JPS5916698B2 - Cathode ray tube spotting method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a so-called spot knocking method for cathode ray tubes in which a voltage higher than the maximum rated voltage is applied to the anode during the manufacturing process of the cathode ray tube in order to provide the cathode ray tube with good withstand voltage characteristics. It is something.

FIG. 1 is an electrical wiring diagram for implementing a conventional spot knocking method for a cathode ray tube.

In the structure, a positive voltage from a high voltage power source 1 for spot non-king is applied to an anode 5 and a fluorescent surface 6 via an anode button 3 and an internal conductive film 4 of a cathode ray tube 2.

In addition, the negative voltage of the high voltage power supply 1 for spot knocking is applied to the cathode 7.
is applied to the heater 8, the first grid electrode 9, the second grid electrode 10, and the focusing electrode 11, respectively.

In such a configuration, the high voltage from the high voltage power supply 1 for spot knocking is applied only between the anode 5 and the focusing electrode 11, so spot knocking can only be performed between the anode 5 and the focusing electrode 11. Ta.

In particular, in this conventional spot knocking method, the cathode 7
Since the temperature of the electrode near heater 8 is low, cathode ray tube 2
When operated, it was impossible to forcibly cause discharge in the tube due to stray emissions emitted from the vicinity of the cathode 7 due to the rise in temperature of the cathode 7 during spot knocking.

The present invention provides a spot 7 knocking method that can eliminate these drawbacks and particularly improve the withstand voltage characteristics during operation.

The present invention will be explained below with reference to the drawings.

FIG. 2 is an electrical wiring diagram showing an embodiment of the cathode ray tube spot knocking method according to the present invention.

In the figure, parts corresponding to those in FIG. 1 are given corresponding symbols.

In this configuration, a voltage equal to or higher than the rated voltage is applied to the heater 8 from an external power source 12 AC power source.

At this time, the temperature of the cathode 7 rises, and thermionic electrons are emitted from the cathode 7 and impact the fluorescent surface 6, causing burnout of the fluorescent surface 6. Therefore, the first grid electrode 9 preferably receives a voltage of -100 to -250V. A voltage is applied from the DC power supply 13 to cut off the thermoelectrons from the cathode 7.

If spot knocking is performed under these conditions,
Since the electrode temperature near the cathode 7 and heater 8 is high, stray emissions are generated from the cathode powder adhering to the cathode 7 and heater 8, which causes an electric field on the anode 5 and the inner wall of the neck tube 14 around it. It is attracted and collides with the inner wall of the neck tube 14 near the cathode 7, the first grid electrode 9, the second grid electrode 10, and the focusing electrode 11, increasing the potential at that point, emitting a blue glow, and causing discharge inside the tube. let

Since this type of discharge has a large proportion of falling through the inner wall of the neck tube 14 to the cathode 7 and heater 8, particles such as cathode powder, which is the source of the above-mentioned stray emissions, can be removed by this discharge, making it possible to remove spotless emissions. The effect of the king becomes even greater.

FIG. 3 is an electrical wiring diagram showing another embodiment of the cathode ray tube spot knocking method according to the present invention.

In the figure, parts corresponding to those in FIGS. 1 and 2 are designated by corresponding symbols.

In configuration i, a negative voltage is also applied from the DC power supply 13 to the second grid electrode 10 in consideration of poor contact of the first grid electrode 9 and the like.

In addition, in order to lower the impedance of the focusing electrode 11 to the ground when a discharge occurs between the anode 5 and the focusing electrode 11, 1. Ground at the shortest distance with a thick conductor of Omrnφ or more.

In the above embodiment, the voltage applied to the heater 8 was the rated voltage or higher, but it may be 0.5 to 2 times the rated voltage, and the voltage applied to the anode 5 is equal to or higher than the rated voltage. A voltage 1 to 3 times that of

As described above, according to the present invention, spot knocking can be performed while the cathode ray tube is in a state close to its operating state without causing burnout of the fluorescent surface, that is, in a state where the electrode temperature near the cathode and heater is high. It is possible to forcibly cause discharge in the tube due to stray emissions emitted from the heater to occur during spot knocking, thus having the effect of greatly reducing this type of discharge in the tube that occurs during operation.

[Brief explanation of the drawing]

FIG. 1 is an electrical wiring diagram for implementing a conventional spot knocking method for a cathode ray tube. FIG. 2 is an electrical wiring diagram showing an embodiment of the spot knocking method according to the present invention. FIG. 3 is an electrical wiring diagram showing another embodiment of the spot knocking method according to the present invention. In the figure, corresponding parts in each figure are given corresponding symbols, 5 is an anode, 7 is a cathode, 8 is a heater, 9 is a first grid electrode, 10 is a second grid electrode, 11 is a focusing electrode, and 12 is an external power source.

Claims (1)

[Claims] 1. Between the heater 8 and the fluorescent surface 6, a cathode T and a grid electrode 9,
10, 11 and an anode 5, the cathode ray tube is provided with DC power supplies 1, 13 and an AC power supply 12, a positive voltage of the DC power source is applied to the anode, and a negative voltage of the DC power source is applied to the grid. A spot knocking method for a cathode ray tube, characterized in that an AC voltage is applied to an electrode and the cathode, and an AC voltage from the AC power source is applied to the heater. 2. The spot knocking method for a Br3 tube according to claim 1, wherein a plurality of the grid electrodes are provided between the electrode and the anode. 3. The DC power supply includes a first DC power supply 1 and a second DC power supply 13, the positive polarity voltage of the first DC power supply is applied to the anode, and the DC power supply closest to the cathode The grid electrode 9 has the first
A negative polarity voltage that is the sum of the voltage of the DC power source and the voltage of the second DC voltage is applied to the grid electrode 10.11 and the cathode T, and the negative voltage of the first DC power source is applied to the grid electrode 10.11 and the cathode T. applied. A method for spot-knocking a cathode ray tube according to claim 2. 4. The cathode ray tube includes a focusing electrode between the anode and the grid electrode, and the focusing electrode is grounded with low impedance. Spot-knocking method for cathode ray tubes described in .