JPH0721999B2 - Explosion-proof cathode ray tube - Google Patents

Description

The present invention relates to an explosion-proof structure for a cathode ray tube.

[Conventional technology]

Figure 3 shows a conventional band-reinforced shear-mask type color cathode ray tube with a rim, which is a type of explosion-proof cathode ray tube (hereinafter referred to as "CR
(T)) (1) Partially cutaway perspective view showing the configuration
The figure is the front view, and the panel (2), the funnel (4), and the neck (5) constitute the envelope (20) of the CRT (1). (3) is a fluorescent screen formed on the inner surface of the panel (2), (6) is a shed mask, (7) is a frit seal between the panel (2) and the funnel (4),
Reference numeral (8) is a rim formed of a metal plate, and a peripheral surface portion (8b) extending along the side surface (2b) of the panel and a bent portion for subsequently pressing the peripheral portion of the front surface (2a) of the panel. The cross-sectional shape having (8a) is normally divided into two on the left and right sides, and is configured to be overlapped and connected at the central portion. (9) is a mounting ear, (10) is a tightening band (hereinafter referred to as “band”), and (12) is a gap between the outer wall surface of the panel (2) and a rim (8) formed of a metal plate. It is a used adhesive resin.

FIG. 5 is a front view of the CRT showing the deformed state of the front surface (2a) of the panel (2) when the inside of the CRT (1) is evacuated to a vacuum.
The amount of deformation is represented by contour lines as shown by the broken lines having substantially the same shape as the rectangular fluorescent screen (3). For convenience of explanation, the tube axis is Z and the longitudinal direction of the panel (2) passing through the tube axis is X.
The direction perpendicular to the X axis passing through the axis and the tube axis Z (the minor axis direction of the panel (2)) is taken as the Y axis, and the diagonal direction of the panel (2) passing through the Z axis is taken as the P axis.

FIG. 6 is a perspective view showing a portion corresponding to the first quadrant in which the CRT (1) is cut along the ZX plane and the ZY plane, and is a diagram showing a distribution of stress applied to the envelope (20) during vacuum evacuation.

Due to the deformation of the panel (2) shown in FIG. 5, the portions (13a) and (13b) surrounded by the hatched broken lines in FIG.
Large stress is applied to. Rim (8) and band (10)
Is provided to reduce this stress. The tightening force of the band (10) allows the side surface (2
b) and the part of the funnel (4) that follows it suppresses the bulge outward and reduces it. The tightening force of the band (10) is the diagonal direction of the panel (2) ( Although it works effectively in the ZP direction), a large tightening force cannot be applied in the ZX and ZY directions. The rim (8) is for effectively applying the tightening force of the band (10) also in the ZX and ZY directions. The rim (8) extends along the side surface (2b) of the panel as shown in FIG. It is formed in a sectional shape having a peripheral surface portion (8b) and a bent portion (8a) that presses the peripheral portion of the front surface (2a) of the panel, and an adhesive resin such as epoxy resin is provided in the gap between the panel (2). (12) is filled and tightened with the band (10), and the rim (8) is integrally fixed to the panel (2) to enhance rigidity. Follow Band (10)
Since the tightening force is applied to each side of the side surface (2b) of the panel in the X and Y directions via the rim (8) and the adhesive resin (12), the explosion-proof effect is improved.

The standard for the explosion-proof effect in each country is that the front surface (2a) of the panel is scratched in advance, and a metal ball or the like collides against the front surface (2a) to implode, and then glass that flies in front of the CRT. Specified by the amount of debris.

In the band-reinforced CRT with rim, the side surface (2b) of the panel is reinforced by the rim (8), and the bent portion (8a) of the rim (8) surrounds the peripheral edge of the front surface (2a) of the panel. It holds down the entire circumference, and it has the effect of suppressing the glass fragments from jumping out in front of the CRT, which gives a good effect.

[Problems to be solved by the invention]

By the way, the width W of the bent portion (8a) of the conventional rim (8) is
As shown in FIG. 4, they were formed to have almost the same width over the entire circumference. However, the envelope (20) has a shape in which the panel (2) approaches the direction close to a flat plate, that is, the direction in which the radius of curvature is large, and the fluorescent screen (3) is formed in a shape closer to a rectangle. This is a problem in enhancing the explosion-proof effect of the cathode ray tube (1).

The present invention has been made for the purpose of solving such problems, and an object thereof is to obtain an explosion-proof cathode ray tube having a large explosion-proof effect.

[Means for solving problems]

The explosion-proof cathode-ray tube according to the present invention has a rim that is mounted around the panel of the envelope and tightens the panel from the periphery, and forms a bent portion that covers the entire periphery of the front surface of the panel,
The bent portion is formed by a difference between a panel peripheral portion having a curvature and a screen having a substantially rectangular shape, and the bent portion of the rim is formed wide from the corner portion to the central portion. To do.

[Action]

According to this invention, the rigidity of the rim is sufficiently increased by forming the bent portion that covers the peripheral edge of the front surface of the panel over the entire circumference of the rim. By widening the bent portion of the rim from the corner portion to the central portion, the bent portion presses the peripheral portion of the front surface of the panel with a wide surface, and the explosion-proof effect is sufficiently ensured.

Example of Invention

 An embodiment of the present invention will be described below.

FIG. 1 is a front view of this embodiment, and FIG. 2 is a perspective view showing a half of the rim (8) of this embodiment. In the figure, the rim (8) is formed with a bent portion (8a) that covers the peripheral edge of the front surface (2a) of the panel (2) over the entire circumference. The width of the bent portion (8a) is formed by the difference between the peripheral portion of the panel (2) having a curvature and the substantially rectangular shadow mask (6) (see FIG. 3). That is, the central portion of each side, that is, Wb and Wa on the X axis and the Y axis are formed to have a width that is wider than the width Wc on the corner portion, that is, the P axis and does not cover the fluorescent screen (3). When the rim (8) thus formed is coated with an adhesive resin and fitted on the side surface of the panel (2) and tightened by the band (10), the bent portion (8)
By the a), the front surface (2a) of the panel (2) is covered with a wide width so that the rigidity of the rim (8) itself is increased and the reinforcing effect of the envelope (20) is improved. At the same time, since the bent portion (8a) holds the front surface (2a) of the panel (2) with a wide surface, the glass fragments are prevented from scattering forward when implosion occurs, so that the explosion-proof effect is improved.

Although the adhesive resin (12) is applied to the rim (8) in the above embodiment, it may be applied to the envelope (20).

In addition, although the above embodiment has described the band-reinforced cathode ray tube with a rim, the rim (8) is integrally formed and is called a shrink link band that is attached to the CRT by shrink fitting. The same can be applied to a cathode ray tube provided with, and the same effect can be obtained.

〔The invention's effect〕

As described above, according to the present invention, the rigidity of the rim is sufficiently increased by forming the bent portion that covers the entire periphery of the front surface of the panel on the rim that tightens the panel of the envelope from the periphery. In addition, the width of the bent portion is widened from the corner portion to the central portion, so that the peripheral portion of the front surface of the panel can be pressed by a wide surface. Therefore, the highly rigid rim widely presses the peripheral portion of the front surface of the panel, and a predetermined explosion-proof effect can be sufficiently improved.

[Brief description of drawings]

FIG. 1 is a front view of an embodiment of the present invention, FIG. 2 is a perspective view showing the shape of the rim in this embodiment, FIG. 3 is a partially cutaway side view of a bunted reinforced CRT with a rim, and FIG. Is its front view, FIG. 5 is a front view showing the deformation of the front surface of the panel when the CRT is evacuated, FIG. 6 is a perspective view showing the stress distribution applied to the envelope, and FIG. 7 is a conventional rim Band reinforced type
It is a partially expanded sectional view of a CRT. (1) ... Cathode ray tube, (2) ... Panel, (2a) ... Front of panel, (3) ... Fluorescent screen, (8) Rim, (8a) ...
Bent section, (10) ... tightening band, (12) ... adhesive resin, (2
0) ... enclosure. In the drawings, the same reference numerals indicate the same parts.

Claims (1)

[Claims] 1. An explosion-proof cathode ray tube equipped with a rim mounted around a panel of an envelope and tightening the panel from the periphery, wherein a bent portion is formed on the rim to cover the peripheral edge of the front surface of the panel over the entire circumference. The bent portion is formed by the difference between the panel peripheral portion having a curvature and the substantially rectangular screen, and the bent portion of the rim is formed wide from the corner portion to the central portion. Explosion-proof cathode ray tube.