JPH0818989A - Chassis for cathode-ray tube - Google Patents

Abstract

PURPOSE:To provide a chassis for cathode-ray tube capable of performing magnetic shielding even when a magnetic field such as geomagnetism. etc., from the outside is applied to the cathode-ray tube, preventing color slippage from occurring by preventing the incorrect landing of an electron beam and further easily designing an internal magnetic shielding member and a chassis member. CONSTITUTION:The chassis 20 is formed by covering the cathode-ray tube except for a screen part 1d, and it is constituted of a chasis front part 21 and a chassis remaining part 22. The chassis front part 21 is constituted of a cold- rolled steel plate of magnetic material, and covers the internal magnetic shielding member 7 up to an opening plane 93 on the electron gun side, and the chassis remaining part 22 is made of aluminum that is a nonmagnetic material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chassis for covering a cathode ray tube (CRT) used in TVs and the like.

[0002]

2. Description of the Related Art In a three-electron beam type color cathode ray tube having a built-in color selection electrode, the deviation of the orbit of the electron beam under the influence of an external magnetic field such as the earth's magnetism is called mislanding. It is known that an undesired result such as color misregistration is caused by causing an undesired phosphor to emit light with a change in the orbit. In order to remove the influence of such an external magnetic field, it is known that an internal magnetic shield member is internally provided so as to surround the electron beam from the color selection electrode along the funnel.

Next, an example of such a color cathode ray tube device will be described with reference to FIG. FIG. 9 is a cross-sectional configuration diagram of a cathode ray tube device including the above-described conventional color cathode ray tube and a chassis that covers the cathode ray tube. In the figure, the tube body is a screen portion 1d provided with a phosphor screen 3 and a skirt continuous with the screen portion 1d. It is composed of a panel composed of the portion 1c, a neck 1a and a funnel 1b. An electron gun 2 is arranged in the neck 1a. 3 is a fluorescent screen, usually
Phosphors that emit red, green, and blue are applied in a mosaic pattern on the inner surface of the screen portion 1d of the panel. Reference numeral 4 denotes a color selection electrode, which is arranged so as to face the phosphor screen 3 and has electron beam 8 passage holes formed in a predetermined arrangement. Reference numeral 5 is a frame, and 7 is a magnetic shield member called an internal magnetic shield (hereinafter abbreviated as IMS). The peripheral portion is fixed to the side of the frame 5 facing the electron gun 2 by welding or the like.
Denoted at 8 is an electron beam, which is deflected by a deflection yoke 9 at a deflection center 91.
The electron beam 8 passing through the electron beam passage hole of the color selection electrode 4 is deflected and scanned through and strikes the phosphor screen 3 to selectively cause the phosphor to emit light. 11 is a screen portion 1d of the panel
A box-shaped chassis that has a top, side, bottom, and rear that covers the cathode ray tube except that the rear of the box is open with ventilation holes, and is made of a magnetic material such as cold-rolled steel plate. It covers the entire cathode ray tube. 12 is an explosion-proof band made of a magnetic material of a cathode ray tube, Z is the tube axis direction, and Y is the minor axis direction perpendicular to Z.

Next, the operation of the above configuration will be described.
The electron beam 8 emitted from the electron gun 2 receives the deflection yoke 9
Is deflected and scanned through the deflection center 91, and the electron beam 8 passing through the electron beam passage hole of the color selection electrode 4 impinges on the phosphor screen 3 to selectively emit the phosphor on the phosphor screen 3. . At this time, if the cathode ray tube is placed in an environmental magnetic field such as geomagnetism, the flight trajectory of the electron beam 8 is bent and the landing point of the electron beam is displaced. The IMS member 7 is provided in order to eliminate the influence of such an environmental magnetic field. That is, in the cathode ray tube covered with the IMS member 7, the environmental magnetic field is weakened by the magnetic shielding,
The bending of the flight trajectory of the electron beam 8 is reduced, and the deviation of the incident position of the electron beam 8 on the fluorescent screen 3 is reduced. In addition, the publication {NIKKEI ELECTRONICS 1987.1.12 (n
(o412) p.174-184} further shows an example in which the entire cathode ray tube device is covered with a cover made of Permalloy.

[0005]

However, in practical use of the cathode ray tube, a chassis made of a magnetic material as shown in FIG. 9 is required, and the presence of the chassis affects the magnetic shielding effect of the IMS. The problem is that the distribution of the magnetic field in the IMS changes, the flight trajectory of the electron beam is bent, and the amount of mislanding increases, so that the IMS member needs to be designed in consideration of the influence of the chassis and becomes very complicated. . Further, the adjustment of the landing and the like of the cathode ray tube is performed only by the cathode ray tube, and the cathode ray tube is assembled into the chassis after the adjustment, so that there is a problem that readjustment is required after the assembly.

Next, in the conventional cathode ray tube chassis, the influence of the chassis on the magnetic shielding effect of the IMS will be described. The conventional cathode ray tube chassis shown in FIG. 9 is a box made of a magnetic material such as a cold-rolled steel plate, and the rear of the box is open with ventilation holes or the like. As linear, the relative permeability of the frame, explosion-proof band and deflection yoke (μ
r) is 150, 1500 and 250, respectively, and the relative magnetic permeability (μr) of the magnetic material of the chassis is 1 (without chassis), 200 or 2000. Under the magnetic field analysis conditions using the combination of the indicated IMS and the relative magnetic permeability of the color selection electrode, 0.4O as a geomagnetism from the outside
The magnetic field strength on the beam orbit and the magnetic field component perpendicular to the beam orbit when a magnetic field of the magnitude of e acts in the tube axis direction of the cathode ray tube were obtained by two-dimensional magnetic field analysis by the finite element method.

[0007]

[Table 1]

The results are shown in FIGS. 10 and 12 are characteristics showing the relationship between the tube axial direction distance from the deflection center and the magnetic field intensity on the orbit when the relative magnetic permeability (μr) of the IMS member of the conventional cathode ray tube device is 1000 and 20000, respectively. FIG. 11 and FIG. 13 show the relative permeability (μr) of the IMS member of the conventional cathode ray tube device of 100, respectively.
FIG. 9 is a characteristic diagram showing the relationship between the tube axis direction distance from the deflection center and the magnetic field component perpendicular to the trajectory in the cases of 0 and 20000. Further, in the figure, a circle indicates a case without a chassis and only a cathode ray tube, a circle indicates a chassis and a relative magnetic permeability of the magnetic material is 200, and a triangle indicates a chassis and the magnetic material. This is the case where the relative magnetic permeability of is 2000. Figure 10
As shown in Fig. 13, the higher the relative permeability of the chassis, the lower the magnetic field strength on the beam orbit. However, since the chassis acts so as to draw in the magnetic flux, it is perpendicular to the beam orbit. Conversely, the magnetic field component is increasing. Therefore, as shown in FIG. 14, the mislanding amount of the beam is increased in the presence of the chassis as compared with the case of only the cathode ray tube (μr = 1). Note that FIG. 14 shows an IM of a conventional cathode ray tube device under the chassis of each of the above relative magnetic permeability.
FIG. 9 is a characteristic diagram showing the amount of mislanding due to the relative magnetic permeability of S. In the figure, ○, ● and Δ marks are the same as above. Thus, it is understood that the conventional cathode ray tube chassis adversely affects the magnetic shielding effect. Further, when covering the entire cathode ray tube with a cover made of permalloy, it is not practical because permalloy is difficult to handle, requires a material more expensive than the main body, and has a complicated structure.

The present invention has been made in order to solve the above problems. Even when a magnetic field such as terrestrial magnetism is applied to the cathode ray tube from the outside, magnetic shielding is possible, a landing mistake of the electron beam is prevented, and the color is prevented. It is an object of the present invention to obtain a chassis for a cathode ray tube which can prevent the deviation and can easily design the IMS member and the chassis member.

[0010]

A cathode ray tube chassis according to claim 1 covers the cathode ray tube by opening a screen portion and covers the IMS so as not to cross a plane including a deflection center and perpendicular to the axis of the cathode ray tube. It is composed of a chassis front part made of a magnetic material and a chassis remaining part made of a non-magnetic material.

In the cathode ray tube chassis according to a second aspect of the present invention, the chassis front portion covers the IMS up to the electron gun side opening surface of the IMS.

In the cathode ray tube chassis according to a third aspect of the present invention, the screen portion is opened to cover the cathode ray tube, and the IMS does not exceed a plane including the deflection center and perpendicular to the axis of the cathode ray tube.
And a chassis front part made of a magnetic material and at least a part of the chassis front part side which is a non-magnetic material.

In the cathode ray tube chassis of the fourth aspect, the screen portion is opened, and the cathode ray tube is covered with a box body having an upper surface, a side surface, a bottom surface and a rear surface.

In the cathode ray tube chassis of the fifth aspect, the nonmagnetic material is made of a nonmagnetic material of aluminum, copper or stainless steel.

According to a sixth aspect of the present invention, in the chassis for a cathode ray tube, the non-magnetic material is a clad material made of a non-magnetic material such as aluminum, copper or stainless steel and a magnetic material.

In the cathode ray tube chassis according to claim 7, the nonmagnetic material is a hole.

[0017]

According to the invention of claim 1, since the front portion of the chassis covering the IMS so as not to cross the plane including the deflection center and perpendicular to the axis of the cathode ray tube is a magnetic body and the rest is a non-magnetic body, the magnetic flux is You can prevent the phenomenon of pulling in,
Even if a magnetic field such as terrestrial magnetism acts on the cathode ray tube from the outside, IM
The change of the magnetic field distribution in S can be prevented, the cathode ray tube can be covered without impairing the magnetic shielding effect of the IMS, the landing mistake of the electron beam can be prevented, and the color shift can be prevented. Since the electron beam is parallel to the cathode ray tube axis from the electron gun to the deflection center with respect to the magnetic field in the cathode ray tube axis direction, the electron beam is not affected by the magnetic field, and the electron beam is emitted from the deflection center to the phosphor screen at the cathode ray line. Since it has an angle with the tube axis and is affected by a magnetic field, the magnetic shielding effect of the chassis front is effective up to a plane including the deflection center and perpendicular to the cathode ray tube axis. When the front part of the chassis exceeds the plane including the deflection center and perpendicular to the cathode ray tube axis, the action of drawing the magnetic field in the cathode ray tube axis direction into the chassis becomes too strong, and the magnetic field distribution in the IMS changes, resulting in the magnetic shielding effect of the IMS. Since the magnetic field component perpendicular to the orbit of the electron beam increases, the adverse effect of increasing the mislanding amount of the electron beam occurs. Also, if the front of the chassis does not cover the IMS, IM
Since the front end of the chassis is present on S,
There is an adverse effect that the magnetic shielding effect of the IMS is impaired due to the end effect that magnetic flux concentrates on the end of the magnetic body.

In the invention of claim 2, since the front part of the chassis covers the IMS up to the electron gun side opening surface of the IMS, there is no magnetic substance outside from the deflection center to the electron gun side opening surface of the IMS. Since magnetic flux is not drawn in as in the case without a chassis, the magnetic field component perpendicular to the electron beam orbit does not increase even if a magnetic field such as the earth's magnetic field acts on the cathode ray tube, preventing electron beam landing mistakes. The color deviation can be prevented, and since the magnetic material portion of the chassis is sufficiently separated from the deflection yoke, it does not affect the magnetic field distribution of the deflection yoke.

In the invention of claim 3, the IMS is arranged so as not to exceed a plane including a deflection center and perpendicular to the cathode ray tube axis.
Since the front part of the chassis that covers the chassis is magnetic and at least a part of the remaining part on the front side of the chassis is non-magnetic, the front part of the chassis and the remaining part are magnetically shielded from each other. It is possible to prevent the phenomenon that the magnetic susceptibility decreases and the magnetic flux is drawn into the chassis, and even if a magnetic field such as the earth's magnetism acts on the cathode ray tube from the outside, it is possible to prevent the change of the magnetic field distribution in the IMS and the magnetic shielding effect of the IMS. It is possible to coat the cathode ray tube without damaging it, prevent landing mistakes of the electron beam, and prevent color misregistration.

In the invention of claim 4, the cover is formed by a box body having an upper surface, a side surface, a bottom surface and a rear surface with the screen portion opened, so that the stability of the chassis is improved.

In the invention of claim 5, since the non-magnetic material is made of any non-magnetic material such as aluminum, copper and stainless steel, the cost is low.

In the invention of claim 6, since the non-magnetic material is a clad material of a non-magnetic material such as aluminum, copper or stainless steel and a magnetic material, the strength of the remaining chassis is increased and the cathode ray tube is supported. It will be easier.

In the invention of claim 7, since the non-magnetic material is a hole, the hole can be formed at the same time when the remaining chassis is press-molded, and the chassis can be easily manufactured.

[0024]

【Example】

Example 1. 1 and 2 are a cross-sectional configuration diagram and a plan view of a cathode ray tube device for covering a cathode ray tube with a chassis according to an embodiment of the present invention, in which reference numeral 20 covers the cathode ray tube except for a screen portion, It is a box-shaped chassis having a top surface, side surfaces, a bottom surface, and a rear surface. 21 is a front part of the chassis extending over the top surface, side surfaces and bottom surface of the box body and having a thickness of 0.2.
It is made of cold rolled steel plate of 8 mm, covers the IMS up to the electron gun side opening surface 93 of the IMS, and 22 is the rest of the chassis and is made of a non-magnetic material over the top surface, side surface, bottom surface and rear surface of the box and has a thickness of 0.8 mm. Uses aluminum.

Next, the frames, the explosion-proof band and the deflection yoke shown in FIGS. 1 and 2 have linear relative magnetic permeability of 150, 1500 and 250 respectively, and the combination of the IMS and the color identification electrode shown in Table 1 is a. Or in case of f, the relative magnetic permeability of the magnetic material of the chassis is 1 (without chassis), 200, 200
The amount of mislanding (μm) when a magnetic field of 0.4 Oe as geomagnetism acts in the tube axis direction of the cathode ray tube from the outside under a magnetic field analysis condition of 0 or 5000 is shown in Tables 2 and 3 together with the above conventional example. Show. Table 2 shows measured values when the IMS has a relative permeability of 1000 (the color identification electrode has a relative permeability of 300), and Table 3 shows the IMS has a relative permeability of 20000 (the color identification electrode has a relative permeability of 5000). Is the measured value of.

[0026]

[Table 2]

[0027]

[Table 3]

3 and 4, the mislanding amount when the relative magnetic permeability of the IMS is 1000 and 20000 is the electron gun side opening surface of the IMS from the deflection center, the color identification electrode from the electron gun side opening surface of the IMS, respectively. The results obtained by detecting for each area from the deflection center to the color identification electrode are shown together with the case where there is no chassis and an example using the chassis shown in FIG. 9 as a conventional example. From FIGS. 3 and 4, the relative permeability of IMS is 1
Example 1 in both cases of 000 and 20000
In the case of the chassis, the amount of mislanding is lower than that of the cathode ray tube alone. Also,
From the figure, it can be seen that the effect of reducing the beam mislanding amount of the chassis of the first embodiment is greater between the deflection center and the electron gun side opening surface of the IMS than between the electron gun side opening surface of the IMS and the color selection electrode. Thus, in Example 1,
As shown in FIGS. 1 and 2, since the chassis front part covers the IMS up to the electron gun side opening surface of the IMS, the magnetic shielding effect of the chassis front part is effective.
Moreover, since the magnetic flux is not drawn from the deflection center to the electron gun side opening surface of the IMS as in the case where there is no magnetic body outside and there is no chassis, even if a magnetic field such as terrestrial magnetism acts on the cathode ray tube from the outside. A magnetic field component perpendicular to the orbit of the electron beam does not increase, and a landing mistake of the electron beam can be prevented and a color shift can be prevented. Further, since the magnetic material portion of the chassis is sufficiently separated from the deflection yoke, it does not affect the magnetic field distribution of the deflection yoke. Further, the adjustment of the landing of the cathode ray tube is prevented from changing the distribution of the magnetic field in the IMS between when the cathode ray tube is used alone and when the cathode ray tube is incorporated into the chassis. It also has the effect of eliminating the need for it and has sufficient strength because it uses a cold rolled steel sheet or the like as the magnetic material. Further, although the case where the non-magnetic material used for the rest of the chassis is aluminum having a thickness of 0.8 mm has been described in the first embodiment, the same effect can be obtained even in the case of copper or stainless steel, and more than this case. When the thickness is thin, the cost is low, and when the thickness is thick, the strength is increased, and the landing mistake of the electron beam 8 and the color shift can be prevented.

Comparative Example 1. A cathode ray tube device was obtained and implemented in the same manner as in Example 1 except that a non-magnetic material was used for the front part of the chassis in place of the magnetic material and a magnetic material was used for the rest of the chassis in the first embodiment. The amount of mislanding was determined under the same magnetic field analysis conditions as in Example 1, and the results are shown in FIGS. From the figure, it can be seen that in this case, not only is there no effect, but the mislanding amount increases.

Comparative Example 2 In Example 1, a cathode ray tube device was obtained in the same manner as in Example 1 except that the front part of the chassis was longer than that in Example 1 and the IMS was covered over a plane including the deflection center and perpendicular to the axis of the cathode ray tube. The amount of mislanding was determined under the same magnetic field analysis conditions as in, and the results are shown in Tables 2 and 3.
According to this, in this case, it is understood that the mislanding amount is larger than that in Example 1 regardless of the relative magnetic permeability of the IMS. This is because when the front part of the chassis exceeds the plane that includes the deflection center and is perpendicular to the cathode ray tube axis, the action of drawing the magnetic field in the cathode ray tube axis direction into the chassis becomes too strong, and the magnetic field distribution in the IMS changes, resulting in the magnetic shielding of the IMS. This is because the magnetic field component perpendicular to the orbit of the electron beam, which impairs the effect, increases.

Comparative Example 3. In Example 1, the cathode ray tube device was obtained in the same manner as in Example 1 except that the chassis front portion was shorter than that in Example 1 and the chassis front portion did not cover the IMS partially.
The mislanding amount was obtained under the same magnetic field analysis conditions as in Example 1, and the results are shown in Tables 2 and 3. According to this, in this case, it can be seen that the mislanding amount is increased as compared with the first embodiment regardless of the relative magnetic permeability of the IMS. If the front part of the chassis does not cover the IMS, the end part of the front part of the chassis exists on the IMS, so that the magnetic flux concentrates on the end part of the magnetic body, and thus the magnetic shielding effect of the IMS. This is because the

Example 2. FIG. 5 is a cross-sectional view of a cathode ray tube device for covering a cathode ray tube with a chassis according to another embodiment of the present invention. In FIG. 5, reference numeral 20 covers the cathode ray tube except for the screen portion, and the top, side and bottom surfaces are covered. And a box-shaped chassis having a rear surface. Reference numeral 21 is a front part of the chassis extending over the top, side and bottom of the box, and is made of a cold-rolled steel plate having a thickness of 0.8 mm. The IMS covers the opening surface 93 of the electron gun side of the IMS, and the remaining part of the chassis is the top of the box. , The side surface, the bottom surface and the rear surface, the rear surface is made of a magnetic material of cold-rolled steel sheet with a thickness of 0.8 mm, and the other is 0.8 m in thickness
m of non-magnetic material of aluminum. As described above, in the second embodiment, as shown in FIG. 5, the chassis structure is such that the front part of the chassis is located up to the electron gun side opening surface of the IMS.
Since the MS is covered, the magnetic shielding effect at the front of the chassis is effective, and since the front of the chassis and the rest are magnetically shielded, the effective permeability of the chassis is reduced and the magnetic flux is transmitted to the chassis. The phenomenon of pulling in can be prevented, and even if a magnetic field such as geomagnetism is applied to the cathode ray tube from the outside, the change of the magnetic field distribution in the IMS can be prevented, and the cathode ray tube is covered without impairing the magnetic shielding effect of the IMS. It is possible to prevent electron beam landing mistakes and prevent color misregistration. Further, since a cold rolled steel plate or the like is used as the magnetic material on the rear surface, the strength is sufficient for attaching a cooling fan or the like. Further, although the case where the non-magnetic material used in Example 2 is aluminum has been described, it is needless to say that the same effect can be obtained when copper or stainless steel is used.

Example 3. FIG. 6 is a cross-sectional configuration diagram of a cathode ray tube device for covering a cathode ray tube with a chassis according to another embodiment of the present invention. In the drawing, 20 covers the cathode ray tube except for the screen portion, and the top surface, side surface, bottom surface And a box-shaped chassis having a rear surface. Reference numeral 21 is a front part of the chassis extending over the top, side and bottom of the box, and is made of a cold-rolled steel plate having a thickness of 0.8 mm. The IMS covers the opening surface 93 of the electron gun side of the IMS, and the remaining part of the chassis is the top of the box. , The bottom surface is composed of a cold-rolled steel sheet having a thickness of 0.8 mm, the side surface, the bottom surface, and the rear surface, and the other is 0.8 m in thickness.
m of non-magnetic material of aluminum. As described above, in the third embodiment, as shown in FIG. 6, the chassis structure has the front part of the chassis up to the electron gun side opening surface of the IMS.
Since the MS is covered, the magnetic shielding effect at the front of the chassis is effective, and since the front of the chassis and the rest are magnetically shielded, the effective permeability of the chassis is reduced and the magnetic flux is transmitted to the chassis. The phenomenon of pulling in can be prevented, and even if a magnetic field such as geomagnetism is applied to the cathode ray tube from the outside, the change of the magnetic field distribution in the IMS can be prevented, and the cathode ray tube is covered without impairing the magnetic shielding effect of the IMS. It is possible to prevent electron beam landing mistakes and prevent color misregistration. Further, since a cold-rolled steel plate or the like is used for the bottom surface, the strength when mounting the circuit component on the bottom surface is sufficient. Further, although the case where the non-magnetic material used in Example 3 is aluminum has been described, it is needless to say that the same effect can be obtained when copper or stainless steel is used.

Embodiment 4 FIG. FIG. 7 is a cross-sectional configuration diagram of a cathode ray tube device that covers a cathode ray tube with a chassis according to another embodiment of the present invention. In FIG. It is a box-shaped chassis with a rear surface. Reference numeral 21 denotes a front part of the chassis extending over the top surface, side surfaces and bottom surface of the box body, which is made of cold-rolled steel plate with a thickness of 0.8 mm.
It covers up to 3 and 22 is the rest of the chassis, the top and side surfaces of the box,
A clad material (non-magnetic material) obtained by joining aluminum (non-magnetic material) and cold-rolled steel sheet (magnetic material) is used over the bottom surface and the rear surface. As described above, in Example 4, the chassis structure covers the IMS up to the electron gun side opening surface of the IMS as shown in FIG. 7, so that the magnetic shielding effect of the chassis front is effective. Moreover, since the magnetic flux is not drawn from the deflection center to the electron gun side opening surface of the IMS as in the case where there is no magnetic body outside and there is no chassis, a magnetic field such as terrestrial magnetism acts on the cathode ray tube from the outside. In addition, the magnetic field component perpendicular to the electron beam trajectory is not increased, and the landing mistake of the electron beam can be prevented and the color shift can be prevented. Further, since the magnetic material portion of the chassis is sufficiently separated from the deflection yoke, it does not affect the magnetic field distribution of the deflection yoke. Further, since the clad material is used, the strength is improved and the cathode ray tube can be easily supported. Furthermore, although the case where the non-magnetic material of the clad material is aluminum has been described in the fourth embodiment, it is needless to say that the same effect can be obtained when copper or stainless steel is used.

Example 5. FIG. 8 is a cross-sectional configuration diagram of a cathode ray tube device for covering a cathode ray tube with a chassis according to still another embodiment of the present invention. In FIG. And a box-shaped chassis having a rear surface. 21 is the upper surface of the box,
0.8mm thickness on front of chassis across side and bottom
Of cold-rolled steel sheet covering IMS up to the electron gun side opening surface 93 of the IMS, and 22 is the rest of the chassis, the upper surface of the box,
A large number of holes are formed as a non-magnetic material on the side surface, the bottom surface and the rear surface. As described above, in the fifth embodiment, the chassis structure covers the IMS up to the electron gun side opening surface of the IMS as shown in FIG. 8, so that the magnetic shielding effect of the chassis front part is effective. In addition, since the front part of the chassis and the remaining part are magnetically shielded, it is possible to prevent the phenomenon that the effective magnetic permeability of the chassis is lowered and the magnetic flux is drawn into the chassis, and the cathode ray tube is protected from the external magnetic field. Even when a magnetic field is applied, it is possible to prevent changes in the magnetic field distribution in the IMS, cover the cathode ray tube without impairing the magnetic shielding effect of the IMS, prevent landing mistakes of electron beams, and prevent color misregistration. Further, since a cold rolled steel plate or the like is used as the magnetic material, it has sufficient strength, and when molding the remaining portion of the chassis by pressing or the like, holes can be formed at the same time, which facilitates the manufacture of the chassis.

In the above embodiment, the case where the chassis is a box has been described, but the same effect can be obtained even if the shape is spherical, elliptical, conical, pyramidal or the like according to the purpose of use.

[0037]

According to the first aspect of the present invention, the screen is opened to cover the cathode ray tube, and the IMS is covered so as not to cross the plane including the deflection center and perpendicular to the axis of the cathode ray tube. The front part of the chassis and the remaining part of the chassis made of a non-magnetic material prevent changes in the distribution of the magnetic field in the IMS even when a magnetic field such as terrestrial magnetism acts on the cathode ray tube from the outside, and the electron beam A cathode ray tube chassis capable of preventing landing mistakes and preventing color misregistration can be obtained.

According to the second aspect of the present invention, since the front portion of the chassis covers the IMS up to the electron gun side opening surface of the IMS, even if a magnetic field such as geomagnetism acts on the cathode ray tube from the outside, the magnetic shield. By doing so, it is possible to prevent changes in the magnetic field distribution in the IMS, to make a cathode ray tube without impairing the magnetic shielding effect of the IMS, to prevent electron beam landing mistakes and to prevent color misalignment, and in addition to the deflection yoke. It is possible to obtain a cathode ray tube chassis that does not have any influence.

According to the third aspect of the present invention, the front of the chassis made of a magnetic material covers the cathode ray tube by opening the screen portion and covers the IMS so as not to cross the plane including the deflection center and perpendicular to the axis of the cathode ray tube. Part and at least a part of the front part of the chassis, which is a non-magnetic part, makes it possible to shield the cathode ray tube even when a magnetic field such as earth's magnetic field acts from the outside. It is possible to obtain a chassis for a cathode ray tube which can prevent the change of the magnetic field distribution of the cathode ray tube, can form the cathode ray tube without impairing the magnetic shielding effect of the IMS, can prevent the landing mistake of the electron beam, and can prevent the color shift.

According to the fourth aspect of the present invention, since the screen portion is opened and the cathode ray tube is covered with the box body having the upper surface, the side surface, the bottom surface and the rear surface, a stable cathode ray tube chassis can be obtained. it can.

According to the invention of claim 5, a low-cost cathode ray tube chassis can be obtained when the non-magnetic material is made of a non-magnetic material of aluminum, copper or stainless steel.

According to the invention of claim 6, when the non-magnetic material is a clad material of a non-magnetic material such as aluminum, copper or stainless steel and a magnetic material, the strength is increased and the cathode ray tube is easily supported. It is possible to obtain a chassis for a cathode ray tube.

According to the invention of claim 7, since the non-magnetic material is a hole, it is possible to obtain a chassis for a cathode ray tube which is easy to manufacture. .

[Brief description of drawings]

FIG. 1 is a cross-sectional configuration diagram of a cathode ray tube device that covers a cathode ray tube with a chassis according to an embodiment of the present invention.

FIG. 2 is a plan view of a cathode ray tube device that covers a cathode ray tube with a chassis according to an embodiment of the present invention.

FIG. 3 is a characteristic diagram showing the correlation between the position of the cathode ray tube and the mislanding amount when the relative magnetic permeability of the IMS is 1000, for comparing one embodiment of the present invention with the conventional example and the comparative example.

FIG. 4 is a characteristic diagram showing the correlation between the position of the cathode ray tube and the amount of mislanding when the relative magnetic permeability of IMS is 20000 for comparing the embodiment of the present invention with the conventional example and the comparative example.

FIG. 5 is a cross-sectional configuration diagram of a cathode ray tube device that covers a cathode ray tube with a chassis according to another embodiment of the present invention.

FIG. 6 is a cross-sectional configuration diagram of a cathode ray tube device that covers a cathode ray tube with a chassis according to another embodiment of the present invention.

FIG. 7 is a cross-sectional configuration diagram of a cathode ray tube device that covers a cathode ray tube with a chassis according to another embodiment of the present invention.

FIG. 8 is a cross-sectional configuration diagram of a cathode ray tube device that covers a cathode ray tube with a chassis according to still another embodiment of the present invention.

FIG. 9 is a cross-sectional configuration diagram of a cathode ray tube device that covers a cathode ray tube with a conventional chassis.

FIG. 10 is a characteristic diagram showing the relationship between the tube axial direction distance from the deflection center and the magnetic field strength on the orbit when the relative magnetic permeability (μr) of the IMS member of the conventional cathode ray tube device is 1000.

FIG. 11 is a characteristic diagram showing the relationship between the tube axis direction distance from the deflection center and the magnetic field component perpendicular to the orbit when the relative magnetic permeability (μr) of the IMS member of the conventional cathode ray tube device is 1000.

FIG. 12 is a characteristic diagram showing the relationship between the tube axis direction distance from the deflection center and the magnetic field strength on the orbit when the relative permeability (μr) of the IMS member of the conventional cathode ray tube device is 20000.

FIG. 13 is a characteristic diagram showing the relationship between the tube axis direction distance from the deflection center and the magnetic field component perpendicular to the orbit when the relative permeability (μr) of the IMS member of the conventional cathode ray tube device is 20000.

FIG. 14 is a characteristic diagram showing the relationship between the relative permeability of the IMS and the mislanding amount under the chassis of each relative permeability of the conventional cathode ray tube device.

[Explanation of symbols]

 1c Skirt 1d Screen 7 Internal magnetic shield 8 Electron beam 91 Deflection center 20 Chassis 21 Chassis front 22 Remaining chassis

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideo Noda, No. 1 Nagaokakyo Baba Institute, Mitsubishi Electric Co., Ltd., Tube Manufacturing Co., Ltd. (72) Hidenori Takita, 6-14 Maruo-cho, Nagasaki-shi Nagasaki Inside the factory

Claims (7)

[Claims] 1. A cathode ray tube provided with a panel comprising a screen portion and a skirt portion connected to the screen portion and an internal magnetic shield provided so as to surround an electron beam passing through a deflection center, and covering the screen portion by opening the screen portion. In a cathode ray tube chassis, the chassis front portion made of a magnetic material covers the inner magnetic shield so as not to cross a plane including the deflection center and perpendicular to the cathode ray tube axis, and a chassis remaining portion made of a non-magnetic material. A cathode ray tube chassis characterized in that 2. The cathode ray tube chassis according to claim 1, wherein a front portion of the chassis covers the inner magnetic shield up to an electron gun side opening surface of the inner magnetic shield. 3. A cathode ray tube having a panel comprising a screen portion and a skirt portion connected to the screen portion and an internal magnetic shield provided so as to surround an electron beam passing through the deflection center, is covered by opening the screen portion. In the cathode ray tube chassis, a chassis front portion made of a magnetic material that covers the inner magnetic shield so as not to cross a plane that includes the deflection center and is perpendicular to the cathode ray tube axis, and at least a part of the chassis front portion side is non-magnetic. A chassis for a cathode ray tube, which is composed of the rest of the body which is the body. 4. The device according to claim 1, wherein the screen portion is opened, and the upper surface, the side surface,
A cathode ray tube chassis, characterized in that the cathode ray tube is covered with a box having a bottom surface and a rear surface. 5. The cathode ray tube chassis according to claim 1, wherein the non-magnetic material is made of a non-magnetic material selected from aluminum, copper and stainless steel. 6. The non-magnetic material according to claim 1, wherein the non-magnetic material is a clad material composed of a non-magnetic material selected from aluminum, copper and stainless steel, and a magnetic material. A cathode ray tube chassis. 7. The cathode ray tube chassis according to any one of claims 1 to 4, wherein the nonmagnetic material is a hole.