JPH06162944A - Mounting structure of inner beam shield and inner magnetic shield on mask and mounting method therefor - Google Patents

Abstract

PURPOSE:To improve the shielding effect of both an inner magnetic shield and an inner beam shield by aligning the joint end of the inner magnetic shield with the joint end of the inner beam shield, and specifying an angle formed with the two shields. CONSTITUTION:An inner beam shield 15 and an inner magnetic shield 16 are welded to each other in such a way as keeping the bent sections thereof aligned with each other. In mounting the shields 15 and 16 on a mask 4, an angle formed therewith is specified at a value between 85 and 90 degrees. According to this construction, an overscan beam 11 is first reflected with the inner beam shield 15 and further reflected with the inner magnetic shield 16, thus traveling in a direction opposite to the mask 4. Consequently, the beam 11 does not reach a phosphor screen and the deterioration of color purity can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for attaching an internal beam shield and an internal magnetic shield to a mask and a method for attaching the mask, and more particularly to an internal beam shield for improving the magnetic shield effect and the beam shield effect during overscan. The present invention relates to a structure for attaching a mask and an internal magnetic shield to a mask and a method for attaching the same.

[0002]

2. Description of the Related Art A cathode ray tube (C
RT) is surrounded by a panel 1 and a funnel 2 as shown in FIG. 5, and an internal beam shield attached to the frame of the phosphor screen 3, the mask 4 as a color selection mechanism, and the mask 4 in order from the panel 1 side. (InnerBeam Shield: IBS)
5, Inner Magnetic Shield (IM)
S) 6, and an electron gun 7 for emitting the electron beam 10 and the like are provided therein.

Internal magnetic shield (IM
S) 6 is provided to protect the trajectory of the electron beam 10 emitted from the electron gun 7 from external magnetism. On the other hand, the internal beam shield (IBS) 5 reflects the electron beam 10 hitting the mask 4 or the internal magnetic shield 6 when the electron beam 10 is scanned (overscanned) outside the effective screen of the phosphor screen 3. It is provided to prevent electrons from hitting the phosphor screen 3.

FIG. 6 is a partial schematic diagram (IMS explanatory diagram) for explaining the reflection state when the overscan beam 11 hits the internal magnetic shield (IMS) 6, and the trajectory of the electron beam is shown in FIG. The overscan beam 11 that hits the inner magnetic shield 6 arranged so as to come into contact with and cover it more closely causes internal reflection, and the reflected electrons hit the fluorescent screen 3 to deteriorate the color purity.

FIG. 7 shows an internal beam shield (IB
(S) is a schematic diagram (IBS explanatory diagram) for explaining the role of 5 and prevents the overscan beam 11 from hitting the mask.

[0006]

The internal magnetic shield and the internal beam shield in the cathode ray tube have conventionally been designed separately. Although the reflected electrons due to the magnetic shield and the electron beam due to overscan are considered for each, there is reflection between the internal magnetic shield and the internal beam shield, and even if each alone does not cause a problem, the reflected electrons are reflected to the fluorescent screen. It may reach and become a problem.

8 and 9 are a schematic diagram of an IMS mounting structure in the case where the internal magnetic shield effect is small and a schematic diagram of the IMS mounting structure in the case of increasing the IMS effect by bringing the internal magnetic shield close to the electron beam. . In particular, FIGS. 9A and 9B show the inner beam shield 5
Is in the state of being deviated from the inner magnetic shield 6 to the right and left sides, respectively. In both cases (a) and (b) of FIG. 9, the electron beam 10 is reflected by the internal beam shield 5 and the internal magnetic shield 6 and reaches the fluorescent screen 3 shown in FIG. Reduce purity. 10 (a) and 10 (b) are diagrams for explaining the electron beam reflection phenomenon in the states of FIGS. 9 (a) and 9 (b). In the figure, an angle α is an angle formed by the perpendicular line from the center of the electron gun to the fluorescent screen and the outermost electron beam, and an angle β is a bending angle of the IMS or IBS.

Considering overscan, the angle α
Takes a value in a certain range, so the angle β cannot be uniquely determined. Therefore, from these figures, the condition of 90 + α-2β = 0 needs to be satisfied. However, in reality α
Is about 40 degrees, β requires an angle of about 65 degrees, which is not effective.

Further, in the tension mask for the Trinitron CRT, the internal beam shield and the internal magnetic shield are attached by welding to the frame of the mask in a welded state. However, this welding-based mounting method deteriorates the tension of the aperture grille (AG) and lowers the IMS mounting yield and accuracy.

Therefore, according to the present invention, in the color cathode ray tube, the effect of the magnetic shield for shielding and protecting the electron beam from external magnetism and the effect of the beam shield for shielding the electron beam at the time of overscan are simultaneously improved. It is an object of the present invention to provide a structure for mounting a mask on a shield and an effective mounting method that does not apply a load to a tension mask using an aperture grill or the like.

[0011]

According to the present invention, there is provided a color cathode ray tube having a mask as a color selecting mechanism and having an inner magnetic shield and an inner beam shield attached to a frame of the mask. The inner beam shield and the inner magnetic shield are characterized in that the joint ends of the inner magnetic shield and the inner beam shield coincide with each other, and the angle formed by the two shields is 85 to 90 degrees. It is solved by the structure of attaching to the mask.

Further, the above-mentioned problem is to attach a thin plate having a first hole to each of at least a pair of opposing frames of a mask as a color selection mechanism of a color cathode ray tube so that an inner beam shield and an inner magnetic shield are provided. The inner beam shield and the inner magnetic shield are attached to the mask by inserting a spring-like locking means into the second hole and the first hole provided in the joint surface or the joint surface of only the inner magnetic shield. It is solved by a method of attaching the inner beam shield and the inner magnetic shield to the mask.

[0013]

According to the present invention, in a color cathode ray tube, an internal magnetic shield (IMS) and an internal beam shield (IB) are used.
S) and the joint end on the opposite side of the free end are the same,
Moreover, the angle formed by the two shields is 85.
As shown in FIG. 2, all of the overscan beams 11 have an IBS 15 and an IMS 16 because they are at about 90 degrees.
Reflects and does not reach the effective screen side (panel side).

In particular, it is more preferable that the IMS 16 and the cathode 16 are mounted so that the most end orbit of the electron beam forming the effective screen of the cathode ray tube is substantially parallel.

Further, according to the present invention, the STC plate attached (welded) to the hole of the mask and the hole provided in the welded portion of the IMS and IBS welded structure having the predetermined angle and the joint end condition as described above. Since the mask is attached to the mask by inserting and fitting the spring-like locking means 18 such as a clip into the hole provided in the thin plate 20, the mask does not require welding with a large load, and the attachment method However, it is simple and can be attached securely.

[0016]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing an embodiment of a structure for attaching an internal beam shield and an internal magnetic shield to a mask according to the present invention. In FIG. 1, the inner beam shield 15 and the inner magnetic shield 16 are joined by welding so that the bent portions of the inner beam shield 15 and the inner magnetic shield 16 coincide with each other (joint ends match). As shown by, the angle formed is defined as 85 to 90 degrees. The internal magnetic shield 16 is substantially parallel to the endmost trajectory of the electron beam to the effective screen, as in the conventional case.

With this structure, as shown in the enlarged view of FIG. 2, the structure for mounting the internal magnetic shield and the internal beam shield (antireflection shield) according to the present invention on the mask is overscanned. The beam 11 is first reflected by the internal beam shield 15 and further reflected by the internal magnetic shield 16 and travels in the opposite direction to the mask 4, so that the beam 11 does not reach the fluorescent screen 3 and the color purity does not deteriorate.

Further, in this embodiment, the antireflection shield is attached to the mask by a hole provided at the joint between the internal beam shield 15 and the internal magnetic shield 16 of the antireflection shield, as shown in FIG. , STC with clip hole
The plate 20 (temperature compensating plate: shown in detail in FIG. 4) is aligned with the clip hole, and the clip 18 is attached through the hole. The STC plate 20 has a thickness of about 1 to 2 mm and is easy to open a hole, and is firmly welded and joined to the frame portion of the mask by welding.

FIG. 3 shows only the internal magnetic shield (IMS) of the antireflection magnetic shields described above.
It is a perspective view for explaining the clip attachment to the STC plate welded to the frame of the mask. As shown in FIG. 3, an aperture grille (AG) 4a is stretched and welded to the frame A member 21a of the mask 4, and the frame B member 21b is welded to the frame A member 21a so as to give tension to the AG 4a. Has been done.
The clip hole 20 is provided on the surface of the frame B member 21b.
an STC plate 20 having a
The STC plate 20 and the IMS 16 are fixed to each other by aligning the clip holes 16a of 4 with the STC clip holes 20a (moving the IMS 16 in the P direction) and inserting clips at four places in the clip insertion direction (arrow Q). In FIG. 3, reference numeral 23 is a spring for fixing the mask to the panel, which is fixed to the frame A member 21a and the frame B member 21b by a spring holder 24, and 25 is an HV.
It is a contactor.

FIG. 4 is a view showing an example of a clip hole on the mask side. Particularly, (a) shows the STC plate with the clip hole shown in FIG. 3, and (b) shows the holder plate with the clip hole. It is a thing. That is, FIG. 4 (b)
As shown in FIG. 5, in the case of a mask of a type that does not use the STC plate 20, 47 spring holders are extended to provide clip holes 24b, and the reflective magnetic shield is formed in the same manner as shown in FIGS. Clip on.

[0022]

As described above, according to the present invention, since the internal magnetic shield can be prevented by the effectively arranged beam shield even when the electron beam is overscanned, the magnetic shield effect can be obtained without impairing the color purity. It can be used effectively. Moreover, the CRT can be attached to the mask by clipping with the STC plate, and problems due to welding and joining can be solved.

[Brief description of drawings]

FIG. 1 is a schematic view of an embodiment of a structure for attaching an internal beam shield (IBS) and an internal magnetic shield (IMS) to a mask according to the present invention.

FIG. 2 is a partially enlarged view of FIG.

FIG. 3 is a perspective view for explaining a clip attachment method of an IMS and an STC plate.

FIG. 4 is a diagram showing an example of a clip hole.

FIG. 5 is an explanatory view of a conventional cathode ray tube.

FIG. 6 is an IMS explanatory diagram.

FIG. 7 is an IBS explanatory diagram.

FIG. 8 is a schematic diagram of an IMS mounting structure having a small IMS effect.

FIG. 9 is a schematic diagram of an IMS mounting structure with increased IMS effect.

FIG. 10 is a reflection phenomenon diagram of an electron beam.

[Explanation of symbols]

 1 Panel 2 Funnel 3 Fluorescent Screen 4 Mask 4a Aperture Grill (AG) 5,15 Internal Beam Shield (IBS) 6,16 Internal Magnetic Shield (IMS) 7 Electron Gun 10 Electron Beam 11 Overscan Beam 16a IMS Clip Hole 20 STC Plate 20a STC clip hole 21a Frame A member 21b Frame B member 23 Spring 24 Spring holder 24a Spring holder with clip hole 24b Clip hole 25 HV contactor

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[Procedure amendment]

[Submission date] June 21, 1993

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

[Fig. 2]

Claims (6)

[Claims] 1. A color cathode ray tube comprising a mask as a color selection mechanism, and an inner magnetic shield and an inner beam shield attached to a frame of the mask, wherein the inner magnetic shield and the inner beam shield are joined together. A structure for attaching an inner beam shield and an inner magnetic shield to a mask, wherein the ends are coincident with each other and an angle formed by the two shields is 85 to 90 degrees. 2. The internal beam shield according to claim 1, wherein the internal magnetic shield and the innermost beam shield of the cathode ray tube are attached so as to be in parallel with an endmost orbit of an electron beam forming an effective screen. Mask mounting structure with internal magnetic shield. 3. Each of at least a pair of opposing frames of a mask as a color selection mechanism of a color cathode ray tube,
A thin plate having a first hole is additionally provided, and a second hole provided on a joint surface between the inner beam shield and the inner magnetic shield or a joint surface of only the inner magnetic shield and the spring-like locking means in the first hole. A method of attaching an internal beam shield and an internal magnetic shield to a mask by inserting the internal beam shield and the internal magnetic shield into the mask. 4. The method of attaching an internal beam shield and an internal magnetic shield to a mask according to claim 3, wherein the thin plate having the first hole is a temperature compensating plate. 5. The method of attaching an inner beam shield and an inner magnetic shield to a mask according to claim 3, wherein the thin plate having the first hole is a spring holder plate. 6. The method of attaching an internal beam shield and an internal magnetic shield to a mask according to claim 3, wherein the spring-like locking means is a clip.