JP2000253427A - Method for inspecting deflection yoke - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a deflection yoke inspection method capable of preventing the generation of surface burning in a television(TV) set in the case of repeating characteristics tests of plural deflection yokes by using an inspecting TV set. SOLUTION: After ending a characteristic test of a deflection yoke 7 attached to a TV set 1, degauss circuit 15 for the TV set 1 is driven. After drawing out a drive cable 9 in the TV set 1 from a drive circuit 11, the yoke 7 is detached from the TV set 1 and a succeeding deflection yoke 7' is attached to the TV set 1. Then the drive cable 9 for the TV set 1 is inserted into the drive circuit 11 and a characteristic test of the yoke 7' attached to the TV set 1 is executed in a state stopping the operation of the circuit 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of inspecting a deflection yoke of a cathode ray tube, and more particularly to a method of inspecting a deflection yoke by sequentially attaching a deflection yoke to an inspection television set and repeating a characteristic test of each deflection yoke. .

[0002]

2. Description of the Related Art When inspecting a deflection yoke provided in a cathode ray tube, a characteristic test of each deflection yoke is performed using a television set for inspection. In this case, first, after attaching the deflection yoke to the neck of the TV set for inspection,
A drive cable of the television set extended from the electron gun at the rear end of the neck portion is connected to a drive circuit. Next, by applying an anode voltage of about 27 kV to the phosphor screen of the television set, the thermoelectrons emitted from the cathode of the electron gun were irradiated as electron beams to the phosphor screen, and the thermoset was attached to the television set in this state. A characteristic test of the deflection yoke is performed. Next, with the application of the anode voltage to the phosphor screen of the television set stopped, the drive cable is removed from the drive circuit, and the deflection yoke subjected to the characteristic test is removed from the television set. Thereafter, a deflection yoke for performing a characteristic test is attached to the television set, and a characteristic test for the next deflection yoke is performed in the same manner.

As described above, in the deflection yoke inspection method in which the characteristic test of a plurality of deflection yokes is repeatedly performed using the television set, the drive cable of the television set is disconnected from the drive circuit while the deflection yoke is being replaced, and the electronic circuit is removed. The cathode portion of the gun cannot be heated by the heater. For this reason, the television set for inspection has a configuration in which an external power supply is connected to the heater for heating the cathode from the cone side so that the cathode can be constantly heated. When performing the inspection, the cathode is constantly heated to emit thermoelectrons, and the anode voltage is applied to the phosphor screen so that the phosphor screen is immediately irradiated with the electron beam. , To improve the efficiency of inspection.

[0004]

However, such a method of inspecting a deflection yoke has the following problems. That is, when performing the characteristic test of the deflection yoke, an anode voltage of about 27 kV is applied to the phosphor screen of the television set. The surface potential does not immediately become 0 kV. Moreover, since the cathode is constantly heated, thermoelectrons are emitted from the cathode even after the end of the characteristic test, and the thermoelectrons are emitted as an electron beam to the phosphor screen where the anode potential is maintained. Become. At this time, since the drive cable of the television set is pulled out of the drive circuit to replace the deflection yoke, the electron beam cannot be deflected on the phosphor screen. Therefore, the electron beam is irradiated on the phosphor screen in a stationary state, and the phosphor screen is burnt.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a deflection yoke inspection method capable of preventing surface burn of a television set when a characteristic test of a plurality of deflection yokes is repeatedly performed using an inspection television set. I do.

[0006]

A method of inspecting a deflection yoke according to a first aspect of the present invention for achieving the above object is characterized in that the method is performed as follows. First, after the characteristic test of the deflection yoke attached to the television set is completed, the Digauss circuit of the television set is operated. Next, with the drive cable of the television set disconnected from the drive circuit, the deflection yoke is removed from the television set, and the next deflection yoke is attached to the television set. Thereafter, a characteristic test of the deflection yoke attached to the television set is performed with the drive cable of the television set plugged into a drive circuit and the operation of the Digauss circuit stopped.

In such a deflection yoke inspection method, after the deflection yoke characteristic test is completed, the drive cable of the television set is removed from the drive circuit while the digauss circuit is operated. Therefore, even if the phosphor screen is irradiated with an electron beam from the electron gun of the television set while the operation of the drive circuit is stopped,
This electron beam is scanned on the phosphor screen by the operation of the Digauss circuit. Therefore, the electron beam does not stop on the phosphor screen.

A method for inspecting a deflection yoke according to a second aspect is characterized in that the method is performed as follows. First,
After the characteristic test of the deflection yoke attached to the television set is completed, the application of the anode voltage to the phosphor screen of the television set is stopped, and the heating of the cathode of the television set is stopped. Next, the deflection yoke is removed from the television set, and the next deflection yoke is attached to the television set. After the anode potential of the phosphor screen decreases, the cathode is reheated. Then, after the cathode is reheated, a characteristic test of a deflection yoke attached to the television set is performed while an anode voltage is applied to the phosphor screen of the television set.

In such a method of inspecting the deflection yoke, after the end of the characteristic test of the deflection yoke, the application of the anode voltage to the phosphor screen is stopped until the anode potential of the phosphor screen is reduced. The heating is stopped and emission of thermoelectrons is interrupted. In addition, even if thermal electrons are emitted from the cathode by reheating, the emitted thermal electrons are irradiated to the fluorescent screen as an electron beam because the anode potential of the fluorescent screen is in a reduced state. There is no. In addition, since the cathode is reheated and thermionic electrons are emitted after the anode potential of the phosphor screen is reduced, the anode is connected to the phosphor screen when performing the next characteristic test of the deflection yoke. By applying a voltage, the thermoelectrons are immediately irradiated on the phosphor screen as an electron beam.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a deflection yoke inspection method to which the present invention is applied will be described below in detail with reference to the drawings.

(First Embodiment) FIG. 1 is a schematic configuration diagram for explaining a deflection yoke inspection method according to a first embodiment of the present invention. First, as shown in FIG. 1A, a television set 1 for inspection is prepared. The television set 1 includes a heater for heating a cathode of an electron gun (not shown) provided at a rear end of a neck 3 and a cone 5.
An external power supply (not shown) is connected from the side, and the cathode is always heated by the external power supply.

Next, a deflection yoke 7 is attached to the neck 3 of the television set 1. At this time, with the drive cable 9 extended from the rear end of the neck portion 3 of the television set 1 pulled out from the drive circuit 11, the deflection yoke 7 is attached to the neck portion 3, and then the drive cable 9 is connected to the drive circuit 11. Insert and connect.

Next, with the operation of the Digauss circuit 15 connected to the Digauss coil 13 provided on the outer periphery of the cone 5 stopped, the flyback transformer (hereinafter, referred to as “thereby”) is applied to the fluorescent screen 17 of the television set 1. FBT) 19
From about 27 kV. As a result, the thermoelectrons emitted from the cathode in the heated state are irradiated on the phosphor screen 17 as an electron beam.

By operating the drive circuit 11 in such a state, the electron beam emitted from the electron gun to the fluorescent screen 17 is scanned in a predetermined state, and the characteristic test of the deflection yoke 7 attached to the television set 1 is performed. Do.

After the characteristic test of the deflection yoke 7 is performed as described above, as shown in FIG. 1 (2), the digauss circuit 15 connected to the digauss coil 13 is operated, and the FBT 19 and the fluorescent screen 17 are connected. The application of the anode voltage to is stopped.

In such a state, the drive cable 9 of the television set 1 is removed from the drive circuit 11, and the deflection yoke 7 on which the characteristic test has been performed is removed from the neck 3 of the television set 1.

Thereafter, the drive cable 9 is inserted into the deflection yoke 7 ′ for performing a characteristic test, and the deflection yoke 7 ′ is attached to the neck 3. Then, as shown in FIG. 1A, the drive cable 9 is connected to the drive circuit 11, and the deflection yoke 7 'is attached to the television set 1.

Next, the operation of the Digauss circuit 15 is stopped, and an anode voltage is applied from the FBT 19 to the fluorescent screen 17. As a result, the thermoelectrons emitted from the constantly heated cathode are converted into electron beams as the fluorescent screen 1.
7 is irradiated.

Thereafter, in the same manner as described above, a characteristic test of the deflection yoke 7 'attached to the television set 1 is performed, and the same steps are repeated thereafter. Thus, the deflection yoke is inspected by repeating the characteristic test of the plurality of deflection yokes 7, 7 'using the inspection television set.

In such a deflection yoke inspection method, after the characteristic test of the deflection yoke 7 is completed, the drive cable 9 is pulled out of the drive circuit 11 while the digauss circuit 15 is operated. For this reason, after the characteristic test is completed, even if the scanning of the electron beam by the drive circuit 11 becomes impossible, the electron beam is scanned on the fluorescent screen 17 by the operation of the digaussian circuit 15. Therefore, even after the characteristic test is completed, even if the thermoelectrons emitted from the cathode which is always in a heated state are irradiated on the phosphor screen 17 as an electron beam, the electron beam is scanned on the phosphor screen 17 by the operation of the Digauss circuit 15. Will be done. As a result, the electron beam does not stop on the phosphor screen 17 and the burning of the phosphor screen 17 can be prevented. In addition, it is possible to prevent exchange loss of the television set for inspection, and to implement the television set at low cost.

(Second Embodiment) FIG. 2 is a schematic structural view for explaining a deflection yoke inspection method according to a second embodiment of the present invention. Note that the same components as those described in the first embodiment are denoted by the same reference numerals and will be described.

First, as shown in FIG. 2A, a television set 1 for inspection is prepared. The television set 1 has a configuration in which an external power supply 21 is connected from the cone 5 side to a heater for heating a cathode of an electron gun (not shown) provided at the rear end of the neck portion 3. The external power source 21 is provided with a switch 23, and the external power source 2 is operated by a timer.
The cathode is heated by ON / OFF of 1. In this case, the cathode is heated by turning on the external power supply 21.

Next, a deflection yoke 7 is attached to the neck 3 of the television set 1. The deflection yoke 7 is attached in the same manner as described in the first embodiment.

Thereafter, an anode voltage of about 27 kV is applied to the fluorescent screen 17 of the television set 1 from an FBT (not shown). As a result, the thermoelectrons emitted from the cathode in the heated state are irradiated on the phosphor screen 17 as an electron beam.

By operating a drive circuit (not shown) in such a state, the electron beam is scanned on the fluorescent screen 17 in a predetermined state, and a characteristic test of the deflection yoke 7 attached to the television set 1 is performed.

After the characteristic test of the deflection yoke 7 is performed as described above, as shown in FIG. 2B, the application of the anode voltage from the FBT to the phosphor screen 17 is stopped, 21 is turned off to stop heating the cathode of the television set 1.

In such a state, the deflection yoke 7 subjected to the characteristic test is removed from the neck 3 of the television set 1.
Removal of the deflection yoke 7 is performed in the same manner as described in the first embodiment.

After that, the deflection yoke 7 ′ for performing the characteristic test is inserted into the neck 3 from the drive cable 9. Then, as shown in FIG. 2A, the deflection yoke 7 'is attached to the television set 1.

After a predetermined time has elapsed since the application of the anode voltage from the FBT to the phosphor screen 17 is stopped, the external power supply 21 is turned on and the cathode of the television set 1 is reheated. Here, when the external power supply 21 is turned on again and the cathode is reheated, the anode potential of the phosphor screen 17 is sufficient such that thermoelectrons emitted from the cathode are not irradiated to the phosphor screen 17 as an electron beam. At the time when the time has elapsed. Phosphor screen 17
The time for reheating the cathode after stopping application of the anode voltage to the cathode is determined in advance by data collection.

Next, after the cathode is reheated, the FBT
, An anode voltage is applied to the fluorescent screen 17. As a result, the thermoelectrons emitted from the heated cathode are irradiated on the phosphor screen 17 as electron beams. Thereafter, a characteristic test of the deflection yoke 7 'attached to the television set 1 is performed in the same manner as described above, and the same steps are repeated thereafter. Thus, the deflection yoke is inspected by repeating the characteristic test of the plurality of deflection yokes 7, 7 'using the inspection television set 1.

In such a deflection yoke inspection method, after the end of the characteristic test of the deflection yoke 7, the period from when the application of the anode voltage to the phosphor screen 17 is stopped to the time when the anode potential of the phosphor screen 17 decreases is reduced. Then, the heating of the cathode is stopped, and the emission of thermionic electrons is stopped. Further, even if thermoelectrons are emitted from the cathode by reheating, the phosphor screen 1
7 is in a state in which the anode potential is lowered, the emitted thermoelectrons are converted into an electron beam to the fluorescent screen 17 until an anode voltage is applied to the fluorescent screen 17 for the next characteristic test of the deflection yoke 7 '. Is not irradiated. For this reason, even if the drive cable is pulled out of the drive circuit during the repetition of the characteristic test and scanning of the electron beam by the drive circuit becomes impossible, the electron beam is not irradiated on the phosphor screen 17 during this time. . As a result, surface burning of the fluorescent screen 17 can be prevented. Moreover, after the anode potential of the phosphor screen is lowered, the cathode is reheated and thermions are emitted, so that when the next characteristic test of the deflection yoke 7 'is performed, the phosphor screen is 1
By applying the anode voltage to 7, the thermoelectrons are immediately irradiated on the phosphor screen 17 as an electron beam. Therefore, the inspection efficiency does not decrease. Further, it is possible to prevent the exchange loss of the television set for inspection, and to implement the system at low cost.

The first embodiment and the second embodiment described above can be implemented in combination.
When combined, the same effects as in the first embodiment and the second embodiment can be obtained.

[0033]

As described above, according to the deflection yoke inspection method according to the first aspect of the present invention, after the deflection yoke characteristic test is completed, the drive cable of the television set is driven with the Degauss circuit operated. With the configuration in which the deflection yoke is replaced by being extracted from the circuit, the electron beam can be scanned on the phosphor screen even when the deflection yoke is replaced. As a result, when the characteristic inspection of the deflection yoke is repeatedly performed, the electron beam does not stop on the phosphor screen, and the burn-in of the phosphor screen can be prevented.

According to the deflection yoke inspection method of the present invention, after the end of the characteristic test of the deflection yoke, the application of the anode voltage to the phosphor screen is stopped until the anode potential of the phosphor screen decreases. During this time, the configuration in which the heating of the cathode is stopped can prevent the phosphor screen from being irradiated with the electron beam until the anode voltage is applied to the phosphor screen for the next characteristic test of the deflection yoke. Therefore, it is possible to prevent the surface of the fluorescent screen from being burnt between the characteristic tests. In addition, since the cathode is reheated after the anode potential of the phosphor screen has dropped, the electron beam is immediately irradiated to the phosphor screen when the next deflection yoke characteristic test is performed. Can be maintained.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a deflection yoke inspection method according to a first embodiment to which claim 1 is applied;

FIG. 2 is a view for explaining a deflection yoke inspection method according to a second embodiment to which claim 2 is applied;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Television set, 7, 7 '... Deflection yoke, 9 ... Drive cable, 11 ... Drive circuit, 15 ... Digauss circuit, 17 ... Phosphor screen

Claims (2)

[Claims] A step of activating a degauss circuit of the television set after a characteristic test of the deflection yoke attached to the television set is completed; and a step of disconnecting a drive cable of the television set from the drive circuit. Is removed from the television set, and the next deflection yoke is attached to the television set.The drive cable of the television set is inserted into a drive circuit, and the operation of the Digauss circuit is stopped, and the television set is attached to the television set. Performing a characteristic test of the deflection yoke provided. 2. After the characteristic test of the deflection yoke attached to the television set is completed, stopping the application of the anode voltage to the phosphor screen of the television set and stopping the heating of the cathode of the television set. Removing the deflection yoke from the television set and attaching the next deflection yoke to the television set; reheating the cathode after the anode potential of the phosphor screen has decreased; and reheating the cathode. Performing a characteristic test of a deflection yoke attached to the television set while applying an anode voltage to the phosphor screen of the television set.