JPH0640487B2 - Electrodeless discharge lamp - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electrodeless discharge lamp which does not have an electrode inside the lamp and discharges and emits a rare gas or metal vapor inside the lamp by a high frequency electromagnetic field from the outside. .

[Prior Art] This type of lamp has been conventionally known. For example, in the lamp disclosed in JP-A-57-78766,
As shown in FIG. 5, a valve 2 is formed so as to cover the air-core coil 1, and a high-frequency current is passed through the air-core coil 1 to discharge the mercury vapor in the valve 2 by an electromagnetic field generated. , The magnetic field due to the cylindrical coil used here is
It is the strongest inside, but in this example, there is no discharge space in that portion, and the bulb 2 is formed exclusively by utilizing the magnetic field outside the coil.

Further, in the lamp disclosed in US Pat. No. 4,568,859, as shown in FIG. 6, in addition to the air core coil 1 as described above, in order to reduce external leakage noise, the bulb 2
Three short loops 3 are arranged along the outer peripheral wall of the. However, with such a configuration, the magnetic flux generated by the short loop 3 is generated in a direction that weakens the original magnetic flux, and therefore the magnetic field in the valve 2 becomes weaker than in the case without the short loop 3. That is, the light output is weakened.

[Problems to be Solved by the Invention] As described above, in the conventional electrodeless discharge lamp, if the light output is efficiently obtained, the leakage noise becomes large, and if the leakage noise is suppressed, the light output efficiency is lowered. There is a problem of doing. Further, the leaked noise as described above may cause a radio interference that adversely affects other devices and the like.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an electrodeless discharge lamp that can effectively utilize the optical output in the lateral direction and has small leakage noise.

[Means for Solving the Problems] In order to solve the above problems, in the electrodeless discharge lamp according to the present invention, a high frequency electromagnetic field is generated by an induction coil wound along the outer wall of a substantially spherical bulb. In an electrodeless discharge lamp that discharges and emits a discharge gas body sealed in a bulb with an electromagnetic field, the dielectric coil is disposed at the lower end of the bulb, and a conductive plate-like body is provided on the plate surface. Is arranged so as to face the surface surrounded by the dielectric coil, and a part of it is in contact with the upper end of the valve.

[Embodiment] FIGS. 1 to 3 show an embodiment of the present invention.
Reference numeral 0 denotes a spherical bulb which is airtight and translucent, and is filled with a rare gas such as argon as a discharge gas body or a metal such as mercury in addition to a rare gas.
Reference numeral 11 denotes an inductive coil wound around the lower outer peripheral wall of the valve 10, reference numeral 12 denotes a conductive plate-like member, which is fixed to the upper portion of the valve 10 so that a part thereof is in contact with the valve 10.
It is formed of a metal such as aluminum, and is fixed with silicon or the like, which has good heat conduction characteristics. Further, the shape and mounting position of the plate-like body 12 are appropriately designed depending on the application.

Inductive coil 1 of electrodeless discharge lamp configured as described above
When a high-frequency current is passed through 1, an electromagnetic field is induced and the discharge gas body in the bulb 10 is excited and ionized. that time,
Visible light is obtained directly by excitation light emission, or bulb 1
The fluorescent material applied to the inner wall surface of No. 0 converts ultraviolet rays generated by discharge excitation into visible light for use. At this time, the plate-shaped body 12 functions as a reflector and is configured to strongly reflect the light from the bulb 10 in the lateral direction. The plate-shaped body 12 also has an effect of reducing noise in the upward direction. That is, of the magnetic flux generated in the inductive coil 11, the valve 1
Those passing through 0 contribute to excited light emission, but other magnetic fluxes become noise. Regarding the leakage noise that penetrates the plate-shaped body 12, the eddy current generated by the magnetic flux that penetrates the plate-shaped body 12 generates a magnetic flux that weakens the penetrating magnetic flux, so that noise can be reduced.

FIG. 4 shows an application example of the electrodeless discharge lamp according to the present invention, which is used for the above-mentioned aviation obstacle lamp. Such an aviation obstruction light has a sealed structure for the purpose of waterproofing, and when the lamp is mounted in the sealed lamp, the lamp temperature rises and the coldest part temperature rises. Therefore, the light output is reduced, and the desired light output cannot be obtained. However, in the present embodiment, the plate-shaped body 12 also functions as a heat dissipation plate, that is, the portion of the bulb 10 in contact with the plate-shaped body 12 is compared. It is kept at an extremely low temperature, and a desired light output can be obtained.
In addition, the presence of the plate-shaped body 12 makes it possible to effectively utilize the light output in the lateral direction, which is particularly effective as an aviation obstruction light.

The present invention is not limited to the above embodiment,
For example, in this embodiment, a copper wire having a diameter of 1 mm was used for the induction coil 11, but any material and wire diameter may be used as long as it is a conductive material. Further, the shape of the bulb is not limited to the spherical shape. Further, a fluorescent substance may be applied to the inner wall surface of the bulb 10 if necessary.

[Advantages of the Invention] As described above, according to the present invention, the induction coil is arranged at the lower end of the substantially spherical valve, and the conductive plate member is arranged at the upper end of the valve. It is possible to provide an electrodeless discharge lamp that can reduce noise and can effectively use light output in the lateral direction of the lamp. Also,
By placing the conductive plate in contact with the upper end of the valve, the plate also functions as a heat dissipation plate, and the portion in contact with the valve plate (cold spot) has a relatively low temperature. It is possible to provide a lamp that can be maintained and obtain a desired light output.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention, FIG. 2 is a sectional view of the same as above, FIG. 3 is a perspective view of an induction coil used in the above embodiment, and FIG. 4 is an electrodeless discharge according to the present invention. FIG. 5 and FIG. 6 are front views of partial cross-sections showing a conventional example, respectively. 10 ... Valve, 11 ... Induction coil, 12 ... Plate-shaped body.

Claims (1)

[Claims] 1. An electrodeless discharge in which a high-frequency electromagnetic field is generated by an induction coil wound along the outer wall of a substantially spherical bulb, and a discharge gas body enclosed in the bulb is discharged and emitted by the high-frequency electromagnetic field. In the lamp, the induction coil is arranged at the lower end of the bulb, and a conductive plate-like body is provided.
So that the plate surface faces the surface surrounded by the induction coil,
Further, the electrodeless discharge lamp is arranged so that a part thereof is in contact with the upper end of the bulb.