JP2003157777A - Color selection structure of cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To curtail adverse effect of external magnetic field in a tube axis direction opening widely for letting electron beams pass. SOLUTION: With the color selection structure 1 with holding an aperture grille 2 arranged in opposition inside a tube on a phosphor screen of a face panel of the cathode-ray tube, protruding parts 2e, 2f protruding toward the phosphor screen from top and bottom ends of a pair of frame H members 4, 5 supporting the aperture grille 2 at a top and bottom positions are fitted to the aperture grille 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a color selection structure in a cathode ray tube, and more particularly to the structure of a color selection structure for improving the shielding characteristics of the cathode ray tube.

[0002]

2. Description of the Related Art FIG. 6 is a perspective view showing the outline of a conventional general aperture grill type color selecting structure 50. As shown in the figure, in the aperture grill 51 as a color selection electrode, the narrow slits 2a formed by the etching process and the grit element bodies between the slits are arranged in a crossed manner.

It should be noted that the X, Y, and Z axes in the figure are set to the Z axis in the tube axis direction when the color selecting structure 50 is at a predetermined position in the cathode ray tube, as will be described later. Fine slit 2
The Y-axis is set in the vertical direction of the screen, which is the direction in which a extends, and the X-axis is set in the horizontal direction of the screen, which is the direction orthogonal to both of these axes. The X, Y, and Z axes are common in each drawing of this specification.

The frame 3 holds the upper and lower long side portions 2b and 2c of the aperture grill 51 by welding, as will be described later, and holds the aperture grill 51 as a slightly cylindrical side surface curved surface. A pair of frame H members 4 and 5 which are curved in parallel and arranged in parallel to each other
And a pair of frame V members 6 and 7 integrally connecting the pair of frame H members 4 and 5.
The pair of frame H members 4 and 5 correspond to the frame frame sides, and the pair of frame V members 6 and 7 correspond to the frame arm portions.

The pair of frame V members 6 and 7 are
The frame H members 4 and 5 are connected to the frame H members 4 and 5 in the vicinity of the left and right ends thereof, respectively, and the aperture grille 51 has elasticity to generate tension in the forming direction of the strip slits 2a. Therefore, frame H members 4, 5
Attaches the aperture grill 51 to the frame V members 6 and 7 in a state where a restoring force is generated, thereby maintaining a tensioned state in which tension is generated.

Further, a pair of frame H members 4, 5,
A spring holder 8 is attached to each of the frame V members 6 and 7 toward the outside. A mounting spring 9 having a mounting hole 9a is mounted on each of the spring holders 8 in a predetermined direction. These mounting springs 9 are used for the color selection structure 50.
Is a member for supporting and fixing inside a glass bubble of a cathode ray tube including a face panel and a funnel (not shown), that is, an engaging pin (not shown) formed on the inner surface of the face panel in the mounting hole 9a of the mounting spring 9. The color selection structure 50 is supported and fixed by inserting. Frame shield 17 installed between each frame member
Serves as a magnetic shield as described later.

FIG. 7 is a view for explaining a conventional method of attaching the aperture grill 51 (FIG. 6) to the frame H members 4 and 5. After that, of the aperture grill 51,
The state of being attached to the frame H members 4 and 5 is referred to as a formed grill, and the state before being attached is referred to as a flat grill 10.

As shown in the figure, the flat grill 10
Forms a slit forming region in which a plurality of thin slits 2a formed by the etching process as described above and grit element bodies formed between the slits are alternately arranged on a flat metal thin plate. Also, flat grill 1
0 indicates an outer peripheral portion (hereinafter, referred to as a peripheral portion) 10a in which no slit is formed around the slit forming area.
Are formed.

As a first step in assembling the foamed grill, as shown in FIG.
The strip slits 2a are placed so that the forming direction thereof is orthogonal to the extending direction of the frame H members 4 and 5, and the strip slits 2a are placed in the peripheral part 10a near the ends of the strip slits 2a and the frame H members 4 and 5. Welding is performed along the welding instruction line 12 located on the mounting curved surface to fix it.

In the flat grille 10, the peripheral portion 10a is set to be relatively wide in order to ensure the rigidity during transportation of the flat grille 10 itself. Since the peripheral portion 10a is unnecessary after the above-described welding process, it is cut out as shown in FIG. 7B in the second stage of forming the grill.

The cathode ray tube is provided with an electron gun inside the tube. For example, as shown in FIG. 6, an electron beam emitted from a starting point 13 of an electron gun (not shown) is moved along an orbit 14 of an aperture grill 51 of an aperture grill 51. It is designed so as to reach the target phosphor 15 on the inner surface of the face panel (not shown) through the narrow slits 2a. However, at this time, the trajectory 14 of the electron beam may change due to the external magnetic field, and if this is significant, the electron beam will not reach the predetermined fluorescent screen position.

In order to prevent this problem, an internal magnetic shield 16 made of a magnetic steel plate is usually arranged inside the cathode ray tube. This internal magnetic shield 16
It is supported and coupled to members such as the frame H members 4 and 5 and arranged so as to cover most of the electron beam trajectory.

[0013]

The magnetic shield characteristics of the cathode ray tube vary greatly depending on the material and shape of the internal magnetic shield. As described above, the inner magnetic shield 16
Is placed so as to cover most of the electron beam trajectory, but openings are made at various locations due to the positional relationship with other parts inside the cathode ray tube, workability during installation in the cathode ray tube manufacturing process, and other reasons. Is provided, and particularly in the tube axis direction, a large opening is provided for passing an electron beam.

Therefore, it can be said that the internal magnetic shield 16 plays a role of controlling the direction of the magnetic field rather than shielding the magnetic field with respect to the magnetic field in the tube axis direction. FIG. 8A shows
FIG. 8B is a front view of the magnetic shield 16 as seen from the face panel side, and FIG. 8B is an explanatory diagram showing how the magnetic shield 16 acts on the tube axis direction magnetic field 31.

Conventionally, the tube shaft opening 16a of the magnetic shield 16 is provided.
It has been attempted to form the opening shape of the above so as to obtain the best shield effect by controlling the magnetic field direction which changes depending on the shape, but there is a limit to the effect of reducing the adverse effect on the electron beam trajectory 14. A more effective method was needed.

An object of the present invention is to solve the above problems,
An object of the present invention is to provide a color selection structure that can more effectively suppress the adverse effect of the tube axis direction magnetic field 31 on the electron beam trajectory 14.

[0017]

A color selection structure for a cathode ray tube according to claim 1, wherein the color selection structure for the cathode ray tube is arranged inside the cathode ray tube such that the color selection electrodes face the phosphor screen of the face panel. The color selection electrode having a peripheral part outside the transmission region of the electron beam, and the color selection electrode,
A frame frame side that supports the frame frame in the vertical direction and a frame arm portion that supports the frame frame side, and the peripheral section has projecting portions that project further outward from the upper and lower ends of the frame frame side. It is characterized in that it is formed so as to include.

According to a second aspect of the present invention, there is provided the cathode ray tube color selecting structure according to the first aspect, wherein the protruding portion protrudes toward the fluorescent screen side in the tube axis direction. . The cathode ray tube color selection structure according to claim 3 is the cathode ray tube color selection structure according to claim 2, characterized in that the protrusions are cut at predetermined intervals. Furthermore, the color selection structure of the cathode ray tube according to claim 4 is the color selection structure of the cathode ray tube according to claim 2, wherein the protrusion width L of the protrusion is the contact between the fluorescent screen and the transmission region surface. The feature is that it is set to 60% or more of the interval Q.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. FIG. 1 is an external perspective view showing a main configuration of a color selection structure 1 according to a first embodiment of the present invention.

The color selection structure 1 of the first embodiment differs from the conventional color selection structure 50 shown in FIG. 6 only in the structure of the aperture grille 2 as a color selection electrode. Therefore, the same or corresponding portions as those of the conventional color selecting structure 50 are designated by the same reference numerals, description of the common portions is omitted, and different points will be mainly described.

In the aperture grille 2, the upper and lower long sides 2b and 2c of the peripheral part thereof are respectively forward from the upper end of the frame H member 4 and the lower end of the frame H member 5, that is, in the plus direction parallel to the Z axis. Upper and lower projecting portions 2e and 2f are formed respectively.
Since the welding surfaces of the frame H members 4 and 5 are slightly curved so that the central portions thereof project as described above, the upper and lower projecting portions 2e and 2f can be bent forward. The cuts 2h are provided at predetermined intervals.

This cut is made in advance on the flat grill 10
It may be formed in the state shown in FIG. 7 or may be formed by a method such as adding a notch processing step to the assembly step of the foamed grill. The protruding width L of each of the protruding portions 2e and 2f is
Inevitably, a pair between the inner surface of the face panel (not shown) (corresponding to the fluorescent surface, its assumed position is indicated by P in FIG. 2) and the slit forming area surface 2g of the formed grill (aperture grill 2 in the attached state). Although it is less than the contact distance Q, in the present embodiment, the protruding width L is set to about 70% of the contact distance Q. The slit forming area surface 2g corresponds to the electron beam transmitting area surface.

Table 1 shows that in the cathode ray tube using the color selecting structure 1 (FIG. 1) of the first embodiment and the cathode ray tube using the conventional color selecting structure 50 (FIG. 6), the magnetic field in the tube axis direction is 0.
FIG. 6 is a relative comparison of the electron beam trajectory change amount at 08 mT, which is actually measured at the upper and lower ends of the screen and the screen corner shown in the schematic view of FIG. 4. As a comparative numerical value, a relative value is compared using a value obtained by converting the amount of change in each part in the conventional case as 100.

[Table 1]

As shown in the table, by adopting the color selection structure 1 according to the first embodiment of the present invention, the change amount is reduced at both the upper and lower ends of the screen and the screen corners, and excellent magnetic shield characteristics are exhibited. ing. By adopting the color selection structure 1 of the present embodiment, the magnetic shield characteristics against a magnetic field in a direction other than the tube axis direction will not be deteriorated more than before.

Next, the factors for obtaining the above-described shield effect will be described with reference to the drawings. Figure 9
FIG. 7 is a schematic view of a cross section of a main part of an internal member of a cathode ray tube adopting the above-described conventional color selecting structure 50 (FIG. 6) as viewed in a lateral direction. Since the portion shown here usually has a vertically symmetrical structure, only the upper half structure is shown here.

The main flow of the magnetic field will be described with respect to the situation in which the tube axial direction magnetic field 31 is applied. Inside the cathode ray tube,
There are a magnetic field 32 that is mainly absorbed by the internal magnetic shield 16, and a first magnetic field 33 and a second magnetic field 34 that leak from the internal magnetic shield 16 and the frame shield 17. The frame shield 17 acts as a part of the internal magnetic shield 16 and serves as a joint with the frame H member 4. This frame shield 17 is rarely installed over the entire longitudinal direction (X-axis direction) of the frame H member 4, and normally, as shown in FIG. 1 or 6, a part of the frame H member 4 is provided. To be joined to.

Therefore, the intensity ratio of the first magnetic field 33 and the second magnetic field 34 is different between the portion with the frame shield 17 and the portion without the frame shield 17, and the frame V members 6, 7 are further provided between the inner magnetic shield 16 and the aperture grill 51. (Fig. 6)
The ratio will also be different if there is. In any case, however, as shown in FIG. 9, the phenomenon in which the magnetic field once goes toward the upper part of the screen and then flows backward toward the lower part of the screen is common.

From the above, when there is a magnetic field in the direction of the tube axis from the back of the screen to the front, that is, in the positive direction of the Z axis, outside the cathode ray tube, the upward component on the electron gun side inside the cathode ray tube. There are many magnetic fields, and conversely, there are many downward magnetic fields on the aperture grill side.

However, the vertical direction of the magnetic field is reversed depending on the direction of the external magnetic field or the upper and lower halves of the screen. The flow of such a magnetic field occurs because the magnetic field has the property of being attracted to the member having the higher magnetic permeability, and in general, the magnetic permeability of the inner member of the cathode ray tube causes the inner magnetic shield 16 and the aperture grille to have a higher magnetic permeability. It is considered that this is due to the fact that the order of magnitude is 1.

The effect of the above magnetic field in the cathode ray tube on the electron beam trajectory will be described with reference to the principle diagram shown in FIG.

In the figure, reference numeral 41 indicates a ferromagnetic material. 42 is the current I present in this field, and Ia and Ib represent its vector components. 43 shows the relationship between the external magnetic field B1, the current Ia, and the force f1, and 44a and 44b are magnetic fields B obtained by changing the external magnetic field B1 by the ferromagnetic body 41, respectively.
2 shows the relationship between B3, current Ib, and forces f2 and f3. Arrow A indicates the direction of the magnetic field in the tube axis direction in the cathode ray tube.

Reference numeral 44a denotes a magnetic field B2 in a state where the external magnetic field B1 is attracted to the ferromagnetic body 41, and 44b denotes
A part of the magnetic field B3 after the external magnetic field B1 has passed through the ferromagnetic body 41 is shown. As indicated by 43 in the figure, a force f1 generated by the external magnetic field B1 and the current component Ia,
Similarly, the magnetic field B2 indicated by 44a and the force f2 generated by the current component Ib have opposite directions and work in a direction of canceling each other. On the other hand, if the external magnetic field B1 passes through the ferromagnetic body 41 and then becomes the direction of the magnetic field B3 shown by 44b,
The direction of the force f3 generated by the action with the current component Ib is the force f1.
Is the same as the orientation of.

Here, the ferromagnetic material 41, the electric current 42, and the external magnetic field B1 are shown in FIG.
6, the electron beam of the cathode ray tube and the magnetic field 31 in the tube axis direction are considered, and the magnetic fields B2 and B3 correspond to the magnetic field flows 32, 33 and 34 in FIG. 9, respectively. Since the direction of the force is the direction that changes the electron beam trajectory 14, the magnetic field corresponding to the magnetic field B3 in FIG. 3 promotes the electron beam trajectory change due to the external magnetic field, which is not preferable from the viewpoint of magnetic shielding. Therefore, in order to improve the magnetic shield performance, it is preferable to reduce the magnetic field component corresponding to the magnetic field B3.

FIG. 2 shows the color selection structure 1 of the first embodiment.
FIG. 10 is a schematic view of a cross section of a main part of the internal member of the cathode ray tube adopting (FIG. 1) as seen in the lateral direction as in the case of FIG. Since the portion shown here usually has a vertically symmetrical structure, only the upper half structure is shown here.

In the conventional case, like the second magnetic field 34 shown in FIG. 9, there is a magnetic field passing through the inside or the vicinity of the aperture grill 51, which is one of the causes of the electron beam trajectory change. In the case of the cathode ray tube adopting the color selecting structure 1 of the form 1 (FIG. 1), since there is the upper protruding portion 2e, the third protruding toward the slit forming area surface 2g of the aperture grill 2 through the inside or the vicinity thereof. A magnetic field 35 is generated.

That is, it can be said that as a result of the magnetic field flow near the aperture grill 2 being dispersed, the second magnetic field 34, which is unfavorable in terms of magnetic shield characteristics, is reduced, and the change in the electron beam trajectory is reduced compared to the conventional case. . Further, the third magnetic field 35 itself has a component directed to the lower side of the screen, which is in the same unfavorable direction as the second magnetic field 34, but the leakage of this magnetic field component by the third magnetic field 35 causes the upward protrusion 2e to leak. Since it occurs at the tip, that is, at a position closer to the end point of the electron beam, the time during which the electron beam is adversely affected is very short, and the influence on the trajectory change is small.

For the above reasons, by adopting the color selecting structure 1 of the first embodiment, it becomes possible to improve the magnetic shield performance against the magnetic field in the tube axis direction.

Next, the color selection structure 1 according to the first embodiment
The protrusion width L of the vertical protrusions 2e and 2f in the Z-axis direction will be described. Table 2 shows a relative comparison of the measured electron beam orbit change amounts at the upper and lower ends of the screen and the screen corner shown in FIG. 4 under the condition that the magnetic field in the tube axis direction is 0.08 mT and the value of the protrusion width L is changed. It was done.

Here, the amount of change in the protruding width L is represented by the ratio (%) of the protruding width L to the contact distance Q shown in FIG. 2, and the amount of change in each part in the conventional case is 100 as a comparative numerical value. The relative value is compared using the converted value.

[Table 2]

The graph of FIG. 5 is a graph of Table 2 above. As shown in FIG. 5 or Table 2, it can be said that the electron beam trajectory change amount decreases with an increase in the protrusion width L when the width exceeds a certain width, and the effect is saturated when the protrusion width L exceeds a certain upper limit value. Therefore, in order to obtain an improvement effect of 10% or more in both the upper and lower edges of the screen and the screen corner, the protrusion width L should be set to 60% or more of the contact distance Q and the best effect should be obtained. If you do 80% to 9
It is preferably set to about 0%.

In the above-mentioned embodiment, the color selection structure adopts the aperture grill type aperture grill as the color selection electrode, but the invention is not limited to this.
Other forms such as a shadow mask type color selection structure may be adopted, and various modes can be adopted.

In the claims and the description of the embodiments mentioned above, "upper", "lower", "left",
Although the terms “right”, “front”, and “rear” are used, these are for convenience and do not limit the absolute positional relationship in the state in which the color selection structure is arranged.

[0043]

According to the color selection structure of the first and second aspects, when an external magnetic field in the tube axis direction is applied, the magnetic field in an unfavorable direction due to the magnetic shield characteristics is suppressed, so that the upper and lower edges of the screen and the screen corners. In both cases, it becomes possible to suppress the electron beam trajectory change due to the magnetic field, and excellent magnetic shield characteristics can be obtained. Further, since the magnetic shield performance against a magnetic field in a direction other than the tube axis direction is not deteriorated, the degree of freedom in designing the internal magnetic shield is increased and the overall magnetic shield performance can be improved.

According to the color selection structure of the third aspect, even if the support surface for supporting the color selection electrode on the frame frame side is curved in the direction in which the center part projects, the projecting part can be bent without difficulty. It will be possible.

According to the color selection structure of the fourth aspect, the present invention can be carried out in a state where effective and preferable magnetic shield characteristics are obtained.

[Brief description of drawings]

FIG. 1 is an external perspective view showing a main configuration of a color selection structure 1 according to a first embodiment of the present invention.

FIG. 2 is a schematic view of a cross section of a main part of an internal member of a cathode ray tube adopting the color selection structure 1 as viewed in a lateral direction.

FIG. 3 is a principle diagram for explaining the influence of a magnetic field in a cathode ray tube on an electron beam trajectory.

FIG. 4 is a schematic diagram showing a place where an electron beam trajectory change amount is actually measured.

FIG. 5 is a graph showing a relative comparison of the results of electron beam trajectory change amounts actually measured by changing the value of the protrusion width L.

FIG. 6 is an outline perspective view showing a schematic outline of a conventional general aperture grill type color selection structure 50.

FIG. 7 is a view for explaining a conventional method of attaching the aperture grill 51 to the frame H members 4 and 5.

FIG. 8A is a front view of the magnetic shield 16 seen from the face panel side, and FIG.
FIG. 7 is an explanatory diagram showing a state of a shield action with respect to the tube axis direction magnetic field 31.

FIG. 9 is a schematic view of a cross section of a main part of an internal member of a cathode ray tube adopting a conventional color selecting structure 50 as viewed in a lateral direction.

[Explanation of symbols]

1 color selection structure, 2 aperture grille, 2a strip slit, 2b upper long side, 2c lower long side,
2e upward protruding portion, 2f downward protruding portion, 2g slit forming area surface, 2h notch, 3 frame,
4, 5 frame H member, 6, 7 frame V member, 8 spring holder, 9 mounting spring, 9a mounting hole, 10 flat grill, 1
2 welding instruction line, 13 starting point, 14 electron beam orbit, 15 target phosphor, 16 internal magnetic shield, 16a tube axis opening, 17 frame shield,
31 tube axial magnetic field, 32 absorbed magnetic field, 3
3 1st magnetic field, 34 2nd magnetic field, 35 3rd magnetic field,
41 ferromagnet, 42 current.

Claims (4)

[Claims] 1. A color selection structure for a cathode ray tube, wherein a color selection electrode is arranged inside a cathode ray tube so as to face a color selection electrode on a phosphor screen of a face panel, the peripheral surface having a peripheral portion outside an electron beam transmission region. The color selection electrode, a frame frame side that supports the color selection electrode in the vertical direction of the screen, and a frame arm portion that supports the frame frame side, and the peripheral section includes upper and lower sides of the frame frame side. A color selection structure for a cathode ray tube, characterized in that it is formed so as to include a protruding portion which further protrudes outward from the end portion. 2. The color selection structure for a cathode ray tube according to claim 1, wherein the projecting portion projects toward the fluorescent screen side in the tube axis direction. 3. The color selection structure for a cathode ray tube according to claim 2, wherein the protrusions are cut at predetermined intervals. 4. The color selection of a cathode ray tube according to claim 2, wherein the protruding width L of the protruding portion is set to 60% or more of a contact distance Q between the fluorescent screen and the transmissive region surface. Structure.