JPH01194245A - Electron gun structure - Google Patents

Abstract

PURPOSE:To provide sufficient resolution by forming a capacitor in connection with an electrode other than electrodes on which dynamic focus voltage is impressed by means of close contact of electrode having a number of holes in a dielectric base plate and covering with dielectric substance. CONSTITUTION:No.3 grid G3 and No.5 grid G5 of an electron gun structure are connected in a tube, and a dynamic focus voltage synchronous with the horizontal deflection current for a deflection yoke is impressed, and a main focusing lens is composed of the grid G5, No.1, No.2 intermediate electrodes 14, 15, and No.6 grid G6. A capacitor 23 is connected to the electrode 14 adjoining to the grid G5. This capacitor 23 is equipped with closely contacting electrodes 26a, 26b having a number of holes at both surfaces of a flat plate shaped dielectric base plate 25, and these electrodes 26a, 26b are covered so that the openings in them are filled with a dielectric covering 27. Thus induction of AC component of the dynamic focus voltage can be removed effectively.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to an electron gun assembly used in a cathode ray tube such as a color picture tube, and in particular, to an electron gun assembly used in a cathode ray tube such as a color picture tube. This article relates to an electron gun assembly.

(Conventional technology) Generally, a color picture tube is as shown in Fig. 7.

It has an envelope 0 consisting of a panel (1) and a funnel ■, and on the inner surface of the panel ω is formed a phosphor screen consisting of a three-color phosphor layer that emits red, blue, and green, and this phosphor screen A shadow mask 0 having a large number of electron beam passing holes formed inside thereof is disposed opposite to the mask 0. In addition, there are 3 electron beams (7i) in the neck (c) of the funnel ■.
An electron gun assembly (8) that emits (7G) and (7R) is provided. This electron gun structure (8) is a cathode that generates three electron beams (7B), (7G), and (7R).

3 electron beams from this cathode (7B), (7G),
(7R) and the above three electron beams (7B).

An apparatus consisting of a plurality of electrodes arranged at predetermined intervals, such as electrodes constituting the main focusing lens that focuses (7G) and (7R) onto the phosphor screen e1), and this electron gun assembly (c). The three electron beams (7B), (7G), and (7R) emitted from the funnel ■
It is deflected horizontally and vertically by a deflection yoke 0 attached to the outside of the phosphor screen G), and the deflected beam scans the phosphor screen G) through a shadow mask, thereby creating a color image on this phosphor screen G). It is designed to be displayed.

However, the focusing of the electron beam usually changes depending on the deflection angle of the deflected beam, and is not constant over the entire surface (on the phosphor screen). , convergence deteriorates, especially at the corners of the screen, and resolution decreases.

Therefore, as shown in FIG. 8, the deflection current (
11) Dynamic focus voltage of several hundred to several ID0OV that changes parabolically in synchronization with (12)
There is an attempt to improve the resolution of an entire screen by applying the electron beam in a superimposed manner and changing its focusing according to the deflection of the electron beam.

However, as mentioned above, by superimposing a predetermined voltage on the focusing electrode, a dynamic focusing voltage (1
2), since there is stray capacitance between the electrodes that make up the electron gun assembly (8), the electrodes other than the one to which the dynamic focus voltage (12) is applied, especially the main focusing lens, The alternating current component of the dynamic focus voltage (12) is also superimposed on the predetermined voltage applied to the adjacent electrode due to electrostatic induction.

Therefore, the temporal change in the potential difference between these adjacent electrodes is no longer limited to the alternating current component of the dynamic focus voltage (12), and the desired focusing cannot be obtained over the entire surface of the phosphor screen, and the resolution of the entire surface of the screen cannot be sufficiently improved. I can't do it.

The problem that occurs when applying this dynamic focus voltage (12) is that the dynamic focus voltage (12)
12) can be solved to some extent by increasing the potential of the AC component. However, in this case, the alternating current component of the dynamic focus voltage (12) superimposed on the adjacent electrode also increases accordingly, so this is not necessarily an effective method. Moreover, normally, a high anode voltage of about 20 to 30 KV is applied to the accelerating electrode constituting the main focusing lens, and a medium voltage of about 7 to 8 KV is applied to the focusing electrode in contrast to this accelerating electrode. Both the predetermined medium voltage applied to the electrodes and the dynamic focus voltage (12) superimposed thereon are supplied via a stem pin that hermetically passes through the stem portion sealing the neck end. Therefore, the resistance of the stem part to which such high voltage is applied and the socket connected to the stem pin of this stem part is high.
The a pressure becomes a problem.

In order to solve such problems, the present applicant has developed an electron gun assembly in which a capacitor is connected to another electrode constituting the main focusing lens adjacent to the electrode to which the dynamic focus voltage (12) is applied. The company filed an application for a cathode ray tube with a small size.

As shown in FIGS. 9 and 10, the electron gun structure includes three cathodes (K) arranged in a -row, a first grid (G1),
, second grid (G2), third grid (G,), fourth grid
grid (G4), fifth grid (G,), first intermediate electrode (14), second intermediate electrode (15), sixth grid (G
G) and a convergence cup (C), each electrode other than the convergence cup (C) is supported and fixed to a pair of insulating supports (not shown) in the above order, and the convergence cup (C) is a convergence cup (C). It is welded and fixed to the 6 grid (G6). Then, the anode voltage supplied to the back side of one of the insulating supports through the convergence cup (C) and the sixth grid (G,) is divided into the first and second insulating supports. A resistor (16) is provided to supply a predetermined voltage to the second intermediate electrodes (14) and (15).

In this electron gun assembly, a voltage of about 150V and a modulated image signal are applied to the three cathodes (K), and the first grid (
G1) is grounded and the second grid (G2) has approximately 600
A voltage of v is applied. The third grid (G1) and the fifth grid (G,) are connected in the tube, and the focusing voltage of about 7 KV and the dynamic focus voltage are applied to the fourth grid (G4), and the second grid (G2) is connected to the fourth grid (G4). ), the same voltage of about 600v is applied. Prefocus lenses for pre-focusing the electron beams 11 emitted from the cathode (K) in the second grid (G2) and the third grid (G3) are also used in the third to fifth grids (G3) to (
G,) forms an auxiliary focusing lens.

Further, a positive t4i voltage of about 20 to 30 KV is applied to the sixth grid (G6), and the first. Second intermediate electrode (14
).

(15) is applied with voltages of about 40% and 65% of this anode voltage, respectively, by the resistance division of the resistor (16), thereby causing the fifth grid (GS).

This first. Second intermediate? The lI poles (14), (15) and the sixth grid (G6) form a main focusing lens that ultimately focuses the electron beam 11 onto the phosphor screen.

A capacitor (17) is disposed on the back side of the other insulating support of the electron gun assembly. In particular, in Figure 9,
This capacitor (17) is connected to the first intermediate electrode (14) adjacent to the fifth grid (G5) to which the dynamic focus voltage is applied, and is grounded, so that electrostatic induction (14) is configured to bypass the alternating current component of the dynamic focus voltage superimposed on the dynamic focus voltage (14), and in FIG. By applying a voltage with a waveform opposite in polarity to the dynamic focus voltage through the dynamic focus voltage (17), the alternating current component of the dynamic focus voltage superimposed on the first intermediate electrode (14) is canceled out by electrostatic induction. is shown. By the way, such a capacitor (17) is required to have the following characteristics.

That is, first, it must be integrally attached to the electron gun structure and placed in a narrow space within the neck, and the electron gun structure must maintain the required characteristics even when the capacitor (17) is attached. Therefore, it must be small. Second, the capacitor (17) is connected to the first intermediate electrode (14) with a relatively high voltage, and especially when the capacitor (17) is grounded, it has a high withstand voltage of several KV to several tens of V. characteristics are required. Thirdly, a large electric capacity is required, especially in the case of bypassing the alternating current component of the dynamic focus voltage superimposed by electrostatic induction. However, the capacitor (17) attached to the electron gun structure is
As shown in the figure, electrodes (20a), (2
0b) are closely formed, and these electrodes (20a), (20
b) is covered with an insulating coating (21), which does not necessarily fully satisfy the characteristics required of the capacitor (17).

(Problem to be Solved by the Invention) As described above, in order to maintain the focusing of the electron beam over the entire surface of the phosphor screen and improve the resolution of the entire screen, the focusing electrode is equipped with a There is an electron gun assembly in which a dynamic focus voltage synchronized with a deflection current flowing through a horizontal deflection coil of a deflection yoke is superimposed on a predetermined voltage and applied. However, when such a dynamic focus voltage is applied, due to electrostatic induction,
21 electrodes other than the focusing electrode to which this dynamic focusing voltage is applied, especially the adjacent electrodes constituting the main focusing lens, are also dynamically applied to the predetermined voltage.
The alternating current components of the focus voltage are superimposed, and the temporal change in the potential difference between adjacent electrodes is no longer limited to the alternating current component of the dynamic focus voltage, making it impossible to obtain the desired focusing over the entire surface of the phosphor screen.

In order to solve this problem, the applicant first connected a capacitor to the electrode constituting the main focusing lens adjacent to the focusing electrode to which the dynamic focusing voltage is applied, and grounded the capacitor. By bypassing the alternating current component of the dynamic focus voltage superimposed on this electrode, or by applying a voltage with a waveform of the opposite polarity to the dynamic focus voltage to the above capacitor, the alternating current component of the dynamic focus voltage superimposed by electrostatic induction can be avoided. filed an application for an electron gun structure designed to offset the By the way, such a capacitor must be small because it must be placed in a narrow space inside the neck along with the electron gun structure, and because it is connected to an electrode to which a relatively high voltage is applied, Superimposed dynamic
A device that bypasses the alternating current component of the focus voltage is required to have high withstand voltage characteristics, and a device that bypasses the alternating current component of the dynamic focus voltage, which is heavily influenced by electrostatic induction, requires a large capacitance. is also required.

This invention was made in view of the above problems, and
By making the capacitor small and having a structure with sufficiently high withstand voltage characteristics and large capacitance, when a dynamic focusing voltage is superimposed on the focusing electrode, it is superimposed on the electrode constituting the adjacent main focusing lens by electrostatic induction. It is an object of the present invention to easily configure a required electron gun structure that bypasses or cancels the alternating current component of a dynamic focus voltage.

[Structure of the invention]

(Means for Solving the Problem) An electron beam that has a plurality of electrodes constituting a main focusing lens, and a dynamic focus voltage synchronized with the horizontal deflection current of a deflection yoke is applied to one of the plurality of electrodes. In the gun body, a capacitor is connected to at least one electrode other than the electrode to which the dynamic focus voltage is applied among the plurality of electrodes constituting the main focusing lens, and the capacitor is connected to the electrodes on both sides of the dielectric substrate. At least one of the electrodes formed in close contact with both surfaces of the dielectric substrate is an electrode having a large number of holes.

This electrode with many holes was covered with a dielectric coating.

(Function) As described above, when a capacitor is connected to at least one electrode other than the electrode to which the dynamic focus voltage is applied among the plurality of electrodes forming the main focusing lens, the main focusing lens is formed. When a dynamic focus voltage is applied to one of the electrodes, the alternating current component of the dynamic focus voltage superimposed on the electrode constituting the adjacent main focusing lens can be removed by electrostatic induction.

Moreover, if the capacitor is made of electrodes that are in close contact with both sides of the dielectric substrate, at least one electrode has many holes, and this electrode with many holes is covered with a dielectric coating. It can be made to have a high withstand voltage characteristic, and a large electric capacity.
A required electron gun structure can be easily constructed.

(Example) Hereinafter, the present invention will be described based on an example with reference to the drawings.

FIG. 1 shows an electron gun assembly for a color picture tube, which is an embodiment of the present invention. This electron gun assembly is an in-line array electron gun assembly, and includes three cathodes (K) arranged in a -row, a first
Grid (G8), 2nd grid (G2), 3rd grid (G,), 4th grid (G4), 5th grid (G
), first intermediate electrode (14), second intermediate electrode (15),
Grid 6 (G6) and Convergence Cup (
C), and each electrode other than the convergence cup (C) has a pair of insulating supports (20a) in the above order.

(20b), and the convergence cup (C) is welded and fixed to its sixth grid (G6).

A resistor (16) formed by forming a resistance path on an insulating substrate, for example, is attached to the back surface of one of the insulating supports (20a) facing the inner surface of the neck. This resistor (1
6) is an internal conductive film (21) formed on the inner surface of the funnel.
), a valve spacer (22) attached to the convergence cup (C) and pressed against this internal conductive film (21)
and the high voltage anode voltage supplied to the sixth grid (6G) through the convergence cup (C'). Second intermediate electrode (14).

(15), one end of which extends to the side of the convergence cup (C), and the other end of the convergence cup (C). grounded, and the intermediate portions are respectively connected to the first. It is connected to the second intermediate electrodes (14) and (15). Furthermore, a capacitor (23), which will be described later, is attached to the same rear surface of the other insulating support (20b), and a fifth grid (G
5) is connected to the first intermediate electrode (14) adjacent to the first intermediate electrode (14).

During operation, this electron gun structure has approximately 15
A voltage of 0V and a modulated image signal are applied, the first grid (G,) is grounded, and a voltage of about 600V is applied to the second grid (G2). Also, the third Grirad (G3
) and the 5th grid (G5) are connected in the pipe, approximately 7K
A dynamic focus voltage (6th
(see figure) is applied. Further, the same voltage of about 600V as that of the second grid (G2) is applied to the fourth grid (G4). Then, the second grid (G2) and the third grid (
A prefocus lens for prefocusing the electron beam emitted from the cathode (K) is formed by the grids (G,), and an auxiliary focusing lens is formed by the third to fifth grids (G,) to (G,). Further, an anode voltage of about 20 to 30 KV is applied to the sixth grid (G,) via the internal conductive film (21), the valve spacer (22), and the convergence cup (C), and electrode (14),
(15) are respectively applied with voltages of about 40% and 65% of this anode voltage divided by resistors (16), thereby causing the fifth grid (G, The second intermediate electrode (14), (15) and the sixth grid (G,
) forms a main focusing lens that ultimately focuses the electron beam onto the phosphor screen.

In particular, in this electron gun assembly, the capacitor (23) connected to the first intermediate electrode (14) adjacent to the fifth grid (G) keeps the electron beam focused uniformly over the entire surface of the phosphor screen. In order to improve resolution, the fifth
When a dynamic focus voltage is applied to the grid (G,), this first intermediate electrode (14)
This capacitor (23
) can be connected to ground or apply a voltage with a waveform of a polarity opposite to that of the dynamic focus voltage to the first intermediate electrode (14).

FIGS. 2 and 3 show an example of such a capacitor (23), in which electrodes (26a ), (26b) are provided in close contact with each other, and the openings of each electrode (26a), (26b) are connected to the dielectric coating (26b).
7), each electrode (26a), (2
6b).

By the way, in general, the capacitance C of a capacitor is.

If the dielectric constant of the dielectric substrate inserted between the opposing electrodes is ε, the opposing area of the electrodes is S, and the distance between the opposing electrodes, that is, the thickness of the dielectric substrate is d, then C=ε ・S/d...・・・・■
It is expressed as Therefore, in order to increase the capacitance C,
It is necessary to increase the dielectric constant ε or the opposing area S- of the electrodes, or to decrease the distance d between the opposing electrodes.6 However, among these factors that increase the capacitance C, the dielectric constant ε
In general, materials with a large dielectric constant ε have lower withstand voltage characteristics, so if a material with a large E is used, the dielectric substrate must be made thicker, which is contradictory to reducing d. become. In addition, changing the material of the dielectric substrate in this way affects not only the relationship between ε and d, but also
This may also affect the characteristics of the electron gun assembly itself.

Furthermore, in order to reduce d, ε must be increased, which causes the same problem. On the other hand, regarding S, since it is a capacitor that is attached to the electron gun structure and placed inside the neck 0, it is impossible to increase the size of the dielectric substrate with flat surfaces on both sides like a conventional capacitor. There is a limit to its size, and it cannot be made too large.

However, as shown in the above embodiment, the dielectric substrate (25
) are provided with electrodes (26a) and (26b) arranged in a matrix shape and having a large number of holes in close contact with each other.

Each electrode (26a), (26b) is covered with a dielectric material (2
7), the opposing area of the electrodes can be substantially increased. For example, as shown in FIG.
= s = d), the surface area can be increased by about 2.5 times compared to a non-porous electrode with a diameter of 1.5 mm. Therefore, by increasing the surface area, the capacitance C can be increased without increasing the size of the entire capacitor. That is, when the capacitor (23) is configured as described above, each electrode (26a) as shown by the capacitor symbol (=) in FIG.

(26b) and each electrode (26a), (2
6b), electric capacitance is also generated on the outer surface of the capacitor through the dielectric wave rIl (27), and the electric capacitance MC can be greatly increased compared to the conventional capacitor shown in FIG. .

Note that the electric capacitance C1 between the outer surfaces of the picture electrodes (26a) and (26b) is equal to the electric capacitance of the dielectric coating (27) fttcz
Since the capacitance C3 and the capacitance C3 of the dielectric substrate (25) are connected in series, it is expressed as follows, and since C1<C3, the capacitance of the entire capacitor is smaller than the area ratio. However, by using a titanate such as barium titanate or a ferroelectric material containing titanate as the dielectric wave 81 (27), C2 can be greatly increased and approached to an area ratio of 1. .

Such a capacitor (23) is made of, for example, alumina (AQ20.
) can be easily formed by using a dielectric substrate (25) and gluing non-magnetic stainless steel plates with required openings formed on both sides thereof, or by printing a conductive paste using thick film printing. .

Note that in the above embodiment, electrodes with a large number of holes were provided in close contact with both sides of the dielectric substrate of the capacitor, but electrodes with such holes were provided only on one side of the dielectric substrate. However, a capacitor with the same effect can be used.

Further, the electrode with a large number of openings of the capacitor and the shape of the openings may have other shapes, for example, as shown in FIG. Moreover, as shown in FIG. 6, a capacitor having the same effect can be obtained by using a mesh-like electrode (26).

〔Effect of the invention〕

A plurality of t!'s constitute the main focusing lens. ! In an electron gun assembly in which a dynamic focus voltage synchronized with a horizontal deflection current of a deflection yoke is applied to the poles, at least one electrode constituting a main focusing lens other than the electrode to which the dynamic focus voltage is applied; A capacitor is connected to the capacitor, electrodes are closely formed on both sides of a dielectric substrate whose at least one side has an uneven surface, and at least one of the electrodes is formed with an electrode having a large number of holes. As a result, it is possible to create a capacitor that is compact, has high voltage resistance characteristics, and also has a large capacitance.When a dynamic focus voltage is applied to one of the electrodes that make up the main focusing lens, the It is possible to easily construct a required electron gun structure that effectively removes the alternating current component of the dynamic focus voltage superimposed on the other electrodes constituting the main focusing lens.

[Brief explanation of the drawing]

Figures 1 to 4 are detailed explanatory diagrams of this invention.
Figures (A) to C) are a front view, a side view, a cross-sectional view taken along the line C--C in Figure (A), and Fig. is a perspective view showing the structure of the capacitor, FIG. 3 is a cross-sectional view of the capacitor, FIG. 4 is a perspective view with a part of the electrode of the capacitor cut away, and FIG. 5 is an electrode of another different structure of the capacitor. FIG. 6 is a partially cutaway perspective view showing electrodes of a further different structure of a capacitor; FIG. 7 is a partially cutaway view showing the overall configuration of a color picture tube; FIG. The figure is a waveform diagram of the dynamic focus voltage applied to one of the electrodes constituting the main focusing lens of the electron gun structure in synchronization with the horizontal deflection current flowing in the deflection yoke.
The figure shows the configuration of the electron gun assembly of the prior application, in which a dynamic focus voltage is applied to one of the electrodes that make up the main focusing lens, and a capacitor connected to the other electrode that makes up the main focusing lens is grounded. Figure 10 shows the configuration of an electron gun assembly that applies a voltage with a waveform of opposite polarity to the dynamic focus voltage to a similarly connected capacitor, and Figure 11 shows the configuration with a part of the capacitor cut away. FIG. 12 is a sectional view thereof. G,...Fifth grid G6...Sixth grid 14...First intermediate electrode 15...Second intermediate electrode 23...Capacitor 25...Dielectric substrate 2
6a, 26b...Electrode 17...Dielectric coating @ 2 Cause 3 Figure 4 Figure 5 Figure b 1 Figure 7 Figure 8

Claims (1)

[Claims] In an electron gun assembly that has a plurality of electrodes constituting the main focusing lens, and a dynamic focus voltage synchronized with the horizontal deflection current of the deflection yoke is applied to one of the plurality of electrodes, the main focusing lens is A capacitor is connected to at least one electrode other than the electrode to which the dynamic focus voltage is applied among the plurality of electrodes, and this capacitor is connected to a dielectric substrate and an electrode that is in close contact with both surfaces of the dielectric substrate. an electron gun, characterized in that at least one of the electrodes in close contact with both surfaces of the dielectric substrate is an electrode with a large number of holes, and the electrode with the large number of holes is covered with a dielectric coating. Structure.