JPH0373090B2 - - Google Patents

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a method for spotting a cathode ray tube, and more particularly to a method for spotting a cathode ray tube incorporating an electron gun having a compound main lens system consisting of six grids. It is about the method.

[Technical background of the invention and its problems]

A conventional spot-noting method for a cathode ray tube has a bipotential electron gun consisting of a heater, a cathode, a first grid, a second grid, a third grid, and a fourth grid.
The grid, the first terminal connected to the second grid, and the anode terminal connected to the sixth grid are respectively connected to a spot knocking power source that generates a pulsed high voltage, and the third grid is set in a floating state. is being carried out.

According to this spot noticing method, the fourth
Glow discharge occurs between the opposing surfaces of the grid and the third grid, and between the opposing surfaces of the third grid and the second grid, causing spotting on these opposing surfaces and their surroundings.

However, now that electron guns having a compound main lens system have been developed to improve the focusing performance of cathode ray tubes, particularly color picture tubes, there are problems with the spot-noting method described above.

Next, an example of an electron gun having a compound main lens system will be explained with reference to FIG.

That is, a cathode 2 having a heater 1 therein, a first grid 3, a second grid 4, a third grid 5, a fourth grid 6, a fifth grid 7, and a sixth grid 8 disposed opposite to the cathode 2; An electron gun consisting of a convergence electrode 9 to which the sixth grid 8 is fixed and a valve spacer 10 provided on the convergence electrode 9 is installed in the neck 11 of the cathode ray tube, and is connected to the second grid 4 and the fourth grid as shown in the figure. 6 is connected and a low voltage of about 600V is applied to the third
Grid 5 and 5th grid 7 are also connected to approximately 7KV.
A medium voltage is applied to the sixth grid 8, and an anode terminal 1 provided in the funnel 12 of the cathode ray tube is connected to the sixth grid 8 via a convergence electrode 9 and a valve spacer 10.
A high voltage of approximately 26 KV is applied from the internal conductive coating 14 connected to the internal conductive film 3.

In this electron gun, the third grid 5, the fourth grid 6, and the fifth grid 7 form a unipotential type auxiliary electron lens, and the fifth grid 7 and the sixth grid 8 form a bipotential type main electron lens. It has a compound main lens system and is designed to improve focus characteristics. As a spot spotting method for a cathode ray tube equipped with an electron gun having such a compound main lens system, a high voltage processing method as shown in FIG. 2, which is similar to the case of the bipotential type described above, can be considered.

That is, the heater 1, the cathode 2, the first grid 3,
The first grid connected to the second grid 4 and the fourth grid 6
terminal 21 from the anode terminal 13 and a second terminal 2 from the anode terminal 13
2 is connected to a spot-knotting power source 31, and spot-knotting is performed with the third grid 5 and the fifth grid 7 in a floating state.

In order to improve focus performance, the bipotential electron gun is made into an electron gun with a compound main lens system.
When applying 25KV to the grid, 4.8KV, which is about 19% of this voltage, is applied to the third grid, but in the electron gun shown in Figure 1, which has a compound main lens system, 25KV is applied to the sixth grid 8. When applying 7KV, which is about 28% of this voltage, is applied to the fifth grid 7 and the third grid 5, making the potential distribution near the second grid steep. As a result, barium (Ba) contained in the cathode is evaporated during cathode activation by temperature activation or current activation in the cathode aging process in the cathode aging process of the cathode ray tube manufacturing process, and a portion of it is transferred to the second grid 4. There has been a phenomenon in which the amount of particles adhering to the periphery of the electron beam passage hole becomes a stray emission source and significantly reduces the withstand voltage characteristics of the cathode ray tube.
However, when using the spot knocking method as shown in FIG. It is not possible to spot spot around the surrounding area.

For this reason, a method has been used in which the second grid 4 is heated exclusively by high-frequency induction heating instead of high-voltage treatment, but this method is a complicated process, and adsorbed gas is released from the heated part during heating, causing the cathode The problem was that the emission characteristics of the cathode ray tubes deteriorated and many tubes had to undergo cathode aging again.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned conventional problems, and it eliminates stray emission sources attached to the second grid of a cathode ray tube equipped with an electron gun having a compound main lens system by spot knocking. It is an object of the present invention to provide a method for spot-notching cathode wiring.

[Summary of the invention]

That is, the present invention includes a heater, a cathode, a first grid,
Electron having a compound lens system consisting of a third grid, a fourth grid, a fifth grid, and a sixth grid, with the second grid and the fourth grid connected to each other, and the third grid and the fifth grid connected to each other. In a spot spotting method for a cathode ray tube incorporating a gun, the second grid, the fourth grid, and the sixth grid are in a floating state, and the first terminal connected to the heater, the cathode, and the first grid is connected to the third grid. A method characterized by applying a predetermined high voltage between the second terminals connected to the fifth grid, and applying a predetermined high voltage to the first terminal, the second terminal and the third terminal from the sixth grid, respectively. This method is characterized by applying a high voltage of .

[Embodiments of the invention]

Next, one embodiment of the present invention will be described with reference to FIG. In the figure, the same reference numerals as in FIGS. 1 and 2 indicate the same parts.

That is, an electron grid consisting of a cathode 2 with a heater 1 therein, and a first grid 3, a second grid 4, a third grid 5, a fourth grid 6, a fifth grid 7, and a sixth grid 8 disposed opposite to the cathode 2. The gun is housed in a cathode ray tube neck 11, and as shown in the figure, the second grid 4 and the fourth grid 6 are electrically connected, the third grid 5 and the fifth grid 7 are electrically connected, and the sixth grid 8 is electrically connected. The internal conductive film 14 of the funnel 12 is connected to the anode terminal 13 via a convergence electrode and a valve spacer (not shown).

The spot spotting method for a cathode ray tube incorporating such an electron gun is to set the second grid 4, fourth grid 6, and sixth grid 8 in a floating state,
A first terminal 21 that electrically connects the heater 1, the cathode 2, and the first grid 3, and a second terminal 22 that electrically connects the third grid 5 and the fifth grid 7 are connected to the spot knocking power source 31. 1 terminal 21, 2nd
This is done by applying a predetermined voltage between the terminals 22 of the. This voltage is usually a pulsed high voltage, and the peak value is 2 to 2 times higher than the voltage applied during actual operation of the cathode ray tube.
3x is used.

According to the spot-knocking method of this embodiment, since the second grid 4 is in a floating state, a voltage divided by the capacitance between each grid is applied. Stray emission sources in the vicinity of the second grid 4 including the first grid 3 side can be removed by spot knocking.

Next, another embodiment of the present invention will be described with reference to FIG. In the figure, the same reference numerals as in FIG. 3 indicate the same parts, and no particular explanation will be given.

That is, in this embodiment, the third terminal 23 from the anode terminal 13 is also connected to the high voltage processing power source 31 to perform spot-knocking.

According to the spot finding method of this embodiment,
Stray emission sources around the second grid 4 can be removed, and the sixth grid 8 and the fifth grid 7, the fifth grid 7 and the fourth grid 6, the fourth grid 6 and the third grid 5, and the third grid 5 It is also possible to spot spot the contact surfaces of and second grid 4 and their surroundings. In this case, the application timing of the pulse-like high voltage for spot-knocking applied to the first terminal 21 and the second terminal 22 and the pulse-like pulse for spot-knocking applied to the first terminal 21 and the third terminal 23 are determined. Of course, the timing of applying the high voltage may be changed.

〔Effect of the invention〕

As described above, according to the cathode ray tube spotting method of the present invention, the electrode to which a low voltage is applied, such as the second grid of an electron gun having a composite main lens system, and the insulating support rod supporting each electrode in the vicinity thereof. Good spot spotting on walls and inner walls,
It is possible to remove stray emission sources extremely easily and reliably, and it is possible to significantly improve the charging voltage characteristics of cathode ray tubes, and its industrial value is extremely large.

[Brief explanation of drawings]

Fig. 1 is a sectional view for explaining the main parts of a cathode ray tube incorporating an electron gun having a compound main lens system, Fig. 2 is an explanatory view of a conventional spotting method for a cathode ray tube,
FIG. 3 is an explanatory diagram of one embodiment of the present invention, and FIG. 4 is an explanatory diagram of another embodiment of the present invention. 1... Heater, 2... Cathode, 3... First grid, 4... Second grid, 5... Third grid, 6... Fourth grid, 7... Fifth grid,
8...Sixth grid, 9...Convergence electrode, 10...Valve spacer, 11...Net,
12...Funnel, 13...Anode terminal, 14...
...inner conductive film, 21...first terminal, 22...second terminal, 23...third terminal, 31...power source for spotting.

Claims (1)

[Claims] 1 Consists of a heater, a cathode, a first grid, a second grid, a third grid, a fourth grid, a fifth grid, and a sixth grid, and the second grid and the fourth grid are electrically connected. In the spot-noting method of a cathode ray tube incorporating an electron gun having a composite main lens system in which a third grid and a fifth grid are connected, the second grid, the fourth grid and the sixth grid are set in a floating state. , a cathode ray tube characterized in that a predetermined high voltage is applied between a first terminal electrically connected to the heater, the cathode, and the first grid, and a second terminal electrically connected to the third grid and the fifth grid. Spot-notsking method. 2 Consisting of a heater, a cathode, a first grid, a second grid, a third grid, a fourth grid, a fifth grid, and a sixth grid, the second grid and the fourth grid are electrically connected, and the third grid and the In the spot spotting method of a cathode ray tube incorporating an electron gun having a composite main lens system in which five grids are connected, the second grid and the fourth grid are connected.
A first terminal electrically connected to the heater, the cathode, and the first grid, a second terminal electrically connected to the third grid and the fifth grid, and an anode electrically connected to the sixth grid, with the grid in a floating state. 1. A method for spotting a cathode ray tube, the method comprising applying a predetermined high voltage to three terminals including a third terminal.