JPH02195635A - Integral implosion-protected cathode-ray tube - Google Patents

Abstract

PURPOSE:To suppress the scattering of glass fragments due to the fracture of a glass bulb so as to prevent the spread of the injury by injecting a suspension of low melting glass powders between a metallic band and the peripheral surface of a tube body and melting and solidifying the low melting glass in the after heating and exhausting processes. CONSTITUTION:After surrounding the skirt surface of a panel 1 with a composite tape consisting of a glass cloth 12 on the both ends in the width direction of which auxiliary cotton tapes 11 coated with adhesive 10 on the one side surface are stuck respectively a frame-like metallic band 8 is thermally expanded to fit on the glass cloth 12 and cooled to clasp it tightly. And after taking off the auxiliary cotton tapes 11 coated with combustible adhesive, a frit glass solution 13 consisting of a suspension of low melting glass powders in a binder is injected into the glass cloth portion between the panel 1 and the metallic band 8, then heating and exhausting processes are carried out. During the exhausting process, the low melting glass powders in the frit glass solution 13 injected between the metallic band 8 and the panel 1 are melted and solidified to fix the skirt surface of the panel to the inner surface of the metallic band tightly.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is designed to suppress the scattering of glass fragments of the bulb to a minimum even if the glass bulb forming the tube body breaks or implodes. Related to reinforced cathode ray tubes.

[Prior art] In a cathode ray tube whose tube interior is evacuated to a high degree of vacuum,
Because pressure equivalent to atmospheric pressure is applied from the outside,
If the tube body is damaged or subjected to an impact, the glass bulb in the tube body may suddenly break or implode, causing glass fragments to scatter.

As a countermeasure to this situation, it is common practice today to tighten the outer periphery of the panel skirt of the glass bulb of a cathode ray tube (normally this area is the maximum outer periphery) with a metal band to relieve stress caused by atmospheric pressure and prevent cracks. Measures are taken to suppress propagation and avoid implosion that would cause glass to scatter widely even if the bulb were to break and the airtightness was broken.

Conventionally, such explosion-proofing means are usually applied after the heating and exhausting process of the cathode ray tube is completed.

However, in order to release adsorbed gas from the glass bulb and other tube internal parts of the cathode ray tube, the glass bulb is heated to approximately 400°C in the exhaust process, so as the temperature rises and the vacuum inside the tube rises, the pressure gradually applied from the outside increases. Due to atmospheric pressure, stress is generated in various glass parts of the bulb even during the exhaust process. Furthermore, when the valve is removed from the exhaust furnace after the exhaust process and exposed to ambient air at room temperature, the valve is rapidly cooled, which also generates stress. Therefore, if the glass bulb is scratched or hit, there is a high risk that it will suddenly break or implode and the glass will scatter during or immediately after the heating and exhaust process. Also,
It is also undesirable for glass shards and the like to be scattered inside the exhaust furnace and make the inside of the furnace dirty.

In recent years, there has been a trend toward favoring cathode ray tubes with large display surfaces, small radii of curvature at the four corners, and nearly flat display surfaces, but such tubes are particularly susceptible to implosion.

Conventionally, Japanese Patent Application Laid-Open No. 62-5533 discloses that before the heating and exhausting step, a heat-resistant insulating material is wrapped around the front outer periphery of the pipe body and the top is tightened with a metal band to prevent implosion, and then, It is disclosed that cathode ray tubes are manufactured by heating and exhausting, but in this process, the metal band thermally expands more than the glass bulb in the heating and exhausting furnace, and the tightening force and therefore the explosion-proof effect are lost, causing an explosion in the exhausting furnace. It states that the above manufacturing method is effective in preventing destruction during rapid cooling when exiting from the exhaust furnace. It has also been stated that glass cloth tape coated with adhesive on both or one side is used as a heat-resistant insulating material, but adhesives, which are organic substances, are generally burned at high temperatures inside the exhaust furnace. This may contaminate the cathode ray tube itself and reduce its explosion-proof effect.

[Problems to be Solved by the Invention] The present invention solves the above-mentioned conventional reinforced cathode ray tube manufactured by tightening the vicinity of the maximum outer circumference at the front of the cathode ray tube with a metal band for implosion prevention before the evacuation process. We have developed a reinforced cathode ray tube that solves this problem and minimizes the scattering of glass fragments even if the glass bulb breaks or implodes during the work process or during actual use after completion. The purpose is to provide.

[Means for Solving the Problems] In order to achieve the above object, in the present invention, a nonflammable cushioning material is wrapped around the front maximum outer circumference of the pipe body, and a metal band for implosion prevention is tightened from above. After that, in the reinforced cathode ray tube manufactured by heating and exhausting, the non-flammable cushioning material and implosion prevention metal band are attached near the front maximum outer periphery of the tube, and then the metal band and the tube are removed. By injecting a liquid containing low melting point glass powder suspended in a binder between the outer circumferential surface and melting and solidifying the low melting point glass in the subsequent heating and exhaust process, the outer surface of the maximum outer circumference of the tube and the metal We decided to firmly attach it to the inner surface of the band. In addition, in order to make it easier to wrap the non-combustible AM material,
Another auxiliary tape with adhesive is added to the widthwise end of the non-combustible cushioning material tape, and this auxiliary tape is used after the non-combustible cushioning material is tightened from the outside with a metal band. Remove it before exhaust work.

[Function] If the above-mentioned measures are taken, the low melting point glass used for the fusion bonding of the panel part and the funnel part of the color cathode ray tube and also used in the present invention will crystallize and solidify once melted. Because of this property, the fixing effect of the low melting point glass between the metal band and the panel skirt according to the present invention is strongly maintained, and it can be used during the heating and exhausting process, when cooling after heating and exhausting, and even during actual use after completion. In either case, even if the valve is destroyed,
Even in the event of an implosion, the scattering of glass fragments and the resulting damage will be kept to a minimum. Note that the adhesive tape used to wrap the nonflammable cushioning material must be removed before placing it in the exhaust furnace, so the adhesive or tape itself (e.g. cotton tape) may burn and cause damage to the cathode ray tube. There is no risk of contaminating the pipe body or the inside of the exhaust furnace.

[Embodiment] Figure 1 is a side view of a reinforced cathode ray tube according to the present invention, in which the panel skirt of the valve is tightened with a metal band via a nonflammable cushioning material before the heating and exhaust process. After forming a tube body 3 by fusion-bonding a glass panel 1 with a colored fluorescent surface formed on its inner surface to a funnel 2 using low-melting glass, an electron gun assembly 5 is supported within a neck portion 4. After inserting the entire glass stem 6 and melting and sealing the stem 6 and the end of the neck portion 4, it is placed around the skirt of the panel 1 or on the melting joint of the panel 1 and funnel 2 made of low melting glass. A nonflammable cushioning material 7, such as glass cloth tape, is wrapped around the entire circumference. However, it is difficult to maintain the condition after wrapping with only non-combustible cushioning material, so as shown in FIG.
A composite type tape is made and used by pasting an auxiliary cotton tape 11 coated with an adhesive 10 on one side. After this composite tape is wrapped around the skirt surface of the panel 1 as shown in FIG. 3, it is tightened with a metal band 8 from above the glass cloth 12 (nonflammable cushioning material 7).

In this case, the metal band 8 has the shape of the outer periphery of the tube at the location where both ends of the metal band are welded and the metal band is to be tightened in advance.
Form into a frame shape depending on the size.

This frame-shaped metal band 8 is heated and expanded, fitted onto the glass cloth 12, cooled, and tightened.

Thereafter, the auxiliary cotton tape 11 with the flammable adhesive was removed, and low-melting glass powder was suspended in a binder on the glass cloth between the panel 1 and the metal band 8, as shown in FIG. After injecting the liquid (hereinafter referred to as frit glass liquid 13), heating and exhaust operations are performed.

This evacuation operation is performed through an evacuation pipe 9 provided through the glass stem 6, and after evacuation, this pipe is tipped off and hermetically sealed. The evacuation work is performed by heating the tube body 3 to, for example, 400° C. in a heating evacuation furnace as usual. During this evacuation step, the low melting point glass powder in the frit glass liquid 13 injected between the metal band 8 and the panel 1 is melted and solidified to firmly adhere the surface of the panel skirt and the inner surface of the metal band. After evacuation, the tube body 3 is taken out from the evacuation furnace.

In the above embodiment, the electron gun is sealed with the valve and then tightened with the metal band 8. However, in some cases, the electron gun may be tightened with the metal band 8 before being sealed. After bonding panel 1 to funnel 2 with low melting point glass, the outer periphery of the skirt of panel 1 was tightened with metal band 8, but conversely, after tightening the skirt of panel 1 with metal band 8, This panel 1 may be fused and bonded to the funnel 2 using low melting point glass.

Further, in the above embodiment, the metal band 8 was previously formed into a frame shape by welding and then shrink-fitted, but it may be tightened with a gold spunt and then caulked to secure the joint using a well-known method.

[Effects of the Invention] As explained above, according to the present invention, the outer surface of the panel skirt and its exterior can be tightened during the heating and exhausting process, in the rapid cooling state after exhausting, and even during subsequent actual use. Since the glass bulb is firmly fixed to the metal band, even if the glass bulb breaks and implodes during any of the above periods, the scattering of glass fragments will be suppressed to a minimum.
The damage will not spread. Note that no contamination of the tube body of the cathode ray tube or the inside of the exhaust furnace occurs during exhaustion.

[Brief explanation of the drawing]

Fig. 1 is a side view of a reinforced cathode ray tube in which the panel skirt is tightened with a metal band via a nonflammable cushioning material before the heating and exhaust process; Fig. 2 is a cross-sectional view of the nonflammable TFTWI material used in the present invention; The figure is an enlarged view showing a state in which glass cloth is wrapped around a panel skirt and the top is tightened with a metal band, and FIG. 4 is an enlarged view showing a state in which a frit glass liquid is injected into the glass cloth under the metal band. 1...Panel, 2...Funnel, 3...
・Tube body, 4... Neck part, 5... Electron gun structure,
6...Glass stem, 7...Nonflammable cushioning material, 8
...Metal band, 9...Exhaust pipe, 1o...Adhesive, 11...Cotton tape, 12...Glass cloth, 13...Frit glass liquid. 13- Fritz π′ UZ bud begging

Claims (1)

[Claims] 1. In a reinforced cathode ray tube manufactured by wrapping nonflammable cushioning material around the front maximum outer circumference of the tube body, tightening it with a metal band to prevent implosion from above, and then heating and exhausting the tube,
After attaching the nonflammable cushioning material and implosion prevention metal band near the front maximum outer circumference of the tube, a suspension of low-melting glass powder is injected between the metal band and the outer circumferential surface of the tube. A reinforced cathode ray tube characterized in that, by melting and solidifying the low-melting point glass in a subsequent heating and exhausting step, the outer surface of the maximum outer circumferential portion of the tube body and the inner surface of the metal band are firmly fixed.