JPH0325833A - Heat cathode grid control electric discharge tube - Google Patents

Abstract

PURPOSE:To make unnecessary a high voltage resistance which is fixed from the outside and expensive, by letting the outer enclosure of a thyratron have the function of resistance. CONSTITUTION:From the upper side, an anode 1, separating grids 2, a control grid 3 and a cathode 4 are respectively arranged at predetermined intervals mutually. Also, flanges 5, 6, 7, 8 which are integral to these, protrude to the outside, and the inside is air-tightly maintained as envelopment is made by means of outer enclosures 0, 10, 11 whose outer perimeters are of a cylindrical shape and of a high insulating quality ceramics, and the bottom portion 12, and gas is filled at the inside. High resistance bodies 27, 28 having a fixed thickness of about 800kOMEGA/cm are painted at the whole of the outer perimeter surfaces of outer enclosures 9, 10, 11. Thus, voltage of a predetermined value is impressed at the anode, separating grids, the control grid, even without the outer fixed resistance.

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention relates to a hot cathode grid-controlled discharge tube (thyratron) whose outer periphery is constructed of a highly insulating envelope for electrode retention and airtightness.
It is related to. ``Prior Art'' In general, a multipolar voltage type thyratron has an anode (1), a separate grid (2), and a separate grid (2), as shown in FIG. A control grid (3) and a cathode (4) are overlapped at a predetermined interval, and each flange portion (
5) (6) (7) (8) is a cylindrical envelope (9)
(10) It is attached so as to partially protrude outward from (11) and the bottom part (12), and inside is H2, D2. Gas such as Ha is hermetically sealed. However, conventionally, the envelopes (9), (10), and (11) and the bottom (12) are made of highly insulating ceramics. A voltage approximately midway between the voltage applied between the anode (1) and the control grid (3) is applied to the separate grid (2). Then,
The potential difference generated on the surfaces of the electrodes facing each other is divided into two, and the voltage that can be applied to the anode (1) can be higher than that of a thyratron that does not have a separate grid (2).

Such a conventional thyratron (13) is used in a grid grounding type as shown in FIG. 6 or in a cathode grounding type as shown in FIG. Both Figures 6 and 7 show examples of use as a discharge switch for a laser tube (l4). Among these, in the case of Fig. 6, the separate grid (2) 1 is connected to the voltage v8 from the high voltage power supply (15) applied to the anode (1) by 50~'IOOM.
A resistor of approximately Ω (16) (17) divides the voltage into 1/2 and supplies it. Also, instead of the voltage dividing resistors (16) and (17), a 172 power source (not shown) of the high voltage power source (15) is provided separately, and this 1/2 voltage power source is connected to the separate grid (2). They can also be combined directly. In the circuit of FIG. 6, as mentioned above, a voltage approximately 1/2 of the power supply voltage v1 is applied to the separate grid (2), the control grid (3) is grounded, and the cathode (4> is grounded). A bias voltage is applied from the auxiliary power supply (18) so that the voltage is higher than that of the grid (3).The high voltage power supply (15) is also connected to the inductor (19), diode (20), capacitor (
21). An inductor (22) is circuited to ground to charge the main capacitor (2l). In this state,
When a negative trigger signal is applied to the cathode (4) of the thyratron (13), the thyratron starts discharging and turns on. When turned on, a circuit is formed consisting of the main capacitor (21), the thyratron (l3), the pre-ionization electrode (23) of the laser tube (l4), the peaking capacitor (24), and the main capacitor (2l); ) is discharged and charges the beaking capacitor (24) through the pre-discharge of the pre-ionization electrode (23). Next, in the laser tube (l4) which has been prepared for discharge by preliminary discharge, the charge of the peaking capacitor (24) is reduced by a circuit consisting of a peaking capacitor (24), a main discharge electrode (25), and a preliminary ionization electrode (23). is injected into the laser gas between the main discharge electrodes (25), the main discharge electrodes (25) are also discharged, and a laser beam of a predetermined wavelength is generated. The above operation is repeated intermittently to generate a pulsed laser. The cathode grounding shown in FIG. 7 is used when the current flowing is smaller than the grid grounding, but its effect is almost the same. "Problems to be Solved by the Invention" When the multipolar polarization type thyratron (l3) as described above is operated, a voltage approximately half of the voltage applied to the anode (1) is applied to the separate grid (2). Since the means for supplying the voltage needs to be constructed outside the thyratron (l3), it is necessary to externally attach an expensive high voltage resistor.

The purpose of the present invention is to provide a thyratron envelope with a resistor function, thereby eliminating the need for external attachments. "Means for Solving the Problems" The present invention provides an anode, a separate grid, a control grid, and a cathode, which are stacked one on top of the other at a predetermined interval, and whose flange portions are airtightly attached with a cylindrical envelope. the anode;
Part or all of the envelope between the separate grid and the control grid is made of a high resistance material.

``Function'' By coating the outer wall of the envelope with a high-resistance material or by making the envelope itself a high-resistance material, a predetermined voltage can be applied to the anode, separate grid, and control grid without any external resistance. is applied. In addition, when the envelope itself is made of a high-resistance element, in order to prevent discharge between this high-resistance element and the internal electrode, it is coated with a coating of 1 kM. An example will be explained based on drawings. In addition,
The same parts as in Figure 5 are given the same reference numerals. In FIG. 1, an anode (1), a separate grid (2), a control grid (3), and a cathode (4) are arranged from above at predetermined intervals.

Also, flanges (5) (6) (7) integrated with these
(8) protrudes outward and is surrounded by a cylindrical highly insulating ceramic envelope (9) (10) (1 1) and a bottom part (12) to keep the inside airtight. Filled with gas. Note that the cathode (4) is provided with a cathode heater (26), and a heater lead wire (26a) protrudes outward from the bottom (12).

In such a configuration, in the present invention, the outer enclosure @ (9
) <10) 800KΩ/c on the entire outer peripheral surface of (11)
! High resistance material (27) (28) (2
9) is applied. Specifically, metal oxides, carbon materials, etc. are formed using a plasma spraying method. The high resistance elements (27), (28), and (29) may be formed in advance into a ring shape and fitted onto the outer periphery of the envelope (9), (10), and (11). In this way, the distance between the anode flange (5) and the separate grid flange (6) and between the separate grid flange (6) and the control grid flange (7) is 40~IOO, respectively.
MΩ, and the distance between the control grid flange (7) and the cathode flange (8) is several MΩ. In particular, the anode flange (5) and the separate grid flange (6)
, between the anode electrode (1) and the high resistance element (27), between the separate grid flange (6), between the separate grid electrode (2) and the high resistance element (27) (28), and between the control grid flange (7). ), control grid electrode (3) and high resistance element (28) (2
In order to make the stray capacitances formed between the high resistance elements (27) and (28) as uniform as possible,
(29) is preferably provided in the same cylindrical shape as the cylindrical envelope (9) (io) (tt) made to match the cylindrical internal electrode. As a result, the stray capacitance formed between the internal electrode and the internal electrode is made uniform, the electric field applied to the internal electrode is made uniform, and the influence on the switching operation during discharge is reduced. However, if these effects do not pose much of a problem, the high-resistance elements (27), (28), and (29) may be attached to the flange (5).
(6) (7) As long as the spaces are connected, it can be made into one or more strips or a grid. It can also be shaped like a spiral. Next, FIG. 4 shows another embodiment of the present invention. In this example, the envelopes (9), (10), and (11) themselves are made of a high resistance material. however. Since the gap between the internal electrode and the high-resistance envelopes (9) and (10) is small, there is a risk of electrical discharge occurring between them. To prevent this,
Highly insulating ceramic layer (30
) (31) is formed. The envelopes (9), (10), and (11) made of such high-resistance materials are formed by dispersing the resistors in highly insulating ceramics and sintering them. Further, the highly insulating ceramic layers (30) (3l) on the inner surface may be integrally molded, or may be formed by plasma spraying ceramics or inserting a ceramic ring on the inner surface. An example in which the thyratron constructed as described above is used in a laser generator is shown in FIGS. 2 and 3. Of these, FIG. 2 shows an example of use in the grid grounding type, and when voltage v1 of the high voltage power supply (15) is applied to the anode (1), the high resistance 2 of the envelopes (8) (9) increases.

? By the way, 50 each of high resistance elements (27) and (28)
MΩ Toshi, Anode (1) Ni V, To L Te 3 0 ~ 4
It was confirmed that when 0 KV was applied, a current of 300 to 400 μA flowed through the high resistance elements (27) and (28), and 15 to 20 KV of 172 of V■ was applied to the separate grid (2).

Figure 3 shows an example of cathode grounding, and the applied voltage V
is applied to the separate grid (2) as a partial pressure in the same way as in Figure 2. Here, the voltage ■1 is the high resistance object (27) (28) (29
), and a positive voltage is applied to the control grid (3). Further, a voltage that is negative with respect to the cathode potential (ground potential in FIG. 3) is applied to the control grid (3) by an auxiliary power supply (18). In this circuit, the auxiliary power is 117K.
Since the internal impedance of (18) is sufficiently small compared to the impedance of the high resistance element (29), the potential of the control grid (3) is
18). In this circuit, the high resistance element (29) is used to supply divided voltage when the auxiliary power supply (18) is not connected or the control grid (3) is open. It works to prevent voltage from being generated. The operation of the laser generator shown in FIGS. 2 and 3 is the same as that shown in FIG. 6 described above, so a description thereof will be omitted. "Effects of the Invention" (1) When supplying a divided voltage to a separate grid, there is no need for an external voltage dividing resistor as in the past.
Eliminates the need for expensive discharge resistors. (2) Since there is no external attachment, it is easy to cool and shield the thyratron.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of a thyratron according to the present invention, FIGS. 2 and 3 are electrical circuit diagrams of an example of using the product of the present invention, and FIG. 4 is a cross-sectional view of another embodiment of the present invention. Figure 5 is a cross-sectional view of a conventional thyratron, and Figures 6 and 7 are conventional electrical circuit diagrams. (1)...Anode, (2>...Separate grid, (3)...Control grid, (4)...
Cathode, (5), (6), (7). (8)...flange part, (9). (to), (l1)...Cylindrical envelope, (l2)...bottom, (13)...thyratron, (14)...laser tube, (15)...high voltage Power supply, (l6) (17)...Voltage dividing resistor, (18)
... Auxiliary power supply, (19) ... Inductor, (20)
...Diode, (21) ...Capacitor, (22
)...inductor, (23)...preliminary ionization electrode.
(24)...Peaking capacitor, (25>...
Main discharge electrode, (26)...Cathode heater, (26a
)...Heater lead wire, (27) (28) (29)
... High resistance material, (30) (31) ... Highly insulating ceramic layer.

Claims (4)

[Claims] (1) In a device in which an anode, a separate grid, a control grid, and a cathode are stacked one on top of the other at a predetermined interval, and their flange portions are airtightly attached using a cylindrical envelope, at least the space between the anode, separate grid, and control grid is A hot cathode grid-controlled discharge tube characterized in that part or all of the envelope is made of a high-resistance material. (2) The hot cathode grid-controlled discharge tube according to claim (1), wherein the envelope is made of highly insulating ceramic, and a high resistance element is formed on the outer peripheral surface of the envelope. (3) The hot cathode grid-controlled discharge tube according to claim (1), wherein the envelope is made of a high resistance material, and a highly insulating layer is formed on the inner peripheral surface of the envelope. (4) The hot cathode grid-controlled discharge tube according to claim (1), wherein the envelope is formed by fitting a high-resistance ring into a highly insulating ceramic.