JP2001345059A - Glass panel of cathode-ray tube and its molding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a glass panel in which a thickness of a phosphor film that is formed on a surface in a face part of the glass panel of a cathode-ray tube can be made uniform and in which a high luminance, a high resolution, and a life-elongation of the cathode-ray tube is made possible. SOLUTION: This is the glass panel for the cathode-ray tube in which the phosphor film is formed on the inner surface of the face part that is a picture image display part. The glass panel for the cathode-ray tube is provided characterizing that the inner surface of the face part of the glass panel is a molded face having minute protrusions arranged nearly regularly on a substantially flat face without undulations.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass panel for a cathode ray tube, and more particularly, to a surface suitable for uniformly applying a phosphor or a non-luminous black substance (black matrix) on an inner surface of a face portion thereof. The present invention relates to a glass panel having the same.

[0002]

2. Description of the Related Art FIG. 8 shows a simplified structure of a cathode ray tube 10. Reference numeral 11 denotes a glass panel having a face portion 12 serving as an image display portion, 13 denotes a funnel which forms an envelope of a cathode ray tube together with the glass panel 11, and 14 denotes a face portion 1.
2 is a phosphor film in which red, blue, and green phosphors and a non-luminescent black material (black matrix) for improving luminance are regularly arranged on the inner surface of the phosphor 2; 15 is an electron gun; Electron beam 17 is irradiated by the electron beam 1
A deflection yoke for electromagnetically scanning 6 over the entire surface of the fluorescent film, and a color selection mechanism (shadow mask) 18 for selectively passing the electron beam 16.

FIG. 7 shows a face portion 12 of a glass panel 11.
5 is a cross section of the fluorescent film 14 formed on the inner surface of FIG. The regularly arranged non-emitting black substances constituting the fluorescent film 14 are indicated by C, and the red, blue and green phosphors are indicated by R, B and G, respectively. A resist layer is generally formed on the inner surface of the face portion 12 using a photoresist method, and then a non-light-emitting black substance or a phosphor is applied by a centrifugal sedimentation method.
Is formed.

In order to apply the fluorescent film made of the non-luminous black substance or the fluorescent substance to the inner surface of the face portion of the glass panel with good adhesion, the inner surface of the face portion has a matte surface.

[0005] Such a matte surface is formed as follows. Generally, as shown in FIG. 4, a glass panel 11 for a cathode ray tube is prepared by putting a predetermined weight of molten glass lump into a molding die 21 and then lowering a plunger 22 having an outer surface shape equal to the inner surface shape of the glass panel 11. Then, the molten glass lump is pushed into a space between the mold 21 and the plunger 22 to be press-molded into a desired shape.

The surface of the plunger 22 which comes into contact with the molten glass lump is roughened with fine irregularities by a so-called blast method, in which an abrasive such as alumina oxide (alundum) or glass beads is sprayed with high-pressure air or high-pressure water. A surface is formed.

[0007] As shown in FIG. 5, the roughened surface formed by blasting on the surface of the plunger 22 is applied to the panel glass 1.
1, the inner surface of the face portion 12 which is the image display surface of the glass panel 11 is made to have a satin finish. The transfer rate, which is the ratio at which the roughened surface of the plunger 22 is transferred to the glass panel 11, is usually about 20 to 40%, and a relatively long wavelength component is well transferred to the inner surface of the glass panel 11 after molding. , Small irregularities are not transferred much.

As shown in FIG. 6, the inner surface of the face portion 12 of the glass panel 11 formed as described above has a pear surface having stipples called stipples.

[0009]

In recent years, however, it has been required to improve the image display accuracy of a cathode ray tube.
No. 574 discloses that by adjusting the thickness of the fluorescent film, the electron beam penetrates to the lower layer of the fluorescent film to cause the phosphor to emit light so that the brightness and resolution of the display image are not reduced. I have. This is because when the electron beam does not penetrate to the lower layer of the phosphor film, the lower phosphor absorbs or scatters the light emitted from the upper phosphor to lower the brightness and resolution.

However, simply thinning the fluorescent film,
Even if the acceleration voltage of the electron beam is increased to make the electron beam penetrate into the lower layer of the fluorescent film, the electron beam directly reaches the glass panel and is irradiated, so that the glass is easily burned (browning). There is a risk that quality will deteriorate over time.

Therefore, a display tube requiring high brightness and high resolution or a projection tube irradiated with an electron beam at a high accelerating voltage has a phosphor film having a uniform thickness particularly on the inner surface of the face portion of the glass panel. It is important to form.

[0012] However, it is known that the rough surface formed by the blasting method causes a certain undulation when an abrasive having a certain particle size distribution is randomly sprayed onto a substrate. The roughness of the rough surface used for glass molding has a wavelength of about several hundred μm. The maximum amplitude of the undulation depends on the degree of roughness, but the roughness of the matte surface suitable for the glass panel is about 1 μm.
m.

As shown in FIG. 7, the inner surface of the face portion of the glass panel formed by the above method is a matte surface having undulation (wavelength W) by transferring the rough surface of the plunger. If a phosphor film having a pitch (P) of approximately 200 to 300 μm between phosphors of the same color is formed on the matte surface, the thickness of each phosphor and the layer of the non-light-emitting black substance is varied by the amplitude of the undulation. However, a fluorescent film having a uniform thickness cannot be obtained.

As described above, the brightness and resolution of the cathode ray tube and the life of the cathode ray tube are greatly affected by the uniformity of the thickness of the fluorescent film applied to the inner surface of the face portion of the panel glass. On the matte surface of the glass panel formed by the plunger roughened using the blast method, the occurrence of undulation is inevitable, and the thickness of the phosphor film is reduced for cost reduction and quality improvement, as described above. The influence of the undulation on the variation in the thickness of the fluorescent film is further increased. For example, when the average thickness of the fluorescent film is 20 μm, the undulation with a maximum amplitude of 1 μm causes a variation of 5% in the thickness of the fluorescent film, but when the average thickness of the fluorescent film is 10 μm, the undulation of the same amplitude is 10%. It results in variation.

Accordingly, an object of the present invention is to make the thickness of the fluorescent film formed on the inner surface of the face portion of the glass panel of the cathode ray tube uniform, and to achieve high brightness, high resolution, and a long life of the cathode ray tube. And to provide a glass panel.

[0016]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is a glass panel for a cathode ray tube in which a fluorescent film is formed on an inner surface of a face portion as an image display portion. And a glass panel for a cathode ray tube, wherein an inner surface of a face portion of the glass panel is a molded surface having fine projections arranged substantially regularly on a substantially smooth surface without waviness. I do.

Further, according to the present invention, a molten glass lump is supplied to a molding die, and then the plunger is lowered to push the molten glass lump between the molding die and the plunger to press-mold the glass panel. By providing a small dent by laser dulling to the surface of the plunger for molding the inner surface of the face of the glass panel, and transferring the surface of the plunger to the inner surface of the face of the glass panel. Forming a glass panel for a cathode ray tube, wherein an inner surface of a face portion of the glass panel is formed into a substantially smooth surface without waviness and a molding surface having minute projections arranged substantially regularly. Provide a way.

[0018]

According to the present invention, since the inner surface of the face portion of the glass panel is formed on the substantially smooth surface without undulations and on the molded surface having minute projections arranged substantially regularly, the phosphor and the non-light-emitting surface are formed. A fluorescent film having a uniform thickness can be formed with good adhesion without causing a thickness variation on a fluorescent film formed by applying a black substance.

As a result, the electron beam can be easily controlled so as to uniformly irradiate the lower layer of the fluorescent film.
There is no fear that light emitted from the upper layer is absorbed by the lower layer or irregularly reflected. Further, since the depth at which the electron beam penetrates into the fluorescent film can be controlled to be constant, the electron beam that passes through the fluorescent film and directly reaches the glass panel does not cause burning (browning) of the glass panel.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a glass panel for a cathode ray tube and a method of forming the same according to the present invention will be described based on embodiments. The same reference numerals are used for the same parts and members as those described above, and the description is omitted.

In this embodiment, as shown in FIG. 2, laser dulling is used for roughening the plunger 22. Laser dulling, unlike conventional blasting, can provide a controlled, regular, predetermined depression in the plunger surface.

The laser dulling machine 30 uses a carbon dioxide laser and transmits a laser beam to the transmission system 3.
1. It comprises a chopper 32 for converting a laser beam into a pulse beam, a numerical control machine tool 33 for accurately positioning the pulse beam on the surface of the plunger 22, and the like.

The diameter of the minute dent formed on the plunger surface can be controlled by changing the degree of the stop of the laser beam by an optical lens system. By changing the time, the depth of the minute depression formed on the plunger surface can be controlled.

Further, by changing the relative moving speed of the pulse beam and the plunger, it is possible to control the interval between the minute depressions formed on the plunger surface.
It is possible to obtain a desired density of minute depressions formed on the plunger surface.

When a glass panel is formed by press molding using the plunger subjected to laser dulling, the inner surface of the glass panel is regulated by the laser dulling process as shown in FIG. The indentation is transferred to the inner surface of the glass panel, and the inner surface of the face becomes a matte surface having a molding surface having fine projections arranged substantially regularly on a substantially smooth surface without waviness.

By applying a phosphor or a non-emissive black substance to the inner surface of the face portion of the glass panel thus formed, as shown in FIG. A membrane can be obtained.

[0027]

As described above, according to the glass panel of the present invention, the molding surface having fine projections regularly arranged without waviness is formed on the inner surface of the face portion, so that the fluorescent substance When a non-luminous black substance is applied to form a fluorescent film, a fluorescent film having a uniform thickness can be obtained, and the cathode ray tube has an excellent effect of achieving high brightness, high resolution, and a long life. is there.

[Brief description of the drawings]

FIG. 1 is a perspective view of an essential part for explaining a molding surface of an inner surface of a glass panel of the present invention.

FIG. 2 is a perspective view showing roughening of a plunger surface by a laser dulling machine.

FIG. 3 is an explanatory cross-sectional view of a main part showing a fluorescent film formed on the inner surface of the face part of the glass panel of the present invention.

FIG. 4 is a partially sectional explanatory view showing a molding die for a glass panel.

FIG. 5 is an explanatory cross-sectional view of a main part showing a situation where the rough surface of the plunger is transferred to the inner surface of the glass panel.

FIG. 6 is an explanatory cross-sectional view of a main part showing a matte surface on the inner surface of a conventional glass panel.

FIG. 7 is an explanatory cross-sectional view of a main part showing a fluorescent film formed on the inner surface of a face part of a conventional glass panel.

FIG. 8 is a sectional view showing a structure of a cathode ray tube.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Cathode ray tube 11 Glass panel 12 Face part 13 Funnel 14 Fluorescent film 15 Electron gun 16 Electron beam 17 Deflection yoke 18 Color selection mechanism (shadow mask) 21 Mold 22 Plunger 30 Laser dull machine 31 Transmission system 32 Chopper 33 Numerical control work machine

Claims (2)

[Claims] 1. A glass panel for a cathode ray tube, wherein a fluorescent film is formed on an inner surface of a face portion as an image display portion,
A glass panel for a cathode ray tube, wherein an inner surface of a face portion of the glass panel is a molded surface having fine projections arranged substantially regularly on a substantially smooth surface without waviness. 2. A method of supplying a molten glass lump to a molding die, and then lowering a plunger to push the molten glass lump between the molding die and the plunger to press-mold the glass panel, By providing a small depression by laser dulling on the surface of the plunger for molding the inner surface of the face portion of the glass panel and transferring the surface of the plunger to the inner surface of the face portion of the glass panel, A method for forming a glass panel for a cathode ray tube, wherein an inner surface of a face portion of the panel is formed into a substantially smooth surface having no undulation and a formed surface having minute projections arranged substantially regularly.