JPH0329238A - High-voltage treatment of cathode-ray tube - Google Patents

Abstract

PURPOSE:To remove a needless electron generation source with good efficiency by impressing a magnetic field on a cathode-ray tube externally for making needless electrons to collide with a high-voltage electrode adjacent to the needless electron generation source. CONSTITUTION:Since field emission 33 emitted from a projection part 32 of a peripheral part of a hole 28 of a second grid 15 is deflected in the peripheral direction by a powerful magnetic field 34 to be impressed from outside to collide with an electrode part near a hole 29 of a third grid 14, the colliding point part is heated. At this time, the third grid 14 is melted to emit a large amount of metal gas. The emitted gas bombards field emission 33 accelerated to high speed to be separated into ions and electrons for being accelerated by a high electric field impressed between electrodes so as to make needless electrons 33 to again bombard the electrode for emitting more gas so that a process such as activation of BaO at the tip of a projection part 32 and high-voltage treatment may be repeated. Discharge is generated near the projection part 32 by repeating such a phenomen to consume big energy and to smooth the projection part.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a high voltage treatment method for cathode ray tubes, which is performed to improve the withstand voltage characteristics of cathode ray tubes. [Prior Art] Fig. 4 shows a partially cutaway side view of a general color cathode ray tube, and as shown in the figure, there are a panel part (+), a funnel part (2), and a neck part (3). The inner conductive film (5) and the outer conductive film (8) are formed on the inner and outer surfaces of the glass bulb (0), respectively. It extends to the inner surface of the neck part (3), and an electron gun assembly (9) is housed in the neck part (3), and an anode terminal (8) is installed in the funnel part (2). FIG. 5 shows an enlarged sectional view of the neck portion (3), and the electron gun assembly (8) housed in the neck portion (3) includes an anode (1l), a fifth grating ( 12), 4th lattice (13), 3rd
A grating (10), a second grating (l5), a first grating (1B), a cathode (l7), a bead glass (l8) that holds these electrodes together, a cup-shaped body (19), a bulb spacer (20 ).The above anode (1l)
and the fourth grid (l3) are electrically connected via the connector (21A), and the anode terminal (8) and the internal conductive film (5
), high pressure is applied from the outside through the substrate (20). Furthermore, the fifth lattice (l2) of letter L and the third lattice (14) are electrically connected via a connector (21B), and a lead wire 17 is attached to the stem (23) of the neck part (3). (
24) From the outside through? ．． 'A high JF is applied.
Similarly, the second case f-(15), the first grid (l6), and the cathode (17) are electrically connected through separate connectors (21C:), and are connected to the stem (23). A voltage is applied from the outside through the attached lead wire (24). - The operating voltage of the multi-step focus type electron gun assembly (9) as shown in L is 9 kV applied to the third grating (10) and several 100 V to the second grating (15). A voltage nearly twice as high as that of the pi-potential electron gun is applied between and the third grid (14). A cathode (17) is arranged at the bottom of the hole (27) of the first grid (l6), and cathode powder (25) is sprayed onto the tip of this cathode (l7).A heater is also installed inside the cando (17). (2B) is arranged. - In the configuration as shown in L, the heater (28
) and cathode (l7) and cathode powder (
25), thermoelectrons are emitted from the surface of the cathode powder (25), and the electron beam (30) penetrates the holes (27) of the first lattice (16) and the holes (28) of the second lattice (l5).
) and the third grid (10 holes (29)) and collides with the fluorescent screen (not shown) formed on the inner surface of the panel part (1). In the aging process, a voltage nearly twice the rated voltage is applied to the heater (26), so the temperature of the cathode (17) increases, and barium oxide (hereinafter referred to as BaO) is removed from the cathode powder (25). (31) is the first lattice (l6)
hole (27). Hole (28) of second grid (l5), third
It is deposited on the periphery of the holes (28) of the grid (14). on the other hand,
Since the holes (28) of the second lattice (15) are punched out using a press, protrusions (32) such as burrs and burrs are formed around the periphery of the holes (2B). This protrusion (32
) causes unnecessary electrons (33) to be emitted from its tip due to the electric field from the third grid (14) when the cathode ray tube is in operation. This unnecessary electron (33) is removed from the protrusion (32)
It is affected by the sharpness of the tip and the number of work in this part. The sharpness of the tip of the protrusion fs (32) is generally expressed by the magnitude of the electric field multiplication coefficient, and in the case of a cathode ray tube that is not subjected to high voltage processing, the value is about 500 to 800. Also,
The work number of the tip of the protrusion (32) is the second lattice (l5)
Since it is made of stainless steel, it is about 4.4 eV, but
By evaporating BaO(31) from the cathode (l7),
1. ? It has decreased to about eV. As mentioned above, the electric field multiplication factor is large and the characteristic function is small, so as determined from the Fowler-Narldheim relation, the unnecessary electrons (33) become large and cause the phosphor screen to emit light unnecessarily during the operation of the cathode ray tube. This caused problems such as: Further, the unnecessary electrons (33) are deflected to the center of the hole due to the electric field from the third lattice (14),
) hole (29), fourth lattice (13), fifth lattice (1
2), positive $4! (11) through the hole (not shown),
In order to reach fluorescence ++'ii (not shown) and emit light,
When adjusting the red, green, and blue cutoffs of color cathode ray tubes, in other words, when adjusting white balance, unnecessary light was emitted, reducing the quality of the cathode ray tube. In order to remove these unnecessary electrons (33), conventionally, by applying a high voltage of 20 to 50 kV between the second grating (l5) and the third grating (14), the protrusion (33), which is a source of unnecessary electrons, is applied. ), a high voltage processing method is adopted in which discharge is generated at the protrusion (32), and the protrusion (32), which is a source of non-yellow electrons, can be melted and vapor deposited and removed by the discharge at the protrusion (32). 'N' in this high voltage processing method. There are two mechanisms for interelectrode discharge /t=, as published in ``Transactions of the Institute of Electrical Engineers of Japan, Vol. 100, No. 9, by Koichi Tsuruta''. The first mechanism is cathode heating. In other words, as shown by the Fowler-Norldhei relational expression, the unnecessary FF element, or field emission, from one minute protrusion increases as an exponential times the magnitude of the electric field applied to the protrusion. When the voltage applied between them is increased, the field emission increases rapidly, generating Joule heat at the tip of the microprotrusion, which eventually melts the microprotrusion and generates a large amount of metal gas. This gas, field emission from the protrusion, and high electric field create a plasma state between the electrodes, causing a discharge and removing the microprotrusion. The second mechanism is anode heating. In other words, similar to the first mechanism, the field emission from the microprotrusions is accelerated by the applied voltage and collides with the anode with high energy, heating and melting the colliding part and producing a large amount of metal gas. is generated. As a result, similar to the first mechanism described above, an electric discharge occurs and the minute protrusion is removed. that's all. The difference between the $1 mechanism and the second mechanism is whether the cathode melts first or the anode melts first. By the way, the unnecessary electrons (33) generated from the projections (32) of the second lattice (l5) are transferred to the third lattice (15) as shown in FIG.
14) through the holes (29) of the phosphor screen or the fourth grid (13). It collides with the fifth grid (12) and the anode (11). Therefore, no discharge can be caused by heating the anode, and only the discharge caused by heating the cathode can be used.
The protrusion (32) had been removed. In particular, the cathode (l
If B a O (31) from 7) is affecting,
Even if the electric field multiplication factor is relatively small, that is, the protrusion (3
2) The tip is not very sharp (but unnecessary).
) becomes large, so that in the second mechanism of cathode heating, which uses Joule heat generated by the current flowing through sharp and narrow nodes, discharge is difficult to occur.
) was difficult to remove. [W1B to be solved by the invention] Since the conventional high-voltage treatment method for cathode ray tubes is configured as described above, discharge cannot be caused by anode heating, and discharge is caused only by cathode heating. When unnecessary electrons are emitted by barium oxide deposited from the cathode, it is difficult to remove the protrusions by generating an effective discharge at the protrusions that are the source of the unwanted electrons. This invention was made to solve the above-mentioned problems, and uses unnecessary electrons generated near the periphery of the holes in the second lattice to promote discharge at the source of unnecessary electrons, thereby eliminating the unnecessary electrons. The purpose of this study is to provide a high-voltage processing method for cathode ray tubes that can efficiently remove the source. [Means for Solving the Problems] A high voltage processing method for a cathode ray tube according to the present invention includes applying a high voltage of 2 to 8 times the rated high voltage between the low voltage electrodes, It is characterized by applying a magnetic field from the outside to cause unnecessary electrons to collide with a high voltage electrode adjacent to the source of unwanted electrons, thereby promoting discharge and removing the source of unwanted electrons. [Operation] According to the present invention, unnecessary electrons emitted from the vicinity of the periphery of the hole between the low voltage electrodes are deflected by an externally applied magnetic field and collided with the electrode adjacent to the source of unnecessary electrons, thereby preventing discharge. It is possible to melt and evaporate the source of unwanted electrons and remove them. [Embodiment of the Invention] An embodiment of the invention will be described below based on the drawings. FIG. 1 is an enlarged sectional view of the low voltage electrode portion of the electron gun assembly, schematically showing a high voltage processing method for a cathode ray tube according to an embodiment of the present invention. In the same figure, (14) to (1B), (2
5) to (32) are the same as the conventional example shown in FIG. 6, so the corresponding parts are given the same reference numerals and their explanation will be omitted. In FIG. 1, (34) is a magnetic field applied from the outside of the cathode ray tube, more specifically, from the outside of the bead glass (18) constituting the neck portion (3). The height is 1t to remove protrusions (32) such as holes and burrs formed on the periphery of the holes (28) of the second grid 05).
In the pressure treatment step, the cathode (17), the first grid (16), and the second grid (15) are short-circuited and grounded, and the third grid (1
A high voltage 2 to 8 times the rated operating voltage of the cathode ray tube is applied to 4), and a strong magnetic field (34) is applied from the outside in a direction perpendicular to the page and extending from the front to the back of the page. In such a configuration, the holes (28) of the second lattice (15)
) The field emission (33) emitted from the protrusion II (32) on the periphery is caused by a strong magnetic field (
34), as shown by the solid line in Figure 1, it is deflected in the outer circumferential direction and collides with the electrode part near the hole (28) of the third grid (10), thereby heating the collision point part.At this time,
Since the gas adsorbed on the outer surface of the third lattice (14) is heated to a higher temperature, the third lattice (l4) melts and releases a large amount of metal gas. The gas released in this way is separated into ions and electrons by impacting the field emission (33) which is accelerated at high speed, and these ions and electrons are accelerated by the high electric field applied between the electrodes. The process shown in Figure 2 of activating BaO at the tip of the protrusion (32) and high-pressure treatment is repeated, as the unnecessary electrons (33) impact the electrode again and release even more gas. ．． By repeating such a phenomenon, electric discharge occurs near the protrusion (32), and a large amount of energy is consumed, causing the protrusion (32
) is smoothed. Conventional discharge by cathode heating is effective when the electric field multiplication coefficient determined by the shape of the protrusion (32) is large, since its cross section is small, so Joule heat is easily generated, but the electric field multiplication coefficient is small and BaO ( 31) is attached and the work function is small, the cross-sectional area is large, so less Joule heat is generated, making it difficult to generate a discharge. However, according to the above configuration, the discharge is caused by anode heating. , a protrusion (32
) can be efficiently removed. The magnitude of the magnetic field (30) applied from outside the cathode ray tube is determined by the gap between the second grating (l5) and the third grating (10) being 01
Since it is narrow at ~1.0 gauss and the voltage applied during high voltage processing is as high as 30 to 50 kV, it needs to be large, and preferably 2000 gauss or more. In addition, since the field emission (33) emitted from the periphery of the hole (28) of the second grid (l5) tends to be deflected toward the center of the hole (28), it is necessary to apply it from the outside. It is necessary to bend the magnetic field (30) toward the outer circumference, so the direction of the magnetic field (30 is 3
It is desirable to change it by 60 degrees. As a specific means for this purpose, as shown in 3rd vlJ, four electrode stones (35) are placed at a phase angle of 90° on the outer periphery of the bead glass (l8) that houses and holds the electron gun assembly (9). A rotating magnetic field is applied using the four-pole electrode stones (35). Note that it is desirable that the frequency of this rotating magnetic field be relatively low. Furthermore, in the above embodiment, the high pressure treatment between the second grating (l5) and the third grating (l4) was explained, but the high pressure treatment between the first grating (1B) and the second grating (15) was explained. The same effect can be achieved when applied to [Effects of the Invention] As described above, according to the present invention, by applying a magnetic field from outside the cathode ray tube and performing high voltage treatment on the low voltage electrodes, discharge at the source of unnecessary electrons can be sufficiently promoted. As a result, unnecessary electron sources formed around the hole periphery of the low-voltage electrode can be efficiently removed.

[Brief explanation of drawings]

FIG. 1 is an enlarged sectional view of a low voltage electrode section schematically showing a high voltage processing method for a cathode ray tube according to an embodiment of the present invention, Is2
The figure is a schematic flow diagram showing the process of high-pressure processing phenomenon, Fig. 3 is a plan view of the main part schematically showing a high-voltage processing method according to another embodiment of the present invention, and Fig. 4 is a general cathode ray tube. 5 is an enlarged vertical sectional side view of the electron gun section of the cathode ray tube shown in FIG. 4, and FIG. 6 is an enlarged sectional view of the low voltage electrode section showing the conventional high voltage processing method for the cathode ray tube be. (9)...
・Electron gun structure, (10... third grating, (l5)...
Second lattice, (16)...First lattice, (l7)...Cathode, (18)...Bead glass, (27)-(2
9)...Grid pores, (31)...BaO. (32)
... Protrusion, (33) ... Unnecessary electron (field emission) (34) ... External magnetic field. Note that the same symbols in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) A cathode ray tube that generates a discharge at the source of unnecessary electrons by applying a high voltage 2 to 8 times the rated high voltage between low-voltage electrodes, and removes the source by melting and evaporating it. In the high voltage processing method described above, a magnetic field is applied from outside the cathode ray tube in parallel with the application of the high voltage described above to cause unnecessary electrons to collide with a high voltage electrode adjacent to the source of unwanted electrons, thereby promoting discharge. A high-voltage processing method for cathode ray tubes, characterized by removing unnecessary electron sources.