JPS5880245A - Magnetron - Google Patents

Abstract

PURPOSE:To reduce the noise and to improve the stability of oscillation without requiring an external power source for a third electrode, by setting the bias voltage of the third electrode for a magnetron to the negative high level for the low anode current while to the negative low level or zero for the high anode current. CONSTITUTION:A cathode heating winding L2 and a high voltage winding L3 are provided at the secondary side of a leakage transformer 61 but the third electrode winding is not provided. The winding L2 is connected to the cathode K of a magnetron 62 having the third electrode while one end of said winding L3 is grounded and the other end is connected together with the cathode electrode of a forward rectifier SR1 to said cathode K through a capacitor C1 and the anode electrode of the rectifier SR1 is grounded. The third electrode D is connected to the cathode K through a reverse rectifire SR2 while grounded through a capacitor C2. Consequently the noise is reduced and the oscillation stability is improved.

Description

[Detailed Description of the Invention] This invention relates to magnetron equipment gK, especially its computer (gK).
The magnetron, which provides a magnetic field perpendicular to the IC and the electric field, is now widely used in electronic equipment such as microwave ovens, but along with this, noise leakage regulations have become stricter. It is on track to be strengthened. Internationally, ζO noise regulations are being implemented or under consideration in each country based on the recommendations of the International Special Committee on Radio Interference (referred to as Cl8PR). Therefore, measures to reduce the noise generated from the magnetron itself are even more effective. I started to get caught up in it, so I stopped myself.

The following are the causes of low frequency noise (for example, below 1001 ain) generated by the magnetron. That is, the first wA schematically shows the seven node panes 2- and cup 225 that are coaxially arranged and constitute nine anodes of the magnetron.
With cathode IJ set to negative and anode pane 2# set to positive, a high voltage of several thousand volts, '\, is applied between the cathode and the anode, and thermionic electrons are emitted from cathode 1j. As a result, space charges near the cathode result in a potential distribution with a downward concave portion that is more negative than the cathode potential, as shown by the dotted curve a in Figure P1. On the other hand, as shown by arrow B, a direct current magnetic field of 11000 to 2000 Gauss is applied to this electron action space 1911C1-11000 to 2000 Gauss in the cathode axial direction, so the electrons leaving the cathode 25 are moved to the cathode 25 by the action of the electric field and the magnetic field. Around t-l 11 times 0% KN generate e.

The generated positive ions reach the valley of the potential distribution shown by curve a, i.e., the I-tension inimum (indicated by symbol m in the figure) &l.
f inflow, the electrons and positive ions in the space charge gradually become neutralized, and as a result, the potential near this valley rises,
As indicated by the negative sign, the potential is raised to a potential equal to or slightly higher than that of the cathode 25. In this state, the potential distribution in the working space becomes like a concentrated curve.Positive ions enter the cathode Kfi. As a next step, a potential mass is again formed by space charges. This series of processes is repeated periodically. As a result, the current between the cathode and the anode, that is, the anode current Ill? IIc It can be assumed that a complex pulsation phenomenon occurs and this leaks to the external circuit as noise. This kind of noise mainly appears as so-called line noise that leaks through the input line, causing various types of electrical disturbances.Therefore, as one of the measures to reduce such noise, , a third electrode is provided near the cathode, and the third electrode is negative 4D@10 to several 1 with respect to the cathode.
It is thought that by applying a potential of 00 V), positive ions that gather at the valleys of the potential distribution, that is, the 4-tensional minimum, are captured by this third electrode, thereby reducing noise caused by glass ions.

In this example, as shown in FIG. 82 and FIG. 3), 3vA is the fleas enlarged garden in FIG.

That is, the cathode end tip 51, the Ii3 electrode tip, y"is, and the end height 11* are solidly layered on one end of the rod-shaped cathode support 11 arranged on the tube axis, and the cathode terminal 16 is placed on the other end. A terminal plate 5shK is fixed to the terminal plate 5shK.A cylindrical cup-P support 3J and a cylindrical third electrode support 67 are coaxially attached to the outside of the rod-shaped cup-P support 32 on the cup-stem side. The other cathode end chip 56 is disposed at a predetermined interval, and is fixed to one end of the cylindrical cathode support 3J;
It is fixed to 4. Further, the cylindrical third electrode support 51
The other third electrode mounting tip 59 is fixed to one end, the other end tip 1, 1slb is fixed to this end tip 5#, and the other end of the third electrode support j1 is fixed to a cathode terminal 61KvA. has been done. Then, the rod-shaped cathode support XZO output part 111Ka is wound into a coil! A tungsten thermal cathode ZS is disposed, and both ends thereof are respectively cathode end tips sx,
stzKwi is being worn. Further, near the cathode 15, a third electrode 60 in the shape of a dome is arranged between the stripes of the cathode 25, and both ends of the third electrode 60 are connected to the third electrode 60.
The end tips for 3 electrodes IS and 1EYC are fixed.

This third electric figure is, for example, W, Me.

A simple substance selected from refractory metals such as TlO or an alloy is placed in the vicinity of the cathode 2jO and in a position that does not impede the flow of electrons from the cathode 2j to the node 7, as shown. . As described above, the coiled wires of the cathode 15, the coiled wires of the three electrodes, and the expanded outer surfaces are alternately arranged on the same inner surface. In addition, 1- in the bacterium is anode pain,
2r is the anode cylinder, xs is the strike ring 6D, these constitute a plurality of cavity resonators, and the anode is formed as a whole. Also, L is the output part. , 19m is the antenna conductor, 1# is f-Rubys, J
i*s J a・aJb Hiro insulating cylinder, 1# is electron working space, s4/Ii exhaust pipe, ss, gill 6th order operation iI! At dawn, the cathode 1j is heated and emits thermoelectrons. A high voltage of several thousand volts is applied between the cathode 25 and the γ node pane 1-, and a DC magnetic field of 1500 gauss II degrees parallel to the tube axis is applied to the electron action space 19. p, oscillates. Microphone U wave energy generated in the cavity resonator is transmitted from the output section xp to an external load through the antenna conductor 29a. Now, when the cathode 25 is heated, a potential valley m is formed in the vicinity of about several 105 m to several 100 μm in front of the cathode 25 as shown in i#A due to the emitted electrons (if there is no iris 3 electrode), but the M3 electrode 60 to cathode 2
511C, for example, when a negative potential of -several 10 to -several oov @ degree is applied, the glass ions that gather toward the valley mK of the potential will be absorbed by this third electrode 60 because the potential is even more negative than this. 3-electrode 601fC@catched. In other words, the glass ions do not get close to the cathode and are
The unstable electron-ion neutralization phenomenon near the cathode does not occur due to the inflow into the electrode iOK, and as a result, noise below 100 MHz is significantly reduced. An example of this noise reduction result is shown in Fig. 4. By the way, if the potential of the third electrode is set to a negative high potential, it is very effective for noise reduction, but if the potential of the third electrode is set to a negative high potential, It has been found that the stability of the magnetron's oscillation tends to be rather inconvenient. An example of this is shown in Fig. 5. That is, as is clear from this fifth point, an increase in the absolute value of the bias voltage of the third electrode results in a decrease in the maximum anode current for stable oscillation. When examining the relationship between anode current and noise, we find that, as shown in Figures 6E and 7, in general, continuous wave magnetrons generate large noise when the anode current is small, for example, about 0.15 μm or less. It can be seen that the noise decreases rapidly at 2 m or more. Therefore, if the anode current is always about 0.
If used at 200 m or more, the noise will be very low and there will be no problem with the company's expenses, but due to the cost, the 7 node power supply for SUMO microwave ovens generally uses a half-wave voltage doubler power supply. Instantaneous anode current from Hirorei to IA
It has repeatedly fluctuated up to 9 times. As described above, if a negative high potential of the third electrode liK is applied for the purpose of reducing noise, the operation stability will be slightly lowered, and conversely, if the third electrode potential is lowered, noise will tend to occur, which is a contradictory tendency.

This invention has been made in view of the above circumstances, and provides a magnetron device that reduces noise, improves oscillation stability, and does not require an external power source for the third electrode.
- aim.

Hereinafter, one embodiment of the present invention will be explained in detail with reference to the drawings. In general, it is necessary to reduce noise by the 4 Ias voltage of the sgam pole because the 7 node current is approximately 0.15
It is preferable not to apply the bias voltage of the iris 3 when the 7th node current is 0.2 µm or more, as seen from the relationship with the 5th magnetron stability.

In other words, an example of the characteristics of the magnetron's anode current and node voltage is shown in Section 8. As is clear from this summary, the anode voltage R is, for example, 1 μm (usually half-wave, which is used in microwave ovens). The difference between the anode voltage at the almost maximum instantaneous anode voltage a) generated in the voltage power supply and the anode voltage at an anode current of 0.15 μm is approximately 50
It can be seen that 0'V is generated. It can be seen from No. 45 that this potential difference, added as a bias voltage to the third electrode, is sufficiently useful for reducing noise. Therefore, if the voltage between the third electrode and the anode is always maintained at the maximum value of the anode voltage, the bias voltage of the third electrode (very negative with respect to the cathode) can be maintained when the node current is low. As the anode IEfIt increases, the bias voltage of the third electrode approaches zero, thereby reducing the influence of a decrease in the stability of the li emission.

Therefore, in this invention, the voltage (potential) of the third electrode of the magnetron is a low anode current and a high potential. An excitation path is used.

- In the middle, the gxFi leakage transformer is connected to the primary side 1-Lihiro commercial power supply #C, and the secondary side has a cathode heating winding @Lss high voltage winding ail Ls,
The cathode heating winding, which does not have an independent three-electrode winding, is connected to the cathode KIIC of the magnetron 6j having the same third electrode as in FIGS. 2 and 3 above. Also, the above-mentioned masterpiece! One end of i L s is grounded, and the other end is connected to forward rectifier 8R via direct capacitor C1.
1 and the cathode K of the magnetron 62.
K is connected. The anode of the rectifier 8R1 is grounded. Further, the third electrode of the magnetron 62 is connected to the cathode via a reverse rectifier SR, and is also grounded via a capacitor C3. Furthermore, the 7 node of the magnetron 62 is also grounded. The above capacitor CI is 0.5 μF%; capacitor C is 9
．． 05μF.

Now, during operation, each part, 1-
The voltage or current waveforms between 2, Mu-ni, Anotom, and Mu-D are 9, ah-4k 11 (Lisurge wave m> becomes as shown in the first wound diagram.Then, for 11 minutes, Mu-D [
TsgT, the maximum value -1em (e.g. -4k
V)', then T gate'r, lIc, then MuX
The voltage between them is discharged by the anode current tbtfifl and becomes Ov, which is the same as T=Tl. scold KA
The voltage between -0 is that the rectifier 98B is in the opposite direction,
From the 31st iE pole, there is no electron emission (if there is electron emission, the charge of capacitor C3 is somehow discharged). On the other hand, the third voltage IID has a negative potential of approximately 4 kV.

In fact, in Figure 11, the parts marked with arrows, each 1
For the value of b, the value on the vertical axis with an arrow (4b
O and @tic are about 4 kV, and when ib=ibm, QV) will be applied to D-.

This is 1 Gnet E! The y device is constructed as described above and shown in the drawings, and uses the power line IA circuit as shown in Figure 9, which reduces noise, improves oscillation stability, and connects the third electrode to No external power supply is required.

That is, in the range of −b=o to 0.1 μm where a lot of noise occurs, the bias voltage of the third electrode has a negative high potential and has a large noise reduction effect, and in the range of large =b, the bias voltage of the third electrode is low, and the stability of the magnetron's oscillation does not deteriorate.Also, the rectifier SR and capacitor C1 are several k
It can be constructed relatively inexpensively by using a material having a withstand voltage characteristic of V.

Incidentally, since FIGS. 12, 14, and 15 show modified examples of the present invention, the same effects as in the above embodiment can be obtained.

That is, in the case of Fig. 12, a resistor 8 is additionally connected in parallel to the capacitors C and K in the above embodiment (Fig. 9), and the time constants τ = C, R = 100 m-. - When this resistor R is added, the charge charged in the capacitor CsK is discharged through the resistor R, so it changes as shown in -bmO in Fig. 13. Therefore, the maximum voltage applied between D- is gbm (sbm) (sbm (abm) *For example, ij abm =
sbm is approximately 3 kV compared to 4 kV K. In this way, by lowering the maximum voltage applied to D-,
- Helps avoid dielectric breakdown between - In addition, it is generally supplied to electronic manufacturers with a built-in rounded choke coil and through-type capacitor to prevent leakage of magnetron noise and harmonics, and is equipped with nine shields and a box. Therefore, this shield is inside the tux, ga
Rectifier-883 and capacitor Cm to apply voltage to t&
(or resistance R).
A microwave oven with reduced noise can be completed without changing the power supply device of the microwave oven.

Examples of this are shown in FIGS. 14 and 15, where 63 is a shield shield. And this shield is Jis 6J
Inside, the above rectifier board 8B! In addition to the capacitor C3, a choke coil 64 and a feedthrough capacitor 65 are provided.

As described above, according to the present invention, a magnetron device of great industrial value can be provided.

[Brief explanation of drawings]

Figure 1 is a schematic diagram showing the noise generation mechanism in a magnetron, Figure 2 is a Wr drawing showing an example of a magnetron equipped with a third electrode to reduce noise, and Figure 3 is a summary of Figure 2. Fig. 4 is a characteristic curve diagram showing the noise reduction by the bias voltage of the third electrode, and Fig. 21g5 is a characteristic curve diagram showing the influence of the bias voltage of the third electrode on the stability of magnetron oscillation. , Figure 6 and Figure #g7 are percent characteristic curve diagrams showing changes in noise due to 7-node turtle flow, No. 8
The figure is a characteristic curve diagram showing the 7-node current vs. anode voltage characteristic, Figure 9 is a circuit configuration diagram showing the power supply circuit used in the magnetron device of the present invention, and Figures 1θ (&) to (d) are the power supply of Figure 9. A waveform diagram showing the voltage of the % part in the circuit or tIILYlc, Fig. 11 is also litharge, waveform-1 12th
figure. FIGS. 14 and 15 are block diagrams of the (b) circuit showing a modification of the present invention, and FIG. 13 is a waveform diagram of the resurge in the power supply (b) circuit of the 12th prisoner. 25'', K...Cathode, 26...7 node vane, 27...Anode cylinder 1, 11B-...Strap ring, 19...Electron action space, 60.D...
・Third electrode, 61... Leakage transformer, 62...
・Magnetron% Ll... Winding, L3... Cathode heating winding -1Ls-... High voltage winding, c, I c, ++
・Capacitor, 8J *8J... Rectifier, Mu... Anode. Applicant's agent Takehiko Suzue Figure 1 9 Figure 2 339, Ibden 47)/+17uv > Figure 6 Figure 7 Anode 't3JL (A) - Figure 8 Figure 9 Figure 10 Figure 11 0-! t) IBM Figure 12 Procedural Amendment 574-9 Showa year ° month Date Director General of the Japan Patent Office Shima 1) Haruki Tono1, Indication of the case Patent Application No. 1988-1'177122, Name of invention magnetron device 3, Relationship with the case of the person making the amendment Patent originator (307) Tokyo Shibaura Electric Co., Ltd. 4, Agent 5 Voluntary amendment 7, Contents of the amendment (1) Details attached to the application Summer, page 11, line 2 rLs
Correct the "J" to "Ll". (2) “Cathode” also on page 11, lines 6-7
Correct the text to read "anode." (3) Correct the word ``anode'' in the 8th line of page l1 to ``cathode.'' (4) Similarly, on page 11, line 1 O, the words "reverse direction" are corrected to "forward direction." (5) Similarly, page 11, lines 6-7 = [Anode...
...discharge," replaces "rectifier 8R.
, so the forward voltage is . (6) Similarly, on page 12, line 6, rsRzJ is corrected to "8R1 and 8R3." (7) Similarly, in the 13th line of page 13, "100" should be corrected to "1000". (8) Similarly, from page 13, line 17 to page 14, line 2, the text ``This is useful for...''
The voltage applied to the steering wheel D- is, after cutting off the im flow,
A natural discharge occurs through the resistor R, which is useful for preventing electric shock during inspection. ” he corrected. (9) In the drawings attached to the application, Figures 8, 9, 11, 12, 13, 14, and 15 are corrected as shown in the attached sheet. Figure 8 Figure 9 Figure 11 Figure 13 ib ibm

Claims (1)

[Claims] It has an electron radiation force node arranged coaxially with each other and an anode containing a cavity resonator, and a magnetic field parallel to the cathode axis is applied to the electron action space between the cathode and the anode, and the magnetic field near the cathode is The magnetron is equipped with a third electrode, and the bias potential is applied to the magnetron OSS electrode. In the Danetron Ik, the bias potential of the 31st iE electrode of the magnetron is set to be a negative high potential when the anode current is low, and to be a zero or negative low potential when the anode current is high. % mold magnetron device.