JPH0456059A - Electrodeless discharge lamp device - Google Patents

Abstract

PURPOSE:To provide a high output spot-form light source, facilitate manufacture, and prolong the lifetime by furnishing an electrode consisting of foil-form conductor on the wall of a light emission tube, and with this electrode, connecting a high frequency generating circuit for impression of a high frequency voltage only at the time of starting. CONSTITUTION:At the other end of a light emission tube 1, a pair of electrode 4, 4 consisting of foil-form conductor are wrapped in the form in tight contact with the tube wall and connected with a high frequency generating circuit 5 through a matching circuit. When a high frequency voltage is impressed between these two electrodes 4, 4, the intra-tube discharge space is tied with electrode 4 in electrostatic bond, and a high frequency electric field is produced around the electrodes 4, 4 in the intra-tube space. Under this electric field electron collides with Xe atom and causes dissociation of Xe atom. If high frequency current is fed to an induction coil 2 in the condition that electrons are supplied sufficiently in this manner, an alternate magnetic field is generated around the induction coil, particularly inside of the light emission tube 1, and inductive electric field is produced in the form as creeping on the inner wall of the light emission tube 1. Thereby discharge is maintained by this inductive electric field.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrodeless discharge lamp device that does not have electrodes inside the lamp and excites discharge gas inside the lamp to emit light using a high-frequency electromagnetic field from the outside.

[Prior Art] Electrodeless discharge lamps have been researched and developed in various places since they have characteristics such as small size, high output, and long life. Although its uses are various, for example, it is being considered to be used as a high-output point light source.

Among such electrodeless discharge lamps, for example,
In the lamp disclosed in Japanese Patent No. 7-78766, as shown in FIG.
The mercury vapor inside the bulb 1 is discharged by the electromagnetic field generated by passing a high-frequency current through this air-core coil 1.The magnetic field produced by the cylindrical coil used here is the strongest inside the bulb. However, in this example, there is no discharge space in that part, and the bulb 11 is formed using only the magnetic field outside the coil.

In addition, the shape of high-output electrodeless discharge lamps that emit light using electromagnetic waves, which have recently been developed in various places, is spherical as shown in FIG. is enclosed, and an induction coil 13 is wound around the valve 12. If a point light source with such a shape is required, the diameter of the bulb 12 must be reduced, but the bulb 12 is spherical, for example, with a diameter of 10 Il 111, and a discharge gas is sealed inside. is very difficult. Furthermore, even if such a small spherical tube is made, the tube wall load, that is, (manpower/surface + 1) increases, and the lamp life is shortened. Furthermore, when using metal vapor discharge, there is a drawback that the vapor pressure increases significantly during discharge, making instantaneous restart difficult.

[Problems to be Solved by the Invention] The present invention has been made in view of the above-mentioned drawbacks, and its purpose is to provide an electrodeless discharge lamp device that is a high-output point light source, is easy to manufacture, and has a long life. It is to obey.

[Means for Solving the Problems] The present invention has the above features! In order to solve the iB problem, an induction coil is wound around a part of a thin and thin light-transmitting arc tube, and a high-frequency current is applied to the induction coil, whereby the same part of the inner space of the arc tube as described above is removed. In the electrodeless discharge lamp device, an electrode made of a foil-like conductor is disposed on the wall of the arc tube, and a high-frequency generating circuit is connected to the electrode for applying a high-frequency voltage only at the time of starting. It is characterized by:

[Example 1] Fig. 1 shows a first example of the present invention, in which 1 is a long tube-shaped arc tube, which is airtight and translucent, and contains xenon as a discharge gas inside. (Xe) gas of 100 Torr is sealed. Note that the inner diameter of the arc tube 1 is 5M.

Reference numeral 2 denotes an induction coil, which is wound around one end of the arc tube l in the shape of a solenoid for several turns, for example three turns, and both ends of the coil 2 are connected to a high frequency generation circuit 3 via a matching circuit (not shown). ing. Further, at the other end of the arc tube 1, a pair of electrodes 4.4 made of a foil-like conductor are provided, for example, with a diameter of 0.5 mm.
It is wound tightly around the tube wall with an interval of 5 am. Each electrode 4, 4 is connected to a high frequency generation circuit 5 via a matching circuit (not shown).

In the electrodeless discharge lamp device configured as described above, when a high frequency voltage is applied between the two electrodes 4.4, the electrode 4 and the discharge space in the tube are connected by electrostatic coupling, and the two electrodes in the space in the tube are connected by electrostatic coupling. A high frequency electric field is generated between 4.4 and 4. Electrons that have gained energy due to this electric field collide with Xe atoms to cause TIH. When a high-frequency current is passed through the induction coil 2 with a sufficient supply of electrons in this way, an alternating magnetic field is generated around the induction coil 2, especially inside the arc tube 1, and this magnetic field causes the arc tube 1 to move. An induced electric field is generated along the inner wall. Therefore, the discharge is maintained by this induced electric field. When the discharge due to the induced electric field is maintained,
Since the discharge by the electrode 4 at the initial stage of startup becomes unnecessary, the high frequency voltage application to the electrode 4 is stopped.

In this way, at the time of starting, the discharge due to the electric field applied between both Ti4. This results in a strong ring-shaped discharge, resulting in a light source that is very close to a point light source.

Although xenon was used as the discharge gas in this embodiment, it is needless to say that the type and pressure of the gas or metal are not limited as long as the discharge gas can be maintained by the power supply means.

Embodiment 21 FIG. 2 shows a second embodiment of the present invention, which differs from the first embodiment in that the arc tube 1 is bent into a U-shape and the induction coil 2 is arranged at the bent part. Since the other configurations are the same as those of the first embodiment, explanations will be omitted by assigning the same reference numerals to the equivalent configurations.

With this configuration, when using arc tubes l of the same volume, the overall size of the device can be made compact. Note that, of course, the same effect can be obtained even if the arc tube l is formed into a substantially annular shape.

[Embodiment 3] FIG. 3 shows a third embodiment of the present invention, which differs from the first embodiment in that in addition to the structure of the first embodiment, a high voltage generating device such as a piezoelectric element is used. High voltage generating element 6 such as
is arranged in such a way that a high voltage is applied to the arc tube l in the vicinity of the electrode 4, and the other configurations are the same as in Example 1, so the description will be given by assigning the same reference numerals to the equivalent configurations. omitted.

With this configuration, it becomes possible to start the discharge even in situations where starting is more difficult. In other words, 1
The high voltage generating element 6 is used to start the first stage, the second stage is started using the electric field between the picture electrodes 4 and 4, and the final discharge is maintained using the induced electric field generated by the induction coil 2. Become.

[Embodiment 4] FIG. 4 shows a fourth embodiment of the present invention. In this embodiment, an electrode 4 made of a foil-like conductor is placed close to the coil end on the ground potential side of the induction coil 2. It is characterized in that it is provided with a high frequency generating circuit 5 that applies a high frequency voltage between the ground potential side end of the induction coil 2 and the electrode 4. Only one number 4 is required, and the configuration is simpler than that of the first embodiment.

[Effects of the Invention] Since the electrodeless discharge lamp device according to the present invention is configured as described above, starting is facilitated by discharge from the electrode made of a foil-like conductor at the time of starting, and the induction coil is activated after starting. In other words, the discharge is a ring-shaped discharge with a strong emission intensity only at the coil winding portion, so a long-life light source that is very close to a point light source can be obtained. Furthermore, since the arc tube is tubular, it is easy to manufacture.

[Brief explanation of drawings]

FIG. 1 is a simplified diagram showing a first embodiment of the invention, FIG. 2 is a simplified diagram showing a second embodiment of the invention, and FIG. 3 is a simplified diagram showing a third embodiment of the invention. , FIG. 4 is a simplified diagram showing a fourth embodiment of the present invention, FIG. 5 is a partially sectional front view showing a conventional example, and FIG. 6 is a simplified diagram showing a different conventional example. l... Arc tube, 2... Induction coil, 3... High frequency generation circuit, 4... Electrode, 5... High frequency generation circuit, 6
...High voltage generating element.

Claims (1)

[Claims] (1) By winding an induction coil around a portion of a long, thin, translucent tubular arc tube and passing a high-frequency current through the induction coil, only the coil-wound portion of the space within the arc tube emits light. The electrodeless discharge lamp device is characterized in that an electrode made of a foil-like conductor is disposed on the wall of the arc tube, and a high-frequency generating circuit is connected to the electrode for applying a high-frequency voltage only at the time of starting. Electrodeless discharge lamp device.