JP2003249389A - Lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting system making the noises hardly leaking from a discharge lamp lighting device to the outside even when the temperature rises in a common mode choke at lighting a discharge lamp on by quantitatively clarifying a relationship between a resonance frequency and an operating frequency for preventing the magnetic saturation of the common mode choke. <P>SOLUTION: The lighting system comprises the discharge lamp lighting device 4 having a printed board 1 on which electronic parts are mounted and a conductive case (a case body 2 and a case cover 3) storing the printed board 1 and connected to the discharge lamp 6 via a lead 5, and a conductive luminaire 9 (a luminaire body 7 and a reflecting plate 8) storing the discharge lamp lighting device 4. The operating frequency f of an inverter circuit is √2 to 1/√2 times the resonance frequency f0 of a LC resonance circuit which consists of an inductor L of the common mode choke and a floating capacitance C formed in an electrical closed loop including the common mode choke. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device with reduced noise.

[0002]

2. Description of the Related Art As a conventional example of this kind, Japanese Patent Laid-Open No. 2001-2001
The thing of 16061 gazette is mentioned. In this device shown in FIG. 16, a filter circuit 13J is connected to a commercial AC power source eJ via a terminal 12J. The filter circuit 13J includes a capacitor C1J, a common mode choke Tr1J, a normal mode choke L1J, a capacitor C2J, a ground capacitor C3J, and It has a grounding capacitor C4J.
The input terminal of the full-wave rectifier 15J is connected to the filter circuit 13J, the inverter circuit 16J is connected to the output terminal of the full-wave rectifier 15J, and the fluorescent lamp FLJ is connected to the inverter circuit 16J. The winding start of the coil of the normal mode choke L1J is located on the side of the inverter circuit 16J. And by configuring in this way,
The noise generated in the inverter circuit 16J and the discharge lamp FLJ is suppressed from flowing to the power supply side.

[0003]

However, in the above-mentioned conventional example, a quantitative method for preventing the noise generated in the inverter circuit from leaking to the outside due to the magnetic saturation of the common mode choke is not presented. . In particular, when the resonance frequency of the resonance circuit due to the stray capacitance formed between the inductor of the common mode choke and the printed circuit board or the lighting equipment and the operating frequency of the inverter circuit satisfy the relationship, the common mode choke It has not been quantitatively elucidated whether the magnetic saturation of the can be prevented.

The present invention has been made in view of the above problems, and its object is to quantitatively clarify the relationship between the resonance frequency and the operating frequency for preventing the common mode choke from causing magnetic saturation. An object of the present invention is to provide a lighting device in which noise generated in the discharge lamp lighting device is unlikely to leak to the outside even when the temperature of the common mode choke rises when the discharge lamp is lit.

[0005]

According to another aspect of the present invention, there is provided a lighting device having a printed circuit board on which electronic components are mounted and a conductive case for housing the printed circuit board, which is connected to a discharge lamp by a lead wire. In a lighting device provided with an inverter circuit type discharge lamp lighting device; and a conductive lighting fixture containing the discharge lamp lighting device; a common mode choke is mounted on a printed circuit board; When the resonance frequency of the LC resonance circuit composed of the stray capacitance C formed in the electrical closed loop including the common mode choke is f0 and the operation frequency of the inverter circuit is f, the operation frequency f is the resonance frequency f0. Is √2 times or more or 1 / √2 times or less.

In such a lighting device, the operating frequency of the inverter circuit is equal to the resonant frequency of the resonant circuit formed by the inductor of the common mode choke and the stray capacitance formed in the electrically closed loop including the common mode choke. When the discharge lamp is normally lit, the resonance current flowing through the resonance circuit can be suppressed to a sufficiently low level so that the common mode choke is not magnetically saturated. In particular, the temperature of the common mode choke rises during normal lighting of the discharge lamp,
Even when the inductor of the common mode choke changes and the resonance frequency changes, the resonance current can be suppressed to a sufficiently low level so that the common mode choke does not magnetically saturate.

An illumination device according to a second aspect is the illumination device according to the first aspect, characterized in that the operating frequency f is not less than twice or not more than 1/2 times the resonance frequency f0.

A lighting device according to a third aspect is the lighting device according to the first or second aspect, wherein the stray capacitance formed in the electrically closed loop is at least between the printed circuit board and the lighting fixture. It is characterized by including.

A lighting device according to a fourth aspect is the lighting device according to the first or second aspect, wherein the stray capacitance formed in the electrically closed loop is at least between the discharge lamp and the lighting fixture. It is characterized by including.

The lighting device according to claim 5 is the lighting device according to claim 1 or 2, wherein the stray capacitance formed in the electrically closed loop is at least between the lead wire and the lighting fixture. It is characterized by including.

An illumination device according to a sixth aspect is the illumination device according to the third aspect, characterized in that a space is provided between the printed board and the bottom plate of the case facing the printed board.

An illumination device according to a seventh aspect is the illumination device according to the sixth aspect, characterized in that a dielectric having a relative dielectric constant of 1 or less is inserted in the space portion.

An illumination device according to an eighth aspect is the illumination device according to the sixth aspect, characterized in that a thermally expansive member is inserted in a space between the printed board and the case.

According to a ninth aspect of the present invention, in the illuminating device according to the third aspect, the printed circuit board has a conductive pattern, and the bottom plate of the case facing the conductive pattern is provided with a notch. It is what

An illumination device according to a tenth aspect is the illumination device according to the ninth aspect, characterized in that the cutout overlaps with the conductive pattern in a plan view.

An illumination device according to an eleventh aspect is the illumination device according to the ninth aspect, wherein the notches have a substantially rectangular shape, and the notches are provided at regular intervals substantially perpendicular to the longitudinal direction of the bottom plate of the case. It is characterized by being provided.

According to a twelfth aspect of the present invention, in the illuminating apparatus according to the fourth aspect, the luminaire has a reflecting plate which is arranged to face the discharge lamp and reflects the light of the discharge lamp. It is characterized in that a notch is provided in the part.

A lighting device according to a thirteenth aspect is the twelfth aspect.
The illuminating device described above is characterized in that a notch is provided at or near the portion of the reflection plate where the potential difference between the discharge lamp and the reflection plate is maximum.

According to a fourteenth aspect of the present invention, there is provided the illumination device according to the fourth aspect, wherein the reflection plate is provided with a recess in accordance with a sectional shape of the discharge lamp in a sectional view perpendicular to a tube axis of the discharge lamp. It is a feature.

A lighting device according to a fifteenth aspect is characterized in that, in the lighting device according to the fifth aspect, the lead wire is supported by a support so that the lead wire does not come into contact with the lighting fixture.

A lighting device according to a sixteenth aspect is the lighting device according to the first or second aspect, wherein the discharge lamp lighting device uses a plurality of discharge lamps connected in series as compatible discharge lamps. It is characterized in that it is arranged at one end side in the longitudinal direction of the fixture, and that the connection point of each discharge lamp and the socket arranged at the other end side in the longitudinal direction of the lighting fixture are connected by a lead wire.

In such an illuminating device, the total length of the lead wires connecting each discharge lamp and the socket can be minimized.

An illumination device according to claim 17 is the illumination device according to claim 16.
In the lighting device described above, the number of discharge lamps is two.

[0024]

DETAILED DESCRIPTION OF THE INVENTION The technical background of the present invention will be described below.

FIG. 1 shows a sectional view of an illuminating device attached to a ceiling surface or the like, and FIG. 2 shows an external perspective view of the illuminating device.

This illuminating device has a printed circuit board 1 on which electronic components are mounted, a conductive case (case body 2 and case cover 3) for housing the printed circuit board 1, and a lead wire 5.
An inverter circuit type discharge lamp lighting device 4 connected to the discharge lamp 6; and a conductive lighting fixture 9 (the lighting fixture body 7 and the reflector 8) housing the discharge lamp lighting device 4. . A common mode choke 10 which is an electronic component is mounted on the printed board 1. The stray capacitance between the printed circuit board 1 and the lighting fixture body 7 is C1, the stray capacitance between the discharge lamp 6 and the reflector 8 is C2 and C2 ′,
The stray capacitance between the lead wire 5 and the lighting fixture body 7 is C3.

An equivalent circuit of such a lighting device can be represented as shown in FIG. Here, the high-frequency noise source is due to the on / off operation of the switching element included in the discharge lamp 6 or the inverter circuit, and the voltage across the discharge lamp 6 during normal lighting is Vs. In such an equivalent circuit, the resonance frequency f0 due to the inductor L of the common mode choke 10 and the stray capacitances C1, C2, C2 ′ and C3 is expressed by the following equation. f0 = 1 / (2π√ (L (C1 + C2 + C2 ′ + C3))) (1) Also, the resonance current iL flowing through the common mode choke 10
Is expressed by the following equation, where f is the frequency of the voltage Vs (this is also the operating frequency of the inverter circuit). iL = (2πf (C2 + C2 ′)) / (1− (2πf) ^ 2 × L (C1 + C2 + C2 ′ + C3)) × Vs (2) Using the formula (2), the operating frequency f and the resonance current iL The relationship (hereinafter, referred to as f-iL characteristic curve) with can be represented by the f-iL characteristic curve shown in FIG. here,
For example, the operating frequency f = 55 (kHz) and the inductance L of the common mode choke 10 considering the temperature rise.
= (10 mH) (for example, a commercial power source is often used in a discharge lamp lighting device for 200 V), stray capacitance C1 = 8
00 (pF) (For simplicity, stray capacitances C2, C
Ignore 2'and C3. ), From equation (1),
f0 = 56.3 (kHz), which is close to the operating frequency of the inverter circuit f = 55 (kHz). For this reason, the resonance current iL becomes large and the common mode choke 10 causes magnetic saturation, and the common mode choke 10
Does not fulfill the function of blocking the noise generated in the discharge lamp lighting device 4. As a result, noise is transmitted through the power line,
It may leak from the lighting fixture 9 to the outside, which may adversely affect external devices such as a telephone and a personal computer that share a power line with the lighting fixture 9.

Further, FIG. 5 shows a common mode choke 10
An example of the saturation magnetic flux density B (mT) with respect to the temperature T (° C) of is shown. The common mode choke 10 has different saturation magnetic flux densities at various temperatures due to differences in core materials and the like, but the gradient of the saturation magnetic flux density with respect to temperature is almost the same for any common mode choke. That is,
The operating temperature range of the common mode choke is -20 ℃ ～ 13
Considering a range of about 0 ° C., the saturation magnetic flux density B changes about twice with respect to room temperature (T = 25 ° C.).

Here, the inductance L of the common mode choke 10 is represented by the following equation, where B is the saturation magnetic flux density of the common mode choke 10, N is the number of turns, and S is the cross-sectional area. L = (B × N × S) / (iL) (3) That is, the inductance L and the saturation magnetic flux density B are in a proportional relationship. Also, the resonance frequency f0 and the inductance L
Has a relationship of the formula (1), the saturation magnetic flux density is 1 /
2B (T = −20 ° C.) to B (T = 25 ° C.) to 2B (T =
130 ° C), the resonance frequency becomes √2 × f
0 (T = -20 ° C) to f0 (T = 25 ° C) to 1 / √2x
It will change to f0 (T = 130 ° C.).

[0030]

EXAMPLE 1 Example 1 of the present invention will be described below with reference to FIG.
It will be described with reference to FIGS.

FIG. 6 is an external perspective view of the discharge lamp lighting device 4 (case body 2 and case lid 3) of the present invention.
FIG. 7 shows a sectional view. Here, the same components as those shown in FIG. 1 are designated by the same reference numerals.

The discharge lamp lighting device shown in FIG. 6 is composed of a conductive metal case body 2 and a conductive metal case lid 3 provided so as to cover the case body 2. The case body 2 has a U-shaped cross section as shown in FIG. 7. Here, the printed circuit board 1 has a power supply side terminal block 11 for supplying power to the inverter circuit mounted on one end in the longitudinal direction of the printed circuit board 1, and also supplies high frequency power to a discharge lamp (not shown). A load side terminal block (not shown) for mounting is mounted on the other end of the printed circuit board 1 in the longitudinal direction.

The case body 2 and the case lid 3 are formed by processing a sheet metal, and the inner surface of each side plate of the case body 2 is provided between the printed circuit board 1 and the bottom plate 2a of the case body 2. Four receiving pieces 12 that contact the printed circuit board 1 are integrally formed on the case body 2 so that the distance can be maintained at a specified distance or more. The four receiving pieces 12 are formed at positions so as to come into contact with the four corners of the printed circuit board 1, respectively. Further, the receiving piece 12 has a bridge shape protruding toward the side surface of the case body 2, and has a cross section parallel to the bottom plate 2a in an arc shape.

Further, four holding pieces 13 for holding the four corners of the printed circuit board 1 between them and the receiving piece 12 are integrally projectingly provided on the inner side surfaces of both side plates of the case main body 2, and the holding pieces 13 are held together. The piece 13 is formed by cutting and raising a part of the case body 2.

Further, on the inner side surfaces of both side plates of the case body 2, there are integrally provided protrusions 14 for restricting the movement of the printed board 1 in the longitudinal direction of the printed board 1. The regulation projection 14 has an end edge on the printed circuit board 1 side separated from the side plate, and the shape of the end edge is formed in an arc shape. The movement of 1 in the longitudinal direction is restricted.

Although not shown, an insulating sheet made of a flame-retardant synthetic resin or the like may be inserted between the case body 2 and the printed board 1. Further, the discharge lamp lighting device 4 has a separately excited inverter circuit, and the inverter circuit may be a charge pump type or combined with a chopper circuit having a grounding capacitor connected to the lighting fixture body 7. It may be an inverter circuit.

In such a discharge lamp lighting device 4, as shown in FIG. 7, the distance between the printed board 1 and the bottom plate 2a is set to d.
And the stray capacitance formed between the printed board 1 and the bottom plate 2a is C1.

Now, the power supply side terminal block 1 of the discharge lamp lighting device 4
Consider a state in which the commercial power supply is turned on and the inverter circuit lights the discharge lamp 6 at the operating frequency f. Considering the temperature rise of the common mode choke 10 in this lighting state,
Let us consider a condition that the operating frequency f and the resonance frequency f0 are not matched, that is, the common mode choke 10 is not magnetically saturated. FIG. 8 shows f similar to that shown in FIG.
-IL characteristic curve is shown, and f-iL characteristic curve C is shown.
In (1), the temperature of the common mode choke 10 is 25 ° C,
C (2) is at 130 ° C. and C (3) is at −20 ° C., respectively. That is, in the normal operating temperature range of the common mode choke 10, the resonance frequency is
It indicates a change in the range of 1 / √2 × f0 to f0 to √2 × f0. Therefore, in order that the operating frequency f does not match the resonance frequency f0, the operating frequency f needs to satisfy the following formula. f> √2 × f0 or f <1 / √2 × f0 (4) Also, consider the worst case where the operating frequency f is near the resonance frequency 1 / √2 × f0 or √2 × f0. Therefore, it is desirable to set the operating frequency f in the range of f> 2 × f0 or f <(1/2) × f0 ... (5). Here, in the separately-excited inverter circuit, an integrated circuit that drives a switching element that constitutes the inverter circuit (for example,
The high voltage integrated circuit IR2110 manufactured by International Rectifier Co., Ltd. has a working temperature range of −20 ° C.
At ˜150 ° C., there is almost no effect of temperature, and therefore the operating frequency f may be considered to be almost constant.

That is, in order for the operating frequency f to satisfy the equation (4) or the equation (5), the capacitance values of the stray capacitances C1, C2, C2 'and C3 are increased from the equation (1), or
Alternatively, it can be reduced. In particular, stray capacitances C1, C2, C
Reducing the capacitance values of 2'and C3 can reduce the leakage current leaking from the discharge lamp lighting device 4, which is more desirable.

Here, the case where the capacitance of the stray capacitance C1 is reduced will be considered. The value of stray capacitance C1 is printed circuit board 1
When the relative permittivity of the space between the case body 2 and the case body 2 is ε, the permittivity of the vacuum is ε0, and the area of the printed circuit board 1 is S, the following formula is given. C1 = (ε × ε0 × S) / d (6) Even if an instantaneous lightning surge voltage of about 5 kV is applied between the printed circuit board 1 and the case body 2, the discharge lamp lights up. It is often set to about 5 (mm) so that the device 4 is not destroyed. Here, for example, consider the discharge lamp lighting device 4 in which the area S of the printed circuit board 1 is 100 (mm) × 200 (mm). Since the relative permittivity ε of the space between the printed board 1 and the case body 2 may be slightly larger than the relative permittivity of air, the relative permittivity ε to 3.0 and the permittivity ε0 to 8. If 8 × 10 ^ (-12) (F / m) and the distance d to 5 (mm), the stray capacitance C1 to 150 (p)
F). Here, assuming that the inductance L of the common mode choke 10 is 10 (mH), the resonance frequency f0 to 100 (kHz) is obtained from the equation (1). The operating frequency f is 40 (kHz), considering the use of dimming.
It is often set to about 100 (kHz). That is, in order to prevent the resonance frequency f0 and the operating frequency f from approaching each other, it is preferable that the distance d be larger than 5 (mm). For example, when the distance is d to 6 (mm), the resonance frequency is f0 to 170 (kHz), and even if the operating frequency f changes between 40 (kHz) and 100 (kHz),
Since the operating frequency f and the resonance frequency f0 are sufficiently separated, the common mode choke 10 does not cause magnetic saturation. Therefore, in the above specific example, the distance d is 6 (m
It can be said that m) or more is desirable. As described above, the distance d may be appropriately set so that the operating frequency f satisfies the expression (4) or the expression (5) depending on the type of the discharge lamp lighting device.

In order to reduce the capacitance of the stray capacitance C1, as an application example, as shown in FIG. 9, the thermally expandable member VB is inserted in the space between the printed circuit board 1 and the case main body 2 to make the thermally expandable member C1. The printed circuit board 1 may be supported by VB. When the heat-expandable member VB is used in this way, when the discharge lamp 6 is turned on and the temperature of the discharge lamp lighting device 4 rises, the heat-expandable member VB also expands and the distance d increases.
Therefore, the stray capacitance C1 becomes smaller than the formula (6),
It is possible to prevent the operating frequency f from matching the resonance frequency f0.

When the discharge lamp lighting device 4 is used exclusively at a low temperature, contrary to the above-described application example, a low temperature contracting member which contracts at a low temperature may be used instead of the thermally expansive member VB. Even in this case, an insulating rubber-based member may be appropriately selected so as to satisfy the expression (4) or the expression (5) at the temperature used. Further, a dielectric material having a relative dielectric constant of 1 or less may be inserted in the space between the printed board 1 and the case body 2. By inserting such a dielectric, the relative permittivity of the space between the printed circuit board 1 and the case body 2 can be reduced, and the stray capacitance C1 can be reduced from the equation (6).

Further, another example for reducing the capacitance of the stray capacitance C1 is shown in FIG. This has a bottom plate 2a facing the conductive pattern 15 shown in FIG. 10 (a) arranged on the back surface of the printed circuit board 1 and a cutout 16 shown in FIG. 10 (b) having a conductive pattern in plan view. It is provided so as to polymerize with 15.

In general, the conductive pattern 15 on which the charges move.
A stray capacitance is likely to be formed in the area of when the high frequency is considered. Therefore, when the discharge lamp lighting device 4 is operating, the bottom plate 2a facing the conductive pattern 15 in which the charges move.
The notch 16a is provided in the. By providing the notch 16a in this way, the distance d can be increased as much as possible by the equation (6), and the capacitance of the stray capacitance C1 can be reduced.

The shape and arrangement of the cutouts 16a are not limited to those in the above embodiment, and for example, in order to simplify the manufacturing process for providing the cutouts, a rectangular cutout is formed as shown in FIG. The notches 16b may be provided at regular intervals substantially perpendicular to the longitudinal direction of the bottom plate 2a. Providing the notch 16b in the bottom plate 2a can also provide the effect of radiating the heat generated from the discharge lamp lighting device 4. In particular, when the notch 16 is provided in the bottom plate 2a facing the portion where the common mode choke 10 is mounted, the effect that the common mode choke 10 is dissipated and magnetic saturation is less likely to occur can be achieved. (Embodiment 2) Hereinafter, Embodiment 2 of the present invention will be described with reference to FIGS.
This will be described with reference to FIG.

In this embodiment, the case where the stray capacitance C2 (or stray capacitance C2 ') between the discharge lamp 6 and the reflector 8 is made small will be considered. Similar to the first embodiment, the relative permittivity between the discharge lamp 6 and the reflector 8 is ε, the permittivity of vacuum ε0, the reflector 8
If the area of the portion facing the discharge lamp 6 of S is S and the distance between the reflector 8 and the discharge lamp 6 is d1, the stray capacitance C2 is expressed by the following equation. C2 = (ε × ε0 × S) / (d1) (7) In FIG. 12, the notch 17a is provided in the vicinity of the portion of the reflector 8 where the potential difference between the discharge lamp 6 and the reflector 8 is maximum. Is provided. Here, the discharge lamp 6 is attached to the lamp socket 18.

During lighting of the discharge lamp 6, a discharge current flows between filaments (not shown) at both ends of the discharge lamp 6. A metallic guard ring (not shown) is provided in the vicinity of the filament of the discharge lamp 6 in order to prevent blackening of the surface glass of the discharge lamp 6 due to thermoelectrons jumping from the filament. Therefore, electrons and ions of plasma are prevented from moving in the tube axis direction of the discharge lamp 6. As a result, the potential gradient in the vicinity of both ends of the discharge lamp 6 becomes sharply higher than in the central portion. That is, the ground voltage at either end of the discharge lamp 6 becomes the maximum of the ground voltage of the discharge lamp 6. If the notch 17a is provided in this portion,
Since the distance d1 becomes large, the stray capacitance C2 is calculated from the equation (7).
Becomes smaller. Then, the size of the notch 17a is appropriately changed so that the operating frequency f satisfies the expression (4) or the expression (5). By providing the notch 17a in the reflection plate 8 in this manner, the operating frequency f can be separated from the resonance frequency f0, and the resonance current iL flowing in the resonance circuit during normal lighting of the discharge lamp 6 does not cause the common mode choke 10 to be magnetically saturated. It can be suppressed to a sufficiently low level, and an effect of radiating heat generated from the discharge lamp lighting device 4 housed in the lighting fixture 9 can be achieved.

Of course, as shown in FIGS. 13 (a) and 13 (b), the notch 1 is formed in the entire reflecting plate 8 facing the discharge lamp 6.
7b may be provided, or as shown in FIG. 13C, the reflection plate 8 may be provided with a recess 8a in accordance with the cross-sectional shape of the discharge lamp 6 in a sectional view perpendicular to the tube axis of the discharge lamp 6. Good.

The circuit configurations, operations, effects and the like not particularly mentioned in the above description are the same as those of the embodiment and the first embodiment of the invention. (Embodiment 3) Hereinafter, Embodiment 3 of the present invention will be described with reference to FIGS.
This will be described with reference to FIG.

In this embodiment, the case where the stray capacitance C3 formed between the lead wire 5 and the lighting fixture 9 is reduced will be considered. Similar to the first embodiment, the relative permittivity between the lead wire 5 and the lighting fixture 9 is ε, the permittivity of vacuum is ε0, and the area of the portion of the reflector 8 that contacts the lead wire 5 is S (approximately the lead wire 5). The length) and the distance between the reflection plate 8 and the lead wire 5 is d2, the stray capacitance C3 is expressed by the following equation. C3 = (ε × ε0 × S) / (d2) (8) That is, the stray capacitance C3 is particularly affected by the length of the lead wire 5 and the distance d2.

In this embodiment, as shown in FIG. 14 (a), the lead wire 5 is supported by the supporting member 19, and the distance d2 is appropriately set so that the operating frequency f satisfies the expression (4) or the expression (5). The size of is set. In particular, it is effective to increase the distance d2 in a single-lamp connected lighting fixture having a long lead wire or a so-called T-span lighting fixture.

Here, as shown in FIGS. 14 (b) to 14 (d), if the supporting member 19 can easily remove the lead wire 5, the workability is improved, which is more preferable. Alternatively, a supporting tool 20 as shown in FIGS. 15 (a) to 15 (c) may be used. When such a support tool 20 is used, even when the lighting fixture 9 vibrates, the support tool 20 absorbs the force due to the vibration, and the distance between the lead wire 5 and the lighting fixture 9 can always be kept constant.

Further, the length of the lead wire 5 may be shortened to reduce the stray capacitance. For example, in the lighting fixture 9 for two lights shown in FIG. 2, when the two discharge lamp lighting devices 4 are connected in series, the discharge lamp lighting device 4 is arranged in the longitudinal direction of the lighting fixture body 7 of the lighting fixture 9. The lead wire 5 connects the connection point of each of the discharge lamps 6 and the socket 18 arranged at the other end of the lighting fixture 9 in the longitudinal direction.

With this structure, the total length of the lead wires 5 connecting the discharge lamps 6 and the sockets 18 can be made as short as possible, and the stray capacitance can be reduced.

Here, the first embodiment is the same as that shown in the third embodiment.
Further, it is more effective to reduce the stray capacitance by combining those shown in the second embodiment.

The circuit configurations, operations, effects, etc., which are not particularly mentioned in the above description, are the same as those in the embodiment mode and the first embodiment.

Here, in the first to third embodiments, the stray capacitance is made small so that the operating frequency f does not coincide with the resonance frequency f0, but of course, the stray capacitance is made large so that the operating frequency f becomes the resonance frequency f0. May not match. In addition, by appropriately combining the first to third embodiments, it is possible to effectively reduce the entire stray capacitance formed in the electrically closed loop including the common mode choke 10, the common mode choke 10 does not cause magnetic saturation, and the discharge lamp. Lighting device 4
It is possible to provide the lighting device 9 in which the noise generated in 1 is unlikely to leak to the outside.

[0058]

The lighting device according to any one of claims 1 to 5, wherein the operating frequency of the inverter circuit is a stray capacitance formed in an electrically closed loop including the inductor of the common mode choke and the common mode choke. Since it does not match the resonance frequency of the resonance circuit formed by, the resonance current flowing through the resonance circuit during normal lighting of the discharge lamp can be suppressed to a sufficiently low level so that the common mode choke does not magnetically saturate. In particular, even when the temperature of the common mode choke rises during normal lighting of the discharge lamp, the inductor of the common mode choke changes, and the resonance frequency changes, the resonance current is kept low enough to prevent the common mode choke from being magnetically saturated. be able to. Therefore, it is possible to provide a lighting device in which noise generated in the discharge lamp lighting device is unlikely to leak to the outside.

In the lighting device according to any one of claims 6 to 11, the stray capacitance formed between the printed circuit board and the lighting fixture can be reduced by a relatively simple manufacturing process, and the discharge lamp can be reduced. During normal lighting, the resonance current flowing in the resonance circuit can be suppressed to a level low enough that the common mode choke does not magnetically saturate. Therefore, it is possible to provide a lighting device in which noise generated in the discharge lamp lighting device is unlikely to leak to the outside.

In the lighting device according to any one of claims 12 to 14, the stray capacitance formed between the discharge lamp and the lighting fixture can be reduced by a relatively simple manufacturing process. During normal lighting, the resonance current flowing in the resonance circuit can be suppressed to a level low enough that the common mode choke does not magnetically saturate. Therefore, it is possible to provide a lighting device in which noise generated in the discharge lamp lighting device is unlikely to leak to the outside.

In the lighting device according to any one of claims 15 to 17, the stray capacitance formed between the lead wire and the lighting fixture can be reduced by a relatively simple manufacturing process, and the discharge lamp can be reduced. During normal lighting, the resonance current flowing in the resonance circuit can be suppressed to a level low enough that the common mode choke does not magnetically saturate. Therefore, it is possible to provide a lighting device in which noise generated in the discharge lamp lighting device is unlikely to leak to the outside.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a lighting device attached to a ceiling surface or the like in an embodiment.

FIG. 2 is an external perspective view of a lighting device attached to a ceiling surface or the like in the embodiment.

FIG. 3 is an equivalent circuit diagram showing an equivalent circuit of the lighting device in the embodiment.

FIG. 4 is an f-iL characteristic curve in the embodiment.

FIG. 5 is a characteristic diagram of temperature-saturation magnetic flux density of a common mode choke.

FIG. 6 is an external perspective view of the discharge lamp lighting device according to the first embodiment.

FIG. 7 is a cross-sectional view of the discharge lamp lighting device according to the first embodiment.

FIG. 8: fi at each temperature of the common mode choke
It is an L characteristic curve.

FIG. 9 is a cross-sectional view of a discharge lamp lighting device in an applied example.

FIG. 10 is an external view showing another application example.

FIG. 11 is an external view showing still another application example.

FIG. 12 is an external view showing a second embodiment.

FIG. 13 is an external view showing an application example of the second embodiment.

FIG. 14 is an external view showing another application example of the second embodiment.

FIG. 15 is an external view showing still another application example of the second embodiment.

FIG. 16 is a circuit diagram showing a conventional example.

[Explanation of symbols]

Printed circuit board 1 2 Case body (case) 2a bottom plate 3 Case lid (case) 4 Discharge lamp lighting device 5 lead wires 6 discharge lamp 8 reflector 8a recess 9 lighting equipment 10 common mode chokes C1, C2, C2'C3 stray capacitance VB thermal expansion member 16a, 16b Notch 17a, 17b Notch 18 socket

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor, Joji Oyama             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.             Inside the company F term (reference) 3K072 AA01 AB01 AC02 AC11 BC01                       DD03 DD04 EB02 FA05 FA08                       FA09 GB01 HA05 HA06

Claims (17)

[Claims] 1. A discharge lamp lighting device of an inverter circuit type having a printed circuit board on which electronic parts are mounted and a conductive case for housing the printed circuit board, and connected to the discharge lamp by a lead wire; And a conductive luminaire for accommodating the device, wherein a common mode choke is mounted on a printed circuit board and is formed in an electrically closed loop including an inductor L of the common mode choke and the common mode choke. L composed of stray capacitance C
When the resonance frequency of the C resonance circuit is f0 and the operation frequency of the inverter circuit is f, the operation frequency f is the resonance frequency f.
An illumination device characterized by being √2 times or more of 0 or 1 / √2 times or less. 2. The illuminating device according to claim 1, wherein the operating frequency f is not less than twice or not more than 1/2 times the resonance frequency f0. Lighting equipment. 3. The lighting device according to claim 1, wherein the stray capacitance formed in the electrically closed loop includes at least a stray capacitance formed between the printed circuit board and the lighting fixture. 4. The lighting device according to claim 1, wherein the stray capacitance formed in the electrically closed loop includes at least the stray capacitance formed between the discharge lamp and the lighting fixture. 5. The lighting device according to claim 1, wherein the stray capacitance formed in the electrically closed loop includes at least a stray capacitance formed between the lead wire and the lighting fixture. 6. The lighting device according to claim 3, wherein a space is provided between the printed board and the bottom plate of the case facing the printed board. 7. The lighting device according to claim 6, wherein a dielectric having a relative dielectric constant of 1 or less is inserted in the space. 8. The lighting device according to claim 6, wherein a thermally expansive member is inserted in a space between the printed board and the case. 9. The lighting device according to claim 3, wherein the printed circuit board has a conductive pattern, and a notch is provided in the bottom plate of the case facing the conductive pattern. 10. The lighting device according to claim 9, wherein the notch overlaps with the conductive pattern in a plan view. 11. The notch has a substantially rectangular shape,
The lighting device according to claim 9, wherein the notches are provided at a constant interval substantially perpendicular to the longitudinal direction of the bottom plate of the case. 12. The lighting device has a reflector plate that is arranged to face the discharge lamp and reflects the light of the discharge lamp, and a cutout is provided in a part of the reflector plate. Lighting equipment. 13. The lighting device according to claim 12, wherein a cutout is provided in the portion of the reflection plate or the vicinity thereof where the potential difference between the discharge lamp and the reflection plate is maximum. 14. The illumination device according to claim 4, wherein the reflection plate is provided with a recess in accordance with the sectional shape of the discharge lamp in a sectional view perpendicular to the tube axis of the discharge lamp. 15. The lighting device according to claim 5, wherein the lead wire is supported by a support so that the lead wire does not contact the lighting fixture. 16. A discharge lamp lighting device using a plurality of discharge lamps connected in series as compatible discharge lamps, wherein the discharge lamp lighting device is arranged at one end side in a longitudinal direction of a lighting fixture, and a connection point of each discharge lamp. The lighting device according to claim 1, wherein the lighting device and a socket provided on the other end side in the longitudinal direction of the lighting device are connected by a lead wire. 17. The lighting device according to claim 16, wherein the number of discharge lamps is two.