JPS63102145A - Cathode-ray tube - Google Patents

Abstract

PURPOSE:To prevent cracks on the screen side from extending on the funnel side and to improve an explosion-proof level by making sealing positions, which are near side central parts of panel side parts, formed on the other end sides in the tube axis direction from the sealing positions of corner parts. CONSTITUTION:Side parts 2b of a square panel 2 are shaped into square cylinders, and each side of them is formed into a nearly elliptical shape in which the part near a side central part 12 is mere wide than a corner part 11. On the other hand, end parts 16 of side parts 4a of a funnel 4 are curved along projecting parts 15 on the panel side parts 2b, and the panel side parts 2b and the funnel side parts 4a are sealed. Subsequently, the positions 7 where the panel 2 and the funnel 4 are sealed on the side central parts 12 are set on the other end sides by Hx and Hy in the Z axis direction from the sealing parts 7 of the corner parts 11, and so strength of the side central parts 12 resisting explosion on a vacuum state can be enlarged, so that cracks generat ed on a screen part 2a can be prevented from extending on the side central parts 12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a picture tube (hereinafter referred to as CRT) used for television receivers, computer terminals, and the like.

[Prior Art J] FIG. 8 is a partially cutaway side view of a conventionally used shadow mask type color CRT. In Figure 1ζ, C
RT (1) consists of a panel (2) whose inner surface is coated with a fluorescent screen (3), and a funnel (2) connected to the panel (2).
4) and a neck (5) containing an electron gun (not shown). The above fluorescent screen (3
), a shadow mask (6) is arranged. When a part of the glass component of such a glass vacuum container breaks for some reason, a phenomenon called implosion occurs.

That is, the glass is drawn into the vacuum, and eventually glass fragments will fly out, and careful efforts must be made to prevent this. For this purpose, the following explosion-proof treatment is generally performed. In other words, the panel (2) is divided into a screen part (2a) and a side part (2b), and a protective tape (8) is pasted on the panel side part (2b), and a metal band αq is wrapped over it. By turning and tightening, vacuum deformation of the glass vacuum container is reduced. Here, when winding the metal band QO, as shown in FIG.
2b), the CRT is mounted and held in the diagonal direction of the screen (3) by tightening a metal band QQ (FIG. 8) using a metal fitting (9). Note that the screen (3) has a rectangular shape,
For convenience of the following explanation, the horizontal axis is defined as x1, the vertical axis is defined as Y1, the diagonal axis is defined as P, and the tube axis of the CRT is defined as 2. 0 is the center of the screen (3).

FIG. 5 is a perspective view of a conventional CRT without explosion-proof treatment. In the figure, the stress distribution of the CRT (1) is shown by the broken line P in FIG. 6, where the broken line part Pi outside the tube wall represents the tensile stress distribution, and the inside broken line part P2 represents the compressive stress distribution. It shows. Here, CRT (1)
In the case of a glass vacuum container such as the one above, since the inside is vacuum, it is important to note that the tensile stress that occurs outside the tube wall (on the atmospheric pressure side) may lead to the glass breaking. is common sense. That is, the side surface extending from the end of the screen part (2a) of the panel (2) to the vicinity of the sealing part (7) between the panel (2) and the funnel (4) is the most important part in terms of explosion-proof performance. Also, on the other hand, [ARevie
w Vo189, Dec, 1978 * Appgi
cation of FiniteElement M
methods to the analysis
f 5tressesin Te1evision
As reported in ``Piature Tubes'',
The sealing part (7) between the panel (2) and the funnel (4), where the sealing is performed with glass solder frit glass, is the most important point in a glass bulb as it is an actual crack source.

Figure 7 is a diagram explaining the shape of the above-mentioned CRT panel. Figure 7 (4) is the shape of a panel with a rotationally symmetrical radius of curvature Rp, which has been used in the past, and Figure CB) is the shape of a panel with a rotationally symmetrical radius of curvature Rp, which has been used recently. , P, (5quare Planer) shows the panel shore. Figure 7 shows the cross sections of the panel (2) along the X, Y, and P axes of the panel (2) and the funnel (4).
) (Fig. 6) are shown superimposed on each other based on the sealing surface (7), and d corresponds to the screen center. Hx + Hy
e HP is the height of the panel side surface portion (2b) from the sealing portion (7).

The screen portion (2a) in FIG. 7(9) is aspherical, and unlike the rotationally symmetrical one in FIG. 7(4), the cross-sectional shape of the screen portion (2a) in each axial section, that is, the radius of curvature RP.
I I RP$t and HP8 are different, and the above height Hx + By.

Their characteristic is that their HP values are close to each other.

By the way, the method for evaluating the explosion-proof performance of a CRT is to damage the screen part (2a) of the panel (2), and when the implosion is forcibly caused, the glass fragments are scattered. It is judged based on how dangerous the situation is to humans. From my experience in conducting such tests,
The key point is how to prevent the cracks generated on the screen portion (2a) side from extending toward the funnel (4) (FIG. 6), and this is a well-known matter.

[Problem that the invention seeks to solve]

However, in the conventional CRT described above, as shown in FIG. 7(A),
The sealing portion (7) of CB) is a flat plane that is perpendicular to the tube axis (two axes) direction. That is, the coordinates of the sealing position of each axial cross section of the X, Y, and P axes are in the same plane. Here, as shown by the shaded area 20 in FIG. )side,
They are concentrated on the panel side part (2b) and the funnel (4), respectively. FIG. 8 shows only the first quadrant, which corresponds to 1/4 of the CRT. The reason for the grain-like distribution is that the deformation caused by the vacuum causes the panel screen surface to deform in a shape that is almost similar to that of the rectangular screen (3), as shown in FIG. A broken line M indicates a contour line of deformation due to vacuum.

Therefore, the sealing part (7), which has poor strength against implosion, is located in the shaded area 20 where the principal stress is large in FIG. 8. Therefore, as explained in FIG. Even if the above-mentioned explosion-proof treatment was carried out, the explosion-proof treatment did not reach the level that would solve the problems described above, and the cracks on the screen part (2a) side extended to the funnel (4) side. However, the problem arises that the CRT (1) implodes.

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a picture tube that can improve the level of implosion resistance.

[Means for solving problems]

The picture tube according to the present invention has a panel having a rectangular screen on one end side in the tube axis direction, and a funnel sealed to the side surface of the panel, and the funnel is sealed near the center of the side of the panel side surface. The attachment position is set closer to the other end in the tube axis direction than the sealing position with the funnel at the corner portion.

[Operation] According to the present invention, the sealing position near the center of the side of the panel side is set closer to the other end in the tube axis direction than the sealing position at the corner, that is, in a direction away from the screen. As a result, the width in the tube axis direction near the center of the side surface of the panel is increased, and the sealing position with the funnel is also moved away from the screen edge of the panel. This suppresses cracks generated on the screen side from extending toward the funnel side.

[Embodiments of the invention] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing a picture tube which is an embodiment of the present invention. In the figure, (2) is a panel with two axes (tube axes)
A square screen part (
2a) is formed. (2b) is the side part of the panel,
Approximately 9 points from each end of the screen part (2a) in the X-axis, Y-axis, and P-axis (diagonal axis) directions toward the funnel (4) side.
Bend 0 degrees and the other end side in the above two axis directions (lower side in Figure 1)
Each extends towards This panel side part (2
b) has a rectangular cylinder shape, and the side surface thereof is formed into a substantially elliptical shape that is wider near the center part (2) of the side than the corner part aυ. In other words, as shown in Figure 2, the side surface of the panel (
2b) The maximum width Hy in the two axial directions at the center of the fire,
Hx is selected to be larger than the width HP in the two axis directions at the corner portion Qυ. In addition, the side part of the panel (
The protrusion (end) of 2b) toward the funnel (4) side is curved in a semicircular arc so as to be convex toward the funnel (4) side, and in a 14-inch CRT, the maximum protrusion of the protrusion (4) The width 4y and ΔHx (<ΔHy) are, for example, 16j
! II and 8 am, respectively. In addition,
The ratio of the X-axis and Y-axis widths of the screen part (2a) is 4:
8.

On the other hand, the funnel (4) is connected to the panel side part (2b).
It consists of a side part (4a) sealed to the side part (4a) and a cone part (4b) connected to the side part (4a). The end α of the funnel side surface (4a) on the panel (2) side is curved concavely toward the neck (5) along the protrusion (end) of the panel side surface (2b). As a result, the panel side surface portion (2b) and the funnel side surface portion (4a) are hermetically sealed via the sealing frit glass, as shown in FIG. Therefore, the panel (2
) and the funnel (4) (hereinafter referred to as the sealing part (7)
). ) is the sealing part (7) at the corner αυ
They are set closer to the other end (downward in FIG. 1) in the two-axis direction by the amount ΔHx and ΔMy (FIG. 2).

In the above configuration, the panel side part (2b) shown in FIG.
Since the protruding part (2) is provided at the center part (2) of the side, the sealing part (7) at the center part of the side A is moved away from the end of the screen part (2a), and the diagonal line in FIG. The position can be shifted from the location where the principal stress is large as shown in part (1).

Therefore, when the CRT (1) is in a vacuum, the strength against implosion at the center of the side is increased, and during manufacturing and transportation processes, etc.
The cracks generated on the screen portion (2a) side are prevented from spreading by the wide center portions of the sides, and are prevented from reaching the funnel (4) side. As a result, the implosion resistance level of the CRT (1) is improved, and a high quality evaluation can be obtained.

In addition, after sealing the panel (2) and funnel (4),
As in the past, explosion-proof treatment is provided using a metal band QQ (Fig. 8).

〔Effect of the invention〕

As explained above, according to the present invention, by setting the sealing positions at the center of the side and the corner at positions different from the tube axis direction, cracks generated on the screen side are suppressed from extending toward the funnel side. Therefore, the possibility of implosion of the picture tube is reduced, and the implosion resistance level can be improved.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the present invention, FIG. 2 is an exploded perspective view of the same embodiment, FIG. 8 is a partially cutaway side view showing the structure of a conventional picture tube, and FIG. Figure 3 is a front view, Figure 5 is a perspective view of Figure 8, Figure 6 is a cross-sectional view showing the stress distribution due to vacuum in a picture tube without explosion protection, and Figures 7 (4) and (6) are conventionally used. FIG. 8 is a perspective view showing the stress distribution of a rectangular screen, and FIG. 9 is a diagram showing the deformation of the screen surface of a picture tube having a rectangular screen due to vacuum. (1)... picture tube, (2)... panel, (2a)...
... Screen part, (2b) ... Panel side part, (4
)...Funnel, (5)...Neck, (7)...
・Sealing position, aυ...corner, o2...center of side, 2...tube axis direction. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] (1) In a picture tube with a vacuum-sealed structure consisting of a panel having a rectangular screen on one end side in the tube axis direction, a funnel sealed to the side surface of the panel, and a neck continuous to the funnel, the side of the side surface of the panel A picture tube characterized in that a sealing position with the funnel in the vicinity of the center portion is set closer to the other end in the tube axis direction than a sealing position with the funnel in the corner portion.