JPH04357661A - Light source - Google Patents

Abstract

PURPOSE:To provide the excitation light of relatively high brightness from an electrodeless discharge lamp. CONSTITUTION:A pair of coils 6A and 6B are wound around an electrodeless discharge lamp 1 of dumbbell shape containing sealed gas, and a capacitor 14 is connected in series to the coils 6A and 6B for the supply of high-frequency current from a high-frequency power supply 16. In this case, a harmonic frequency due to the coils 6A and 6B, and the capacitor 14 is tuned to the frequency of the power supply 16 for exciting the gas in the tube 1 with magnetic field, thereby obtaining the excitation light of high brightness.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light source suitable for application to, for example, an atomic gyroscope.

0002

2. Description of the Related Art An example of a conventional light source for an atomic gyroscope is the technology disclosed in US Pat. No. 4,544,891. This light source is shown in Figure 7.
As shown in the figure, lamp housings 2 and 3 are attached to a container 1, and pump lamps 6 for pumping are inserted into holes 4 and 5 formed in the lamp housings 2 and 3, respectively.
(pump lamp) and a readout lamp 7 for reading are arranged. The pump lamp 6 and the lead-out lamp 7 each have a hollow dumbbell shape (
It is a discharge tube without electrodes (hereinafter also referred to as an electrodeless discharge tube), which has a tubular portion with spherical portions at both ends, and has an isotope such as Hg204 sealed inside. Excitation coils 8 and 9 are wound around one end of the spherical portions of the pump lamp 6 and lead-out lamp 7.

In use, energy is given to the above-mentioned isotope by passing a high-frequency current through the excitation coils 8 and 9, and this isotope is discharged to release energy from the tubular portions of the pump lamp 6 and readout lamp 7. Excitation light is emitted. It is said that this excitation light can be used as a light source for an atomic gyroscope by irradiating a nuclear magnetic resonance cell (not shown) constituting the nuclear reactor gyroscope.

0004

By the way, it is generally desirable that the intensity (brightness) of the excitation light irradiated onto the above-mentioned nuclear magnetic resonance cell be as high as possible. This is because the spin directions of atoms in a nuclear magnetic resonance cell can be aligned in one direction. However, there was a problem in that the brightness obtained with the above-mentioned conventional light source was not very high.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a light source from which relatively high-intensity excitation light can be obtained from a discharge lamp.

[0006]

[Means for Solving the Problems] The light source of the present invention includes, for example,
As shown in FIG. 1, a discharge lamp 1 having a tubular portion 2 and hollow spherical portions 3A and 3B formed at both ends of the tubular portion 2 and having no electrodes and filled with gas, and an excitation lamp are provided. In the light source, the excitation coils 6A, 6B are arranged approximately in the 4-direction of the tube axis of the discharge lamp 1. A pair of coils are arranged at substantially symmetrical positions from the center portion 5 and wound so as to generate magnetic flux in the same direction as the tube axis 4 direction.

[0007]

[Operation] According to the present invention, a pair of excitation coils 6A,
6B is used to excite the gas inside the dumbbell-shaped discharge lamp 1, it becomes possible to supply a relatively large amount of electric power to the discharge lamp 1, and the brightness of the excitation light emitted from the discharge lamp 1 ( strength) can be made relatively high.

[0008]

Embodiments Hereinafter, embodiments of the light source of the present invention will be described with reference to the drawings. A. First Embodiment In FIG. 1, 1 is an electrodeless discharge lamp (hereinafter referred to as a discharge lamp), and this discharge lamp 1 has a tubular part 2,
Hollow spherical portions 3 formed at both ends of this tubular portion 2
A and 3B, and He4 gas is sealed inside. The gas to be filled is not limited to He4, but rare gases such as xenon gas and neon gas can be used. The discharge lamp 1 is made of optical glass. As shown in the sectional view of FIG. 2, this discharge lamp 1 has a total length L3 of approximately 90 mm, and lengths L1 and L2 of the tubular portion 2 and the spherical portions 3A and 3B are approximately equal and approximately 30 mm. The length L1 of the tubular portion 2 may be selected to be 1 to 2 times the length L2 (outer diameter) of the spherical portions 3A and 3B. Further, the tube inner diameter d1 of the tubular portion 2 is formed to be 2 to 4 mm, and the tube outer diameter d2 is formed to be approximately 9 mm. Further, the wall thickness d3 of the spherical portions 3A and 3B is approximately 1 to 2 mm. A pair of coils 6A and 6B as excitation coils having the same radius and the same number of turns are installed at substantially symmetrical positions from the substantially central portion 5 (see FIG. 1) in the direction of the tube axis 4 of the discharge lamp 1 formed in this manner. is wound and arranged, and this coil 6A
, 6B are wound so as to generate magnetic flux in the same direction when a high frequency current is supplied. That is, this first
In this embodiment, the coils 6A and 6B constitute Helmholtz coils. Input terminal 7 of coils 6A and 6B,
9 are interconnected and connected to the hot side wire 13 of the coaxial cable 12. Further, the input terminals 8 and 10 of the coils 6A and 6B are connected to each other, and are connected to the ground side wire 15 of the coaxial cable 12 through the variable capacitor 14. This coaxial cable 12 is connected to a high frequency power source 16 with an output of 1W to 50W. This high frequency power supply 16
The frequency of is selected to be 50MHz. The frequency is 10
Approximately MHz to 100 MHz is sufficient. The electrical equivalent circuit of the light source shown in FIG. 1 can be drawn as shown in FIG. 3 (the mutual inductance caused by the coils 6A and 6B is omitted).

In use, a high frequency current is supplied from a high frequency power supply 16 through the coaxial cable 12 to the coils 6A and 6B of the light source constructed as described above. In this case, by adjusting the capacitance value of the variable capacitor 14 and tuning the coils 6A, 6B connected in series with the variable capacitor 14, a relatively large current can be generated in the coils 6A, 6B due to resonance. is supplied. At this time, the magnetic flux in the direction of the tube axis 4 of the discharge lamp 1 becomes maximum, and the molecules of the gas sealed in the tube are excited, in other words,
High-frequency electromagnetic energy is supplied to the gas molecules, and excitation light is generated from the tubular portion 2 in a direction substantially perpendicular to the tube axis 4 . In this embodiment, since the length L1 of the tubular portion 2 is relatively short, this excitation light can be regarded as light from a point light source, and relatively high brightness can be obtained (compared to the conventional technology). double). In fact, it was observed that strong light was emitted from the substantially central portion 5 in the direction of the tube axis 4. The light is emitted from the substantially central portion 5 of the tube shaft 4 because the coils 6A and 6B are arranged symmetrically with respect to the central portion 5 of the tube shaft 4. Further, the wavelength of this excitation light is constant due to its nature. Note that the variable capacitor 14 described above may be adjusted so that the brightness of the emitted light is maximized, or may be adjusted so that the high frequency current supplied from the high frequency power supply 1 is at its peak value. Furthermore, in contrast to the conventional light source shown in FIG. 7 in which the coils are arranged only in one spherical part, in this embodiment two coils 6A and 6B are arranged in parallel connection. Therefore, it is possible to make the inductance of the coil relatively small. Therefore, there is an advantage that the influence of stray capacitance is relatively small and tuning is relatively easy. At the time of this tuning, as can be easily understood from FIG. 3, the relationship shown in the following equation (1) is established. (2πf)2・Ls・C1=1...
(1) Here, f is the frequency of the high frequency power supply 16, Ls is the combined inductance of the coils 6A and 6B, and C1 is the combined capacitance of the variable capacitor and the stray capacitance. In this way, according to the first embodiment described above, a high-intensity light source with a constant wavelength can be obtained.

B. Second Embodiment FIGS. 4 and 5 show the configuration of a second embodiment and its electrical equivalent circuit. Furthermore, this figure 4 and figure 5
In the figure, parts corresponding to those shown in FIGS. 1 and 3 are given the same reference numerals. In this second embodiment, when the variable capacitors 21 and 22 are tuned, the relationships shown in the following equations (2) and (3) approximately hold true. (2πf)2・L2・C2=1...
(2) (2πf)2・L3・C3=1...
... (3) Here, f is the frequency of the high frequency power supply 16, L2 is the inductance of the coil 6A, and L3 is the inductance of the coil 6.
The inductance B, C2 and C3 are the capacitances (including stray capacitance) of the variable capacitors 21 and 22, respectively. According to this second embodiment, variable capacitors 21, 22
can be adjusted independently, making adjustment operations easier. As mentioned above, the variable capacitors 21, 22
may be adjusted so that the brightness of the emitted light is maximized, or may be adjusted so that the high frequency current supplied from the high frequency power supply 1 is at its peak value. In this way, according to the second embodiment described above, a high-intensity light source with a constant wavelength similar to that of the first embodiment can be obtained.

C. Third Embodiment The configuration of this third embodiment is shown in FIG. Furthermore, this figure 6
In the figures, parts corresponding to those shown in FIGS. 1 to 5 are given the same reference numerals. In this example, the coils 6A and 6B shown in FIGS. 1 and 2 are respectively Helmholtz coils 2.
5A, 25B, and its Helmholtz coil 25A
, 25B are arranged at positions corresponding to the connecting portion 29 between the spherical portion 3A and the tubular portion 2 and the connecting portion 30 between the spherical portion 3B and the tubular portion 2. With this configuration, the amount of magnetic flux passing through the tubular portion 2 in the direction of the tube axis 4 becomes relatively large, making it possible to obtain a light source with higher brightness and a more uniform wavelength.

It goes without saying that the present invention is not limited to the above-described embodiments, and can take various configurations without departing from the gist of the present invention.

[0013]

As explained above, according to the light source of the present invention, a pair of coils are used as excitation coils to drive the dumbbell-shaped discharge lamp, so a relatively large amount of electric power is applied to the discharge lamp. The effect is that the brightness of the emitted light output from the discharge lamp can be made relatively high.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an embodiment of a light source according to the present invention.

FIG. 2 is a cross-sectional view of an electrodeless discharge lamp among the light sources shown in FIG. 1.

FIG. 3 is an electrical equivalent circuit diagram of the light source shown in FIG. 1.

FIG. 4 is a diagram showing the configuration of another embodiment of the light source according to the invention.

5 is an electrical equivalent circuit diagram of the light source shown in FIG. 4. FIG.

FIG. 6 is an electrical circuit diagram showing the configuration of still another embodiment of the light source according to the present invention.

FIG. 7 is a diagram showing the configuration of a light source according to the prior art.

[Explanation of symbols]

1 Discharge lamp 2 Tubular part 3A, 3B Spherical part 4 Pipe shaft 6A, 6B coil 16 High frequency power supply

Claims (1)

[Claims] Claim 1: An electrodeless discharge lamp having a tubular part and a hollow spherical part formed at both ends of the tubular part and filled with gas, an excitation coil, and a discharge lamp for excitation. In a light source comprising a high-frequency power source that supplies a high-frequency current to the coil, the excitation coil is disposed at a substantially symmetrical position from the substantially central part in the tube axis direction of the discharge lamp, and the magnetic flux is directed in the same direction as the tube axis direction. A light source characterized by being a pair of coils wound so as to generate.