KR20030062516A - The Flat Type C-CRT - Google Patents

Abstract

The present invention relates to a flat brown tube, and more particularly to a flat CRT tube which prevents the occurrence of cracks at the corner of the rail by adjusting the width of the panel joint of the rail and the cutting curvature of the rail corner.

The rail has a stepped groove formed on the surface in contact with the panel in the extending direction of the rail, the panel joint of the rail is divided into the inner junction and the outer junction by the groove portion, the inner junction width and the outer junction The relationship between the widths is characterized by satisfying the following equation.

Inner Junction Width / Outer Junction Width <1

The rail structure of the present invention has an effect of preventing cracking of the panel by allowing the stress applied to the panel to be dispersed by increasing the volume of the groove part.

Description

Flat CRT {The Flat Type C-CRT}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat brown tube, and more particularly, to a flat CRT which prevents the occurrence of cracks at the corners of the rail by adjusting the width of the panel joint of the rail and the cutting curvature of the rail corner.

In the conventional flat CRT, as shown in FIG. 1, R, G, and B fluorescent films 2 are coated on the inner surface, and a panel 1 having explosion-proof glass is fixed on the front surface thereof. At the rear end, the funnel 6 is fused with fritted glass. In addition, the fluorescent film emits color by the electron beam 9 emitted from the electron gun inserted into the neck portion 8 of the funnel. Inside the panel, a rail 5 capable of supporting the shadow mask 3 and the inner shield 7 is fused by the fritted glass 4. The shadow mask 3 has a plurality of holes formed in the inner surface to pass the electron beam, and is mounted at regular intervals from the inside of the panel. The shadow mask is thermally expanded by the electron beam emitted from the electron gun, which causes the shadow mask to deform. Therefore, in order to prevent deformation of the shadow mask due to thermal expansion, the shadow mask is tensioned and welded to the rail. In addition, the inner shield (7) for shielding the cathode ray tube is less affected by the external geomagnetic is welded to the rail.

Conventional rails are composed of two long side rails 5a and two short side rails 5b as shown in FIG. 2a, and grooves 5c are formed in the extension direction of the rails on the surface contacting the panel as shown in FIG. 2b. The long side rails 5a and the short side rails 5b have the same shape only in length.

The rails are automatically supplied by the automatic welding machine, and then the position of the rail is welded with a laser to form a rectangular frame shape. At this time, the groove is formed on the surface welded to the panel, the liquid glass frit glass is applied to the groove and dried, and the panel and rail are passed through a high-temperature furnace at about 400 ° C. in contact with the inner surface of the panel. Fusion. When the thickness of the upper end of the fused rail is polished to a desired amount by a desired dimension, and the shadow mask is welded on the laser, a single assembly including the rail and the panel is made. However, in the frit glass coating process, due to the temperature difference between the photoresist, the graphite, the phosphor, and the panel-rail assembly and the temperature difference between the various injection liquids, a strong thermal stress is generated at the contact portion between the panel and the rail attached to the inner surface of the panel. Is likely to develop into.

The panel-rail assembly is then passed through a high temperature furnace of about 400 ° C. and fused with the funnel using fritted glass. However, at this time, another thermal stress is generated between the funnels made of glass, and thus a greater stress is applied to the corners of the rails, thereby increasing the possibility of cracking.

As described above, in the manufacturing process of the CRT having a flat inner surface and an outer surface of the panel, stress due to temperature change is inevitably generated. In particular, the conventional rail, which serves to maintain a constant distance between the shadow mask and the fluorescent film, generates 15% of cracks in the manufacturing process.

The factor that most affects the cracks generated between the stainless rails and the glass panels is a thermal change acting externally. When heat is applied to the rail and the panel, both of them undergo thermal expansion. Since the thermal expansion of the panel and the glass is different from each other, when the external thermal shock is strong, cracks do not endure thermal stress. This stress imbalance is also prominent at the corners, the fusion points of the rail assemblies. 3 is a diagram showing the stress imbalance in the panel. As shown in the drawing, tensile stress is applied at the center of the panel, and tensile stress and compressive stress at the corners intersect to cause stress cracking.

Therefore, conventionally, the corner portion of the rail is cut at a constant curvature as shown in FIG. 4B in order to prevent stress from being concentrated at the corner portion. At this time, a hole is formed in the corner portion of the rail due to the cutout of the rail outside the panel, and the fritted glass applied to the groove of the rail to leak the rail into the panel is leaked through the hole when the rail is welded to the panel. The shape shown in FIG. 5 is formed.

In addition, the amount of fritted glass applied to the rail groove portion also affects the crack of the panel. The larger the amount, the smaller the volume of the rail groove portion is. However, the conventional rail structure prevents the fritted glass from flowing down and at the same time does not form a groove portion that is advantageous to reduce the occurrence of cracks.

Accordingly, an object of the present invention is to provide a flat CRT tube which prevents the occurrence of cracks at the corners of the rail by adjusting the width of the panel joints of the rails and the cutting curvature of the rail corners in order to solve the problems described above.

1 is a cross-sectional view of a flat CRT tube of the prior art,

2a to 2b is a view showing a rail structure of the prior art,

3 is a diagram showing a stress distribution of a panel with a rail of the prior art;

4a to 4b is a detailed view showing a rail structure of the prior art,

5 is a view showing a corner portion fritted glass shape of the prior art,

6a to 6b are views showing the rail structure of the present invention and

Fig. 7 is a diagram showing a corner fritted glass shape of the present invention.

*** Explanation of symbols for the main parts of the drawing ***

1 panel 3 shadow mask 4 fritted glass

5: rail 6: funnel

The technical means of the present invention for achieving this object is a panel having a flat inner and outer surfaces having a phosphor screen on the inner surface, a funnel connected to the panel, and arranged at regular intervals with respect to the phosphor screen on the inner surface of the panel to serve as color screening. In the flat CRT tube including a shadow mask and a rail attached to the inner surface of the panel for holding and fixing the shadow mask, the rail is formed in the step of extending the direction of the rail on the surface in contact with the panel in the step shape The panel joining portion of the rail is divided into an inner joining portion and an outer joining portion by the groove portion, and the relationship between the inner joining portion width and the outer joining portion width satisfies the following equation.

Inner Junction Width / Outer Junction Width <1

Preferably, the corner portion of the rail is cut at a constant curvature, and the relationship between the width of the outer junction portion of the rail and the radius of curvature of the corner portion is characterized by satisfying the following equation.

Outer joint width / corner cut radius of curvature ≥ 0.3

Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.

The present invention is to solve the problem of cracking the panel by complementing the shape of the rail assembly and the shape of the rail corner portion as described above.

Figure 6a, Figure 6b is a view showing the rail shape of the present invention, consisting of two long side rails (5a) and two short side rails (5b) as in the prior art, as shown in Figure 2b extending the rail on the surface in contact with the panel The groove portion 5c is formed in the direction, and the long side rails 5a and the short side rails 5b have the same shape except that they differ only in length. In addition, the panel joint of the rail is divided into an inner joint and an outer joint by the groove portion 5c, and the rail structure of the present invention has a different cross-sectional shape of the groove portion to which frits glass is applied. The square was used to increase the volume.

Increasing the volume of the rail groove portion is to increase the amount of fritted glass to prevent the occurrence of cracks by dispersing the stress. However, since parts such as shadow masks are welded to the rail assembly, the volume of the grooves cannot be increased indefinitely.

In addition, in order to increase the volume of the inner groove portion of the rail, the width of the panel joint portion of the rail should be reduced. If the width, in particular, the width of the outer joint portion is reduced too much, a hole is formed in the corner portion when the rail corner portion is cut at a constant curvature. This is because the fritted glass leaks from the cracks and causes cracks in the panel.

Therefore, the present invention allows the relationship between the panel outer junction width T1, the inner junction width T2 and the cut radius of curvature R of the corner portion of the rail to satisfy the following equation in view of the above problems.

T1 / R ≥ 0.3

T2 / T1 〈1

In the case of the prior art, as shown in FIG. 4, the width of the panel outer junction is less than 0.3 compared to the radius of curvature of the rail corner, so that a hole is formed in the corner and thus the fritted glass has a shape as shown in FIG. 5. As described above, the shape of fritted glass is increased to increase the concentration of stress to the corner portion, resulting in panel cracking, resulting in a defective rate of 15% or more.

However, in the case of the present invention, the width of the panel outer junction is 0.3 or more compared to the radius of curvature of the rail corner, so that no holes are formed in the corner, and the fritted glass forms the shape as shown in FIG. 7. As a result, stress concentrations were significantly relieved at the corners, and panel crack failure rate was reduced to 0.2%.

Moreover, in order to increase the volume of a rail groove part, this invention made the width | variety of the panel inner junction part of a rail smaller than the outer junction part width | variety. Therefore, the fritted glass is applied a lot in the rail and the stress is dispersed, thereby reducing the defect of panel cracking.

Table 1 below compares the embodiments of the present invention with the prior art.

TABLE 1

division Prior art The present invention Width of rail groove 3.8 3.3 Area of rail groove 4.6 9.9 Inner Junction Width / Outer Junction Width 1.0 0.56

As can be seen in Table 1, the present invention has a smaller width of the rail joint compared to the prior art, and the width of the panel joint is increased, and the area of the rail groove is increased by 200% or more compared to the prior art, so that the frittglass effectively disperses the stress. Panel crack failure rate can be reduced in the manufacturing process.

In addition, according to the present invention, the width of the inner joint is 0.56 relative to the width of the outer panel of the panel, and the width of the outer joint is 0.32 with respect to the radius of curvature of the rail corner. Therefore, a hole as in the prior art does not occur.

As described above, the rail structure of the present invention has an effect of preventing cracking of the panel by allowing the stress acting on the panel to be dispersed by increasing the volume of the groove portion.

In addition, the flat CRT can be recycled even if a defect occurs during the manufacturing process, if the crack prevention structure of the present invention is applied, there is no damage to the panel and funnel, so the recyclability of the defect increases, thereby reducing the production cost. have.

Claims (2)

A panel having an inner and outer surface having a phosphor screen on an inner surface thereof, a funnel connected to the panel, a shadow mask disposed at a predetermined interval with respect to the phosphor screen on the inner surface of the panel to serve as color screening, and the shadow mask being fixedly supported In a flat CRT comprising a rail attached to an inner surface of a panel for The rail has a stepped groove in the extending direction of the rail on the surface in contact with the panel, The panel joint of the rail is divided into an inner joint and an outer joint by the groove, A relationship between the inner junction width and the outer junction width satisfies the following equation. Inner Junction Width / Outer Junction Width <1 The method of claim 1, The corner portion of the rail is cut at a constant curvature, and the relationship between the width of the outer junction portion of the rail and the radius of curvature of the corner portion satisfies the following equation. Outer joint width / corner cut radius of curvature ≥ 0.3