JPS60172144A - Electron gun structure - Google Patents

Abstract

PURPOSE:To obtain a stable highly precise cathode-ray tube by mechanically supporting a cup-like electrode body and a metallic pressing plate touching the outer surface of the terminal plate of said cup-like electrode by means of a common support strut through supporting pins. CONSTITUTION:A large diameter hole is formed in the center of the thick terminal plate 31 of a cup-like electrode body (G1a). Then a thin metallic plate 32 having an electron beam hole (h1) is welded to the terminal plate 31 in such a manner as to face the large diameter hole to the electron beam hole (h1). Next, a metallic pressing plate (G1b) having a hole (h) with a diameter sufficiently larger than electron beam holes (h1) and (h2) is brought into contact with the terminal plate 3 of the cup-like electrode body (G1a). The cup-like electrode (G1a) and the metallic pressing plate (G1b) are mechanically supported by burying the outer ends of their supporting pins 2 in a support strut 1. Owing to the above constitution, the shift of the electron beam hole (h1) of the terminal plate 3 in the axial direction is suppressed. As a result, the separation of the electron beam hole (h1) and a cathode (K) is maintained at a preset minute level.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an electron gun assembly used, for example, in a 1% 11Ifj fineness cathode ray tube.

BACKGROUND ART AND PROBLEMS The electron gun of a cathode ray tube, for example, as shown in Fig. 1, has a cathode, a first grid electrode Gt (control electrode), a second grid electrode G2 (acceleration electrode), and a main electron lens. The third grid electrode G3 (first anode), the fourth grid electrode G4 (focusing electrode), and the fifth grid electrode Gs (second
anodes) are arranged sequentially, and the first to fifth grid electrodes 01 to
G5 is a common support pillar, that is, a bead glass (11), and each outer end of a support bottle (2) welded to the outer peripheral surface of each grid electrode is embedded and connected to each other while maintaining a predetermined positional relationship. hs, h2 and hs are the first and second
and shows the passage of the electron beam through the third grid electrode.

The first grid electrode G1 consists of a cup-shaped electrode, and an electron beam passage hole 1i1 is formed in its end plate (3). The cup-shaped electrode is formed by drawing and molding a metal plate with a thickness of 0.2 mm, for example, and its end surface &(3) is
The imaging part (31) is made of the cup-shaped electrode itself, and the thickness is, for example, 50μ, welded to the part where the electron beam passage hole h1 is formed.
It consists of a thin metal plate (32) of
By drilling an electron beam passage hole h1 in 2),
The fine electron beam passage hole h1 can be formed with surface precision.

The cathode is disposed within a cup-shaped first grid electrode Gi. The cathode includes, for example, an impregnated cathode body (made of a thermionic emitter, for example, a porous sintered body of tungsten impregnated with an emitter material) at the upper end of the cathode sleeve (7) in which a heater (61 is housed). 8) has an indirectly heated configuration in which a cup-shaped first grid electrode G is attached.
In l, an insulating substrate (9) made of, for example, a ceramic ring plate is supported by a retainer (11) with a spacer α interposed between the insulating substrate (9) and the end plate (3). . A through hole (12) is bored in the substrate (9),
The cathode sleeve (7) is inserted into the through hole (12), and in this state, the cathode sleeve (7) rests, and the cathode sleeve (91)
mechanically supported. Base of cathode sleeve (7) &
(The support for 91-1 will be left over from the FiMi on the board (9).
By inserting and welding the cathode sleeve (7) into the upper end of the sleeve-shaped holder (14) welded into the small-diameter opening of the funnel-shaped boulder (13), the large-diameter opening end of which is brazed with solder (soldering). It will be done.

However, in an electron gun using such a cup-shaped first grid electrode G□, as shown in FIG. 3) is the group i'(ji
Since the electron beam bulges out from the state as shown by the dashed line box, the substantial distance between the electron beam passage hole hl of the first grid electrode G1 and the cathode I changes.
This has a great influence on the characteristics of cathode ray tubes, which are particularly required to have high definition. That is, in a high-definition cathode ray tube, it is particularly required to reduce the diameter of the electron beam spot, and for this reason, the electron beam passage hole h1 of the first grid electrode Gl is made sufficiently small to focus the beam. . However, when the electron beam passage hole h1 of the first grid electrode G1 is made smaller in this way, the distance d01 between the electron beam passage hole h1 of the first grid electrode G1 and the cathode is reduced in terms of cutoff characteristics and current characteristics. It is necessary to make it smaller.

In other words, the beam current cutoff cathode voltage, the cutoff voltage HKco, and the maximum cathode current MIK have the following relationship: Kco=A-MIK'=...+11, so if there is sufficient brightness, that is, a sufficiently large cathode In order to make MIK as large as possible so that the current IK can be taken out, it is required that the cut-off current (fEKco) be as deep as possible.

On the other hand, this cutoff voltage HKco has the following relationship. Here, φ is the diameter of the electron beam passage hole h1, and d12 is the first diameter.
and the interval between the second grid electrodes, tl is the thickness of the electron beam passage hole h1, that is, the thin metal plate (32) of the end plate (3).
) thickness. As is clear from this, when the diameter φ of the °C electron beam passage hole h1 is reduced in an attempt to narrow down the electron beam and make its spot smaller, nKco becomes shallower. Therefore, in order to obtain a deep EKco despite reducing the diameter of the electron beam passage hole h1, it is necessary to reduce the thickness tl and the spacing aOt, especially the thickness tl, which have a relatively large influence on the EKco from equation (2). However, this thickness 1. Since there are restrictions on making this thin due to problems in mechanical strength and processing of the electron beam passage hole, the thickness tl is made small and the first and second
It is also required to reduce the distance dOZ between the grid electrodes 01 and 02.

In addition, as the cutoff voltage EKco is increased, the so-called working area S of the ζ cathode can be made smaller, and thereby the divergence angle θ of the electron beam can be made smaller, and the width of the beam can be made smaller. You can obtain the effect of

However, the cathode working area S is 5=(ht
. area)XDr... is given by (3). Here, Dr is the drive rate, and this drive rate Dr is EKco, 1! Kc.

Here, EK is the cathode voltage and Ed is the drive voltage. However, as the cutoff voltage EKco deepens, the drive ratio Dr decreases and the cathode working area 'rS
becomes smaller. If the cathode working area S becomes smaller as shown in d, the angle θ at the emission 11 of the electron beam becomes smaller. 3 and 4 illustrate the relationship between the size of the working area and the divergence angle of the electron beam, and the broken lines in the figures indicate equipotential surfaces. Wl and W2 are each %t of the working area and have a relationship of wt > W2. Now, assuming that the beam current is constant, the electrons emitted from the working area of the cathode are
The divergence angles θ1 and θ2 from the crossover point P formed by the lens thread 2 between the grid electrode G1 and the second grid electrode are θ1>θ2.

In this way, the cutoff voltage [! When reducing Kco, the working area can also be reduced, and the beam emission II
& Since the angle can be made smaller, the beam spot diameter can be made smaller, making it possible to obtain a high-definition cathode ray tube.

As mentioned above, in order to improve the surface definition of a cathode ray tube, it is desirable to deepen the cutoff voltage BKco of the electron gun assembly, and for this purpose, it is necessary to reduce the distance d01 between the cathode K and the second grid electrode. However, as explained in FIG. 2, when using the force/knob-shaped grid electrode G1, the end plate (3) bulges outward during operation, resulting in a gap (101 is large). As a result, the EKco becomes shallow.In other words, the definition of the cathode ray tube is lowered.
Let's put it away.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned drawbacks and improves the distance between the cathode and the first grid electrode, that is, the distance between the cathode surface and the electron beam passage hole h1 formed in the first grid electrode, even during operation. The object of the present invention is to provide an electron gun assembly that can reliably maintain a small initial spacing and obtain a stable random density cathode ray tube.

SUMMARY OF THE INVENTION The present invention provides at least a cathode, an @1 grid electrode,
The first grid electrode is made up of a cup-shaped electrode body having an end plate having an electron beam passage hole, and a holding metal body that is brought into contact with the outer surface of the end plate. The cup-shaped electrode body and the holding metal body are mechanically supported by a common support column via support pins, and the cathode is arranged in the cup-shaped electrode body so as to face the electron beam passage hole.

Embodiment An example of an electron gun assembly according to the present invention will be described with reference to FIG. In this example, as explained in Figure 1,
In the case where the cathode and the first to fifth grid electrodes 01 to G5 are arranged in sequence, the parts in FIG. 5 corresponding to those in FIG.

In the present invention, °ζ defines the first grid electrode GL, in particular the cup-shaped electrode body G1a and the outward direction of the end plate (3) thereof;
It also includes a restraining metal body Gzb that comes into contact with the second grid electrode G2 side. End m of cup-shaped electrode body Gsa
1 plate [31, for example, has a thick end face of the cup-shaped electrode body Cta itself and a through hole (4) with a large inner diameter in the center of (31), and an electron is inserted into the through hole (4). Beam passage hole h
Thickness 1. =50 μM gold bA I
The t9 root (32) is configured by welding θ.

Further, the holding metal body G11l is brought into contact with the end plate (3) of the cup-shaped electrode body 01a. This restraining metal body Gxb may be constructed from a thick metal plate. A through hole having a diameter sufficiently larger than the electron beam passage holes hx and h2 is bored in a portion of the metal body Gzb facing the electron beam passage holes h1 and h2. The metal body G1b and the cup-shaped electrode body Qta are made of the same metal material, for example, stainless steel.
US 304 (8Nk -18Cr - balance Pe)
It can be configured by

Then, ζ, support hinges (2) are welded to the outer peripheries of each cup-shaped electrode body 01a and the holding metal body Gtb of the first grid electrode G1, and support the outer ends of each support pin (2). Pillars are embedded in Zunawaji bead glass (1) to provide mechanical support for people. Here, the second to fifth grid electrodes 02
~G6, the mounting position of the support pin (2) to the cup-shaped electrode body G1a of the first grid electrode @4G1 and the metal body Gzb, and therefore the arrangement W position of the bead glass (1), are set to the central axis of the electron gun. On the other hand, ζ, two, or three can be arranged at equal angular intervals.

- As described above, according to the electron gun assembly in which the temporary holding metal body Gzb is disposed in contact with the end plate (3) of the first grid electrode G1 having the electron beam passage hole h1, during its operation. , a temperature rise occurs in the cup-shaped first grid electrode G1 due to heating from the cathode side, and its end plate (3) tends to bulge. 11, the bulge is suppressed and suppressed. Therefore, the displacement of the electron beam passage hole h□ of the end plate (3) in the axial direction is suppressed. The distance d01 between the electron beam passage hole hi and the cathode is designed in advance by
The interval is maintained at the initial minute interval during non-operation or at the start of operation.

In the example shown in FIG. 5, the metal body Grb is a thick plate-shaped body, but for example, as shown in the examples shown in FIGS. 6 to 8, each metal body Gib is shaped like a cup. Electrode body G
It is composed of a relatively thin cup-shaped metal body having an end plate (33) on the ta side, and the end plate (33) is formed on the outside, that is, on the cup-shaped electrode main body G 1a' side, due to thermal expansion due to temperature rise. The expansion of the end plate (3) of the main body Gta is suppressed by the force of the bulge caused by the l:% expansion of each end plate (33) of the holding metal body G1b. ), therefore the electron beam passing hole h1
It is also possible to maintain the initial position without being displaced.

In this case, as shown in FIG. 6, for example, the metal body Gzb is made relatively shallow to reduce its heat capacity, and by further increasing its area, the electrode body Gl
When heating the metal body Gtb, the end plate (33) of the metal body Gtb efficiently bulges toward the main body Gla, and a large force is obtained to reliably suppress the bulge of the end plate (3) of the main body Cta. Eggplant. Alternatively, as in the example shown in FIG. 7, the main body G1a and the metal body G1b are made of the same material and have substantially the same shape and size, so that the end plates (33) and (
31) can be made to bulge out evenly in the phase M, so that these bulging forces cancel each other out. Alternatively, for example, as shown in FIG. 8, if it is necessary to reduce the area of the holding metal body G1b due to spatial constraints, etc., the holding metal body G1b may be manufactured from a material whose thermal expansion coefficient is lower than the main body GxaO. By doing so, a large bulge can be obtained even in a small area, and the bulge of the end plate (3) of the main body Gxa can be reliably suppressed. For example, the main body 01a can be made of 42 alloy (42Ni I'e , thermal expansion coefficient α−
'C was prepared by 5,3X 1o-I'/'c),
Press the metal body Gsb to SUS 304 (8Ni −
10 can be prepared by L8Cr-Fe+α-16X 10-6/'C). Now, in this configuration, the short side of the electron beam passing hole +11 of the first grid electrode G1 is 0.25.
The tuna has a rectangular shape with a long side of 0.65 mm, and the distance aOt between it and the cathode is 70 μm. The operating time from power-on and the cutoff voltage 1! When the relationship with Kco was measured with the initial value of EKco as 100%, almost no fluctuation was observed as shown by the solid line in No. 9 and 1. In comparison, the BKco of the conventional structure is greatly reduced as indicated by the broken line in the figure.

Although the illustrated example shows a single-beam electron gun configuration, it is also possible to use a double-beam electron gun configuration in which a plurality of cathodes are arranged with respect to a common grid electrode, and the electron gun configuration can also be It is not limited to the unipotential type described above, and various configurations such as a pipotential type can be adopted.

Effects of the Invention As described above, the present invention effectively suppresses the displacement of the end plate (3) of the first grid electrode G1 having the electron beam passage hole during operation, thereby reducing the fluctuation of the force/off voltage. In particular, since it is possible to avoid fluctuations that would make the beam spot shallower, it is possible to avoid fluctuations that would increase the electron beam spot diameter, and it is possible to maintain the beam spot diameter at a predetermined small diameter when it is cold. However, when applied to a high-resolution cathode ray tube, stable and excellent images can be obtained.

[Brief explanation of the drawing]

Figure 1 is an enlarged cross-sectional view of a conventional electron gun assembly, Figure 2 is an explanatory diagram thereof, Figures 3y, 1 and 4 are diagrams showing the relationship between seven beam divergence angles in the cathode working area, and Figure 5. is a linear enlargement of an example of an electron gun structure according to the present invention 11J+
FIGS. 6 to 8 are enlarged cross-sectional views of essential parts of other examples of the electron gun assembly according to the present invention, and FIG. 9 is a characteristic curve diagram thereof. K is a cathode, 01 to G5 are first to fifth grid electrodes,
(1) is a support column, (2) is a support pin, Gza is a cup-shaped electrode body of the first grid, and Gxb is a metal body. Same Hidemori Matsukuma 1, ,H:,',l,,ζ. If diagram

Claims (1)

[Claims] At least a cathode, a first grid electrode, and a second grid electrode are arranged in sequence, and the first grid electrode includes a cup-shaped electrode body having an end plate having an electron beam passage hole, and a cup-shaped electrode body having an end plate having an electron beam passage hole. The cup-shaped electrode body and the clamp metal body are mechanically supported by a common support column via a support pin, and the cathode is connected to the cup-shaped electrode body. an electron gun assembly disposed within the interior so as to face the electron beam passage hole;