JP3463482B2 - Discharge lamp lighting device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp lighting device, and more particularly to a discharge lamp lighting device provided with a high frequency power supply circuit for supplying high frequency power to the discharge lamp.

[0002]

2. Description of the Related Art FIG. 8 is a circuit diagram of a conventional discharge lamp lighting device, and FIG. 9 is a schematic view thereof. This discharge lamp lighting device is disclosed in Japanese Unexamined Patent Publication No. 7-326484. An electrodeless discharge lamp lighting device for applying a high-frequency electromagnetic field to the electrodeless discharge lamp to emit light.

This discharge lamp lighting device has a DC power supply circuit 2 (for example, a step-down chopper circuit) that performs AC / DC conversion by inputting DC power from an AC power supply 1, and is transparent or has a spherical shape with a phosphor coated on its inner surface. Inert gas, discharge gas such as metal vapor in glass bulb (eg mercury, rare gas, etc.)
, An electrodeless discharge lamp 3 in which is enclosed, a high-frequency power supply coil 4 arranged closely along a spherical outer circumference of the electrodeless discharge lamp 3, and an oscillator for supplying a high-frequency current to the high-frequency power supply coil 4. 5 and the high-frequency power amplifier 6, and the matching circuit 7 for efficiently transmitting high-frequency power to the electrodeless discharge lamp 3 by matching impedances of the high-frequency power supply coil 4 and the high-frequency power amplifier 6 to eliminate reflection. The oscillator 5, the high-frequency power amplifier 6, and the matching circuit 7 are included in the high-frequency power supply circuit 9.

The oscillator 5 and the high frequency power amplifier 6
From several MHz to several hundreds M for the high frequency power supply coil 4
By passing a high frequency current of Hz, a high frequency electromagnetic field is generated in the high frequency power supply coil 4 to supply high frequency power to the electrodeless discharge lamp 3, and a high frequency plasma current is generated in the electrodeless discharge lamp 3 to generate ultraviolet rays or It is designed to generate visible light.

The DC power supply circuit 2 is connected to the power supply input terminals of the oscillator 5 and the high frequency power amplifier 6. The oscillator 5 and the high-frequency power amplifier 6 operate at several MHz to several hundreds MHz as described above, and these are collectively referred to as a high-frequency region. On the other hand, the DC power supply circuit 2 that performs AC / DC conversion is It operates at tens of Hz to hundreds of kHz,
Hereinafter, this is referred to as a low frequency region.

The electrodeless discharge lamp lighting device, which is the discharge lamp lighting device configured as described above, has a low frequency region and a high frequency region, respectively, in order to block noise radiated by space conduction from the high frequency region. The shield cases 20 and 21 made of metal having conductivity are separately housed. Also,
Shield case 2 containing a circuit that operates in the low frequency range
Reference numeral 1 denotes a shield case 20 accommodating a circuit that operates in a high frequency region, which is electrically connected to each other by input lines 30 without being adjacent to each other so as to be electrically isolated from each other. The shield case 20 is provided with a series circuit of the capacitors 31 and 32, and a capacitor 33 that connects the connection point of the capacitors 31 and 32 and the inner wall of the shield case 20. There is. The capacitors 31, 32, and 33, which are impedance elements, form the second ground circuit 72.

The power supply line 10 of the DC power supply circuit 2 is also drawn from the shield case 21.
In order to prevent noise from leaking from the outside to both sides, both ends of the power supply line 10 wired in the shield case 21 are connected to the inner wall of the shield case 21 via capacitors 11 and 12, and the shield case 21 is It is installed on the ground. The capacitors 11 and 12 which are impedance elements form a first ground circuit 71.

[0008]

However, in the electrodeless discharge lamp lighting device which is the conventional discharge lamp lighting device configured as described above, the shield case 20 is not grounded to the ground, and therefore the shield case 20 itself. Becomes a noise source and a lot of high frequency noise leaks to the outside. In the worst case, this high frequency noise reaches the power supply line 10 outside the shield case 21 and reaches the power supply line 10. There is a problem that there is a risk that it will leak to the outside.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a discharge lamp lighting device in which high frequency noise generated in a high frequency power supply circuit is reduced from leaking to the outside. is there.

[0010]

In order to solve the above problems, the present invention provides a load circuit including a discharge lamp and a high frequency power supply for supplying high frequency power to the load circuit. In a discharge lamp lighting device comprising a power supply circuit and a direct current power supply circuit connected to an alternating current power supply to supply direct current power to the high frequency power supply circuit, the direct current power supply circuit includes a chopper circuit and its operating frequency is several tens kHz. From several hundred k
Hz and the operating frequency of the high frequency power supply circuit is several MHz
To several hundred MHz, at least the high-frequency power supply circuit and the DC power supply circuit are housed in a grounded conductive shield case, and an impedance element is provided between the input end side of the DC power supply circuit and the shield case. And a shield case connected between the input end side of the high frequency power supply circuit and the shield case by a second ground circuit formed of an impedance element, and the input end side of the load circuit and the shield. The case is connected to the case by a third earth circuit including an impedance element ,
The first to third ground circuits are
Impedance is 1st earth circuit> 2nd earth circuit
Path> third ground circuit .

According to the invention of claim 2, claim 1
The discharge lamp lighting device as described above, wherein the high-frequency power supply circuit
However, the input end side includes an electrolytic capacitor for smoothing,
The vicinity of the negative terminal of this electrolytic capacitor and the shield case
The second earth circuit is provided between the second earth circuit and the second earth circuit .

According to the invention of claim 3, the discharge lamp is
Including load circuit and supplying high frequency power to this load circuit
The high frequency power supply circuit and the high frequency power
A DC power supply circuit for supplying DC power to the source circuit.
In the discharge lamp lighting device according to claim 1,
The operating frequency including the PA circuit is from several tens of kHz to several hundreds of kHz.
z and the operating frequency of the high frequency power supply circuit is several MHz.
From several hundred MHz to at least the high frequency power circuit
Conductive shield grounded to DC power supply circuit
It is housed in a case and is connected to the input end side of the DC power supply circuit and the shield.
1st which consists of an impedance element between the field case
Connected with the ground circuit of the high frequency power supply circuit
Between the impedance case and the shield case
The load circuit is connected with the second ground circuit
Impedance between the input end side of the
Connected by a third ground circuit composed of a capacitor element, the high-frequency power supply circuit includes an electrolytic capacitor for smoothing on the input end side, and the electrolytic capacitor is provided between the vicinity of the negative terminal of the electrolytic capacitor and the shield case. A second grounding circuit is provided.

In the invention according to claim 4, the discharge lamp is
Including load circuit and supplying high frequency power to this load circuit
The high frequency power supply circuit and the high frequency power
A DC power supply circuit for supplying DC power to the source circuit.
In the discharge lamp lighting device according to claim 1,
The operating frequency including the PA circuit is from several tens of kHz to several hundreds of kHz.
z and the operating frequency of the high frequency power supply circuit is several MHz.
From several hundred MHz to at least the high frequency power circuit
Conductive shield grounded to DC power supply circuit
It is housed in a case and is connected to the input end side of the DC power supply circuit and the shield.
1st which consists of an impedance element between the field case
Connected with the ground circuit of the high frequency power supply circuit
Between the impedance case and the shield case
The load circuit is connected with the second ground circuit
Impedance between the input end side of the
Connected by a third ground circuit consisting of a device , between the output end of the DC power supply circuit and the shield case,
Fourth consisting of impedance elements and connecting between them
It is characterized by the provision of a ground circuit.

According to the invention of claim 5, claim 4 is provided.
In the discharge lamp lighting device described above, the impedance of each of the first to fourth earth circuits is such that the impedance of each earth circuit is a first earth circuit, a fourth earth circuit> a second earth circuit, a third earth circuit. Was formed to be
Is characterized by .

According to the invention of claim 6,
4 or the discharge lamp lighting device according to claim 5,
Serial DC power supply circuit, comprises an electrolytic capacitor for smoothing the output end side, between the negative potential side and the sheet <br/> Rudokesu of this electrolytic capacitor, provided with the fourth ground circuit
It is characterized by

[0016]

[0017]

[0018]

1 is a circuit diagram of a discharge lamp lighting device according to a first embodiment of the present invention, and is different from the conventional example shown in FIG. An input terminal (or a high-frequency power source) of a load circuit 40 including the point where the circuits that configure the low-frequency region and the high-frequency region are housed in one shield case 22 and the electrodeless discharge lamp 3 and the high-frequency power supply coil 4. The point is that a capacitor 41, which is an impedance element that constitutes the third earth circuit 73, is provided between the output end of the circuit 9) and the shield case 22, and the other configuration is similar to that of the conventional example shown in FIG. . Therefore, the same components as those of the conventional example are designated by the same reference numerals and the description thereof will be omitted.

FIG. 2 shows a schematic view of the discharge lamp lighting device of the present embodiment, and the effects of the present embodiment will be described below. The low frequency noise generated in the DC power supply circuit 2 having the step-down chopper circuit is caused by the capacitor 11 which is an impedance element.
And 12 and a second earth circuit 72 composed of capacitors 31, 32, and 33, which are impedance elements, flow into the shield case 22 and, as shown by a broken line 60 in FIG. Since they cancel each other, low frequency noise generated in the DC power supply circuit 2 can be reduced. Further, the high frequency noise generated in the high frequency power supply circuit 9 and the load circuit 40 causes the second ground circuit 72 including the capacitors 31, 32 and 33 which are impedance elements.
And a third earth circuit 73 composed of a capacitor 41 which is an impedance element, flow into the shield case 22 and cancel each other as shown by a broken line 61 in the figure to reduce the high frequency power supply circuit 9 and the load. The high frequency noise generated in the circuit 40 and leaking to the outside of the shield case 22 can be reduced.

In the present embodiment, the impedance Z1 of one earth circuit 71 composed of the capacitors 11 and 12, the impedance Z2 of the second earth circuit 72 composed of the capacitors 31, 32 and 33, and the capacitor. When the impedance Z3 of the third ground circuit 73 composed of 41 is formed so that Z1>Z2> Z3, the high frequency noise generated in the high frequency power supply circuit 9 and the load circuit 40 is transmitted through the DC power supply circuit 2 and the power supply line. It becomes difficult to return to 10 and the high frequency noise can be further significantly reduced. Further, in the present embodiment, since the matching circuit 7 is a circuit that performs impedance matching of both the high frequency power supply coil 4 and the high frequency power amplifier 6 to eliminate reflection, whichever of the high frequency power supply circuit 9 and the load circuit 40 is used. May be contained in both, and may be contained in both.

FIG. 3 is a circuit diagram of a second embodiment of the discharge lamp lighting device according to the present invention.
Of the high frequency power supply circuit 9
Is a half-bridge inverter circuit, and the load circuit 40 is a discharge lamp 50 having electrodes. Then, the second ground circuit 72 is configured by a capacitor 34 in place of the capacitors 31, 32, 33 in the first embodiment, and the input end side of the high frequency power supply circuit 9 and the shield case 22 are connected to the second ground. In addition to being connected via the circuit 72, the output end side of the DC power supply circuit 2 and the shield case 22 are connected by a fourth ground circuit 74 composed of a capacitor 42 which is an impedance element. Since the configuration is substantially the same as that of the first embodiment, the same components as those of the first embodiment are designated by the same reference numerals, and the duplicated description will be omitted.

FIG. 4 shows a schematic view of the discharge lamp lighting device of the present embodiment, and the effects of the present embodiment will be described below. The low-frequency noise generated in the DC power supply circuit 2 is shielded via a first earth circuit 71 including the capacitors 11 and 12 which are impedance elements and a fourth earth circuit 74 including the capacitor 42 which is an impedance element. 22 and cancel each other as indicated by a broken line 62 in the figure, so that low frequency noise generated in the DC power supply circuit 2 can be reduced. Further, the high frequency noise generated in the high frequency power supply circuit 9 and the load circuit 40 is caused by the second ground circuit 72 including the capacitor 34 which is an impedance element,
3rd which consists of the capacitor 41 which is an impedance element
Flow into the shield case 22 through the ground circuit 73 of FIG. 2 and cancel each other out as shown by the broken line 63 in the figure to further reduce the noise. Therefore, the high frequency power circuit 9 and the load circuit 40 generate the shield case 22. High-frequency noise leaking to the outside of the vehicle can be reduced more reliably.

In the present embodiment, the impedance Z1 of one earth circuit 71 composed of the capacitors 11 and 12, the impedance Z2 of the second earth circuit 72 composed of the capacitor 34, and the third impedance composed of the capacitor 41. When the impedance Z3 of the ground circuit 73 and the impedance Z4 of the fourth ground circuit 74 including the capacitor 42 are formed such that Z1 and Z4> Z2 and Z3, the high frequency generated by the high frequency power supply circuit 9 and the load circuit 40. It becomes difficult for noise to be transmitted through the DC power supply circuit 2 and returned to the power supply line 10, so that high-frequency noise can be significantly reduced.

FIG. 5 shows a schematic circuit diagram of the third embodiment of the discharge lamp lighting device of the present invention. The difference from the second embodiment is that there is no capacitor 42 and the high frequency power supply is provided. The circuit 9 includes an electrolytic capacitor 43 for smoothing the DC output of the DC power supply circuit 2 on its input end side, and a second earth circuit 72 is provided between the negative electrode terminal of the electrolytic capacitor 43 and the shield case 22. The configuration is the same as that of the second embodiment except that the capacitor 34 is provided. Therefore, the same components as those of the second embodiment are designated by the same reference numerals, and a duplicate description will be omitted. Omit it.

With this structure, the high frequency power supply circuit 9 operates using the electrolytic capacitor 43 as a power supply, so that high frequency noise generated from the high frequency power supply circuit 9 can be further prevented from being transmitted to the DC power supply circuit 2.

In this embodiment, the electrolytic capacitor 43 for smoothing the DC output of the DC power supply circuit 2 is used.
Is provided on the input end side of the high frequency power supply circuit 9, but the present invention is not limited to this, and the electrolytic capacitor 43 may be provided on the output end side of the DC power supply circuit 2.

FIG. 6 is a schematic circuit diagram of a fourth embodiment of the discharge lamp lighting device of the present invention. The difference from the first embodiment is that the shield case 22 and the shield case 22 are different from each other. The case 23 is provided, and in the shield case 23, the matching circuit 7 and a third earth circuit 73 including a capacitor 44 which is an impedance element and a ferrite bead 45 in place of the capacitor 41 are provided, and the output end side of the matching circuit 7 is provided. And the shield case 23 are connected via the third earth circuit 73, and the shield case 2
2 and the shield case 23 are housed in the instrument body 24, and the inner wall of the instrument body 24 is electrically connected to each other. Others are substantially the same as those of the first embodiment. Therefore, the same components as those in the first embodiment are designated by the same reference numerals, and the duplicated description will be omitted. Here, the instrument body 24 is grounded. Even with this configuration, it is possible to reduce high-frequency noise generated in the high-frequency power supply circuit 9 and the load circuit 40 and prevent the high-frequency noise from leaking to the outside of the instrument body 24.

FIG. 7 shows a schematic circuit diagram of a fifth embodiment of a discharge lamp lighting device of the present invention. The difference from the fourth embodiment is that the shield case 22 is replaced by a direct current. A shield case 25 for housing the power supply circuit 2 and a shield case 26 for housing the high frequency power supply circuit 9 are provided.
The input end side of the DC power supply circuit 2 and the shield case 25 are connected via the first ground circuit 71, and the input end side of the high frequency power supply circuit 9 and the shield case 26 are connected via the second ground circuit 72. , Shield case 23,
25 and 26 and the load circuit 40 are housed in the instrument main body 24 having the translucent lid 25, and the shield cases 23 and 2
5, 26 and the inner wall of the instrument main body 24 are electrically connected, and other points are substantially the same as those in the fourth embodiment, and therefore the same configuration as that of the fourth embodiment is the same. The reference numerals are given and the duplicated description is omitted. Even with this configuration, the same effect as that of the fourth embodiment can be obtained.

It should be noted, in the above respective embodiments may be any as long as the high-frequency power supply circuit unit for converting DC power to AC power. Also, the earth circuit, which is composed of a capacitor that is an impedance element and is connected to the shield case, makes the high-frequency impedance between the input end of the high-frequency power supply circuit and the shield case appear small even if it is composed of other impedance elements. Any structure may be used.

[0030]

As described above, according to the present invention, the high frequency noise generated in the high frequency power supply circuit causes the high frequency noise generated in the first to third ground circuits. Since they flow into the shield case via the electrodes and cancel each other, the high frequency noise generated in the high frequency power supply circuit and leaking to the outside of the shield case can be reduced. Special
In the invention according to claim 1, a high frequency power supply circuit and
High frequency noise generated in the load circuit is transmitted to the DC power supply circuit.
It becomes difficult to return to the power line, and the high frequency
Wave noise can be reduced. In addition, claim 2 or
In the invention according to claim 3, the high frequency power supply circuit is electrolytic.
High-frequency power supply circuit because it operates with a capacitor as a power supply
The high frequency noise generated from the
It can be difficult to feel.

In the inventions according to claims 4 to 6, the high-frequency noise generated in the high-frequency power supply circuit is the first noise.
Strike through the shield case through the third earth circuit
They occur in the high frequency power circuit because they are canceled out and reduced.
The high frequency noise that leaks to the outside of the shield case can be reduced.
In addition to the above, since the fourth earth circuit is provided in addition to the first to third earth circuits, the high frequency noise generated in the high frequency power supply circuit flows to the shield case through the first to fourth earth circuits. The high-frequency noises generated in the high-frequency power supply circuit and leaking to the outside of the shield case can be further reliably reduced.

Further, in the inventions according to claims 1 to 6 , even if the DC power supply circuit includes a chopper circuit, high frequency noise and noise generated from the chopper circuit leak to the outside of the shield case. Can be reduced.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a first embodiment of a discharge lamp lighting device of the present invention.

FIG. 2 is a block configuration diagram of the above.

FIG. 3 is a circuit diagram showing a second embodiment of a discharge lamp lighting device of the present invention.

FIG. 4 is a block configuration diagram of the above.

FIG. 5 is a block configuration diagram showing a third embodiment of a discharge lamp lighting device of the present invention.

FIG. 6 is a block configuration diagram showing a fourth embodiment of a discharge lamp lighting device of the present invention.

FIG. 7 is a block configuration diagram showing a fifth embodiment of a discharge lamp lighting device of the present invention.

FIG. 8 is a circuit diagram showing a conventional discharge lamp lighting device.

FIG. 9 is a block configuration diagram of the above.

[Explanation of Codes] 1 AC power supply 2 DC power supply circuit 3, 50 Discharge lamp 9 High frequency power supply circuit 11, 12, 31, 32, 33, 34, 41, 42, 4
4,45 Impedance elements 22, 23, 25, 26 Shield case 40 Load circuit 43 Electrolytic capacitor 71 First earth circuit 72 Second earth circuit 73 Third earth circuit 74 Fourth earth circuit

Claims (6)

(57) [Claims] 1. A load circuit including a discharge lamp, a high frequency power supply circuit for supplying high frequency power to the load circuit, and a direct current power supply circuit connected to an alternating current power supply for supplying direct current power to the high frequency power supply circuit. In the discharge lamp lighting device, the DC power supply circuit includes a chopper circuit, the operating frequency of which is from several tens of kHz to several hundred kHz, and the operating frequency of the high frequency power supply circuit is from several MHz to several hundred MHz, and at least the high frequency power supply circuit. And the DC power supply circuit are housed in a grounded conductive shield case, and the input end side of the DC power supply circuit and the shield case are connected by a first ground circuit composed of an impedance element, The input terminal side of the high frequency power supply circuit and the shield case are connected by a second ground circuit including an impedance element, and the load is connected. The input terminal side of the circuit and the shield case are connected by a third ground circuit composed of an impedance element , and the first to third ground circuits are connected to each other .
The impedance of each earth circuit is the first earth
Circuit> Second earth circuit> Third earth circuit
A discharge lamp lighting device characterized in that it is formed in . 2. The high-frequency power supply circuit is smoothed on the input end side.
Comprising an electrolytic capacitor for this electrolytic capacitor
Between the vicinity of the negative electrode terminal of the
The discharge lamp lighting device according to claim 1, further comprising a ground circuit (2 ). 3. A load circuit including a discharge lamp, and this load circuit
High frequency power supply circuit that supplies high frequency power to the AC power supply
Directly connected to supply DC power to the high frequency power circuit
A discharge lamp lighting device comprising a
The DC power supply circuit includes a chopper circuit and its operating frequency is
From several tens of kHz to several hundreds of kHz,
The operating frequency is from several MHz to several hundred MHz, and at least
The high frequency power supply circuit and the DC power supply circuit were grounded
The DC power supply is housed in a conductive shield case.
There is an impedance between the input side of the circuit and the shield case.
Connect with the first earth circuit consisting of a dance element,
Between the input end of the frequency power supply circuit and the shield case
Connect with a second ground circuit consisting of an impedance element
The load circuit and the shield case
The third ground times to be be between the between the impedance element
The high-frequency power supply circuit includes a smoothing electrolytic capacitor on the input end side, and the second ground circuit is provided between the negative electrode terminal of the electrolytic capacitor and the shield case. discharge lamp lighting device you wherein a. 4. A load circuit including a discharge lamp, and this load circuit
High frequency power supply circuit that supplies high frequency power to the AC power supply
Directly connected to supply DC power to the high frequency power circuit
A discharge lamp lighting device comprising a
The DC power supply circuit includes a chopper circuit and its operating frequency is
From several tens of kHz to several hundreds of kHz,
The operating frequency is from several MHz to several hundred MHz, and at least
The high frequency power supply circuit and the DC power supply circuit were grounded
The DC power supply is housed in a conductive shield case.
There is an impedance between the input side of the circuit and the shield case.
Connect with the first earth circuit consisting of a dance element,
Between the input end of the frequency power supply circuit and the shield case
Connect with a second ground circuit consisting of an impedance element
The load circuit and the shield case
A third earth circuit consisting of an impedance element
Are connected by road, the DC power supply between the output terminal of the circuit and the shield case, the fourth discharge lamp lighting device you characterized in that a grounding circuit for connecting it between them from the impedance element . 5. The impedance of each of the first to fourth ground circuits is such that the impedances of the respective ground circuits are: first ground circuit, fourth ground circuit> second ground circuit, third ground circuit. The discharge lamp lighting device according to claim 4, wherein the discharge lamp lighting device is formed. 6. The DC power supply circuit includes an electrolytic capacitor for smoothing on the output end side, and the fourth ground circuit is provided between the negative potential side of the electrolytic capacitor and the shield case. The discharge lamp lighting device according to claim 4 or 5, characterized in that.