JPS59175542A - Heater assembling structure for electron gun - Google Patents

Abstract

PURPOSE:To uniformly set the operating temperature of three cathodes and improve reliability by setting the heater assembling size of central heater structure to the value smaller than the heater assembling sizes in both sides. CONSTITUTION:The heater assembling size lb of the heater structure 1b at the center is set shorter than the heater assembling size lac of the heater structures 1a, 1c located in both sides and substantial resistance of heater structure 1b at the center is smaller than that of heater structurs 1a, 1c located in both sides. When a voltage is applied to the heater structures 1a, 1b, 1c, a heater current flows equally to the three heater structures. But, since a resistance value of heater structure 1b at the center is smaller than that of the heater structures 1a, 1c in both sides, generation of heat from the heater structure 1b at the center is reduced to a small value. As a result, the operating temperature of cathode 2b at the center which receives the heat by irradiation from both sides can be set equally to the cathodes 2a, 2c.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electron gun heater assembly used in an in-line electron gun.

Generally, the structure near the cathode and heater of an in-line electron gun is as shown in FIG. In the same figure, (1&)
l(Ib) l(10) is the heater structure, (2a), (2
b) t(20) are 6 cathodes. These cathodes (
2&), (2b) 1 (20) is linearly supported and fixed to bead glass (not shown) via a cathode support (not shown). Cathode (2a), (2b) 1 (20
) respectively include a substantially cylindrical cathode sleeve (2), a substantially cap-shaped cathode base (support) welded to the top of this sleeve (2), and an electron-emitting material coated on the top surface of this cathode base (2). It is composed of substances. On the other hand, each of the heater structures (1&), (it:+), and (io) is formed from a metal plate and has both ends welded together with the heater αυ, as shown in FIG. It is composed of a substantially U-shaped heater tab (2). The above heater structure (1a)
, (1b), C1a) are incorporated as follows. First, connect each heater (company) to its corresponding cathode sleeve (
(2) was carefully inserted into the interior of the company and cut in the prescribed manner! l! R
Cut with. Thereby, the six heaters are electrically connected in series.

The reason why the above heater structure (Ia) #(Ib)l (10) has been widely used in recent years is that the heater assembly dimension t (1
This is because it has the advantage of being able to easily and accurately obtain the values (see Figure 2), and as a result, variations in cathode temperature and heater current can be reduced.

However, heater structures (la), (1b), (Ie
) by applying voltage to the cathodes (2&), (2b), (2c)
When the temperature of the central cathode (2b) is brought to an operating temperature of approximately 800°C, the central cathode (2b) is connected to the cathodes (2a) and (2
The cathodes (2&) on both sides receive side radiation heat from Q).
, the temperature is higher than that in (2o). This is due to the reducing impurity elements M2 and S contained in the cathode substrate (support).
The evaporation rate of l is accelerated, causing a phenomenon in which the electron emission characteristics deteriorate in a short period of time, and there are disadvantages such as a change in color tone called white balance collapse during use. In particular, in small electron guns, the above-mentioned disadvantages are significant because the cathodes are close to each other.

This invention was made in order to eliminate the above-mentioned drawbacks. Among the three heater assemblies, the heater assembly dimensions of the central heater assembly are set smaller than those of the heater assemblies on both sides. It is an object of the present invention to provide a heater assembly structure for an electron gun that does not have the above-mentioned disadvantages by making the operating temperature of the cathode uniform.

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

FIG. 3 shows an example of a heater assembly structure for an electron gun according to the present invention, and the same parts as in FIG.

In FIG. 6, the heater assembly dimension tb of the central heater structure (1b) is the same as that of the heater structures (ia) located on both sides thereof.
(IQ) is set shorter than the heater assembly dimension tac.

That is, the substantial resistance value of the central heater structure (1b) is smaller than the resistance values of the heater structures (Ia) and (1c) located on both sides.

On the other hand, the six heater structures (1a), (1b), No.) are electrically connected in series. Therefore, when a voltage is applied to the three heater structures (Ia), (1b), and (1c), the flowing heater current is
, (Ib), and (10) have the same value. However, the resistance value of the central heater structure (1b) is smaller than that of the heater structures (1a) and ('io') on both sides. Therefore, the amount of heat generated by the heater assembly (1) is calculated from Joule's law of "(heater current) l x resistance value", and the amount of heat generated from the central heater assembly (1b) having a small resistance value becomes small.

As a result, the central cathode (2
b) the operating temperature of the cathode (2a) located on both sides, (
20).

FIG. 4 shows the characteristics of the cathode temperature in the heater assembly of the electron gun of the present invention in comparison with that of a conventional structure. As already shown in the characteristics of the conventional type, there was a temperature difference of 10° C. between the central heater structure and the heater structures on both sides. On the other hand, according to the present invention, as shown by characteristic a, the central heater structure (1b) and both side heater structures (1a)
, (la) is almost eliminated, and the operating temperature of the cathode can be made uniform.

As described above, in this invention, by setting the heater assembly dimensions of the central heater structure to be smaller than the heater assembly dimensions on both sides, it is possible to make the operating temperatures of the six cathodes uniform, thereby improving reliability. can contribute to the improvement of

[Brief explanation of the drawing]

FIG. 1 is a front sectional view showing a conventional electron gun heater assembly structure, FIG. 2 is a configuration diagram of the heater structure, and FIG. 6 is a front sectional view showing an example of the electron gun heater assembly structure according to the present invention.
FIG. 4 is a characteristic diagram showing the characteristics indicating the operating temperature of the cathode in the heater assembly of the present invention in comparison with the conventional one. (1a), (1b), (IQ)--Heater structure, (2
a), (+ to 2), (2G)... cathode, 01)...
Heater, ■...Heater tab, (217...Cathode sleeve, tb, A&A...Assembly dimensions. In the drawings, the same reference numerals indicate the same or equivalent parts. Agent: Makoto Kuzuno - Example 1) Figure 1Figure 2Figure 3Figure 4j''4 1 1 1 1c 1b la

Claims (1)

[Claims] (1) Insert each heater of the six heater structures, each consisting of a heater and a heater tab to which both ends of the heater are welded, into each of the cathode sleeves of the three cathodes arranged in a straight line. In the heater assemblies of electron guns that are electrically connected in series, of the three heater assemblies mentioned above, the heater assembling dimensions of the central heater assemblies are set to be smaller than the heater assembling dimensions of the heater assemblies on both sides. Characteristic electron gun heater assembly structure.