JPH07211270A - Cathode-ray tube and manufacture of display surface panel for cathode-ray tube - Google Patents

Abstract

PURPOSE:To maintain a space between a linear negative electrode and a light emitting surface inside of a display surface panel constant by forming the shape of a display surface panel before sealing into a curved surface projecting outside, and setting a degree of curvature so as to be flat under the internal pressure reduction condition. CONSTITUTION:At the time of manufacturing a display surface panel a belt-like float glass, which is flown under the fused tin bath condition, is passed through an annealing furnace, and a display surface panel 3 for cathode-ray tube is segment from this belt-like float glass. In this case, temperature distribution inside of the annealing furnace is set so that temperature of the upper surface side of the belt-like float glass is lower than that of the lower surface side and that a temperature difference between the lower surface and the upper surface becomes larger as it comes outside in the cross direction of the belt-like float glass. Shape of the panel 3 before sealing is curved so as to be projected outside at a degree, which can be flat under the condition that the inside pressure is reduced after the sealing. A space between a linear negative electrode 41 forming an electron gun unit 4 and the light emitting surface of the side surface of the panel 3 is thereby maintained constant, namely, range distance of the electron beam can be maintained constant on one negative electrode wire 41.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat type cathode ray tube used for a TV receiver, a computer display, etc., and a method for manufacturing a glass display surface panel constituting the cathode ray tube.

[0002]

2. Description of the Related Art A flat panel cathode ray tube has a structure in which a display surface panel and a rear panel are sealed together, the inside pressure is reduced, and an electron beam from an electron gun provided inside is formed on the inside surface of the display surface panel. It is configured to illuminate the surface to develop color. Regarding the shapes of the display surface panel and the rear panel, as disclosed in Japanese Patent Publication No. 5-46047, the display surface panel is dish-shaped and the electron gun unit is incorporated inside the display surface panel. Alternatively, there is a display panel in which the electron gun unit is incorporated inside the rear panel having a flat plate shape and a box shape.

By the way, in the cathode ray tube, since the inside of the cathode ray tube is evacuated after the display surface panel and the back surface panel are sealed, the display surface panel is deformed inward. If this amount of deformation is large, the distance (electron beam range) between the electron gun unit and the light emitting surface inside the display surface panel is not constant, and the image quality deteriorates.
Therefore, in the case where the display surface panel has a dish shape, as disclosed in Japanese Patent Application Laid-Open No. 5-761, the direction in which the display surface panel is deformed by vacuum drawing using a jig at the time of sealing is used. A means for removing the jig after sealing while applying deformation in the opposite direction is disclosed.

[0004]

Sealing while deforming the display surface panel is performed when an excessive force acts on the display surface panel and is easily damaged during sealing, and when the display surface panel is dish-shaped. Is easily deformed, but is difficult to deform when it is flat. Therefore, the distance between the linear cathode that constitutes the electron gun unit and the light emitting surface on the inner surface of the glass display surface panel is not constant on one linear cathode wire, and it is difficult to obtain high image quality.

[0005]

In order to solve the above problems, the cathode ray tube according to the present invention is based on the premise that the opening of a dish-shaped rear container is sealed by a flat plate display panel made of glass. The shape of the display surface panel before sealing was a curved shape that was convex toward the outside, and the degree of this curvature was flat after sealing when the inside was depressurized. here,
The degree of curvature of the display surface panel is a / Ls ≦ 1.0 × 1 where Ls is the short side of the display surface panel and a is the maximum recess amount.
It is preferably 0 ^-3, and the difference in average linear expansion coefficient between the glass display surface panel and the glass back container at 30 ° C to 350 ° C is 1.0 x 10 ^-6 / ° C or less. Is preferred.

Particularly, when the display surface panel has a shape obtained by cutting a cylinder in the axial direction, the axial direction of the display surface panel and the linear cathode forming the electron gun unit are arranged in parallel.

Further, when the electron beam coloring prevention layer is formed at a depth position where the electron beam reaches the inner surface layer portion of the glass display surface panel, Na ₂ O in the electron beam coloring prevention layer is formed.
The molar ratio of K ₂ O and K ₂ O is 0.3 ≦ Na ₂ O / (Na ₂
O + K ₂ O) ≦ 0.7.

On the other hand, in the method of manufacturing the display surface panel according to the present invention, the strip-shaped float glass poured out in the molten tin bath is passed through the annealing furnace, and the display panel for the cathode ray tube is cut out from the strip-shaped float glass. In the manufacturing method according to the above, the temperature distribution in the annealing furnace is set such that the upper surface side is lower than the lower surface side of the strip-shaped float glass, and the temperature difference between the lower surface side and the upper surface side is closer to the outer side in the width direction of the strip-shaped float glass. I made it bigger.

[0009]

Since the shape of the glass display surface panel before sealing is curved outwardly to the extent that it becomes flat when the inside is depressurized after sealing, the linear shape of the electron gun unit is formed. The distance between the cathode and the light emitting surface on the inner surface of the glass display surface panel, that is, the range of the electron beam is constant on one linear cathode line.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is a sectional view showing a state before sealing the cathode ray tube according to the present invention, FIG. 2 is a sectional view showing a state after sealing the cathode ray tube, and FIG. 3 is a glass constituting the same cathode ray tube. FIG. 3 is a perspective view of a display surface panel made of glass, and an outer portion of the cathode ray tube 1 is composed of a glass-shaped back container 2 having a dish shape and a glass display surface panel 3 having a plate shape.

An electron gun unit 4 is arranged in the rear case 2. The electron gun unit 4 has a linear cathode (line cathode) 41 from which an electron beam is emitted, a control electrode 42, a signal modulation electrode 43, a focusing electrode 44, It is composed of a horizontal electrode 45 and a vertical electrode 46.

The display surface panel 3 is hermetically attached to the opening of the rear case 2 accommodating the electron gun unit 4 through a sealing frit (low melting point lead glass) 5, and the inner surface thereof is irradiated with an electron beam. As a result, a fluorescent surface 3a that emits color is formed.

Further, the shape of the display surface panel 3 before sealing is a curved shape which is convex outward. The degree of this curvature is made flat in the state shown in FIG. When a glass plate having a general thickness is used, when the short side length of the display surface panel 3 is Ls and the maximum recess amount is a, a / Ls ≦ 1.0 × 10 ⁻³ ,
Preferably 3.5 × 10 ⁻⁴ ≦ a / Ls ≦ 7.0 × 10 ⁻⁴
By doing, it becomes flat. Then, by becoming flat, the linear cathode 41 and the light emitting surface 3a on the inner surface of the display surface panel 3 are formed.
And the distance of the electron beam, that is, the range of the electron beam, is constant on one linear cathode ray, and high image quality can be obtained.

Further, if the average linear expansion coefficient of the glass material forming the rear case 2 and the display panel 3 is significantly different, the rear case 2 or the display panel 3 may be damaged by residual stress after sealing. It is preferable that the difference in average linear expansion coefficient between the both at 30 ° C. to 350 ° C. is within 1.0 × 10 ⁻⁶ / ° C. Since the larger the size, the easier it is to break. Therefore, when the diagonal length of the back container 2 or the display surface panel 3 is 254 mm (10 inches) or more, the difference in average linear expansion coefficient is within 5 × 10 ⁻⁷ / ° C., When it is 508 mm (20 inches) or more, it is preferable that the difference in average linear expansion coefficient is within 3 × 10 ⁻⁷ / ° C.

Further, since an electron beam is applied to the inner side surface of the display surface panel 3 at a high pressure, electron beam browning is likely to occur, and further, the display surface panel 3 is pulled inward after sealing, so chemical strengthening should be performed. Is preferred.

The chemical strengthening is carried out by immersing a glass plate in a molten salt containing K ions to exchange Na ions in the glass for K ions. This chemical strengthening is applied to the inner surface of the display surface panel 3 at least to the depth at which the electron beam reaches.

The display surface panel 3 of the cathode ray tube preferably has a compressive stress of 25 kgf / mm ² or more due to the chemical strengthening. For this purpose, Na ions and K ions in the electron beam coloring preventing layer formed by the chemical strengthening are preferable. Is a molar ratio of 0.3 ≦ Na ₂ O / (Na ₂ O + K ₂ O) ≦ 0.7
And The following (Table 1) shows a composition example of a glass plate that can be used as the display surface panel 3.

[0018]

[Table 1]

FIG. 4 is a perspective view showing another embodiment of the glass display surface panel, and the display surface panel 3 according to this embodiment.
Has a shape obtained by cutting a cylinder in the axial direction (cylindrical). When the display surface panel 3 is sealed to the rear container, the axial direction of the display surface panel 3 and the linear cathode that constitutes the electron gun unit housed in the rear container are parallel to each other. With such a structure, the range of the electron beam becomes more constant on one linear cathode ray.

By the way, in order to obtain the cylindrical display surface panel 3, it is advantageous in terms of efficiency to cut the sheet glass manufactured by the float method. FIG. 6 is a plan view of the manufacturing apparatus of the display surface panel, FIG. 7 is a view showing the float glass before cutting seen from the AA direction of FIG. 6, and the manufacturing apparatus is the tin bath 1.
The annealing furnace 11 is provided on the downstream side of 0, and the belt-shaped float glass 12 drawn out from the tin bath 10 is cooled while being conveyed on the roller 13 to be molded.

In the present invention, unlike the normal cooling, the belt-shaped float glass 12 is positively and non-uniformly cooled. That is, the temperature distribution in the annealing furnace 11 is such that the upper surface side is lower than the lower surface side of the band-shaped float glass 12, and the temperature difference between the lower surface side and the upper surface side gradually increases toward the widthwise outer side of the band-shaped float glass 12. I am trying to become. By providing such a temperature difference, the band-shaped float glass 12 is curved as shown in FIG. 7, and thus the display surface panel 3 curved by a predetermined amount can be obtained only by cutting this.

FIG. 5 is a cross-sectional view showing another embodiment of the display surface panel. In this embodiment, the back container 2 is molded by gob molding, and the display surface panel 3 has a peripheral edge. A flange portion 3b that is recessed inward is formed.

[0023]

As described above, according to the present invention,
Since the shape before sealing of the glass display surface panel of the cathode ray tube such as a flat CRT is a curved shape that is convex toward the outside to the extent that it becomes flat in a state where the inside is depressurized after sealing,
The distance between the linear cathode forming the electron gun unit and the light emitting surface on the inner surface of the glass display surface panel, that is, the range of the electron beam is constant on one linear cathode wire, and high image quality is obtained.

In particular, the shape of the glass display surface panel is formed by cutting a cylinder in the axial direction, and the axial direction of the glass display surface panel and the linear cathode constituting the electron gun unit are arranged in parallel. The range of the electron beam can be kept constant, and higher image quality can be achieved.

Further, since the glass display surface panel does not have a concave shape inward after sealing, the rigidity of the cathode ray tube itself is improved.

Further, the molar ratio of Na ₂ O and K ₂ O is 0.3 ≦ Na ₂ O / (Na _{2) at} the depth position where the electron beam reaches the inner surface layer portion of the glass display panel. O + K ₂ O) ≦
By forming an electron beam coloration preventing layer of 0.7, the occurrence of electron beam browning can be suppressed.

Further, as a method for producing a glass display surface panel, a method is used in which a band-shaped float glass poured in a molten tin bath is passed through an annealing furnace and cut out from the band-shaped float glass. The temperature on the upper surface side is lower than that on the lower surface side of the float glass, and by increasing the temperature difference between the lower surface side and the upper surface side toward the outer side in the width direction of the band-shaped float glass, the band-shaped float glass naturally bends into a curved shape. A desired glass display panel for a cathode ray tube can be obtained by simply molding and cutting as it is.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a state before sealing a cathode ray tube according to the present invention.

FIG. 2 is a sectional view showing a state after sealing the cathode ray tube.

FIG. 3 is a perspective view of a glass display surface panel constituting the cathode ray tube.

FIG. 4 is a perspective view showing another embodiment of the glass display surface panel.

FIG. 5 is a sectional view showing another embodiment of the glass display surface panel.

FIG. 6 is a plan view of a manufacturing apparatus for a glass display surface panel that constitutes a cathode ray tube according to the present invention.

FIG. 7 is a view showing a glass display surface panel before cutting as seen from the direction AA of FIG.

[Explanation of symbols]

1 ... Cathode ray tube, 2 ... Rear container, 3 ... Display panel, 4 ...
Electron gun unit, 10 ... Tin bath, 11 ... Annealing furnace, 12 ... Float glass, 41 ... Linear cathode.

Claims (6)

[Claims] 1. A cathode ray tube in which an electron gun unit is provided in a glass-shaped back container in the shape of a dish, and the opening of the back container is sealed with a glass display surface panel to reduce the pressure inside the cathode ray tube. The shape of the face panel before sealing is a curved shape that is convex toward the outside, and the degree of this curvature is flattened after the sealing when the inside is depressurized. tube. 2. The cathode ray tube according to claim 1, wherein the glass display surface panel has a shape obtained by cutting a cylinder in an axial direction, and the glass display surface panel and an electron gun unit are arranged in an axial direction. A cathode ray tube characterized in that the constituent linear cathodes are arranged in parallel. 3. The cathode ray tube according to claim 1, wherein the degree of curvature of the glass display surface panel is a / Ls, where Ls is the short side of the display surface panel and a maximum recess amount is a.
A cathode ray tube, wherein ≦ 1.0 × 10 ⁻³ . 4. The cathode ray tube according to claim 1, wherein the glass display panel and the glass rear container are provided.
The difference in the average coefficient of linear expansion between 0 ° C and 350 ° C is 1.0 x
A cathode ray tube characterized by being within 10 ⁻⁶ / ° C. 5. The cathode ray tube according to claim 1, wherein an electron beam coloration-preventing layer is formed at a depth position where the electron beam reaches an inner surface layer portion of the glass display surface panel, and the electron beam coloration layer is formed. A cathode ray tube characterized in that the ratio of Na ₂ O and K ₂ O in the prevention layer is 0.3 ≦ Na ₂ O / (Na ₂ O + K ₂ O) ≦ 0.7 in terms of molar ratio. 6. A manufacturing method in which a band-shaped float glass poured out into a molten tin bath is passed through an annealing furnace, and a display panel for a cathode ray tube is cut out from the band-shaped float glass, wherein the temperature distribution in the annealing furnace is band-shaped. A display surface for a cathode ray tube, characterized in that the temperature of the upper surface side is lower than that of the lower surface side of the float glass, and the temperature difference between the lower surface side and the upper surface side is gradually increased toward the width direction outer side of the strip glass float glass. Panel manufacturing method.