JPS6164048A - Triode type electron gun - Google Patents

Abstract

PURPOSE:To make it possible to avoid an influence of a suspending electric field such as bead glass and neck glass by making the anode side of a control grid concave. CONSTITUTION:An electrode G1 is to be cylindrical having a base while an opening part 13 having the relatively large diameter is formed in the center of its base side. an electrode G2 is to be cylindrical having the base while the base side of said electrode G2 is welded to the base side of the electrode G1 and the electrode G2 is to be en bloc with the electrode G1. An opening part 24 having the small diameter is formed in the center of the base side of the electrode G2. Thereby, as the electrode G2 is cylindrical, an electron beam path between the cathode K and the electrode G3 is shielded by said electrode G2 to the outside such as bead glass 15 and neck glass. Accordingly, an influence of a suspending electric field such as bead glass 15 and neck glass can be avoided.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a triode-type electron gun comprising a cathode, a control grid, and at least one anode, which is suitable for use in, for example, high-definition picture tubes with minute bright spots. Regarding.

C. Prior Art] As an electron gun, for example, a tetrode (as shown in Fig. 5) is used.
A 4-pole type is known. In the same figure, (1)
is the cathode, (2) is the control grid, (3) is the first anode, (4)
is the second anode. This tetrode type electron gun is the first
It is widely used because the cutoff voltage can be set using the anode (3). However, this tetrode type electron gun is not suitable for a high-definition picture tube with a minute bright spot. Since the diameters of the openings (2a) and (3a) are small, alignment of these openings (2a) and (3a) becomes very difficult, and the so-called G1
In the case of a drive, the presence of the first anode (3) increases the electrode capacity, making it unsuitable for high frequency drives.

Further, as an electron gun, for example, a triode (three pole) type as shown in FIG. 6 is known.

In the figure, (5) is a cathode, (6) is a control grid, and (7) is a cathode.
) is the anode. In this triode type electron gun, the cutoff voltage is uniquely determined by the potential of the anode (7). This triode-type electron gun has a configuration similar to the above-mentioned tetrode-type electron gun, for example, except that the first anode (3) is removed, and there are no problems such as alignment of the aperture or large electrode capacitance. It is suitable for use in high-definition picture tubes with bright spots.

[Problem that the invention seeks to solve]

However, in conventional triode-type electron guns, the electron beam path between the cathode (5) and anode (7) is exposed to the outside of the bead glass, neck glass, etc., as shown in Figure 6. However, there are problems in that bright spot distortion, cutoff voltage fluctuations, focus voltage fluctuations, etc. occur due to the influence of floating electric fields from bead glass, neck glass, etc. Therefore, in the present invention, the influence of floating electric fields such as bead glass and neck glass is avoided in a triode type electron gun.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention provides a triode type electron gun in which the anode side of the control grid has a concave shape.

[Function] In the above configuration, the concave portion of the control grid shields the electron beam path between the cathode and the anode, thereby avoiding the influence of floating electric fields from bead glass, neck glass, etc.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 1 and 2.

Figure 1 shows the overall configuration, and in the figure, K
is a cathode, G1 and G2 are first and second grid electrodes, these electrodes G1 and G2 are electrically connected, and a voltage of, for example, 500 cm is applied thereto. Further, G3, G4 and G5 are cylindrical third, fourth and fifth electrodes constituting the focusing electrode.
The electrodes G3 and G5 are grid electrodes, for example, 30
For example, 6KV is applied to the electrode G4.
is applied, resulting in a unipotential configuration.

Further, (8) is a cylindrical G5 shield having a flange (8a), and the flange (8a) is welded to the electrode G5 in a suspended position. This G5 shield (8) prevents the getter, which will be described later, from adhering to the electrode G4, etc., and even if the length of the electrode G5 is short, the electron lens between the electrodes G4 and 05 is prevented. is formed correctly.

Further, (9) is a cylindrical getter shield having an expanded portion (9a), and the side other than the expanded portion (9a) is overlapped and welded to the G5 shield (8). The getter shield (9) prevents the getter α from flying to unnecessary areas. In addition, a slit (11) is formed in the expanded portion (9a) of the getter shield (9), and the induced current flowing through the expanded portion (9a) when the getter Ql is heated is suppressed, thereby preventing heating of the getter shield (9). It can be suppressed.

Further, (12) is an arc suppressor, which is formed in a ring shape and is arranged so as to surround the small diameter portion g3 of the electrode G3. An intermediate voltage between the voltage applied to the electrode G2 and the voltage applied to the electrode G3 is applied to this arc suppressor (12). For example, this arc subreflexor (12) is electrically connected to the electrode G4, and 6 KV is applied thereto. By disposing this arc suppressor (12), for example, the electric field between the high voltage electrode, the low voltage electrode, and the inner wall surface of the neck is stabilized, and for example, the eccentricity and high potential electric field from electrode G3 to electrode G2, etc. are extended. Electrode G from the inner wall of the neck (not shown)
Discharge to the second grade is effectively suppressed.

Note that the electrodes G1, G3-G5 are each fixed to the bead glass via fixing pins (not shown).

Figure 2 shows the cathode K, electrodes G1 and G2 in Figure 1.
, G3 are shown on an enlarged scale, and these parts will be described in detail.

In FIG. 2, the electrode G1 has a cylindrical shape with a bottom surface,
An opening (13) with a relatively large diameter is formed at the center of the bottom side. This electrode G1 is fixed to the bead glass (15) with a pin (14) welded to its outer surface.

Further, a cathode disk (16) made of ceramic and having a fixed cathode K is inserted into the electrode G1 via a spacer (17) and fixed with a retainer (18). The cathode also includes a cylindrical inner sleeve (19a) having a bottom surface and a cylindrical outer sleeve (19a) on the outside thereof.
19b), and this cathode has a disk (
16), and is fixed to the disk (16) using a holder (20). Further, a heater (21) is inserted inside the inner sleeve (19a) of the cathode, and this heater (21) is inserted into the inner sleeve (19a) of the cathode.
The terminal of 1) is connected to the pin (2) planted on the disk (16).
2) A heater rest (23) made of a conductor fixed to
). A predetermined voltage is applied to the heater (21) via the heater rest (23).

Further, the electrode G2 has a cylindrical shape with a bottom surface, and this electrode G2 has a cylindrical shape with a bottom surface.
For example, the bottom side of the electrode G1 is welded to the bottom side of the electrode G1, and the electrode G2 is integrated with the electrode G1.

At the center of the bottom side of this electrode G2 is a small diameter aperture (which determines the beam diameter of the electron beam, that is, the bright spot diameter).
24) is formed.

This example is configured as described above, and the electric Pis G1 and G
2 are integrated to function as a control grid and have a triode type configuration.

According to this example, since the electrode G2 is cylindrical, this electrode G2 is cylindrical.
2, the electron beam path between the cathode and the electrode G3 is directed to the outside of the bead glass (15), neck glass, etc.
will be shielded. Therefore, the influence of floating electric fields such as the bead glass (15) and neck glass can be avoided.

Further, since the electrode G2 is cylindrical, an electron lens is formed in the electrode G2 portion and acts as a prefocus lens, so that the divergence angle of the electron beam can be suppressed. Further, according to this example, since the diameter of the opening (13) of the electrode G1 is made large, the diameter of the opening (24) of the electrode G2 is increased.
There are no words in which alignment is a problem.

As shown in FIGS. 1 and 2, instead of increasing the diameter of the opening (13) of the electrode G1 and decreasing the diameter of the opening (24) of the electrode G2, the reverse may be used. Alternatively, the diameters of the openings (13) and (24) may both be made large, and a member having an opening with a small diameter may be disposed between the electrodes G1 and 02.

In addition, as shown in FIGS. 1 and 2, the electrodes G1 and G
It is also conceivable to keep the two parts separate, as opposed to integrating them. However, in that case, the support of electrode G2, 7
This is disadvantageous in terms of voltage supply to the 11-pole G2, accuracy, etc.

Next, another embodiment of the present invention will be described with reference to FIGS. 3 and 4. In FIGS. 3 and 4, parts corresponding to those in FIG. 2 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

First, the example in Figure 3 shows the electrode G and G2 in the example in Figure 2.
is realized by one electrode G12. This electrode G12 has a cylindrical shape with a bottom surface, and the bottom surface side is the electrode G12.
3 has a concave shape with a step, and in the center there is an aperture (25) with a small diameter that determines the beam diameter of the electron beam.
is formed. This electrode G12 is fixed to the bead glass (15) with a pin (26) welded to its outer surface. Furthermore, a cathode disk (27) made of ceramic and having a projection (27b) as a spacer is inserted into the electrode G12, and a retainer (28) is inserted into the electrode G12.
) is fixed. Also, this disk (2
7) is projected from an opening (27a) formed in the center corresponding to the opening (25) of the electrode G12, and is fixed to the disk (27) using a holder (20). In addition, the terminal of the heater (21) inserted into the inner sleeve (19a) of the cathode is connected to the disc (
27) is connected to a heater rest (30) made of a conductor fixed to a pin (29). and,
A predetermined voltage is applied to the heater (21) via the heater rest (30).

The example in FIG. 3 is constructed as described above, and the electrode G12 is
Since the third side has a concave shape, it is possible to obtain the same effect as in the example shown in FIG. 2 described above.

Next, in the example of FIG. 4, the electrode G1 in the example of FIG. 2 is shaped like a flat plate, and an opening (31) with a relatively large diameter is formed in the center thereof. Then, the end of this electrode Gt is directly fixed to the bead glass (15).

Further, a cathode disk (32) made of ceramic or wood is fixed to the opposite side of the electrode G1 from the electrode G3.

In addition, the cathode has salt 81 in the center of the disk (32).
An opening formed corresponding to the opening (32) of the 1G construction (
32a), and the holder (2
0) and (33) to be fixed to the disk (32). In addition, the terminal of the heater (21) inserted inside the inner sleeve (19a) of the cathode is connected to the disk (32).
It is connected to a heater rest (35) made of a conductor fixed to a pin (34) planted in the heater rest (35). A predetermined voltage is applied to the heater (21) via the heater rest (35). Furthermore, the bottom side of the electrode G2 similar to the example in FIG. 2 is welded to the electrode G3 side of the electrode G1, and the electrode G2 is integrated with the electrode G1.

The example in FIG. 4 is constructed as described above, and since the electrode G2 is cylindrical, it is possible to obtain the same effects as in the example in FIG. 2 described above.

(Effects of the Invention) According to the present invention described above, the anode side of the control grid has a concave shape, and this part shields the electron beam path between the cathode and the anode. Moreover, since an electron lens is formed in this concave portion and acts as a priocus lens, the divergence angle of the electron beam can be suppressed.

[Brief explanation of drawings]

1 and 2 are block diagrams showing one embodiment of the present invention, FIGS. 3 and 4 are block diagrams showing other embodiments of the present invention, and FIGS. 5 and 6 are block diagrams, respectively. FIG. 1 is a configuration diagram showing a tetrode type and triode type electron gun. (13) and (24) are respectively openings, K is a cathode, and G
1, G2 and G3 are first, second and third grid electrodes, respectively.

Claims (1)

[Claims] A triode-type electron gun comprising a cathode, a control grid, and at least one anode, wherein the anode side of the control grid has a concave shape.