JPS5885253A - Cathode-ray tube - Google Patents

Abstract

PURPOSE:To enable spot knocking operation to be effectively performed by connecting a conductive wire, which has an electric-discharge gap, parallel to a path which connects the high-voltage electrode of an electron gun to a high- electric-resistance conductive film provided inside the funnel. CONSTITUTION:An inner conductive film 8 provided inside the funnel 2 of a cathode-ray tube, consists of a film 8a with a low electric resistance and a film 8b with a high electric resistance. A high voltage is applied to a high-voltage electrode 10a of an electron gun 10 through the high-electric-resistance conductive film 8b. Here, a conductive wire 13 having a discharge gap 15 is connected parallel to the path of the conductive film 8b. Therefore, when artificial electric discharge is generated in the high-voltage electrode 10a of the electron gun 10 during spot knocking so as to remove stains and foreign substances, the electric discharge can be carried out through the conductive wire 13 and the discharge gap 15. As a result, the effect of spot knocking can be exhibited without receiving any influence of the high-resistance conductive film 8b.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention prevents undesirable discharge from occurring between the high-voltage electrode and the low-voltage electrode of an electron gun built in a vacuum container during operation and adversely affecting operating circuits, etc. Therefore, by increasing the electrical resistance of a part of the internal conductive film on the inside of the vacuum container
This relates to a cathode ray tube using this as a soft arc conductive film.

Fig. 1 shows a conventional cathode ray tube with this gutter. In Fig. 0, (1) is a panel generally made of glass, (2) is a conical or cylindrical funnel connected to panel (1), (3) is a cylindrical neck part, (4) is a neck part (3
) is a stem whose end is closed. These are hermetically sealed to each other, forming a vacuum container (5) as a whole. A fluorescent film (6) and an aluminum film (7) are provided as an anode on the inner surface of the panel (1).
Among them, the aluminum film (7) is electrically connected to the internal conductive film (8). This internal conductive film (8) is provided extending over almost the entire inner surface of the funnel (2), and a part of it is connected to the anode terminal (9). This anode terminal (9) is provided through the funnel (2) while maintaining airtightness, thereby making it possible to apply a voltage to the internal conductive film (8) from the outside. . A portion of the internal conductive film (8) further extends toward the neck portion (3).

Next, an electron gun (G) is provided on the inner surface of the neck portion (3). The electron gun (to) consists of a high voltage electrode (10a) and a low voltage electrode (1ob) that are insulated from each other. In general, the low voltage electrode (10b) consists of a plurality of electrodes, but in the following description, all electrodes facing and adjacent to the high voltage electrode (10g) are referred to. In addition, high voltage electrode (10
Although a member is required to maintain the mutual positional relationship between the electrodes, including 1), this member is omitted in FIG. High voltage electrode (1
A conductive spring (b) is attached to the inner conductive film (8), which contacts the internal conductive film (8).
and a high voltage electrode (10a) are electrically connected. The low voltage electrode (10b) is connected to a lead wire (6), which passes through the stem (4) in an airtight manner. Therefore, a voltage can be applied to the low voltage electrode (1ob) via this lead wire (2).

When operating this cathode ray tube, the anode terminal (11)
Through the anode fluorescent film (6), aluminum film (7)
, a high voltage (referred to as an anode voltage) of loKV or more is generally applied to the internal conductive film (8) and the high voltage electrode (lOa), while the low voltage electrode (lOa) is applied through the lead wire (b).
Generally, a relatively low voltage of 1/2 or less of the above voltage is applied to b). However, the high voltage electrode (tOa) and the low voltage electrode (10b) are usually placed very close to each other inside the neck part (3) because of the need to focus the electron beam, which is their original operation. Therefore, undesired discharges between these electrodes often occur during operation. When such a discharge occurs, both electrodes (1
0m) - (10b)O becomes almost completely conductive temporarily, and a large amount of charge stored in the aluminum harakiri and internal conductive film (8) instantly flows to the low voltage electrode (10b). As a result, a significantly high voltage is induced on the lead wire (2) side, causing various problems such as destruction of the operating circuit.

Several measures have been taken to eliminate such inconveniences. The first method is an operation called spot knocking, which is performed in the manufacturing process of cathode ray tubes. This operation is performed after the inside of the tube is evacuated to create a vacuum, and then the general operation is performed between the anode terminal (9) and the lead wire (6), that is, between the high voltage electrode (10a) and the low voltage electrode (1ob). Apply a voltage with a significantly higher potential difference (for example, twice the maximum rating) than the current voltage (generally low voltage electrode (1o
b) is grounded and the anode terminal (9) or high voltage electrode (1
0a)) to cause an artificial discharge between them, and this artificial discharge destroys dirt and foreign objects on the electrodes that may cause discharge during normal operation. This is an operation to prevent discharge from occurring at high voltage during subsequent operation. A second means for eliminating the inconvenience caused by internal discharge of a cathode ray tube during operation is to make a part of the internal conductive film high in resistance. This - for example, connects the inner conductive membrane (6) to the anode terminal (
9) and the area close to the fluorescent film (6) and the area relatively close to the electron gun a, that is, the funnel (neck part (3)).
divided into an area closer to the neck part (3) than the area near the connection part of
The first internal conductive film (8a) with relatively low electrical resistance is provided in the former region as in the conventional case, and the latter region is made of a material with significantly higher electrical resistance than the first internal conductive film (8a). In this method, a second internal conductive film (8b) is provided. Second internal conductive film (8b) made of a material with high electrical resistance
is hereinafter referred to as a soft arc conductive film. If the soft arc conductive film (8b) is provided as described above, in the unlikely event that the high voltage electrode (10m) and low voltage electrode (1ob) are connected during operation.
), the discharge current flows through the soft arc conductive film (8b), causing a significant potential drop here. Therefore, the internal conductive film (8)
The entire charge stored throughout will no longer flow away due to discharge, and the discharge will stop early.
It is possible to greatly reduce the adverse effects on operating circuits and the like. However, although this method of providing a soft arc conductive film (8b) is very effective in eliminating the adverse effects of discharge, it has a significant drawback in that it is harmful in reducing the number of discharges. This is because the provision of the soft arc conductive film (8b) significantly impairs the effect of the nine-spot non-king operation described above. In other words, spot knocking is effective by artificially generating a discharge and destroying dirt and foreign matter that may cause the discharge with a large instantaneous current during the discharge. This is because (8b) has the effect of limiting this large current.

This invention was devised in order to eliminate the disadvantages of providing a soft arc conductive film as described above, and it is designed to prevent a spark discharge circuit that substantially shorts the soft arc conductive film during spot knocking. The purpose is to provide a Kuken pole ray tube by placing it in a #M ray tube.

Next, embodiments of the present invention will be described with reference to FIGS. 2 to 6. In Fig. 2, (to) is a conductive wire preferably made of metal, and this conductive wire (to) is divided into two at the middle part, and one of the conductive wires (13a) formed in this way is divided into two. Each split end is insulated by an insulator made of an insulating material such as ceramic so that the split end faces the other conductive wire (13b) with a constant distance l. Retained. Here, the above-mentioned constant interval l' forms a discharge gap. The gear spacing l of this discharge gap (to) is such that no discharge occurs even if the cathode ray tube is operated by applying the maximum rated high voltage (anode voltage) to the high voltage electrode (10a), but the spot knocking voltage (generally, The high-voltage electrodes (10a) are designed to ensure that discharge occurs when a voltage approximately twice the maximum rating of the IC is applied to both ends. Further, one of the conductive wires (ui) has a curved contact portion (to) at the tip, which is connected to the first conductive film C with low resistance.
am) K electrically connected. Furthermore, the other conductive wire (ub) has its base connected to the high voltage electrode (10) of the electron gun (g).
It is connected to a) by welding or the like.

Considering the case where a spot knocking operation is performed with such a configuration, when a high voltage is applied to the anode terminal (9), this voltage is applied to the first internal conductive film (8a) and the soft arc conductive film (8b). High voltage electrode (LOA)
If there is dirt or foreign matter on the electrode, the low voltage electrode (
lob). At the moment when a discharge occurs, the high voltage electrode 1iii (10a) is in the same state as if it were directly electrically connected to the low voltage electrode (1ob), and a voltage drop occurs across the high resistance soft arc conductive film (8b). Therefore, a spot non-king voltage is generated at both ends of the discharge gap, and discharge starts there. Once this Kaede discharge starts, it continues until all the charges accumulated in the internal conductive film (8) are substantially eliminated.
The discharge between a) and the low piezoelectric conductor (10b) also continues during that time, and the amount of discharged charge is reduced by the high resistance soft arc conductive film (8
Even if b) is provided, there is no substantial effect, and therefore the conventional spot non-king effect is exhibited. Moreover, during normal operation, the discharge gap (to) does not start discharging when the maximum rated voltage of the cathode ray tube is applied, so in the unlikely event that the high voltage electrode (101) and low voltage electrode (101) of the electron gun
Even if a discharge occurs between the soft arc conductive film (
Since the potential lowering effect of 8b) is fully exerted and the discharge current or discharge charge per discharge is limited, damage to the cathode ray tube operation circuit etc. due to discharge is prevented.

In what has been explained above, a discharge gap (2) is formed in the middle part of the conductive wire (to) connecting the first internal conductive film (8a) and the high voltage electric wire 1i (10a). From K, 1. No discharge gap is provided in the middle of the line (to), and the tip thereof is opposed to the first internal conductive film (8a) as shown in FIG. A discharge gap (to) may be formed between this first internal conductor II (8a) and the tip of conductor #i (to). In this case, in order to keep the discharge gap (to) constant Some kind of contrivance is required; for example, it is not possible to support the vicinity of the tip of the conductor m with an insulator Q4).

In general cathode ray tubes, it is not necessary to specifically provide members corresponding to conductive wires, but it is possible to modify and utilize members already used for other purposes.

One example is the funnel getter in a color cathode ray tube. Conductive! I (to) is 7
FIG. 4 shows an example of a case in which the spring (b) for holding an anchor ivy is also used. A funnel getter is well known in cathode ray tubes, and is a getter container that evaporates the getter to maintain the degree of vacuum inside the tube.
is placed at an appropriate position in the funnel (2), and generally the electron gun (10 The getter is inserted into and held in the funnel (2) from the side of the getter.
7m) is bent so as to press the side surface of the funnel (2), and the tip (17a) is also processed so as to obtain an appropriate contact state without damaging the internal conductive film (8). The reason why the getter container (B) is placed in this position is because there is a problem with where the getter material that evaporates from the container will adhere. This can exactly fulfill the role of the conductive wire (2) described above.

That is, as shown in FIG. 6, the part of the internal conductive film (8) near the electron gun 01) is made of a high-resistance soft-arc conductive film (8b), and the getter holding spring (b) is made of a high-resistance soft arc conductive film (8b), for example. It is divided into two parts (TYB) and (17C) at the middle part, and these are mechanically connected with an insulator (B), and a discharge gap (TYB) is provided between them.
) should be formed. In this case, the tip (17a) of the getter holding spring (b) is the part that is not the soft arc conductive film (8b), that is, the first internal conductive film (b).
It is necessary to be in contact with

Strictly speaking, the maximum rating or spot knocking voltage of the high-voltage electrode (10a) used in the explanation for setting the discharge starting voltage of the discharge gap (to) is based on the maximum rating of the high-voltage electrode (Ion). It should be noted that the voltage applied to the adjacent low voltage electrode (10b) should be used as a reference. In the above explanation, the fluorescent film (6) is provided as an anode on the inner surface of the panel (1), but the invention is not limited to this, and can also be applied to cathode ray tubes having anodes other than the fluorescent film (6). Needless to say, the same can be applied.In addition, if the internal conductive film (8) is provided over a sufficiently large area, the resistance between two points at a certain distance can be evaluated. can do.

As described above, the present invention connects the internal conductive film connected to the anode terminal to the high voltage electrode of the electron gun through the internal conductive film with higher resistance, and parallelizes the high resistance conductive film with electric heat. Since a conductive wire is provided in the gap and a discharge cap is formed on a part of the conductive wire, the discharge starting voltage of this gap is set to be higher than the maximum rated anode voltage during operation of this cathode ray tube and lower than the spot non-king voltage. This prevents discharge between the high and low voltage electrodes constituting the electron gun, and prevents adverse effects on external operating circuits.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway side view showing a conventional cathode ray tube, FIG. 2 is an enlarged vertical sectional side view of main parts of a cathode ray tube according to an embodiment of the present invention, and FIG. 3 is a side view with a partial cutaway showing a conventional cathode ray tube. FIG. 4 is a longitudinal side view showing the configuration of a funnel getter; FIG. 6 is an enlarged longitudinal side view showing the main parts of a cathode ray tube according to another embodiment of the present invention. It is a diagram. (1)...Panel, (2)...Funnel, (5)
...Vacuum '8m, (11), C8m>...Internal conductive film, (8b)...Soft arc conductive film, (9)
...Anode terminal, α...Electron gun, (10m)...
・High voltage electrode, (lob)...Low voltage electrode, (b)...
Conduction spring, (to), (13a), (13b)...
Conductive wire, (To)...Discharge gap, (To)...Contact portion, (B)-(17b), (17c)...Getter holding spring, (To)...Getter container. In the figures, the same reference numerals indicate the same or similar parts. Agent Shin Kuzuno (1 other person)

Claims (1)

[Claims] 0) A vacuum container containing an electron gun having a high voltage electrode and a low voltage electrode facing and adjacent to the high voltage electrode, and a first electrode provided on the inner surface of the vacuum container and connected to an anode terminal. an internal conductive film, and a second internal conductive film that is provided on the inner surface of the vacuum container, electrically connects the first internal conductive film and the high voltage electrode, and has a higher electrical resistance than the first internal conductive film. A cathode ray tube comprising a conductive film, a conductive wire connecting the first internal conductive film and the high-voltage electrode in parallel to the second internal conductive film, and a discharge gap formed in the conductive wire. . (2) The cathode ray tube according to claim 1, wherein the discharge starting voltage in a vacuum of the discharge gap is higher than the maximum rated voltage of the operating voltage applied to the high voltage electrode with reference to the low voltage electrode. (3) The cathode ray tube according to claim 1 or 2, wherein the conductive wire also serves as a spring for holding a getter for maintaining the degree of vacuum within the tube.