JPS61267223A - Electron tube - Google Patents

Abstract

PURPOSE:To shorten the build-up time considerably by providing a heater where the portion facing against the electron emission material layer applied onto the cathode is wound in double. CONSTITUTION:The tip section inserted into the sleeve 1 of heater 2 is wound in double and facing through Ni base 3 against an electron emission material layer 4. When forming the tip section of heater 2 into double coil, production of heat at the tip section will increase resulting in shortening of build-up time even for same heating power.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a heater structure for an electron tube.

[Conventional technology]

Figure 3 is a partially enlarged sectional view showing the structure of the conventional cathode part of a cathode ray tube, which is a type of electron tube equipped with an indirectly heated cathode.
1) is a sleeve, (2) is a heater, the core wire (2a) is covered with a 1m (2b) insulating layer, formed into a roughly twisted shape as shown in the figure, and inserted into the sleeve (1). be done. (3) is a Ni base fitted to the end face of the sleeve (1), (4) is an electron emitting material layer deposited on the surface of the Ni base (3), and (1) to (4) are At the cathode (
5). (6) is the first grid, (7) is the second grid, the cathode (5), the first and second grids (6)
1, +71 and other grids not shown are:
It is held by a bead galanu (8) and constitutes an electron gun.

FIG. 4 is a partially enlarged cross-sectional view showing another conventional example, in which the sleeve (1) is mounted on the surface of the ceramic base (9), and the coiled portion of the heater (2) is attached to the sleeve. (1
).

The cathode (5) configured in this way is connected to the heater (2).
By applying electricity to the sleeve (1) and the Ni base (3), the electron emitting material layer (4) is heated to around 800°C,
Emit thermoelectrons.

[The critical point that the invention attempts to solve]

In the conventional indirectly heated type electrode, the time required (build-up time) from when the heater (2) starts to be energized until thermionic electrons are emitted was about 5 seconds.

Although it is convenient to shorten this build-up time, it is difficult to shorten it without adversely affecting other circuit characteristics, so in equipment that requires a quick start, the heater should be supplied with a current lower than its rated value. A method has been adopted in which electricity is turned on in advance, but there was a tradeoff that the amount of electricity consumed beforehand increased.

The object of the present invention is to realize an electron tube equipped with an indirectly heated cathode that has a short build-up time.

[Means for solving problems]

The electron tube according to the present invention includes a heater whose portion facing the electron emitting material layer coated on the cathode is wound twice.

[Effect]

In the double-wound portion of the heater, the heating cover increases in the narrow portion, so the electron emitting material layer can be efficiently heated, thereby shortening the build-up time.

[Embodiment of the Invention] FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, which is applied to the conventional cathode shown in FIG.

In this embodiment, the tip portion of the heater (2) inserted into the sleeve (1) is wound twice, and the double wound portion emits electrons through the Nl base (3). It is located at a position opposite to the material layer (4).

If the tip of the heater (2) is formed into a double coil shape as shown in the example, the amount of heat generated at the tip increases, and the build-up time can be shortened even with the same heating power. According to experimental examples, the build-up time of 5 seconds was reduced to 3 seconds in this example applied to a conventionally configured cathode.

FIG. 2 is a sectional view of another embodiment of the present invention, which is applied to the conventional example shown in FIG. 4 above.

In this embodiment, the central portion (the portion facing the electron-emitting material layer (4)) of the heater (2) mounted within the sleeve (1) is wound twice.

In this example, as in the above example, a significant reduction in build-up time was achieved with the same heater power.

〔Effect of the invention〕

As explained above, the present invention has the shape of the heater installed in the sleeve of the cathode as a double coil in which the portion opposite to the electron emitting material layer coated on the sleeve is wound twice. Therefore, it is possible to significantly shorten the build-up time without increasing the heater power.

[Brief explanation of drawings]

1 and 2 are respectively sectional views of one embodiment of the present invention, and FIGS. 3 and 4 are longitudinal sectional views respectively showing the structure of the cathode portion of a conventional electron gun.・Sleeve, (2)...Heater, (3)・
...Ni base, (4) ...electron emitting material layer, (5)
···cathode. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] (1) An electron tube having an indirectly heated cathode, characterized in that the electron tube is equipped with a heater whose portion facing the electron emitting material layer coated on the cathode is wound twice.