JPS631704B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a light source device, and more particularly to a light source device that emits light based on hydrogen gas or deuterium gas sealed in a sealed container.

Hydrogen light sources generally employ a sealed hot cathode type light emitting method using direct current discharge.

FIG. 1 is a longitudinal sectional view of a conventional hydrogen light emitting device, and FIG. 2 is a sectional view taken along line AA' in FIG.
A coil type hot cathode 1 is placed in the center of a cathode chamber 10, and a plate-shaped anode 2 is placed in an anode chamber 9. Cathode chamber 1
0 and the discharge light emitting chamber 11 are both cylindrical shapes that are open in the vertical direction, and the anode chamber 9 is in the shape of a closed box that is also closed in the vertical direction and is supported by the stem 8 by a conductor 12 that is integrally formed with the partition plate 3. ing. In addition, the above cathode 1
The anode 2 and the anode 2 are similarly supported on the stem 8 by conductors, and these conductors are taken out through the stem into the lower part of the tube body 7.

As shown in Fig. 2, the tube body 7 is a cylindrical glass tube, with a part of it protruding, and a quartz window that allows ultraviolet rays to pass through well is attached to the tip of the tube so as to be perpendicular to the emission line 13, and deuterium is sealed therein. are doing. In addition, cathode chamber 1
A discharge path hole 6 is provided in the partition plate between the discharge light emitting chamber 11 and the discharge light emitting chamber 11, and a hole 4 is provided between the discharge light emitting chamber 11 and the anode chamber 9.
There is a light extraction window hole 5 at the light exit of the discharge light emitting chamber 11.

In the conventional hydrogen light emitting device configured as described above, the cathode 1 is heated and DC power is applied continuously or intermittently between the cathode 1 and the anode 2 to generate continuous light or intermittent light. was.

The above-mentioned conventional hydrogen light source is not necessarily sufficient in terms of the light intensity that can be obtained, and if the anode current is increased to obtain a large light intensity, not only will the light emission become unstable, but the lifespan will be extremely shortened. In particular, the clean-up phenomenon in which the sealed gas is deposited on the tube wall or electrode surface together with sputtered metal and the pressure of the sealed gas is reduced is remarkable, resulting in a short life.

SUMMARY OF THE INVENTION An object of the present invention is to provide a light source device that has a long life and is difficult to reduce the pressure of the sealed gas over a long period of time.

The present invention provides an isolation member that includes a first electrode and a filament in a sealed container, a second electrode between which high-frequency discharge is performed, and a through hole for maintaining the discharge. A first electrode was provided inside the isolation member, a filament and a second electrode were provided outside the isolation member, and a direct current discharge was possible between the first electrode and the filament. It is characterized by

In a preferred embodiment of the present invention, a first electrode, a second electrode, and a filament are provided in a sealed container, and power is supplied to cause high-frequency discharge between the first electrode and the second electrode. A high-frequency power source is provided, an isolation member having a through hole for maintaining the discharge is provided, a first electrode is provided inside the isolation member, and a second electrode and a filament are provided outside the isolation member. Then, after causing a DC discharge between the first electrode and the filament, the first electrode and the second
Control means are provided for causing high frequency discharge between the electrodes. In a preferred embodiment of the present invention, the first electrode has a recess, preferably in the shape of a cylinder or a bowl with a bottom. The second electrode has a ring shape with a light passage hole, and the first electrode and the second electrode are short-circuited in terms of direct current. The filament consists of a tungsten coil coated with oxide. The separating member or restricting member is provided in continuous contact with or in close proximity to the inner wall of the sealed container. The suitable high frequency power for use is 3 to 35 watts, and the high frequency power supply is one that can pulsate high frequency current and can vary the waveform of the pulsation. The diameter of the recess formed in the first electrode is larger than the diameter of the through hole of the isolation member.

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

FIG. 3 is a vertical sectional view showing a schematic structure of an embodiment of the present invention, and FIG. 4 is a sectional view taken along line BB' in FIG.

First, hydrogen (H ₂ ) or deuterium (D ₂ ), which is a gas that takes part in maintaining the discharge and emitting light, enters the tube body 22.
Enclosed from 1.5Torr to 25Torr. The tube body 22 has a light extraction window 23 made of transparent quartz for extracting light 28 to the outside, and supports a first electrode 20, a second electrode 21, etc. in the opposite direction of this window, and seals the inside of the tube. In addition, the conductors 29, 30 for introducing power have a stem 25 for sealing. Stem 25 is made of hard glass.

Inside such a tube body 22, a light extraction window 23 and a first electrode 21 are arranged such that the first electrode 20 and the second electrode 21 are centered on the vertical central axis of the tube body 22.
0, the second electrode 21 and the limiting member 24 are arranged to face each other. The first electrode is shaped like a cylinder or a bowl with a bottom, and the discharge section 33 is hollow and is made of a highly heat-resistant material such as molybdenum, tungsten, or tantalum. The second electrode 21 is made of nickel, has a ring shape, and is arranged so that the light 28 can effectively pass through a hollow portion in the center.

Further, a restricting member 24 for restricting discharge is placed around the first electrode 20 to maintain a continuous gap while surrounding the first electrode without touching the first electrode 20. Placed in close contact with or close to. The limiting member 24 has a radiation density enhancement hole 27, and this through hole is connected to the first electrode 20.
and the second electrode 21 on the central axis of the light 28 . The first electrode 20 is connected to the stem 25 by a conductor 30.
It is connected via a switch 26 so that it can receive the supply of high frequency power from the high frequency power supply 32. The conductor 29 of the second electrode 21 is held by the stem 25 and is connected to receive high frequency power from a high frequency power source 32, and is also connected to a switch device 52 so that heating power for the filament 34 is supplied. ing. Further, the second electrode is connected and held to an electrically insulating material 35.
The filament 34 is connected to the conductor 29 and the conductor 31, and heating power is supplied from the DC power supply 51 via the switch device 52. The DC supply conductor 31 serves as an auxiliary means at the start of discharge.

Here, the switch device 52 is operated to turn on according to a command from the control device 50, and the DC power source 51 is turned on.
Then, a DC voltage of 10 volts (V) for heating is applied to the filament 34 through the conductor 29 and the conductor 31, and the filament 34 is heated to about 900°C.
Subsequently, the switch 26 is activated by a command from the control device 50.
Then, a DC voltage of approximately 400 V is applied between the filament 34 and the first electrode 20 from the auxiliary discharge power supply 37 to start discharge. The switch 26 can be selectively operated to connect the contact 39 to the contact 38 or 40 or to leave it in a free state. 41 is a relay control terminal for causing the switch 26 to operate. First electrode 2
0 and the filament 34, the first electrode 20 and the second electrode 2 are
The switch 26 is switched so that 1 is discharged, and high frequency power is applied from the high frequency power source 32.

If an attempt is made to start the discharge using only high frequency power, a very high high frequency voltage will be required, which is undesirable from the handling point of view. As described above, discharge is started at a relatively low voltage using the hot cathode 34, and as a result, ionized ions and electrons are present in the space between the first electrode 20 and the second electrode 21. By causing high frequency discharge between both electrodes, the above-mentioned drawbacks can be overcome.

Hydrogen or deuterium gas sealed in the tube body 22 is excited and generated by the high-frequency discharge, and is guided outside through the light extraction window 23 and used as a light source for various spectroscopic analyzers.

The high frequency power source 32 preferably has a frequency of 5 MHz to 250 MHz, and a power of 3 watts to 35 watts.
Can be applied. If the frequency is below 5MHz, the discharge becomes unstable. That is, a temporal drift of the discharge and a change in the discharge position occur. In addition, at 250 MHz or higher, high frequency loss increases, and the molecularization efficiency of hydrogen or deuterium (the rate at which hydrogen or deuterium molecules are separated by a high frequency electric field and these atoms recombine) is poor.
The discharge state also becomes unstable.

FIG. 5 shows the relationship between the frequency of high-frequency power applied between the electrodes and the emission intensity. The vertical axis shows the luminescence intensity,
The horizontal axis shows frequency on a logarithmic scale. The results of this implementation are that the first electrode 20 is made of molybdenum, has a bottomed cylindrical shape, has an outer diameter of 8 mm, a total length of 10 mm, an inner diameter of 3.5 mm, and a depth of 5 mm.
This is what I got as. The second electrode 21 is a ring-shaped electrode made of nickel metal, and has an outer diameter of 8 mm, a height of 2 mm, and an inner diameter of 5 mm. First electrode 20 and second electrode 2
1 and 10mm apart. Further, in the first electrode 20, the limiting member 24 is made of a molybdenum plate with a thickness of 0.15 mm, and the diameter of the radiation density enhancement hole 27 is 1.0 mm.

Inside the tube 22 is deuterium with a purity of 99.99%.
7Torr is included. The high frequency power applied between the electrodes was 9W. Under the above conditions, the emission intensity at a frequency of 28 MHz is sufficiently higher than that of conventional hot cathode type DC discharge type hydrogen discharge tubes, and the lifespan due to the gas clean-up phenomenon is about 300 hours in conventional cases. On the other hand, in the case of high-frequency discharge, this clean-up phenomenon is not observed, and operation can be continued until the end of life is determined by other causes.
The lifespan is several times longer than that of conventional products, that is, the lifespan is over 1000 hours.

FIG. 6 shows the relationship between high frequency power and emission intensity. The vertical axis shows light intensity, and the horizontal axis shows high frequency power. The experimental conditions were the same as when obtaining the relationship shown in Figure 5, but the frequency was set to 28MHz. Here, if the power exceeds 35W, the discharge will spread, the electrode temperature will rise due to high frequency loss, and the life of the light source will be shortened. Also
Below 7W, the luminous intensity decreases and the discharge becomes unstable, while below 3W it becomes difficult to discharge.

Next, the relationship between the pressure of the filled gas and the luminescence intensity will be explained based on the experimental results shown in FIG. Figure 7 is under the same conditions as Figure 6 (however, the power was 9W)
It was measured. That is, when the gas pressure is 1.5 Torr or less, the light intensity is high to some extent, but the discharge becomes unstable and reliability is poor. Moreover, if it exceeds 25 Torr, a practically sufficient light intensity cannot be obtained. When the frequency and power are changed here, although there is a slight change in the absolute value, the tendency remains the same.

Next, the radiation density enhancement hole 27 in the restriction member 24 will be explained using FIG. This radiation density enhancement hole 27 is intended to limit the discharge path of the high-frequency discharge between the first electrode 20 and the second electrode 21, and also to have a constriction effect, thereby increasing the emission intensity and stability. be. Figure 8 shows the filled gas pressure is 9 Torr.
The other conditions were the same as in the measurement shown in FIG. The vertical axis shows the light intensity on a logarithmic scale, and the horizontal axis shows the hole diameter of the radiation density enhancement hole. If the hole diameter is less than 0.8 mm, the light intensity will be high but unstable due to the relationship with the power source. Under these conditions, a very high voltage power supply is required to ensure stable operation. Also, the pore diameter is 2.5
When it exceeds mm, the constriction effect weakens, resulting in insufficient light and instability.

Next, the electrode shape will be explained. First electrode 20
When comparing the case where the plate was flat and the case where the plate was shaped like a bowl, it was found that the light intensity was more than three times higher in the case where the plate was shaped like a bowl, and the effect was remarkable. When the first electrode 20 is made into a cylinder, the one with open ends and the one with a bottom are more than 2.5 times superior in light intensity to the one with an open end. It was found through experiments that it was clearly superior in terms of stability.

The second electrode 21 was disposed opposite the first electrode 20 in order to make the high frequency electric field uniform between the second electrode 21 and the first electrode 20, and was ring-shaped so that light could pass through the center. Further, in order to prevent the first electrode 20, the second electrode 21, and the limiting member 24 from being deteriorated by sputtering due to ion bombardment, both electrodes are short-circuited in terms of direct current. As a result, a decrease in light intensity due to spatter metal adhering to the light extraction window 23 and reducing the transmission of the light 28 can be prevented, and a longer life can be achieved.

Furthermore, by bringing the limiting member 24 and the tube body 22 into close contact with each other or in close proximity to each other, loss of high frequency power can be reduced and operation can be performed with high efficiency.

According to the embodiment described above, the lifespan is much longer than that of the conventional one. Further, even if the light intensity is increased, electrode wear due to spatter is small, so the S value can be increased, the S/N ratio can be improved, and the accuracy of spectroscopic analysis can be improved. Furthermore, since light emission can be sustained only by high-frequency discharge, the gas clean-up phenomenon is almost eliminated, and there is no adhesion of metal elements to the light extraction window, making it possible to downsize the tube body.

In the above description, it is assumed that the second electrode is located inside the tube, but it may be located on the surface outside the tube or in the vicinity thereof. Further, when the second electrode is located inside the tube, a grounded shield electrode may be provided on the outer surface of the tube.
Further, although the shape of the second electrode is ring-shaped, other shapes may be used, and the second electrode is not limited to the above shape as long as it can perform high-frequency discharge with the first electrode.

Furthermore, if the inner diameter of the cavity 33 of the first electrode is smaller than the diameter of the radiation density enhancement hole 27 of the limiting member, the emission intensity will be significantly reduced. Furthermore, if the high-frequency power is modulated and the high-frequency power is supplied in a pulse wave shape between the first electrode and the second electrode to extract modulated light with a pulse waveform, the electric circuit for light reception processing will not be complicated. This has the advantage that the amount of heat generated is small.

When obtaining pulsed light using DC discharge as in the past, it is necessary to insert a shutter intermittently in the middle of the optical path, or
Alternatively, it is common to obtain power by intermittent power supply. In particular, in the case of the latter intermittent power method, DC discharge requires a high voltage each time the starting voltage is intermittent, and as a result of the intermittent application of high voltage, electrodes and gas wear out significantly, accelerating deterioration. .
Discharging using only high frequencies can eliminate these drawbacks, and even though it requires a relatively simple power source, it can provide powerful pulsed light, resulting in a high S/N ratio, and when used as a light source for analysis, it can improve the accuracy of analysis. will improve.

As explained above, according to the present invention, it is possible to prevent the pressure of the sealed gas from decreasing, resulting in a long life.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing the structure of a conventional hydrogen light emitting device, FIG. 2 is a sectional view taken along line A-A' in FIG. 1, and FIG. 3 is a partial cross section of a hydrogen light emitting device according to an embodiment of the present invention. 4 is a sectional view taken along line B-B' in FIG. 3, FIG. 5 is a diagram showing the relationship between emission intensity and frequency, and FIG.
Figure 7 shows the relationship between emission intensity and high frequency power.
The figure shows the relationship between the emission intensity and the gas pressure, and FIG. 8 shows the relationship between the emission intensity and the diameter of the radiation density enhancement hole. 20... First electrode, 21... Second electrode, 22... Pipe body, 24... Limiting member, 26, 52... Switch, 3
2...High frequency power supply, 34...Filament, 37,5
1... DC power supply, 50... Control device.

Claims (1)

[Claims] 1. A light source device in which hydrogen gas or deuterium gas is sealed in a sealed container and which generates light emission based on the sealed gas as discharge occurs, wherein a first electrode and a filament are provided in the sealed container. , a second electrode is provided between which high-frequency discharge occurs between the first electrode, an isolation member having a through hole for maintaining the discharge is provided, and the first electrode is disposed inside the isolation member. A light source device, wherein the filament and the second electrode are disposed outside the isolation member, and a direct current discharge is possible between the first electrode and the filament. 2. The light source device according to claim 1, wherein the first electrode has a recess. 3. The light source device according to claim 1 or 2, wherein the second electrode is disposed within the sealed container and facing the first electrode. 4. In the light source device according to claim 1 or 2, the through hole of the isolation member has a hole diameter.
A light source device characterized by having a diameter of 0.8 to 2.5 mm. 5. In the light source device according to claim 1, 2, or 3, the sealed gas pressure is 1.5
A light source device characterized in that the output voltage is between 25 Torr and 25 Torr. 6. The light source device according to claim 1, 2, or 3, wherein the frequency of the high-frequency power that causes the high-frequency discharge is 5 to 250 MHz. 7. The light source device according to claim 1, 2, or 3, wherein the filament is disposed at a position offset from the optical axis. 8. A light source device in which hydrogen gas or deuterium gas is sealed in a sealed container and obtains light emission based on the sealed gas as discharge occurs, wherein a first electrode, a second electrode, and a filament are provided in the sealed container, A high frequency power source is provided for supplying power to cause high frequency discharge to occur between the first electrode and the second electrode, an isolation member having a through hole for maintaining the discharge is provided, and an isolation member is provided inside the isolation member. The first electrode is disposed on the outside of the isolation member, the second electrode and the filament are disposed on the outside of the isolation member, and after a DC discharge is caused between the first electrode and the filament, the first electrode and the filament are disposed on the outside of the isolation member. A light source device comprising a control means for causing high frequency discharge between the second electrodes.