and the circuit elements including the switching elements Q1 and Q2 can be protected.

2 to 4 are schematic views of a connector CN connecting the output terminal Ta and the connection terminal Ka, and the output terminals Tb1 and Tb2 and the connection terminal Kb. 2 is a top view thereof, FIG. 3 is a side view thereof, and FIG. 4 is an exploded perspective view thereof. (First Configuration Example of Connector CN) The connector CN main body is made of an insulating material, and the output terminals Ta, Tb1, and Tb2 are attached thereto. As shown in FIG. 3, each of the output terminals Ta, Tb1, and Tb2 penetrates the printed circuit board P, and the vicinity H of the tip of the terminal is soldered to the pattern formed on the back surface of the printed circuit board P with the solder Y. And are electrically connected. As shown in FIG. 4, the connection terminal Ka of the coaxial cable K is inserted into the connector CN so as to connect to the output terminal Ta, and the connection terminal Kb is connected to the output terminals Tb1 and Tb2. It is fixed by a screw B through the lid portion AA. In this way, the lighting unit U1 and the lamp unit U
And 2 are electrically connected.

As shown in FIGS. 2 and 4, the output terminal T
Partition X that insulates a from the output terminals Tb1 and Tb2
1 is provided. In addition, the second connector CN shown in FIG.
As in the configuration example, the connection terminal Kb may be bifurcated by providing the partition X2 that insulates and separates the output terminal Ta, the output terminal Tb1 and the output terminal Tb2.

A third configuration example of the connector CN is shown in the top view of FIG. The difference from the first configuration example of the connector CN shown in FIGS. 2 to 4 is that the output terminal T mounted on the connector CN1 is different.
Lengths Lta, Ltb1, L of a, Tb1, Tb2
The relation of tb2 is Lta> Ltb1≈Ltb2 (1), and the connection terminal Ka is connected to the output terminal Ta and the connection terminal Kb is connected to the output terminals Tb1 and Tb2. So that the connector CN
Insert it inside and connect the connection terminals Ka and Kb to the connector CN2.
The same configurations as those of the other first configuration examples are denoted by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 6, by fixing the connection terminals Ka and Kb with the connector CN2, the lighting unit U1
When separating the lamp unit U2 from the lamp unit U2, the connection terminal K
a and the output terminal Ta are disengaged from each other, and the output terminal Tb1,
The rate at which Tb2 and the connection terminal Kb are disengaged is substantially equal. According to the formula (1), the connection terminal Kb comes off first, and then the connection terminal Ka comes off. That is, in the circuit shown in FIG. 1, one end of the primary winding n1 of the transformer T1 and the ground are surely removed first, so that the resonance circuit 3 is surely opened and the oscillation of the inverter circuit INV1 is stopped. In the first configuration example of the connector CN shown in FIGS. 2 to 4, the connection terminal Ka and the connection terminal Kb are disengaged at the same time due to their shapes, but the third configuration example of the connector CN shown in FIG. 6 is more reliable in connection. It is possible to remove the terminal Kb first.

A fourth configuration example of the connector CN is shown in the top view of FIG. The difference from the third configuration example of the connector CN shown in FIG. 6 is that the length L of each of the output terminals Ta, Tb1, Tb2 is L.
The relationship between ta, Ltb1, and Ltb2 is Lta>Ltb1> Ltb2 (2), which is the same as other third structural examples. The description is omitted by attaching the reference numerals.

With this configuration, the lighting unit U
1 and the lamp unit U2 are separated, the output terminals Tb2, Tb1, and the output terminal Ta are connected in this order to the connection terminals Ka, K.
It is possible to remove b. That is, in the circuit shown in FIG. 1, since the ground and the one end of the primary winding n1 of the transformer T1 are surely removed in order, the resonance circuit 3 is surely opened and the oscillation of the inverter circuit INV1 is stopped. .

In the connector examples shown in FIGS. 6 and 7,
Although the formulas (1) and (2) are satisfied, any shape may be used as long as the connection terminal Kb is separated from the connection terminal Ka as described above. Furthermore, the output terminal Tb2
May have any shape as long as it is configured to come off earlier than the output terminal Tb1. For example, as in the fifth and sixth connector configuration examples shown in FIGS. 8 and 9, the output terminal Tb2 that is exposed is shown. Ltb21 may be longer than the length Ltb11 of the exposed output terminal Tb1. In addition, as in the seventh connector configuration example shown in FIG. 10, the output terminal Tb2 is connected to the connection terminal Kb rather than the output terminal Tb1.
You may comprise so that it may be located in the front-end | tip part.

Here, as shown in FIG. 11, the output terminal Tb1
When is removed first, a closed loop is formed by the inductance element L1, the capacitor C4, the induction coil 4, and the switching element Q2, and unstable resonance occurs in the closed loop, a resonance current flows through the switching element Q2, and stress is applied to the switching element Q2. It will cost you. On the other hand, as shown in FIG. 12, when the output terminal Tb2 is disconnected first, the capacitor C
3, C4, induction coil 4, primary winding n1 of transformer T1
Due to this, a closed loop is formed, no resonance current flows through the switching element Q2, and stress is less likely to be applied to the switching element Q2.

(Second Embodiment) FIG. 13 shows a circuit diagram of a second embodiment according to the present invention.

The difference from the first embodiment shown in FIG. 1 is that the resistor R4, the capacitor C4, the induction coil 4, the electrodeless discharge lamp La, and the coaxial cable K make the lamp unit U2.
And the output terminal Ta is connected to the output terminals Ta1, T
This is because the inductance element L1 is separated into a2 and one end of the inductance element L1 is used as the output terminal Ta1 and one end of the capacitor C3 is used as the output terminal Ta2, and the same configurations as those of the other first embodiment are denoted by the same reference numerals. Omit it.

With this configuration, the connection terminal K
Even when at least one of a and Kb is disconnected, the capacitor C3, which is a component of the resonance circuit 3, is surely opened,
Oscillation of the inverter circuit INV1 surely stops.

(Embodiment 3) FIG. 14 shows a circuit diagram of a third embodiment according to the present invention.

The difference from the second embodiment shown in FIG. 13 is that the capacitor C3 is connected to the primary winding n1 of the transformer T1.
It is divided into a capacitor C31 connected between the output terminals Ta1 and Tb2 via a capacitor and a capacitor C32 connected between the output terminals Ta2 and Tb1. Description is omitted by attaching the same reference numerals.

Here, if the resonance between the inductance element L1 and the capacitor C32 is strong and the resonance between the inductance element L1 and the capacitor C31 is weak, it is set as follows.
When the lamp unit U2 is detached, both ends of the capacitor C32 are opened, and the resonance circuit including the inductance element L1 and the capacitor C31 is opened. Although a weak vibration of the resonance circuit including the inductance element L1 and the capacitor C31 remains, the circuit element is not stressed so that the circuit element can be protected.

(Embodiment 4) A circuit diagram of a fourth embodiment according to the present invention is shown in FIG.

The difference from the second embodiment shown in FIG. 13 is that the inductance element L1 is connected between the output terminal Ta1 and the connection point A2.
And the inductance element L11 connected between the output terminal Ta2 and the connection point A2. The same components as those of the second embodiment are denoted by the same reference numerals and the description thereof will be omitted.

Here, for example, the inductance element L11
When the value of is set to be larger than that of the inductance element L12 so that the resonance between the inductance element L12 and the capacitor C3 is strong and the resonance between the inductance element L11 and the capacitor C3 is weak, when the lamp unit U2 comes off. One end of the inductance element L12 is opened, and the resonance circuit including the inductance element L12 and the capacitor C3 is opened. Although a weak vibration of the resonance circuit including the inductance element L11 and the capacitor C3 remains, the inductance value of the inductance element L11 is larger than the combined inductance value of the inductance elements L11 and L12, that is, the impedance value is large, and thus the resonance current is large. The current is limited, and a large stress is not applied to the circuit element, so that the circuit element can be protected.

(Fifth Embodiment) FIG. 16 shows a circuit diagram of a fifth embodiment according to the present invention.

The difference from the second embodiment shown in FIG. 13 is that the primary winding n1 and the output terminal Tb2 of the transformer T1 are different.
A high impedance element (for example, a high resistance) Z is inserted between them, and the same configurations as those of the other second embodiment are denoted by the same reference numerals and the description thereof will be omitted.

Here, the connection terminal Kb is the output terminal Tb1,
High impedance element Z when connected to Tb2
Is short-circuited, the normal operation is performed, and when the connection terminal Kb is disconnected, the high impedance element Z is inserted between the primary winding n1 of the transformer T1 and the ground, so that the vibration due to resonance is appropriately damped. A large stress is not applied to the circuit element, and the circuit element can be protected.

In the above second to fifth embodiments,
The resistor R4 and the capacitor C4 are connected to the coaxial cable K and the connection terminals Ka and K even between the coaxial cable K and the induction coil 4.
It may be either between b and b. Further, the structure of the connector may be as shown in FIGS. 2 to 10 or a combination thereof.

(Sixth Embodiment) FIG. 17 shows a circuit diagram of a sixth embodiment according to the present invention.

The difference from the conventional example shown in FIG. 18 is that the capacitor C3 is connected to the inductance element L1 and the transformer T.
A capacitor C33 inserted between the primary winding n1 of
A capacitor C3 connected in parallel between the connection terminals Ka and Kb
Divided into 4 and a resistor R4, capacitors C4 and C34
Is disposed in the lamp unit U2, and the same configurations as those of the other conventional examples are denoted by the same reference numerals and the description thereof will be omitted.

Here, if the resonance between the inductance element L1 and the capacitor C34 is strong and the resonance between the inductance element L1 and the capacitor C33 is weak, it is set as follows.
When the lamp unit U2 is detached, both ends of the capacitor C34 are opened and the resonance circuit including the inductance element L1 and the capacitor C34 is opened. Although a weak vibration due to the resonance circuit composed of the inductance element L1 and the capacitor C33 remains, the circuit element is protected without a large stress. Moreover, it is not necessary to provide a plurality of output terminals Ta and Tb.

However, during normal lighting, the inductance element L
1, because the resonance current flowing through the capacitor C34 flows through the connector that connects the lighting unit U1 and the lamp unit U2 to each other, for example, the capacitor C34 is connected to the connection terminal Ka,
By disposing the capacitor C34 close to Kb and shortening the wiring length between the capacitor C34 and the inductance element L1, it is possible to reduce the influence of the impedance component existing on the resonance loop.

[0049]

According to the first aspect of the invention, since the resonance circuit stops the vibration due to the resonance, the size can be reduced and the stress applied to the circuit element can be reduced.
An electrodeless discharge lamp lighting device capable of improving circuit efficiency and stably lighting an electrodeless discharge lamp can be provided.

According to the second aspect of the present invention, by adding the impedance element to the resonance circuit, the vibration due to the resonance is attenuated, so that the size can be reduced, the stress applied to the circuit element can be reduced, and the circuit efficiency can be improved. Also, it is possible to provide an electrodeless discharge lamp lighting device capable of stably lighting the electrodeless discharge lamp.

According to the third aspect of the present invention, by changing the constant of the resonance circuit, vibration due to resonance is weakened, miniaturization is possible, and stress applied to the circuit element is reduced.
An electrodeless discharge lamp lighting device capable of improving circuit efficiency and stably lighting an electrodeless discharge lamp can be provided.

According to the inventions of claims 4 and 5,
Since the first output terminal is opened first, the vibration due to resonance is stopped or damped, so that the size can be reduced.
An electrodeless discharge lamp lighting device capable of reducing stress applied to a circuit element, improving circuit efficiency, and stably lighting an electrodeless discharge lamp can be provided.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a first embodiment according to the present invention.

FIG. 2 is a schematic top view of a first configuration example of the connector.

FIG. 3 shows a schematic side view of the connector.

FIG. 4 shows an exploded perspective view of the connector.

FIG. 5 shows a schematic side view of a second configuration example of the connector.

FIG. 6 shows a top view of a third configuration example of the connector.

FIG. 7 shows a top view of a fourth configuration example of the connector.

FIG. 8 shows a top view of a fifth configuration example of the connector.

FIG. 9 shows a top view of a sixth configuration example of the connector.

FIG. 10 shows a top view of a seventh configuration example of the connector.

FIG. 11 is a circuit diagram showing connection of connectors.

FIG. 12 is another circuit diagram showing the connection of the connector.

FIG. 13 is a circuit diagram showing a second embodiment according to the present invention.

FIG. 14 is a circuit diagram showing a third embodiment according to the present invention.

FIG. 15 is a circuit diagram showing a fourth embodiment according to the present invention.

FIG. 16 is a circuit diagram showing a fifth embodiment according to the present invention.

FIG. 17 is a circuit diagram showing a sixth embodiment according to the present invention.

FIG. 18 is a circuit diagram showing a conventional example according to the present invention.

[Explanation of symbols]

 3 Resonance circuit 4 Induction coil INV Inverter circuit Ka connection terminal Kb connection terminal La Electroless discharge lamp Ta output terminal Tb output terminal U1 Lighting unit U2 Lamp unit Z Impedance element

Claims (5)

[Claims] 1. An electrodeless discharge lamp, an induction coil which is disposed in the vicinity of the electrodeless discharge lamp and supplies high-frequency power to the electrodeless discharge lamp by supplying a high-frequency current, and at least one switching element. And an inverter circuit that converts a direct current power source into alternating current high frequency power and supplies the alternating current to the induction coil, and a resonance circuit connected to an output end of the inverter circuit, and at least the electrodeless discharge lamp In the electrodeless discharge lamp lighting device in which a lamp unit is configured by the induction coil and a lighting unit is configured by at least the inverter circuit, the resonance is achieved by opening the connection between the lamp unit and the lighting unit. An electrodeless discharge lamp lighting device characterized by opening a circuit. 2. The electrodeless discharge lamp lighting device according to claim 1, wherein the lamp unit and the lighting unit are opened instead of opening the resonance circuit by opening a connection between the lamp unit and the lighting unit. An electrodeless discharge lamp lighting device, wherein an impedance element is added to the resonance circuit by opening a connection with a lighting unit. 3. An electrodeless discharge lamp, an induction coil which is disposed close to the electrodeless discharge lamp, supplies high-frequency power to the electrodeless discharge lamp by supplying a high-frequency current, and at least one switching element. And an inverter circuit that converts a direct current power source into alternating current high frequency power and supplies the alternating current to the induction coil, and a resonance circuit connected to an output end of the inverter circuit, and at least the electrodeless discharge lamp In the electrodeless discharge lamp lighting device in which a lamp unit is configured by the induction coil and a lighting unit is configured by at least the inverter circuit, the resonance is achieved by opening the connection between the lamp unit and the lighting unit. An electrodeless discharge lamp lighting device characterized in that circuit vibration is weakened. 4. The lamp unit has two connection terminals, the lighting unit has at least three output terminals, and when the connection between the lamp unit and the lighting unit is opened. The electrodeless discharge lamp lighting device according to any one of claims 1 to 3, wherein at least the first output terminal connected to the ground is opened first. 5. The electrodeless discharge lamp according to claim 1, wherein the connection terminal connected to the first output terminal is shorter than the other connection terminals. Lighting device.