JPS598991B2 - color cathode ray tube device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color cathode ray tube device with improved convergence characteristics.

FIG. 1 shows a color cathode ray tube device to which the present invention is applied.

In the figure, 1 is a panel forming a part of the vacuum container, 2 is a fluorescent film formed on the inner surface of panel 1, and 3 is a shadow mask that functions as a color selection electrode, in which a large number of regular numbers L are formed. It is attached to a frame 4 made of a relatively thick metal plate to maintain its shape.
The frame 4 is held within the panel 1 by retainers 5.

Reference numeral 6 denotes a funnel that is joined to the panel 1 and forms a part of the vacuum vessel, and its shape is approximately cone-shaped.On the top side of this cone, there is a funnel that also forms a part of the vacuum vessel. A neck part T made of cylindrical glass is joined, and a compound electron gun 8 made of a set of a plurality of electron guns is installed inside the neck part T (the compound electron gun 8 is held in the neck part T). (Drawing of the mechanism is omitted) The present invention can be applied to any number or arrangement of the individual electron guns constituting the composite electron gun 8, as long as it consists of a set of a plurality of electron guns. But here, there are three electron guns Ba, 8b, and 8c.
A case will be explained in which the lines are lined up in a horizontal plane.

Now, the electron guns Ba, 8b, and 8c are lined up in a row in a horizontal plane, and among them, 8b is arranged to coincide with the central axis of the color cathode ray tube in question, that is, the central axis of the neck part 1. This is hereinafter referred to as the central electron gun 8b,
When the composite electron gun 8 is viewed from the side of the panel 1, the electron guns on the left and right sides of the center electron gun 8b are respectively called the left electron gun Ba.
This will be called the right electron gun 8c. During operation of this color cathode ray tube device, a deflection yoke 30, which is a magnetic device for deflecting an electron beam as will be described below, is attached near the connection point between the funnel 6 and the network portion 7.

The composite electron gun 8 includes a plurality of electron beams 20 (electron guns 8a,
8b, 8c respectively electron beams 20a, 20b
, 20c) toward the fluorescent film 2.
0a, 20b, and 20c are bent (deflected) by the magnetic field generated by the deflection yoke 30 and strike a desired location on the fluorescent film 2, causing it to emit light.

For this purpose, the deflection yoke 30 has a horizontal deflection magnetic field (consisting of substantially vertical magnetic flux) that deflects the electron beam 20 in a substantially horizontal plane and a vertical deflection magnetic field (consisting of substantially horizontal magnetic flux) that deflects the electron beam 20 in a substantially vertical plane. ) is generated in the part of the vacuum vessel through which the electron beam 20 passes, and the strength of the deflection magnetic field in each direction (density of magnetic flux)
It is configured so that it can be controlled.

In a color brown device for general television, the point of incidence of the electron beam 20 on the fluorescent film 2 is configured to scan the fluorescent film 2 almost evenly, and for this reason both horizontally and vertically. As is well known, the strength of the deflection magnetic field changes in the form of a sawtooth wave. Generally, the repetition frequency of this sawtooth wave is much higher in the horizontal deflection magnetic field than in the vertical deflection magnetic field.In the NTSC system, the former is 15.75 kHz, and the latter is 15.75 kHz. It is well known that the frequency is 60 hertz.

Now, in order for such a color cathode ray tube device to exhibit satisfactory performance, the plurality of electron beams 20a, 20b, 20c constituting the electron beam 20 must be connected to the phosphor film 2.
No matter which part of the top it is directed toward, it meets at one point on the fluorescent film 2. That is, it is necessary to obtain convergence, and therefore special attention is paid to the distribution of the deflection magnetic field generated by the polarization yoke 30, and in some cases, there may be a structure on the neck portion 7 for the sole purpose of convergence. It is common practice to include an auxiliary deflection device (not shown). When convergence is not perfect, it is called misconvergence, but even if a deflection device (deflection yoke 30 and the above-mentioned auxiliary deflection device) designed to generally have perfect convergence characteristics is used, this is often not possible for color cathode ray tubes. When it is attached to , a miss:1 error is observed.

One of these is misconvergence due to the eddy current of the getter device.

This will be explained below. In FIG. 1, reference numeral 9 denotes a getter device to be described below, including a spring 10 and an electron gun front substrate 1.
1 to the composite electron gun 8. The getter device 9 is a device for providing a metal film, generally called a getter film, which has gas adsorption properties mainly containing barium, on the inner wall of the funnel 6 of the cathode ray tube by vapor deposition.
Initially, it contains a large amount of barium, but this vapor deposition is carried out during the color cathode ray tube manufacturing process, generally after evacuation, by heating the getter device 9 from outside the vacuum chamber with high frequency. Although it is completely unnecessary after completion, it has no choice but to remain in the vacuum container, and as shown in Figure 2, a ring-shaped getter container 9A made of non-magnetic stainless steel and a It is made up of the included Getsuta 9B.

The reason why the Getsuta container 9A is ring-shaped is to make it easier for current to flow and the temperature to rise when high frequency heating is applied from the outside of the vacuum container. The barium to be deposited is in a stable state in the air, and nickel is used as an auxiliary material so that metallic barium can be easily obtained by heating. The ash-like substance remains after vapor deposition. Such a getter device 9
As shown in FIG. 1, the deflection yoke 30 is generally attached near the part where the deflection magnetic field is generated.

This is because this area is convenient for depositing the getter film as widely as possible on the inner surface of the funnel 6, and the getter device 9 also deposits the composite electron via the spring 10 and the electron gun front substrate 11. The gun connected to the gun 8 is used to exhaust air during the manufacturing process of color cathode ray tubes and deposit getters, and if it is discovered that the characteristics of the electron gun, etc. are defective, the electron gun is replaced with a new one. Generally, the getter device is replaced with a new one at the same time as the electron gun is replaced, as it is generally done to evacuate the getter again. . The getter device 9 is generally quite heavy, and since it is undesirable for it to shake inside the vacuum container in various ways, it is generally arranged so that it is at the bottom under normal operating conditions of the color cathode ray tube device. Furthermore, it is necessary to consider the convenience of external high-frequency heating during the process for the ring-shaped gettuta container 9A, and in the end, the funnel 6
Under normal operating conditions, it is placed approximately parallel to the wall at the center of the bottom edge. Now suppose that such a color cathode ray tube device is put into operation, for example, for television.

As is well known, in general television, effective scanning in the horizontal direction is performed when the fluorescent film 2 is observed through the panel 1.
The horizontal deflection is performed from the left end to the right end of the fluorescent film 2, and therefore the horizontal deflection magnetic field generated by the deflection yoke 30, and therefore the magnetic flux, has an approximately constant gradient (time change) from the downward maximum value to the upward maximum value during the effective scanning period. (the ratio of which is approximately constant) changes. The speed of this change is quite rapid, as can be estimated relatively easily from the horizontal scanning frequency of 15.75 kHz mentioned above. However, if the aforementioned ring-shaped getter device 9 is placed in a horizontal deflection magnetic field that changes rapidly over time, an oozing current will flow within the getter device as a result of this time change. This swirling current generates a new magnetic flux and therefore a magnetic field, which disturbs the magnetic field of the deflection yoke 30. Since this newly generated magnetic flux is generated in a direction that prevents the change in the horizontal deflection magnetic field of the deflection yoke mentioned above, during the effective scanning period, the getter device 9 consistently forms a ring shape as shown at 40 in FIG. (FIG. 3 shows the funnel 6 cut along a plane perpendicular to the tube axis and viewed from the side where the fluorescent film 2 was placed.)

). During the effective scanning period, as mentioned earlier, the horizontal deflection magnetic field changes at a substantially constant rate with respect to time. 40 is approximately constant. Therefore, if the electron beams 20 (20a, 20b, 20c) are deflected and reach the center of the lower side of the screen (phosphor film 2), that is, near where the getter device 9 is located, the influence of the disturbing magnetic flux 40 will be affected. 4, the center electron beam 20b is directed in the direction of arrow 21b, and the left electron beam 20a is directed in the direction of
The right electron beam 20c receives a force in the direction a and in the direction of the arrow 21c. (The observation direction in FIG. 4 is the same as in FIG. 3.) For this reason, when the fluorescent film 2 is observed from the front, a misconvergence pattern as shown in FIG. 5 occurs. That is, near the center of the lower side of the screen (phosphor film), as shown in FIG. 5, the horizontal line 23a drawn by the left electron beam 20a is shifted below the horizontal line 23c drawn by the right electron beam 20c.

Since the figure drawn by the central electron beam 20b is located between the figures drawn by the electron guns on both sides, it is omitted from the figure. In this case, the vertical lines are also slightly affected, but as is clear from Figure 4, the horizontal components of the arrows 21a, 21b, and 21c are almost the same, so the lines are only slightly bent at the problem part, and this is considered a convergence shift. The effect can be almost ignored. In order to eliminate such misconvergence, the present invention proposes a method of arranging a suitable magnet near the getter device 9 in view of the above-mentioned circumstances in which it occurs.

FIG. 6 shows an embodiment of the present invention.

In the figure, 50 is a permanent magnet, and generally the funnel 6
The getter device 9 provided on the outer wall near the getter device 9 has a substantially plate-like shape and is magnetized in the direction of the thickness of the plate. This permanent magnet 50 is arranged with respect to the getter device 9 as shown in FIG. (The observation direction in FIG. 7 is the same as in FIG. 3.
However, in order to show the relationship between the getter device 9 and the permanent magnet 50, unnecessary parts such as the funnel 6 are omitted from the diagram. That is, it is magnetized so that the north pole is on the upper side and the south pole is on the opposite side. Therefore, the magnetic flux generated by the permanent magnet passes through the getter device 9 from bottom to top, as shown at 41 in FIG. This is due to the disturbance magnetic flux 4 caused by the eddy current of the getter device 9 mentioned earlier.
Since it is completely opposite to 0, if the size of the magnet, strength of magnetization, etc. are appropriately selected, it is possible to almost cancel out the disturbing magnetic flux 40, and the above-mentioned inconvenient misconvergence can be eliminated.
In short, the present invention provides a permanent magnetic flux near the getter device 9 in order to cancel the effective influence of the stray magnetic flux 40, and its position does not necessarily have to coincide with the getter device 9; It doesn't matter if it's off. Further, the permanent magnet 50 may be attached to the funnel 6, or the inner surface of the deflection yoke 30, or the position may be adjusted. In order for the permanent magnet itself not to disturb the original magnetic field generated by the deflection yoke 30, its relative magnetic permeability is preferably close to 1, so as not to damage the funnel 6 made of glass and the insulating layer of the winding of the deflection yoke 30. For this purpose, a rubber or plastic material mixed with ferrite magnetic material is suitable. Although the above explanation has been made using an example in which the electron guns are arranged in a horizontal line, the application is not limited to this.

Further, the number of individual electron guns constituting the composite electron gun 8 is not limited to three, and two or four or more can be used.
Further, the getter device 9 does not necessarily have to be connected and held on the side of the composite electron gun 20, but may be connected and held on the shadow mask 3, therefore, the frame 4, etc. as the case may be.

[Brief explanation of drawings]

1 and 2 are block diagrams showing a color cathode ray tube device to which the present invention is applied, FIG. 3 is an explanatory diagram illustrating the occurrence of the same undesirable turbulent magnetic flux in a conventional color cathode ray tube device, and FIG. Figure 5 is an explanatory diagram explaining how an electron beam is unfavorably bent by turbulent magnetic flux, Figure 5 is a characteristic diagram showing the pattern of misconvergence caused by turbulent magnetic flux, and Figures 6 and 7 are from the book. FIG. 1 is a configuration diagram showing an embodiment of the invention. 1 is the panel, 2 is the fluorescent film, 3 is the shadow mask, 4 is the frame, 5 is the holding part, 6 is the funnel, 7 is the neck part,
8 is a composite electron gun, 8a is a left electron gun, 8c is a right electron gun, 8b is a center electron gun, 9 is a getter device, 9a is a getter container, 9b is a getter ash, 10 is a spring, 11 is the front part of the electron gun substrate, 20 is an electron beam, 20a is a left electron beam, 2
0c is the right electron beam, 20b is the center electron beam, 30
is the deflection yoke, 40 is the disturbing magnetic flux, 41 is the magnetic flux, 50
is a permanent magnet.

Claims (1)

[Scope of Claims] 1. A panel, a funnel, a neck portion, an electron gun housed in the neck portion that emits an electron beam, a deflection yoke attached near a connection point between the funnel and the neck portion, and the funnel. a getter device installed in the area within the influence of the magnetic flux generated by the deflection yoke; A color cathode ray tube device characterized in that the funnel is provided with a magnet that generates magnetic flux that substantially cancels out the influence of magnetic flux. 2. The color cathode ray tube device according to claim 1, characterized in that the permanent magnet is located near the getter device. 3. A color cathode ray tube device according to claim 1, characterized in that the permanent magnet has a plate shape arranged substantially parallel to the funnel wall and is magnetized in the direction of the thickness of the plate. 4. The collar according to claim 1 or 3, characterized in that the getter device is provided at the center of the lower side of the funnel, and the permanent magnet is magnetized so that the side facing the funnel becomes the north pole. CRT device. 5. The color cathode ray tube device according to claim 1, wherein the permanent magnet is made of a rubber or plastic material mixed with a magnetic material.