JPH0131258B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electron gun assembly, and more particularly to an electron gun assembly configured to suppress the discharge current within a color picture tube.

For example, a bipotential type electron gun assembly installed in a color picture tube has a structure shown in FIG.

That is, this electron gun assembly 1 has a plurality of electrodes including a cathode 3 with a heater 2 therein, a first grid 4, a second grid 5, a third grid 6, a fourth grid 7, and a convergence electrode 8. The electrodes other than 8 are fixed to a support 9 made of bead glass or the like through implanted portions 3 ₁ , 4 ₁ , 5 ₁ , 6 ₁ , 7 ₁ provided on each electrode. In addition, the convergence electrode 8 has no particular implantation part,
It is fixed to the fourth grid 7. Note that a valve pacer 10 is attached to the upper end of the convergence electrode 8.

Next, a color picture tube incorporating the above-mentioned electron gun assembly 1 will be explained with reference to FIG.

This color picture tube has a panel 12 having a phosphor surface 11 on the inner surface of which a phosphor layer that emits red, green, and blue light in the form of dots or bands is regularly deposited upon the impingement of an electron beam. , a net 14 connected to this panel 12 via a funnel 13;
An electron gun assembly 1 housed in the net 14, a shadow mask 16 for selectively hitting a desired phosphor layer with the electron beam 15 emitted from the electron gun assembly 1, and a shadow mask 16 formed on the inner surface of the funnel 13. a conductive coating 17, an anode terminal 18 for applying an anode voltage to the conductive coating 17, and a getter 20 provided so as to come into contact with the inner surface of the funnel 13 via a getter support 19 fixed to the convergence electrode 8. It is made up of.

In order to operate a color picture tube with such a configuration, a high anode voltage of 25KV to 30KV is applied from the convergence electrode 8 and the fourth grid 7 via the anode terminal 18, the conductive coating 17, and the bulb spacer 10. is applied to the final focusing electrode. In addition, 20% of this anode voltage is applied to the third grid 6.
A voltage of about 30% is applied, and a main electron lens section is formed between the third grid 6 and the fourth grid 7. Furthermore, a so-called three-pole portion is formed between the cathode 3, the first grid 4, the second grid 5, and the third grid 6. Therefore, in this electron gun assembly 1, the potential difference between the fourth grid 7 and the third grid 6 is the largest, about 20 KV.

However, when this color picture tube is incorporated into a color television apparatus and operated, discharge within the tube may occur due to various causes. This intraluminal discharge tends to occur between the third grid 6 and the fourth grid 7, where the potential difference is the largest. The value of the discharge current during this tube discharge varies depending on the external circuit conditions, but it is extremely large and can destroy semiconductor elements such as transistors and integrated circuit elements built into television equipment. It has become a technical problem.

In order to suppress this discharge current, the conductive coating 17 between the anode terminal 18 and the bulb spacer 10 has conventionally been used.
When a tube discharge occurs with a resistance of about 400Ω,
Measures are taken to reduce the discharge current through the resistance.

However, even if a resistive portion is formed in the conductive film 17 in this way, in a color picture tube, in order to increase the degree of vacuum inside the tube, it is necessary to scatter getter material from the getter 20, and this getter material is generally made of conductive Ba. Since Ba is the main component, this Ba adheres to the conductive film 17, making it difficult to maintain the resistance of the conductive film 17 at a predetermined value. Furthermore, Getsuta Support 19
is formed from a conductive member, and the getter 20 is provided on the getter support 19 so as to be in contact with the conductive coating 17. Therefore, even if the conductive coating 17 has a desired resistance as described above, this getter 2
0 and the getter support 19, making it difficult to set the resistance of the conductive film 17 to a predetermined value.

The present invention has been made in view of the above-mentioned conventional drawbacks, and an object of the present invention is to provide an electron gun assembly capable of effectively suppressing discharge current during tube discharge.

Next, one embodiment of the electron gun assembly of the present invention will be described with reference to FIG.

That is, the electron gun assembly 21 has a cathode 23, a first grid 24, a second grid 25, a third grid 26, which are housed in a heater 22, a fourth grid 27 as an electrode element forming a final acceleration electrode, and a convergence electrode 28. Implanted portions 23 ₁ , 24 ₁ , 25 ₁ , 26 where each of these electrodes is provided
₁ , 27 ₁ , and 28 ₁ to a pair of supports 29 . The pair of supports 29 are provided with a pair of resistors 29a as shown by diagonal lines on one end side of an insulator made of bead glass, and in particular, in this example, the fourth grid 2 as the final accelerating electrode
The convergence electrode 7 and the convergence electrode 28 are separated and implanted and fixed adjacent to the respective resistor 29a portions.

Such a resistor 29a is made of glass with CeO ₂ ,
A predetermined amount of oxides such as V ₂ O ₅ and Fe ₂ O ₃ are mixed into the insulator that regulates the space between the other implanted parts 23 ₁ , 24 ₁ , 25 ₁ , 26 ₁ and has a low resistance value. 4 grid 27 and convergence electrode 28 implantation part 27 ₁ ,
A predetermined resistance is provided between 28 _{and 1} . Incidentally, a valve spacer 30 is attached to the convergence 28 as one electrode element of the final acceleration electrode.
is provided.

Next, the color picture tube built into the electron gun assembly 21 will be explained with reference to FIG. This color picture tube consists of a panel 3 having a phosphor surface 31 on the inner surface of which a phosphor layer of red, green, and blue colors generated by the impingement of an electron beam is regularly deposited in the form of dots or bands.
2, a net 34 connected to this panel 32 via a funnel 33, an electron gun assembly 21 housed in this neck 34, and an electron beam 35 emitted from this electron gun assembly 21 to a predetermined phosphor. A shadow mask 36 that is selectively injected into the layer, and a conductive coating 3 formed on the inner surface of the funnel 33.
7 and a getter 40 provided so as to come into contact with the inner surface of the funnel 33 via a getter support 39 fixed to the convergence electrode 28.

When operating a color picture tube with such a structure, a high voltage of 25KV to 30KV is applied to the anode terminal 38, the conductive coating 37, and the valve spacer 3.
0 to the convergence electrode 28, which is one electrode element of the final accelerating electrode, and further applied to the fourth grid 27, which is one electrode element of the final accelerating electrode, via a resistor 29a. Further, a voltage of about 20% to 30% of this anode voltage is applied to the third grid 26, and the third grid 26 and the fourth
A main electron lens section is formed between the grids 27.
Furthermore, a so-called three-pole portion is formed between the cathode 23, the first grid 24, the second grid 25, and the third grid 6. Therefore, in this electron gun assembly 21, the potential difference between the fourth grid 27 and the third grid 26 is the largest, about 20 KV.

By the way, when this color picture tube is incorporated into a color television device and operated, an anode voltage is applied to the convergence electrode 28 and the fourth grid 27 when no discharge occurs in the tube, and the anode voltage is applied to the convergence electrode 28 and the fourth grid 27. A main electron lens is formed between the grids 26 and reproduces a color image on the phosphor surface 31, but due to various reasons, the discharge within the tube is particularly
When a discharge occurs between the grid 27 and the third grid 26, the resistor 29a lowers the potential of the fourth grid 27 and suppresses the discharge current.

Further, the resistor 29a of the electron gun assembly 21 of this embodiment
Since the getter 40 is located inside the neck 34 of the color picture tube, Ba etc. will not adhere even if the getter 40 is scattered, and the initially determined resistance value can be maintained as it is. There will be no undesirable results due to adhesion of substances such as. Furthermore, the spacing between the implanted portions 27 ₁ and 28 ₁ can always be made uniform using a spacer or the like when assembling the electron gun assembly, and "variations" due to the electron gun assembly can be extremely reduced.

Next, another embodiment of the electron gun assembly of the present invention will be described with reference to FIG. The same parts in the figure as in FIG. 3 are given the same reference numerals, and the explanation will be omitted.

That is, in this embodiment, no resistor is provided on the support 29, the convergence electrode 28 and the fourth grid 27 are separated, and the implanted portions 27 and 28 are separated from each other.
The resistor 41 is implanted and fixed adjacent to the support body 29 made of an insulator through the implantation portions 27 and 28.
It is characterized by having been provided separately. By doing so, it becomes possible to provide a predetermined resistance regardless of the spacing between the planted portions 27 and 28.

In all of the above-mentioned embodiments, the convergence electrode and the fourth grid are separated in the bipotential electron gun structure, but the present invention is not limited to this. It goes without saying that the present invention can be applied as is to those formed with plate-shaped or shallow dish-shaped electrode elements, as well as to unipotential type electron gun structures, tripotential type electron gun structures, and electron gun structures of other structures.

[Brief explanation of drawings]

FIG. 1 is a simplified elevational view showing an example of a conventional electron gun structure, FIG. 2 is an explanatory sectional view of a color picture tube incorporating the electron gun structure of FIG. 1, and FIG. 3 is an electron gun of the present invention. A simplified elevational view showing one embodiment of the structure, FIG. 4 is an explanatory cross-sectional view of a color picture tube incorporating the electron gun structure of FIG. 3, and FIG. 5 is another embodiment of the electron gun structure of the present invention. FIG. 1, 21... Electron gun structure, 7, 27... Fourth grid, 8, 28... Convergence electrode, 9,
29...Support, 29a...Resistor.

Claims (1)

[Claims] 1. In an electron gun assembly in which a plurality of electrodes, one end of which is the final acceleration electrode, are fixed to a support body through implants provided on each electrode at predetermined intervals, the final acceleration The electrode is separated into multiple electrode elements each having an implanted part and placed adjacent to each other.
An electron gun assembly characterized in that a resistor is disposed between the implanted portions of the separated electrode elements.