JP6518369B2 - Analog amplification vacuum tube, vacuum tube - Google Patents

Description

  The present invention relates to a vacuum tube operating as an analog amplifier.

  A fluorescent display tube is known as a technique related to a vacuum tube, and for example, the structures shown in Patent Documents 1 and 2 are known. In Patent Document 1, a linearly stretched filament that emits thermoelectrons at a predetermined temperature or higher is called a "heater H". Then, an anode ("Anode 4" of Patent Document 1) disposed in parallel to the filament, and a grid disposed between the filament and the anode so as to face the anode (First Patent See Figure 2). The basic structure of Patent Document 2 is the same as Patent Document 1. Further, as a control method of the fluorescent display tube shown in Patent Documents 1 and 2, a driving method shown in Non-Patent Document 1 is known.

Japanese Utility Model Publication No. 49-5240 JP 2007-42480 A

Noritake Ise Electronics Co., Ltd., "Fluorescent display tube (VFD) in general Application method Drive method-Drive method", [search on December 19, 2014], Internet <https://www.noritake-itron.jp/cs/ appnote / apf100_vfd / apf201_houshiki.html>.

  Due to demands from users who prefer vacuum tube characteristics, mainly in the music industry, there is a demand for vacuum tubes to be used as analog amplifiers, and there are vacuum tubes that can be used as analog amplifiers. However, there is a problem that production volume is decreasing and it is difficult to raise prices and obtain them. On the other hand, a cheap and popular fluorescent display tube, which is a kind of vacuum tube, is digital control as can be seen from the driving method shown in Non-Patent Document 1, and it is not used as an analog amplifier. It can not be used for analog amplification.

  It is an object of the present invention to provide a vacuum tube which is similar in structure to a cheap and easily obtainable fluorescent display tube and is easy to use as an analog amplifier for acoustic signals.

  The vacuum tube of the present invention has a linearly stretched filament which emits thermal electrons, and two sets of grids and an anode. Both of the anodes are formed in the same plane on a planar substrate. The filament is disposed parallel to the planar substrate and at a position facing both of the anodes. Each of the grids is disposed between the anode and the filament so as to face the same set of anodes with a first predetermined spacing and have a filament and a second predetermined spacing. A filament intermediate fixing portion is provided which fixes the filament at a position corresponding to an intermediate point between the two sets of anodes.

  According to the vacuum tube of the present invention, since the filament is fixed in the middle, the fundamental frequency of the vibration of the filament can be easily increased. In other words, it is easy to use as an analog amplifier for acoustic signals because it is easy to make the frequency difficult to be detected by human beings.

FIG. 2 is a plan view of the vacuum tube of Example 1; FIG. 2 is a front view of the vacuum tube of Example 1; FIG. 2 is a side view of the vacuum tube of Example 1; Sectional drawing in the AA of FIG. The figure which shows a mode that the anode and the insulating layer were formed on the glass substrate. The figure which shows a mode that the anode was formed on the glass substrate. The figure which shows the shape of an insulating layer. Three views (a plan view, a front view, a side view) of an anchor. The figure which shows the example of the shape of a grid. The figure which shows gettering. The figure which shows the example of the amplification circuit which used the vacuum tube. The figure which shows the relationship between anode voltage Va and electric current _{Ip in a} fluorescent display tube for every voltage of a grid. 0.3mm approximately the distance between the anode and the grid spacing of the filament and the grid showing the relationship between the anode voltage V _a and current I _p in the case of the order of 0.4mm for each voltage grid FIG.

  Hereinafter, embodiments of the present invention will be described in detail. Note that components having the same function will be assigned the same reference numerals and redundant description will be omitted.

  FIG. 1 is a plan view of the vacuum tube of the present invention, FIG. 2 is a front view, FIG. 3 is a side view, and FIG. 4 is a cross-sectional view taken along line A-A of FIG. The vacuum tube 100 has a linearly stretched filament 110 which emits thermoelectrons at a predetermined temperature or higher, two sets of grids 130-1 and 130-2, and anodes 120-1 and 120-2. Both of the anodes 120-1 and 120-2 are formed on the same surface of the planar substrate (glass substrate 125). The filament 110 is disposed parallel to the planar substrate (glass substrate 125) and at a position facing both of the anodes 120-1 and 120-2. Each of the grids 130-1 and 130-2 is opposed to the same set of anodes 120-1 and 120-2 with a first predetermined distance and has a second predetermined distance with the filament 110, It is disposed between 1,120-2 and the filament 110. The filament intermediate fixing portion 113 fixes the filament 110 at a position corresponding to an intermediate point between the two sets of anodes 120-1 and 120-2. Furthermore, if the first predetermined interval is 0.15 mm or more and 0.35 mm or less and the second predetermined interval is 0.2 mm or more and 0.6 mm or less, it can be easily used for analog amplification. In FIG. 1, a part of the grids 130-1 and 130-2 is not shown so that the positions of the anodes 120-1 and 120-2 can be seen. In the actual vacuum tube 100, since mesh grids 130-1 and 130-2 (see FIG. 9) exist on the anodes 120-1 and 120-2, the anodes 120-1 and 120-2 are difficult to see. It is.

  Next, a specific example of a structure for realizing the above features will be described. FIG. 5 shows the anodes 120-1 and 120-2 and the insulating layer formed on a glass substrate. FIG. 6 is a view showing the anodes 120-1 and 120-2 formed on a glass substrate, and FIG. 7 is a view showing the shape of the insulating layer. The glass substrate 125 has an exhaust hole 151, and the anodes 120-1 and 120-2 are formed on one surface of the glass substrate 125. Anode terminals 121-1 and 121-2 are connected to the anodes 120-1 and 120-2. The anodes 120-1 and 120-2 may be formed of, for example, a thin film of aluminum. The insulating layer 126 may be made of, for example, low melting point glass, and has anode openings 127-1 and 127-2 and terminal openings 128-1 and 128-2. The vacuum tube 100 seals the case 180 and the glass substrate 125 and evacuates air from the exhaust hole 151 to evacuate the inside. Then, the exhaust hole plug 150 is fitted in the exhaust hole 151. Although not shown in FIG. 5, a sealing low-melting glass may be further disposed at a portion of the glass substrate 125 in contact with the case 180. In addition, electrical contact with the outside is made by the terminal 190.

  The filament 110 is a direct cathode. For example, the filament 110 may be coated with barium oxide so as to emit thermoelectrons when heated to about 650 ° C. by passing a direct current. In this example, the above-mentioned “temperature above predetermined level” is 650 degrees, but it is not limited to 650 degrees. FIG. 8 shows three views (plan view, front view, side view) of an anchor 115 for applying tension to the filament 110. As shown in FIG. One end of a plate spring 117 is disposed at a part of the anchor body 116, and the other end of the plate spring 117 is a filament fixing portion 118. For the anchor 115, SUS (stainless steel material) or the like may be used. The anchor 115 is attached to the filament support member 111, and the filament 110 is fixed to the filament fixing portion 118 of the anchor 115 by welding or the like. Reference numeral 112 in FIG. 4 denotes a welding point. A filament intermediate support member 119 is attached at a position corresponding to the midpoint between the two sets of anodes. The filament intermediate fixing portion 113 is formed by fixing the filament 110 to the filament intermediate support member 119 by welding or the like. The distance between the filament 110 and the anodes 120-1 and 120-2 is determined by the length of the filament support member 111 and the filament intermediate support member 119, and the tension of the filament 110 can be adjusted by the plate spring 117 of the anchor 115.

  The filament 110 is heated by the flow of direct current, and is heated to a predetermined temperature or more at which thermal electrons can be emitted. However, since there is heat transfer to the filament supporting member 111 and the filament intermediate supporting member 119 at the welding point 112 and the filament intermediate fixing portion 113, the temperature of the filament 110 in the vicinity thereof is heated to a predetermined temperature or more capable of emitting thermal electrons. Can not. Therefore, the centers of the grids 130-1 and 130-2 are opposed to the position of 1⁄4 from one end (one of the welding points 112) of the filament 110, and the filament intermediate fixing portion 113 It may be at a dividing position (the middle point of the two welding points 112). With such an arrangement, the filament 110 at a position opposite to the anodes 120-1 and 120-2 can be located farthest from the filament supporting member 111 and the filament intermediate supporting member 119, so sufficient heat from the filament 110 can be obtained. Electrons can be emitted.

  FIG. 9 shows an example of the shape of the grid. The grid 130 is mesh-like and may be made of SUS or the like. As described above, in FIG. 1, a part of the grid 130 is omitted to clearly show the anodes 120-1 and 120-2. The actual grids 130-1 and 130-2 are the grids 130 shown in FIG. The grids 130-1 and 130-2 are fixed to the grid support members 132-1 and 132-2. Depending on the thickness of the grid support members 132-1 and 132-2, the distance between the anodes 120-1 and 120-2 and the grids 130-1 and 130-2, and the distance between the filaments 110 and the grids 130-1 and 130-2 Is decided.

  That is, in the vacuum tube 100, the grid supporting member 132-has a spacing (first predetermined spacing) between the anodes 120-1 and 120-2 and the grids 130-1 and 130-2 of 0.15 mm or more and 0.35 mm or less. It is realized by 1,132-2. The distance (second predetermined distance) between the filaments 110 and the grids 130-1 and 130-2 is 0.2 mm or more and 0.6 mm or less because the filament support member 111, the filament intermediate support member 119 and the grid support member 132 -1, 132-2.

  The gettering 140 is shown in FIG. The getter ring 140 is flashed by high frequency induction heating, and by depositing a metal barium film on a part of the case 180, it plays a role of increasing the vacuum degree or maintaining the vacuum degree. The getter shield 142 is a member for shielding the getter ring 140 from the filament 110, the grids 130-1 and 130-2, and the anodes 120-1 and 120-2. In the case of a fluorescent display tube, the effect of the gettering on the characteristics of the display can be ignored regardless of where it is placed in the case, so it is not necessary to consider the position of the gettering from the viewpoint of the characteristics. However, when using two sets of anodes 120-1 and 120-2 and grids 130-1 and 130-2 as amplifiers for stereo signals, the effect of gettering 140 is necessary to make the characteristics of the two sets of amplifiers uniform. It turned out that it can not ignore. Therefore, in order to match the characteristics of the two sets of amplifiers, it is desirable that the getterings 140 be disposed equidistantly from each of the grids 130-1 and 130-2.

An example of an amplification circuit using a vacuum tube 100 is shown in FIG. The filament 110 is connected to a direct current voltage source 310 (e.g., 0.7 V) and heated to a predetermined temperature (e.g., 650 degrees) at which thermal electrons are emitted. An anode voltage source 320 is applied to the anodes 120-1 and 120-2 through the resistors 330-1 and 330-2. Then, for example, a stereo left channel signal v _L to which a predetermined bias is added is input to the grid 130-1, and a stereo right channel signal v _R to which the same bias is added is input to the grid 130-2. Ru. In this case, the voltage V _{L at} the anode terminal 121-1 is the output of the left channel, and the voltage V _{R at the} anode terminal 121-2 is the output of the right channel.

Next, the necessity of the first predetermined interval and the second predetermined interval of the present invention will be described. A typical fluorescent display tube is also arranged so as to face the anode between the filament and the anode, a linear filament stretched to emit thermoelectrons at a predetermined temperature or more, an anode disposed parallel to the filament, and And a grid. However, in a general fluorescent display tube, the distance between the anode and the grid is about 0.5 mm or more, and the distance between the filament and the grid is about 1.0 mm or more. Also, the fundamental frequency of the natural vibration of the filament is not considered. In the case of a fluorescent display tube, since ON / OFF control is performed, it is necessary to avoid that current flows halfway when changing the voltage of the grid. Therefore, the dimensions are as described above. FIG. 12 shows the relationship between the anode voltage V _a and the current I _p in the fluorescent display tube for each voltage of the grid. The numbers shown beside the lines in FIG. 12 are grid voltages (volts). The distance between the anode and the grid is about 0.5 mm, and the distance between the filament and the grid is about 1.0 mm. When the anode voltage Va is 10 V, _a halfway current flows when the grid voltage is around 4 V, but it is OFF when the grid voltage is 3 V or less, and ON when it is 5 V or more. Also, even if the voltage of the grid is changed around 4 V, the range in which the linearity can be obtained is considered to be narrow, and it can be seen that it is difficult to use for analog amplification. Incidentally, some possibly region linearity is obtained an anode voltage V _a to a higher region than 30V is present. However, in order to use as an analog amplifier, it is necessary to always apply the anode voltage, so the anode voltage V _a can not be increased in consideration of the influence of thermal expansion. Supplementally, when used as a fluorescent display tube, it is not necessary to always apply an anode voltage since human afterimage is also used. In other words, the fact that the anode voltage can not be increased is also the reason that it is difficult to use as an analog amplifier in contrast to the use as a fluorescent display tube.

13, about 0.3mm spacing of the anode and the grid spacing of the filament and the grid showing the relationship between the anode voltage V _a and current I _p in the case of the order of 0.4mm for each voltage of the grid. From this figure, if the bias voltage 3V, and 1V maximum value of the amplitude of the input signal, it can be seen that the anode voltage V _a is obtained substantially linear amplification characteristics in a range of more than about 4V. Therefore, it can be used as a vacuum tube for analog amplification. Although the experimental example shown in this application is only FIG. 13, if the distance between the filament 110 and the grids 130-1 and 130-2 is 0.2 mm or more and 0.6 mm or less, the general fluorescence described using FIG. It can be a vacuum tube that can be used more easily for analog amplification than a display tube. That is, if the second predetermined distance of the vacuum tube of the present invention is set to 0.2 mm or more and 0.6 mm or less, the flow of electrons from the filament to the anode can be changed in an analog manner by the potential of the grid. Easy to use.

  Further, when the distance (first predetermined distance) between the anodes 120-1 and 120-2 and the grids 130-1 and 130-2 exceeds 0.35 mm, the grid support members 132-1 and 132-2 are bent and formed. There is a need. On the other hand, if the distance between the anode and the grid (first predetermined distance) is 0.15 mm or more and 0.35 mm or less, the grid support members 132-1 and 132-2 can be configured simply by punching out a flat plate. In this case, since the distance between the anode and the grid is determined only by the thickness of the grid support member, a highly accurate distance can be maintained. Further, when the grid support members 132-1 and 132-2 are bent and formed, the grids also easily vibrate and cause noise. When the grid support members 132-1 and 132-2 are formed by flat plate punching, the vibration of the grid can be suppressed, and the vacuum tube can be easily used for analog amplification.

  Further, as described above, if the filament is fixed in the middle, the wavelength can be shortened in the vibration of the filament, so it is easy to increase the fundamental frequency. In other words, it is easy to use as an analog amplifier for acoustic signals because it is easy to make the frequency difficult to be detected by human beings. Then, if the fundamental frequency of the natural vibration of the filament 110 is set to 3 kHz or more, the influence of the vibration of the filament 110 can be made a frequency that human beings can not easily hear. Such adjustment of the frequency may be realized by adjusting the material and thickness of the filament 110, the length from the welding point 112 to the filament intermediate fixing portion 113, and the tension given by the anchor 115. The higher the basic frequency, the better, and if it can be adjusted to 10 kHz or more, noise due to the vibration of the filament can be made inaudible to humans.

Reference Signs List 100 vacuum tube 110 filament 111 filament support member 112 welding point 113 filament intermediate fixing portion 115 anchor 116 anchor main body 117 plate spring 118 filament fixing portion 119 filament intermediate support member 120 anode 121 anode terminal 125 glass substrate 126 insulating layer 127 opening for anode 128 Terminal opening 130 Grid 132 Grid support member 140 Gettering 142 Getter shield 150 Exhaust hole plug 151 Exhaust hole 180 Case 190 Terminal 310 DC voltage source 320 Anode voltage source 330 Resistance

Claims (9)

A linear amplification filament emitting thermoelectrons, and an analog amplification vacuum tube having two sets of grids and an anode,
Both of the anodes are formed on the same surface on a planar substrate,
The filament is disposed parallel to the planar substrate and at a position facing both of the anodes,
Each of the grids is disposed between the anode and the filament so as to face the same set of the anode with a first predetermined spacing and to have the filament and a second predetermined spacing,
A vacuum tube for analog amplification, comprising a filament intermediate fixing portion for fixing the filament at a position corresponding to an intermediate point between the two sets of the anodes. The vacuum tube for analog amplification according to claim 1, wherein
The second predetermined interval is 0.2 mm or more and 0.6 mm or less. A vacuum tube for analog amplification. The vacuum tube for analog amplification according to claim 1 or 2, wherein
The vacuum tube for analog amplification, wherein the first predetermined interval is 0.15 mm or more and 0.35 mm or less. The vacuum tube for analog amplification according to any one of claims 1 to 3, wherein
The vacuum tube for analog amplification, wherein the filament has a fundamental frequency of natural vibration of 3 kHz or more. A vacuum tube for analog amplification according to any one of claims 1 to 4, wherein
The center of each of the grids is opposed to a position 1/4 from one end of the filament, and the filament intermediate fixing portion is a position bisecting the filament. A vacuum tube for analog amplification. The vacuum tube for analog amplification according to any one of claims 1 to 5, wherein
A vacuum tube for analog amplification, wherein both of the anodes have the same size. The vacuum tube for analog amplification according to any one of claims 1 to 6, wherein
The analog amplification vacuum tube, wherein the grid and the set of anodes are both one anode for one grid. A linear filament which emits thermoelectrons, and a vacuum tube having two sets of grids and an anode,
Both of the anodes are formed in the same size on the same surface on a planar substrate,
The filament is disposed parallel to the planar substrate and at a position facing both of the anodes,
Each of the grids is disposed between the anode and the filament so as to face the same set of the anode with a first predetermined spacing and to have the filament and a second predetermined spacing,
A vacuum tube comprising a filament intermediate fixing portion for fixing the filament at a position corresponding to an intermediate point between two sets of the anodes. A linear filament which emits thermoelectrons, and a vacuum tube having two sets of grids and an anode,
Both of the anodes are formed on the same surface on a planar substrate,
The filament is disposed parallel to the planar substrate and at a position facing both of the anodes,
Each of the grids is disposed between the anode and the filament so as to face the same set of the anode with a first predetermined spacing and to have the filament and a second predetermined spacing,
A filament intermediate fixing portion for fixing the filament at a position corresponding to an intermediate point between the two sets of the anodes;
A vacuum tube, wherein the grid and the set of anodes are both one anode for one grid.

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