JPH06203808A - Solenoid magnetic field type electric discharge lamp and lighting system using same - Google Patents

Abstract

PURPOSE:To reduce the resistance to high-frequency current so as to increase coil efficiency and to enhance the coupling efficiency of an exciting coil to a bulb by regulating the relationship between the bore of each of the pair of circular discs forming the exciting coil and effective current path width. CONSTITUTION:A high-frequency exciting coil 20 for causing a plasma discharge in a bulb 10 is formed by a pair of circular discs 21 each of a flat cross section. The discs 21 have their inner peripheral edges made to approach each other and have their outer peripheral edges spaced apart from each other. When the bore of each disc 21 is d1 and the effective path width for a current flowing in the circumferential direction of the discs 21 is W, 0.06<=W/d1<=0.5. When the width W of each disc 21 becomes too large a high frequency current flows at the outer peripheral portion of each disc, deteriorating the efficiency of energy supply to the bulb 10. As the bore d1 increases the inner edge of each disc 21 is separated from the bulb 10, so their coupling efficiency deteriorates. As the bore d1 decreases the inner peripheral edge of each disc 21 approaches the bulb 10 with the coupling efficiency of the coil to the bulb increased so that the efficiency of high-frequency power supply is enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solenoid magnetic field discharge lamp in which plasma is generated in a bulb by a high frequency excitation coil, and a discharge substance in the bulb is discharged or emits light by this discharge, and an illumination using the same. Regarding the device.

[0002]

Conventional high pressure metal vapor discharge lamps, or HIs
In the D discharge lamp, electrodes made of high melting point metal are sealed at both ends of the arc tube bulb, arc discharge is generated between these electrodes, and the luminous metal enclosed in the bulb is ionized and excited to emit light. Has become. However, a lamp having such electrodes requires electrode parts because the electrodes must be arranged inside the bulb, and the sealing structure for these electrodes is complicated, preventing leakage from the electrode sealing part. Therefore, there are various drawbacks such as the need to take special measures to do so and the electrodes being eroded because they are exposed to the discharge space.

As a lamp that eliminates such drawbacks,
Attention is paid to a solenoid magnetic field type discharge lamp. In the solenoid magnetic field type discharge lamp, a discharge material or a luminescent material is enclosed in a transparent bulb, and a high frequency excitation coil is arranged so as to surround the bulb, and a plasma is generated in the bulb by the excitation coil. The discharge substance is discharged by means of the above, and it is also referred to as an electrodeless discharge lamp because there is no electrode inside the bulb, and the above-mentioned problems in the case of an electrode type lamp can be solved.

By the way, in this type of solenoid magnetic field type discharge lamp, since discharge is performed with a low impedance, it is necessary to flow a high frequency of a large current of about 20 amperes in the excitation coil, and the resistance loss in the coil causes a lamp loss. It has a major impact on overall efficiency. That is, in this type of solenoid magnetic field type discharge lamp, the efficiency of the excitation coil is the main factor that influences the lamp efficiency. Therefore, it is desired to improve the efficiency of the excitation coil.

Conventionally, for example, Japanese Patent Laid-Open No. 12275/1990
Japanese Patent Publication No. 3 discloses a solenoid magnetic field type discharge lamp, in which, in order to improve the efficiency of the excitation coil, loss of high frequency current due to the excitation coil surrounding the valve is reduced, and this coil radiates from the valve. It has been proposed that it is important not to block the light that is emitted. In this publication, the conductivity of the surface of the excitation coil is increased and the reflectance is increased.

However, the means for reducing the high-frequency loss of the excitation coil is not only dependent on the conductivity and the reflection characteristics of the surface of the excitation coil, but according to the research conducted by the present inventors,
It has been found that it is necessary to increase the surface area to reduce the skin resistance, reduce the heat loss, and reduce the light shielding effect of the coil.

That is, the conventional coil uses a wire having a circular cross section, and therefore the surface area is relatively small when compared in the case where the cross sections are the same. It is known that high-frequency current in a conductor flows on the surface of the conductor. The larger the surface area, the larger the current path (skin effect), and the smaller the resistance. From this,
If the cross-sectional shape is made non-circular instead of circular, the surface area is increased and therefore the resistance can be reduced. Also, as the resistance becomes smaller, less heat is generated and the rise in coil temperature is prevented.In addition, if the cross-sectional shape is made non-circular, the surface area increases and the heat dissipation effect increases, so the coil temperature decreases. Therefore, the coil efficiency is increased and obstacles such as surface oxidation and creep deformation are prevented. From this, the applicant has focused on making the cross-sectional shape of the coil non-circular, as proposed in Japanese Patent Application No. 3-247664.

In this case, if the adjacent coils are close to each other, an induced current is generated between them, and the two coils have a thermal effect on each other, and the light emitted from the bulb is blocked. Therefore, the cross-sectional shape of the conductor of the excitation coil is a flat plate shape having a flat shape along the direction intersecting the coil axis direction, thereby increasing the surface area, reducing the high frequency resistance and reducing the temperature rise, Further, there are advantages that the thickness of the conductor can be reduced, the distance between the adjacent conductors can be increased, and the light shielding effect can be reduced.

[0009]

However, in order to increase the surface area to enhance the skin effect and to increase the heat radiation area to suppress the temperature rise, the conductor forming the coil is made flat and its annular circle is formed. It is sufficient to increase the width w of the plate, but even if the width w of the flat annular disc is increased, there is a problem that the outer shape of the lamp becomes large, and the high-frequency current is the outer periphery of the annular disc. There is concern that the coupling efficiency of the high frequency power to the valve arranged at the center will be significantly reduced since it flows through the section.

When the width is the same, increasing the inner diameter of the annular disc increases the surface area of the annular disc. In this way, the valve and the annular disc are separated from each other, and the coil and the valve are separated from each other. Coupling efficiency is significantly reduced.

The present invention has been made in view of the above circumstances. An object of the present invention is to improve the coil efficiency of the excitation coil itself and the coupling efficiency with the valve, thereby improving the overall efficiency. The present invention is intended to provide a solenoid magnetic field type discharge lamp and an illuminating device using the same.

[0012]

According to the first solenoid magnetic field type discharge lamp of the present invention, a discharge substance is enclosed in a translucent bulb, and a high frequency excitation coil is arranged so as to surround the bulb. In the solenoid magnetic field type discharge lamp in which plasma is generated in the bulb by the exciting coil, the high frequency exciting coil has a flat annular disc having a width extending in a direction intersecting with the coil axis direction around the coil axis. Arranged more than one turn, this circular disc has an inner diameter of d ₁ (m
m), where w (mm) is the effective passage width of the current flowing in the circumferential direction, 0.06 ≦ w / d ₁ ≦ 0.5 is satisfied.

The second solenoid magnetic field type discharge lamp of the present invention is such a solenoid magnetic field type discharge lamp in which a mercury-free discharge substance is enclosed in a translucent bulb, and the inside diameter of the bulb is d (mm ), The high-frequency excitation coil has one or more turns of a flat annular disc having a spread in a direction intersecting with the coil axis direction, and the annular disc is
The inner diameter is d ₁ (mm), the effective passage width of the current flowing in the circumferential direction is w (mm), the frequency of the high-frequency power flowing to this exciting coil is f (MHz), and the rated input P (watt) to this exciting coil is In this case, 0.06 ≦ w / d ₁ ≦ 0.5 10 ≦ f ≦ 100 10 ≦ d ≦ 50 250 ≦ d · f ≦ 7.5P is satisfied. The lighting device of the present invention is characterized by being provided with a cooling device which blows cooling air onto the discharge lamp to forcibly cool it by air.

[0014]

In this type of solenoid magnetic field type discharge lamp, if the width w of the annular disc becomes too large, not only the lamp system becomes large, but also the light shielding effect increases, and the high frequency current causes the annular disc Since it flows through the outer peripheral part of the valve, the efficiency of energy supply to the valve installed in the central part deteriorates. When the inner diameter d ₁ of the annular disc is increased, the inner edge of the annular disc is separated from the valve, so that the coupling efficiency is reduced. On the other hand, when the inner diameter d ₁ of the annular disc is reduced, the inner peripheral edge of the annular disc approaches the valve and the coupling efficiency between the coil and the valve increases, so that the energy supply efficiency increases.

Therefore, in the solenoid magnetic field type discharge lamp of the present invention, the resistance of the high frequency current can be reduced by regulating the relationship between the inner diameter d ₁ and the width w of the pair of annular discs forming the excitation coil. The rise in temperature is suppressed, the coil efficiency is increased, the coupling efficiency between the coil and the valve is increased, and the high frequency power supply efficiency is increased.

Further, in the lighting device of the present invention, the solenoid magnetic field type discharge lamp is forcedly cooled by the cooling device, so that the lamp efficiency is further improved and the efficiency of the entire system is improved.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 show a first embodiment of the present invention. In the drawings, reference numeral 1 is a solenoid magnetic field type discharge lamp, and 10 is an arc tube bulb thereof. The arc tube bulb 10 is made of a high melting point glass such as synthetic quartz or a transparent ceramic material such as alumina, and has an elliptic spherical shape. In the bulb 10, a luminescent substance which emits light by an arc discharge 12 induced by plasma, for example, a metal halide, NaI-CeI ₃
Is enclosed. In addition to the light emitting substance, at least one rare gas for starting such as argon, xenon, krypton, neon, etc. is enclosed in the bulb 10.

A starting thin tube 15 is connected to one end of the valve 10 on the center line. This thin tube 15
Is preferably made of the same material as the valve,
It is isolated from the inside of the valve 10 via a partition wall 16. At least one of argon and krypton, for example, is filled in the thin tube 15 as a rare gas for starting.

A starting electrode 17 is attached to the starting thin tube 15. In the case of the present embodiment, the reduced diameter portion 14 is formed in the middle of the thin tube 15, and the split ring type starting electrode 17 is fitted into the reduced diameter portion 14.

Such a starting electrode 17 is used for the capacitor 1
It is connected to a starting circuit 18 including 8a, 18a 'and an impedance 18b, and this starting circuit 18 is connected to a high frequency oscillation circuit 26 via a matching box 25.

The starting circuit 18 has a switching means 3
0 is provided. Although not shown in detail, the switching means 30 is composed of an electronic switch or the like, and intermittently opens and closes the starting circuit 18 until the lamp is started. In other words, the switching means 30 has a function of alternately turning on and off, such as turning on the starting circuit 18 for 1 second, turning off for 1 second, and then turning on for 1 second again.

It should be noted that the switching means 30 can be switched so as to stop the on / off repetition and keep the off state when a signal from the optical sensor 31 is received. The optical sensor 31 emits a signal by detecting the light emitting state of the bulb 10.

An excitation coil 20 is arranged around the valve 10. The excitation coil 20 has one end connected to the high-frequency transmission circuit 26 via the matching box 25 and the other end connected to the earth 27,
13.56 MH supplied from this high-frequency oscillator circuit 26
A high frequency current of about z is applied. Due to such a high frequency current, a magnetic field is generated in the excitation coil 20 along the coil axis direction O-O of the excitation coil 20,
As a result, a donut-shaped arc discharge 12 due to plasma is generated in the bulb 10 housed in the central space of the coil 20 so as to surround the coil axis OO. The arc discharge 12 ionizes and excites the luminescent metal to emit light, which passes through the bulb 10 and is emitted to the outside.

In the excitation coil 20, the conductor corresponding to the coil wire is composed of a pair of annular metal discs 21, 21 having high conductivity such as high-purity aluminum, copper, or silver. These pair of annular discs 21, 21
Are arranged so as to face each other along the coil axis O-O direction, and part of the inner peripheral portion is welded to each other to be connected to each other to form a spiral energization path. That is, the pair of annular discs 21 and 21 are not continuous in the circumferential direction, but are separated from each other in the circumferential direction, and the inner peripheral portion of one annular disc 21 and the other annular disc 21 are separated from each other. And the inner peripheral portion thereof are partially connected to each other to form a spiral energization path as a whole.

In this case, the connecting projection 22a is formed on the inner peripheral portion of the one circular disc 21 and the other circular disc 2 is formed.
The connection projection 22b is also formed on the inner peripheral portion of 1, and the connection projections 22a and 22b are abutted and welded to each other so that the entire energization path has a spiral structure.

The inner peripheral edges of the pair of annular discs 21, 21 are close to each other, and the outer peripheral edges have a distance L larger than the distance 1 between the inner peripheral edges. Further, in the case of this embodiment, the annular discs 21 and 21 have a flat plate shape which is wide in the radial direction. And these ring-shaped disks 2
When the inner diameters of 1 and 21 are d ₁ mm and the width of the effective current-carrying path, that is, the substantial width is w, 0.06 ≦ w / d ₁ ≦ 0.5 (1).

As a concrete example of the dimensions, when the outer diameter of the valve 10 is 32 mm, the ring-shaped circular plates 21 and 21 which become the coil wire.
Has a plate thickness t of 2 mm, an inner diameter d ₁ of 35 mm, and an effective current path width w
Is 14 mm, the distance l between the inner peripheral edges of the adjacent circular disks 21, 21 is 2 mm, and the distance L between the outer peripheral edges is 8 mm. The operation of the solenoid magnetic field type discharge lamp having such a configuration, that is, the electrodeless discharge lamp will be described.

When the lamp is started, a starting voltage is supplied from the high-frequency oscillation circuit 26 to the starting electrode 17, and a high-frequency current is passed through the exciting coil 20 at the same time to generate an electric field in the bulb 10 by the high-frequency magnetic field. Then, a potential difference occurs between the starting electrode 17 and the electric field in the bulb 10, and the rare gas in the thin tube 15 causes glow discharge.

Therefore, an electric field gradient is generated between the glow discharge in the thin tube 15 and the electric field in the bulb 10,
Therefore, plasma discharge is induced in the bulb 10 and a ring-shaped discharge 12 is generated.

In the case of the present embodiment, the starting voltage is intermittently supplied to the starting electrode 17 by the action of the switching means 30. Therefore, glow discharge is intermittently generated in the thin tube 15. Therefore, the electric field acts on the partition 16 intermittently, and the concentrated electric field is not continuously applied to the partition 16, so that the temperature rise of the partition 16 is suppressed and the partition 16 does not melt.

When the lamp is started in this manner, the light-emitting substance in the bulb 10 is ionized and excited to emit light.
When this light emission is detected by the optical sensor 31, the switching means 30 stops its operation, and thereafter the starting circuit 18 is left open while the lamp is lit.

In the solenoid magnetic field type discharge lamp which operates as described above, the high frequency excitation coil 20 for inducing plasma discharge in the bulb 10 is constituted by a pair of annular discs 21 and 21 having a flat cross section. The surface area increases when the values are the same as when the values are circular.

Therefore, the skin effect is expanded and the loss of high frequency current is reduced. That is, as the surface area increases, the flow path becomes larger and the current resistance is reduced, so that the coil efficiency is improved. Further, since the surface area is large, the heat dissipation area is increased, the cooling property is improved, and the surface temperature of the coil is lowered in combination with the decrease in the current resistance. This means that the energy wastedly released as heat is reduced, the coil efficiency is improved, and the temperature of the coil is lowered, so that obstacles such as surface oxidation and creep deformation are prevented.

Further, since the pair of annular discs 21 and 21 are spread in the radial direction, the structure is such that they extend along the radial direction in which the magnetic force lines extend, and the magnetic force lines form the annular discs 21 and 21.
21 is less obstructed. Therefore, each circular disc 2
The proportion of eddy currents generated in Nos. 1 and 21 is reduced, and Joule heat is prevented from being generated to reduce heat generation.

Furthermore, since the annular discs 21, 21 have a larger gap L between their outer peripheral edges than their inner peripheral edges, the valve 10
The ratio of blocking the light emitted from is reduced, and the irradiation efficiency is improved. Further, as shown in the formula (1), the respective annular discs 21 and 21 are set to 0.06 ≦ w / d ₁ ≦ 0.5, so that the energy efficiency supplied from the excitation coil 20 to the valve 10 is improved. To do.

That is, when the width w of the annular discs 21, 21 is increased, the cross-sectional area is increased, the electric resistance is decreased, and the surface area is increased, so that the heat dissipation area is increased and the coil efficiency is improved. However, if the width w becomes too large, the electric current will flow around the outer circumferences of the annular discs 21 and 21, and the valve 10 installed at the center of the coil 20 will be described.
Since it flows through a portion far from the valve 10, the efficiency of energy supply to the valve 10 deteriorates.

When the inner diameter d ₁ of the annular discs 21, 21 is increased, the width w of the annular discs 21, 21 must be increased in order to maintain the electric resistance below a predetermined level. The same inconvenience occurs as when the size is increased. When the inner diameter d ₁ of the annular discs 21, 21 is increased,
Since the inner edges of the annular discs 21, 21 are separated from the valve 10, the coupling efficiency is reduced.

On the other hand, when the inner diameter d ₁ is reduced, the inner peripheral edges of the annular discs 21, 21 approach the valve 10 and the annular disc 2
Since the clearance dimension s between the outer peripheral surface of the inner peripheral edge of the valve 1, 21 and the valve 10 is reduced and the coupling efficiency is increased, the energy supply efficiency from the coil 20 to the valve 10 is increased. From this, if the widths w of the circular disks 21, 21 are the same, it is advantageous to reduce the inner diameter d ₁ .

The plate thickness t of the circular discs 21, 21 is one of the factors that determine the size of the cross-sectional area. The circular discs 21, 21 of this type are made of high-purity aluminum, copper, or A pair of ring-shaped metal discs with excellent conductivity such as silver 2
The plate thickness t is formed by about 1 and 21 to about 2 mm,
This value is set to around 2mm and there is no significant change.
If the plate thickness t fluctuates around 2 mm, the amount of change can be ignored, and thus the plate thickness t is not particularly limited. From such a viewpoint, when the present inventors conducted an experiment, as shown in FIG. 2, the relationship between the inner diameter d ₁ of the annular discs 21 and the width w was 0.06 ≦ w / d ₁ ≦ 0.5. It was confirmed that the overall efficiency can be improved by using (1).

In FIG. 2, the vertical axis represents the coil 20 to the valve 10.
The energy efficiency of the energy transfer is shown, and the value of w / d ₁ is shown on the horizontal axis. The coil inner diameter d ₁ is taken as a parameter. When the effective current path width w of the coil is changed for the same coil inner diameter, the value of w / d ₁ is changed from 0.06 to 0.5.
It can be confirmed that if the ratio falls within the range, it is possible to keep the efficiency reduction within 5% from each peak.

It should be noted that the shorter the gap dimension s between the inner peripheral edges of the annular discs 21, 21 and the outer peripheral surface of the valve 10, the higher the coupling efficiency, and the higher the energy supply efficiency from the coil 20 to the valve 10. , This clearance dimension s is for valve 10
It is necessary to determine it in consideration of variations in the coil 20, the device not shown, and the like. In other words, the valve 10, the coil 20, or a device (not shown) may have processing variations,
There are variations in assembly, and the positional relationship between the valve 10 and the coil 20 is not always arranged with high precision as designed. For example, when the valve 10 and the coil 20 are arranged so as to be eccentric to each other, it is necessary to align the coil center with the arc center to prevent the arc from being biased or fluctuating. From this, the circular disc 21,
The clearance dimension s between the inner peripheral edge of 21 and the outer peripheral surface of the valve 10 is
Rather, it is better to set it to about 2 mm in anticipation of the adjustment margin. If the allowance gap dimension s is provided in the direction intersecting with the coil axial direction in this manner, the dimensions and the interrelationships of the valve 10, the coil 20, or a device (not shown) or the like may be obtained even if the degree of coupling is sacrificed. When there are variations, the position can be adjusted within the range of this dimension s = 2 mm, the arc center of the plasma discharge 12 and the coil center can be easily aligned, and it is possible to prevent deterioration of startability and efficiency. Since the valve 10 and the coil 20 do not interfere with each other, the assembly is easy. Next, another embodiment in which the above expression (1) is satisfied will be described with reference to FIGS. 3, 4, 5, and 6.

The second embodiment shown in FIG. 3 is a case where a pair of ring-shaped metal discs 21, 21 constituting the high-frequency excitation coil 20 are bent in the middle of the radial direction. metal disk 21, the effective channel width w of the current flowing in the circumferential direction can be expressed as w = w1 + w2, thereby, is satisfied _{0.06 ≦ w / d 1 ≦ 0.5} ... (1) Good.

The third embodiment shown in FIG. 4 is a case where a pair of ring-shaped metal disks 21, 21 constituting the high-frequency excitation coil 20 are curved in the radial direction, and the ring-shaped metal disk having such a structure is used. In the plate 21, the effective passage width w of the current flowing in the circumferential direction corresponds to the length w ′ along the curve (w = w ′), whereby 0.06 ≦ w / d ₁ ≦ 0.5 (1 ) Is satisfied.

In the fourth embodiment shown in FIG. 5, the pair of ring-shaped metal disks 21, 21 constituting the high frequency excitation coil 20 are
One is arranged horizontally and has a small width w ₃ , while the other is inclined and has a large width w _4.
This is an example in which (w ₃ <w ₄ ), and the ring-shaped metal discs 21 and 21 having such a structure have an effective passage width w of the current flowing in the circumferential direction as the narrow metal disc 21. Width w ₃ (w = w ₃ ), and based on this, 0.06 ≦ w / d ₁ ≦ 0.5 (1) may be satisfied.

In the fifth embodiment shown in FIG. 6, radially extending slits 23 are formed around each of a pair of ring-shaped metal discs 21, 21 constituting the high-frequency excitation coil 20. Radiating fins 24 ... Are formed around each of the metal disks 21, 21. In this case, the heat radiation fins 24 allow the heat of the annular discs 21, 21 to escape, so that the temperature rise of the annular discs 21, 21 can be effectively prevented. Moreover, in this case, the high-frequency current concentrates on the inner peripheral portions of the annular discs 21, 21 and flows in the circumferential direction, so that the coupling efficiency of the high-frequency magnetic field with the plasma discharge 12 generated in the bulb 10 is increased.

In such a structure, the effective passage width w of the current flowing in the circumferential direction corresponds to the width from the inner peripheral edge of the ring-shaped metal disk 21 to the inner end edges of the slits 23 ... 0.06 ≦ w / d ₁ ≦ 0.5 (1) should be satisfied. 7 and 8 show a sixth embodiment of the present invention and show an illuminating device using the solenoid magnetic field type discharge lamp 1 as a light source.

In FIG. 7, reference numeral 40 is a pole of an illuminating device for illuminating roads such as highways, and an illuminating device 41 is installed at the upper end. The height H of this pole 40 is
The wavelength λ of the high frequency current supplied to the solenoid magnetic field type discharge lamp 1 is set to be λ / 2 or an integral multiple of λ / 2. For example, when the output frequency of the high frequency oscillation circuit 26 is 13.56 MHz, the wavelength λ is 22.1 m, while the height H of the pole 40 is λ / 2 = 11.1.
It is set to 05m.

Lighting device 4 attached to the tip of pole 40
As shown in FIG. 8, the instrument body 42 has a lower surface opening closed by a prism cover 43, and a reflecting mirror 44 is installed in the instrument body 1. This reflector 44
The solenoid magnetic field type discharge lamp 1 shown in FIG. 1 is installed at a predetermined position therein. The light emitted from the discharge lamp 1 is reflected by the reflecting mirror 44, and the irradiation direction is controlled by the prism cover 43 to irradiate the road. A main lighting circuit including a high-frequency oscillating circuit 26 and a matching circuit 25 for maintaining the lighting of the discharge lamp 1 as shown in FIG. A starting circuit component 46 for starting the discharge lamp is housed.

One of the annular discs 21 of the high-frequency excitation coil 20 which constitutes the discharge lamp 1 has its ends integrally extended and is mechanically and electrically connected to the printed circuit board 45, and the other one. The circular disc 21 is connected to the earth electrode 27 (FIG. 1) with the instrument body 42 as the earth.
The instrument body 42 has the same potential as the ground through the pole 40.

A fan 47 is provided in the instrument body 42, and the fan 47 blows air for cooling to the discharge lamp 1 through ducts 48 and 49.
The fan 47 is designed to be operated while the discharge lamp 1 is lit, so that the solenoid magnetic field type discharge lamp 1 is always forcibly cooled from the ducts 48, 49 by the wind generated by the fan 47 during lighting. . For this reason, even if the tube wall of the valve 10 is heated by the plasma formed in a ring shape along the tube wall, the tube wall is forcibly cooled, so that the valve 10 is deformed or ruptured, and an undesired reaction of the encapsulating material. And the temperature rise of the excitation coil 20 can be suppressed.

As a result, the electric field strength can be increased and concentrated to improve the startability, the lamp can be made into a single tube to be miniaturized, and the coil can be cooled so that a large electric power can be obtained. Can also be added, and the luminous efficiency can be increased.

The discharge lamp 1 is grounded via the luminaire 41 and the pole 40, and the height H of the pole 40 is set to 1/2 of the wavelength λ or an integral multiple of λ / 2. Therefore, the lighting fixture 41 and the ground are equal in voltage and current, the pole 40 does not act as a distributed constant circuit, and a high voltage is prevented from being applied to the pole 40, preventing uncontrollability and failure of the lighting circuit. can do. 9 to 12 each show an example of a dimmable solenoid magnetic field type discharge lamp.

That is, there is no conventional lamp that controls the light output to dimm the solenoid magnetic field discharge lamp during or every time it is turned on. However, for optimal brightness, light distribution, power saving, etc., dimming control of this type of solenoid magnetic field type discharge lamp 1 is required. Therefore, each of the embodiments shown in FIGS. 9 to 12 proposes a system for dimming the electrodeless discharge lamp.

In the case of the seventh embodiment shown in FIG. 9, this coil 20 is arranged along the coil axis direction of the high frequency excitation coil 20.
A conductive metal plate 90 or a mesh or a bar is arranged apart from the. Although the detailed configuration of the conductive metal body 90 is omitted, it is movable along the coil axis direction, that is, it is provided so as to be able to come into contact with and separate from the excitation coil 20.

In the case of such a configuration, the conductive metal body 90 and the excitation coil 20 are electrically coupled to equivalently lower the impedance of the lamp, and an eddy current flows through the conductive metal body 90 to consume power. . Therefore, the valve 1 is originally
Part of the power to be input to 0 is released to the conductive metal body 90, the power to be input to the bulb 10 is reduced, and the light amount of the lamp is reduced. This dimming ratio increases as the coupling distance between the conductive metal body 90 and the coil 20 increases as the distance between the conductive metal body 90 and the excitation coil 20 decreases. That is,
By variably controlling the distance between the conductive metal body 90 and the excitation coil 20, the brightness can be controlled and so-called dimming becomes possible.

In the case of the eighth embodiment shown in FIG. 10, instead of the conductive metal body 90 of FIG. 9, a dummy lamp 95 that does not emit light is separated from the coil 20 along the coil axial direction of the high frequency excitation coil 20. The dummy lamp 95 is provided so as to be freely attached to and detached from the excitation coil 20. The dummy lamp 95 has a bulb filled with a rare gas and performs the same function as the conductive metal body 90 of FIG.

That is, when the dummy lamp 95 is brought close to the coil 20, the dummy lamp 95 is electrically coupled to the coil 20, and a part of the current of the coil 20 flows into the dummy lamp 95. Therefore, the bulb 10 is originally intended. The power that must be input to is reduced. Therefore, dimming becomes possible by variably controlling the distance between the dummy lamp 95 and the coil 20. In the case of the ninth embodiment shown in FIG. 11, the valve 10
On the other hand, dimming is performed by moving the high frequency excitation coil 20 along the coil axis direction.

In this case, the following operation is achieved. In other words, arc discharge generated in a ring shape by plasma 1
2 tends to occur near the valve wall on the major axis of the valve 10 having the largest diameter. When the coil 20 is moved along the axial direction, the arc discharge 12 does not move, but the center of the magnetic field moves with the movement of the coil 20, and the amount of magnetic flux passing through the arc discharge 12 of the bulb 10 is reduced. Decrease. Therefore, since the magnetic force input to the arc discharge 12 is reduced, the amount of light emission is reduced and the light is reduced. Therefore, when the bulb 10 and the high-frequency excitation coil 20 are relatively displaced along the coil axis direction, dimming becomes possible.
In the case of the tenth embodiment shown in FIG. 12, dimming is performed by inclining the high frequency excitation coil 20 with respect to the ellipsoidal bulb 10.

Also in this case, the arc discharge 12 generated in a ring shape by the plasma tends to be generated on the major axis of the bulb 10 having the largest diameter and in the vicinity of the bulb wall. Is tilted so as to intersect the bulb axis, the arc discharge 12 does not move, but the center of the magnetic field tilts with the tilt of the coil 20, and thus the magnetic flux passing through the arc discharge 12 of the bulb 10. The amount decreases.

For this reason, the magnetic force input to the arc discharge 12 is reduced, so the amount of light emission is reduced, and the bulb 10 is accordingly reduced.
When the and high-frequency excitation coil 20 are relatively inclined, dimming becomes possible.

Next, an eleventh embodiment of the present invention will be described with reference to FIG. This eleventh embodiment is a valve 10
A rare gas discharge lamp in which mercury is not enclosed is described. In the case of a lamp not using mercury, the Penning effect cannot be expected and there is a problem that the starting performance of the lamp is not good.

That is, in the solenoid magnetic field type discharge lamp, an electric field is generated in the circumferential direction inside the bulb 10 due to an electromagnetic induction action, but in the case of anhydrous mercury, the Penning effect cannot be expected, so the strength of the electric field induces the start. However, the glow discharge diffused from the gas probe 15 into the bulb 10 is difficult to transfer to the ring-shaped arc discharge. Generally, the electric field E (V) generated in the circumferential direction is expressed by the following equation by dividing the voltage obtained from Faraday's law of electromagnetic induction on the inner diameter surface of the lamp by the circumferential length.

[0064]

[Equation 1]

Here, r is the radius of an imaginary circle centered on the coil axis on the equatorial plane of the valve 10, and when the coil axis coincides with the valve axis, it is regarded as equal to the inner diameter d of the valve 10. Good. μ is magnetic permeability, ω is angular frequency, H (x)
Is the component of the magnetic field in the coil axis direction at the position x from the coil axis on the equatorial plane of the valve 10.

Since H (x) is usually almost constant in the coil or tends to increase toward the peripheral portion, E (V) is considered to increase as r increases, and similarly E (V) increases. V) increases as the frequency f of the high-frequency current input to the excitation coil 20 increases, and therefore, it may be considered that the starting can be facilitated by increasing r and the frequency f. As a result of repeated experiments based on such analysis, 10 ≦ f ≦ 100 (2) 10 ≦ d ≦ 50 (3) 250 ≦ d · f ≦ 7.5P (4) should be satisfied. I found out. However, here f
Is the excitation frequency, d is the inner diameter of the valve, and P is the input to the high frequency excitation coil 20. The above equations (2) to (4) are values obtained by an experiment, and this experiment will be described.

The inner diameter d = 2r of the valve 10 shown in FIG.
The excitation frequency f and the rated input P to the excitation coil 20 were variously changed to judge whether the starting performance was acceptable or not. The results are shown in Tables 1 to 5 below. However, the size of the excitation coil 20 was changed according to the following relationship according to the valve inner diameter d. d ₁ mm = d + 4, D (coil outer diameter) mm = 4.8d +
8, lmm = 0.1d, Lmm = 0.3d

As a judgment condition, the valve temperature is P
/ D ² Since the upper limit of the rated input power at the time of lighting is set, the power applied to the excitation coil 20 at the time of starting does not exceed this upper limit, and the value is 0.5 w / mm ² And The upper limit of the excitation frequency f was 100 MHz.

The test method is P = 0.5d ² The electric power determined by was applied to the lamp, and all the lamps that were turned on in 20 tests were passed, and the lamps that failed to start even once were rejected.

[0070]

[Table 1]

[0071]

[Table 2]

[0072]

[Table 3]

[0073]

[Table 4]

[0074]

[Table 5]

The startability tends to deteriorate in the high frequency f region, because the inner diameter d ₁ of the excitation coil 20 becomes larger than that of the frequency f, and the coil loss increases. Conceivable. Since this type of loss is proportional to the input power P, the upper limit of the d · f value is proportional to the input power P. Therefore, from the above tables, if the formulas (2) to (4) are satisfied, the startability of the mercury-free solenoid magnetic field type discharge lamp can be improved. In the embodiments shown in FIG. 7 and subsequent figures, it is needless to say that the annular disc of the high frequency excitation coil satisfies 0.06 ≦ w / d ₁ /w≦0.5 (1) in any of the examples.

[0076]

As described above, according to the solenoid magnetic field type discharge lamp of the present invention, the coil efficiency of the excitation coil is improved and the high frequency power supply efficiency from the excitation coil to the bulb is improved. Efficiency is improved.

Further, according to the lighting device of the present invention, since the solenoid magnetic field type discharge lamp is forcibly cooled by the cooling air,
The temperature rise of the coil and bulb is suppressed, the lamp efficiency is further improved, and the efficiency of the entire system is improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a solenoid magnetic field type discharge lamp showing a first embodiment of the present invention.

FIG. 2 is an inner diameter d ₁ and a width w of the high frequency excitation coil of the same embodiment.
The characteristic diagram of the experimental result showing the relationship with.

FIG. 3 is a sectional view of a solenoid magnetic field type discharge lamp showing a second embodiment of the present invention.

FIG. 4 is a sectional view of a solenoid magnetic field type discharge lamp showing a third embodiment of the present invention.

FIG. 5 is a sectional view of a solenoid magnetic field type discharge lamp showing a fourth embodiment of the present invention.

FIG. 6 is a perspective view, partly in section, of a high frequency excitation coil showing a fourth embodiment of the present invention.

FIG. 7 is a side view of a road lighting device showing a fifth embodiment of the present invention.

FIG. 8 is a cross-sectional view showing the main parts of the lighting device of the embodiment.

FIG. 9 is a sectional view of a solenoid magnetic field type discharge lamp showing a sixth embodiment of the present invention.

FIG. 10 is a sectional view of a solenoid magnetic field type discharge lamp showing a seventh embodiment of the present invention.

FIG. 11 is a sectional view of a solenoid magnetic field type discharge lamp showing an eighth embodiment of the present invention.

FIG. 12 is a sectional view of a solenoid magnetic field type discharge lamp showing a ninth embodiment of the present invention.

FIG. 13 is a sectional view of a solenoid magnetic field type discharge lamp showing a tenth embodiment of the present invention.

[Explanation of symbols]

1 ... Solenoid magnetic field type discharge lamp 10 ... Bulb
12 ... Arc discharge 15 ... Starting thin tube 17 ... Starting electrode
18 ... Starter circuit 20 ... Excitation coil 21, 21 ... Annular disk 25 ... Matching box 26 ... High frequency oscillation circuit 40 ... Pole 41 ... Lighting fixture
42 ... Instrument body 43 ... Prism cover 44 ... Reflector
47 ... Fans 48, 49 ... Duct 90 ... Conductive metal plate 95 ... Dummy lamp

Claims (3)

[Claims] 1. A discharge substance is enclosed in a translucent bulb,
In a solenoid magnetic field type discharge lamp in which a high-frequency excitation coil is arranged so as to surround the bulb, and plasma is generated in the bulb by the excitation coil, the high-frequency excitation coil is arranged in a direction intersecting the coil axis direction. A flat circular disk with a spread around the coil axis 1
This ring-shaped disc is arranged with more than one winding, and 0.06 ≤ w / d ₁ ≤ 0.5 where the inner diameter is d ₁ (mm) and the effective passage width of the current flowing in the circumferential direction is w (mm). Solenoid magnetic field type discharge lamp characterized by being satisfied. 2. A mercury-free discharge substance is enclosed in a translucent bulb, and a high-frequency excitation coil is arranged so as to surround the bulb, so that plasma is generated in the bulb by the excitation coil. In the solenoid magnetic field type discharge lamp described above, the inner diameter of the bulb is set to d (mm), and the high-frequency excitation coil has a flat ring-shaped disc that extends in a direction intersecting with the coil axis direction around the coil axis.
This ring-shaped disk is arranged with more than one winding, the inner diameter is d ₁ (mm), the effective passage width of the current flowing in the circumferential direction is w (mm), the frequency of the high frequency power flowing to this excitation coil is f (MHz), Assuming that the rated input P (watt) to the excitation coil is 0.06 ≦ w / d ₁ ≦ 0.5 10 ≦ f ≦ 100 10 ≦ d ≦ 50 250 ≦ d · f ≦ 7.5P Characteristic solenoid magnetic field type discharge lamp. 3. A lighting device in which the discharge lamp according to claim 1 or 2 is housed in a lighting fixture, wherein the lighting fixture is provided with a cooling device for blowing cooling air to the discharge lamp to forcibly cool it. Lighting equipment.