JP3489211B2 - Electrodeless discharge lamp - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve which does not have a main electrode in a bulb and applies a high-frequency electromagnetic field to the discharge gas sealed in the bulb from outside the bulb. The present invention relates to an electrodeless discharge lamp that emits a discharge gas by generating a high-frequency annular discharge therein. 2. Description of the Related Art Conventionally, as shown in FIG. 7, an electrodeless discharge lamp in which a spherical bulb 1 filled with a discharge gas is arranged near the center of an induction coil 2 formed in a donut shape. Has been proposed (JP-A-6-13190). Generally, a mixed gas of an inert gas and mercury vapor is used as the discharge gas. Further, in this electrodeless discharge lamp, the thickness of the induction coil 2 in the direction of the center line of the induction coil 2 is formed to be gradually increased from the inner peripheral side to the outer peripheral side. In this configuration, when a high-frequency current is applied to the induction coil 2, a high-frequency electromagnetic field formed around the induction coil 2 acts on the discharge gas inside the bulb 1, as shown by a broken line in FIG. An arc discharge (high-frequency annular discharge) 7 having an annular discharge path is generated inside the bulb 1. Therefore, the discharge gas is excited or ionized to emit light. [0004] The electrodeless discharge lamp having the above-described structure is relatively easy to start up initially, but has no electrodes in the bulb 1. It has the problem of being difficult. In addition, since the vapor pressure of mercury vapor increases exponentially due to the temperature rise after the start, there is a problem that it is difficult to achieve impedance matching with a high-frequency power supply provided for supplying a high-frequency current to the induction coil 2. ing. Since the impedance matching is caused by a change in the vapor pressure of mercury vapor, if the mercury vapor is not contained in the discharge gas, the matching can be easily achieved, but there is a problem that the initial start becomes difficult this time. If a high voltage is applied to the induction coil 2, the coil can be forcibly started, but a problem arises in that a high-frequency power supply as a lighting circuit becomes large. SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and to provide an electrodeless discharge lamp in which initial starting and restarting are easy, and impedance matching can be easily achieved even if mercury is not required. Things. In order to achieve the above object, according to the present invention, there is provided a bulb in which a discharge gas is made of a light-transmitting material, and a high-frequency current which is disposed close to the bulb and is energized. An electrodeless discharge lamp that emits a discharge by causing a high-frequency electromagnetic field formed around the induction coil to act on a discharge gas in the bulb, and that is formed in a spiral shape in one plane, and two elementary coils are opposite winding, between Ryomoto coils on the center line of the vortex winding
Connecting outer ends between the Ryomoto coil is spaced a distance mutual inductance occurs in together when placed in the <br/> axially
Using an induction coil in which both elemental coils are connected in series,
A valve is arranged near the center of the spiral of the coil. A spiral is formed in one plane and opposite to each other.
Ryomotoko two element coils, the center line of the vortex winding is Ki
Separated by the distance where mutual inductance occurs between the coils
And coaxially arranged, and the outer ends of the two coils
Both elementary coils in a manner to connect the Judges with use of induction coils connected in series, than are arranged the valve near the center of the spiral of Ryomoto coil, a high frequency electromagnetic field is formed around the induction coil The discharge gas in the vicinity of the tube wall inside the bulb is concentrated on the discharge gas within the range of the thickness of the induction coil, and the initial start and restart are facilitated by applying a strong electromagnetic field to the discharge gas. . That is, the magnetic flux density of the magnetic field formed by the induction coil is proportional to the number of turns of the induction coil. It is thought that the field can act, but if an induction coil of such a shape is used, the amount of light that is shielded by the induction coil out of the light emitted from the bulb increases, and as a result, the amount of emitted light decreases become. On the other hand, by using an induction coil formed in a spiral shape in one plane, the number of turns of the induction coil can be increased as in the case of using a cylindrical induction coil long in the center line direction. In this way, a strong electromagnetic field can be applied to the discharge gas, but the thickness of the induction coil is small and light can be emitted from the bulb in almost all directions. It is less. In addition, since starting or restarting is facilitated , impedance matching can be easily achieved without filling mercury in the bulb. [0010] Moreover, they are formed in a spiral shape and opposite to each other.
Using two elementary coils that are wound, the two elementary coils are swirled.
Between the two element coils on the center line
And the outside of the coil
Since an induction coil in which both element coils are connected in series is used to connect the ends, the inductance of the induction coil can be increased by adding the mutual inductance between the element coils to the inductance of each element coil. As compared with the case where the induction coil having the same number of turns (that is, the same size) is formed in a single spiral, the terminal voltage can be increased, and as a result, a strong electric field is generated inside the bulb. It can be formed to improve the starting performance. [0012] [Example] (the basic configuration) Basic configuration of the present embodiment are shown in FIG. In the illustrated example, a spherical bulb 1 and an induction coil 2 formed in a spiral shape in one plane including the center of the bulb 1 as shown in FIG. 2 are used, and the center of the induction coil 2 and the center of the bulb 1 are used. Are substantially matched. The bulb 1 has an inner diameter of 24 mm, and 1.3 × 10 ⁴ Pa (≒ 100 To
About rr) xenon gas is sealed. The induction coil 2 is made of a silver-nickel wire having a diameter of 2 mm and a length of 7 to 10 mm.
A single-pole trigger electrode 3 is disposed in the vicinity of the center line of the induction coil 2 and in the vicinity of the outer peripheral surface of the bulb 1. A trigger pulse is applied. A high-frequency power supply 5 is connected to the induction coil 2 via a matching circuit 6, and a high-frequency current from the high-frequency power supply 5 is supplied to the induction coil 2. Are matched. Since the trigger electrode 3 is electrostatically coupled to the internal space of the bulb 1, when a trigger pulse is applied to the trigger electrode 3 by the trigger circuit 4, electrons are generated inside the bulb 1. The electrons collide with the xenon atoms and ionize the xenon atoms (ie, form a streamer). On the other hand, when a high-frequency current is applied to the induction coil 2 by the high-frequency power supply 5, a high-frequency electromagnetic field is formed inside the bulb 1, and the high-frequency electromagnetic field acts on electrons generated inside the bulb 1 by application of a trigger pulse. However, the state where ionization of xenon atoms is repeated is maintained. As a result, arc discharge (high-frequency annular discharge) as shown in FIG.
7 occurs and discharge light emission occurs inside the bulb 1. In the basic configuration shown in FIG .
Even if the number of turns is increased and the high-frequency electromagnetic field acting on the internal space of the bulb 1 is strengthened, the light emitted from the bulb 1 is hardly emitted because the thickness of the induction coil 2 is sufficiently smaller than the diameter of the bulb 1. Can be taken out without shading. That is, the output light flux per input power is increased. In order to increase the high-frequency electromagnetic field acting on the internal space of the valve 1, an induction coil 2 is provided.
Since the output light flux does not decrease even if the number of turns is increased, the startability can be improved by increasing the number of turns. Furthermore, since starting and restarting are easy,
There is no need to seal mercury in the bulb 1, and impedance matching can be easily achieved. [0015] (Example) Thus, the present embodiment 3, as shown in FIG. 4, element coils 2a of the same shape formed in a spiral shape in a plane. 2b
Are arranged coaxially with their center lines aligned, and the configuration other than the induction coil 2 is the same as the basic configuration . Amphibious coil 2
As shown in FIG. 5, a and 2b are oppositely wound (in the figure, the elementary coil 2a is left-handed from inside to outside, and the elementary coil 2b is right-handed from inside to outside). Thus, the outer ends are integrally continuous. The two coils 2a and 2b are spaced apart from each other by a distance (about 2 mm) about the wire diameter of the induction coil 2. The equivalent circuit of the induction coil 2 having this configuration is as shown in FIG.
Since mutual inductance is generated between the two coils 2a and 2b, the induction coil 2 functions as a transformer. Now, it is assumed that the inductances of the elementary coils 2a and 2b are equal and L ₀ respectively. The mutual inductance between the two coils 2a and 2b is represented by M. At this time, the inductance L of the induction coil 2
Is represented by the following equation. L = 2L ₀ ± 2M Here, the sign of the mutual inductance is
When the magnetic fluxes generated by a and 2b are in the same direction, they are positive, and when the magnetic fluxes are in opposite directions, they are negative. Mutual inductance M
Is expressed by using a coupling coefficient k, M = kL ₀ , and L = 2 (1 + k) L _{0. Since} the coupling coefficient k is generally considered to be 0 <k ≦ 1, 2L ₀ ≦ Since L ≦ 4L ₀ , the inductance L of the induction coil 2 is larger than the simple addition of the inductances L ₀ of the elementary coils 2a and 2b, and may be twice as large as the maximum value. Incidentally, when the induction coil 2 was formed using the elementary coils 2a and 2b having an inductance of 260 nH, an inductance of 833 nH could be obtained. As described above, when the inductance L of the induction coil 2 increases, the voltage across the induction coil 2 increases, and the electric field strength of the electric field formed around the induction coil 2 increases, thereby improving the startability. Conceivable. Moreover,
Since the elementary coils 2a and 2b forming the induction coil 2 are spiral, an annular strong electric field is also formed inside the bulb 1, and it is easy to shift to an annular arc discharge formed during stable lighting. Further, similarly to the basic configuration , the output light flux from the bulb 1 is hardly blocked by the induction coil 2, so that the output light flux can be increased. The other configuration is the same as the basic configuration. When a trigger pulse is applied from the trigger circuit 4 to the trigger electrode 3, electrons are generated inside the bulb 1 and collide with the xenon atoms, and the xenon atoms are converted. Ionize. When high-frequency power is supplied from the high-frequency power supply 5 to the induction coil 2 through the matching circuit 6, the induction coil 2 is electrostatically coupled to a streamer formed inside the bulb 1, maintains the streamer, and releases the streamer to the valve. Thus, an annular discharge path from the initial discharge state to a stable lighting state is formed. The discharge gas in the actual施例described above is not intended to be limited to the xenon gas may be used other single gas or gas mixture. Further, the charging pressure of the discharge gas is not limited to the above value. Further, the shape and dimensions of the valve 1 are not limited to the above embodiment. The number of turns of the induction coil 1 is not particularly limited as long as it is two or more turns in the first embodiment and more than two turns in the second embodiment. According to the present invention, a spiral shape is formed in one plane.
Re and two elementary coils are opposite wound together, mutual inductance generated between Ryomoto coils on the center line of the vortex winding
Both element together is separated by a distance are coaxially arranged with
Connect both element coils in series by connecting the outer ends of the coils
With use of the induction coil continued were, than are arranged the valve near the center of the spiral of Ryomoto coil, inside the valve in the range of about the thickness of the induction coil a high-frequency electromagnetic field is formed around the induction coil Intensively act on the discharge gas in the vicinity of the tube wall, and there is an advantage that initial startup and restart can be easily performed by applying a strong electromagnetic field to the discharge gas. In addition, since starting and restarting are easy, mercury does not need to be sealed in the bulb, and there is an advantage that impedance matching can be easily achieved. In addition, by using an induction coil formed in a spiral in one plane,
As in the case of using a cylindrical induction coil that is long in the center line direction, the number of turns of the induction coil is increased so that a strong electromagnetic field can be applied to the discharge gas. There is an advantage that the light can be emitted to the light source and the amount of light blocked by the induction coil is reduced. In addition, they are formed in a spiral shape and are opposite to each other.
Using two elementary coils that are wound, the two elementary coils are swirled.
Between the two element coils on the center line
And the outside of the coil
Since an induction coil is used in which both element coils are connected in series so that the ends are connected, the inductance of the induction coil can be increased by adding the mutual inductance between the element coils to the inductance of each element coil. As compared with the case where the induction coil having the same number of turns is formed in a single spiral, the terminal voltage can be increased, and as a result, a strong electric field is formed inside the valve to improve the startability. There is an advantage that you can.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic configuration diagram showing a basic configuration . FIG. 2 is a perspective view showing an induction coil used for a basic configuration . FIG. 3 is a schematic configuration diagram showing an embodiment. Figure 4 shows an embodiment, (a) represents a partially broken side view,
(B) is a plan view. 5 is a perspective view showing an induction coil used in the examples. 6 is an equivalent circuit diagram of the induction coil used in the examples. FIG. 7 is a partially broken perspective view showing a conventional example. [Description of Signs] 1 Valve 2 Induction coil 2a Element coil 2b Element coil

Claims (1)

Claims: 1. An induction coil, comprising: a bulb made of a light-transmitting material and filled with a discharge gas; and an induction coil disposed in close proximity to the bulb and through which a high-frequency current is supplied. The electrodeless discharge lamp emits light by causing a high-frequency electromagnetic field formed around the electrode to act on a discharge gas in the bulb, and each of the electrodeless lamps is formed in a spiral shape in one plane and opposite to each other.
The number of elementary coils, phase between Ryomoto coils on the center line of the vortex winding
Distance each other inductance is generated by spaced together when positioned coaxially connecting the outer end between the Ryomoto coil
An electrodeless discharge lamp characterized by using an induction coil in which two coils are connected in series in a shape such that a bulb is arranged near the center of the spiral of the two coils.