JP2000200572A - Cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cathode-ray tube capable of being press-molded easily, and having sufficient strength against an atmospheric pressure load and high reliability, concerning a cathode-ray tube for dividingly scanning a phosphor screen by an electron beam emitted from plural electron guns. SOLUTION: A vacuum envelope 10 has such a glass panel 12 that a phosphor screen 20 is formed on the inner face, a glass rear envelope 14 installed oppositely to the glass panel 12, and two glass funnels 18 equipped with necks 16 respectively. The rear envelope 14 has a flat bottom wall 14a, and the plural glass funnels 18 are connected to the bottom wall of the rear envelope 14 by thermal welding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode ray tube, and more particularly, to a cathode ray tube which scans a phosphor screen by dividing the screen into a plurality of regions by electron beams emitted from a plurality of electron guns.

[0002]

2. Description of the Related Art In recent years, various studies have been made to meet demands for a high-definition cathode-ray tube for high-definition broadcasting or a large screen associated therewith. In order to achieve a higher resolution of the cathode ray tube, the electron beam spot diameter on the phosphor screen must be reduced.

[0003] On the other hand, conventionally, an attempt has been made to improve the electrode structure of an electron gun or to enlarge and extend the diameter of the electron gun itself, but no satisfactory results have yet been obtained. The biggest cause of this is that the distance from the electron gun to the phosphor screen increases as the size of the cathode ray tube increases, and the magnification of the electron lens becomes too large. Therefore, it is important to reduce the distance (depth) from the electron gun to the phosphor screen in order to realize high resolution. Further, if the deflection angle of the electron beam is wide, the magnification difference between the center and the periphery of the screen increases. For this reason, wide-angle deflection is not advantageous for achieving high resolution.

To solve the above-mentioned problems of the conventional cathode ray tube, for example, US Pat.
No. 1706, U.S. Pat. No. 4,777,407, JP-A-50-17167, and JP-B-39-25.
No. 641, JP-B-42-4928, JP-B-5
Japanese Patent Laid-Open No. 4-12035 discloses a cathode ray tube having a glass funnel having a plurality of necks and having a structure in which a phosphor screen is integrated.

[0005] That is, such a cathode ray tube has a vacuum envelope comprising a panel, a funnel connected to the panel and having two funnel-shaped cones, and two necks connected to the funnel. It has a vessel. A deflection device is mounted outside each funnel cone, and an electron gun is disposed inside each neck.

In the cathode ray tube having the above structure, the electron beams emitted from the respective electron guns are deflected by the magnetic fields generated by the corresponding deflecting devices, and the corresponding two phosphor screens integrally formed on the inner surface of the panel. Is divided and scanned. The images drawn on the phosphor screen by the divided scanning are connected by controlling signals applied to the electron gun and the deflecting device, thereby reproducing one image having no cut or overlap on the front surface of the phosphor screen.

However, in such a cathode ray tube, the strength of the concave portion where the funnel-shaped cone portions are connected to each other is reduced with respect to the atmospheric pressure load. This is particularly noticeable in a large cathode ray tube. Further, in the case of press-molding a glass funnel having the above-described shape, the glass funnel may be broken at the time of pressing due to a difference in thermal expansion coefficient and a difference in cooling rate between the press die and the glass.

On the other hand, Japanese Patent Application Laid-Open No. 7-45215 discloses a plurality of glass funnels having a glass neck provided with an electron gun and a glass rear envelope provided opposite to a glass panel. There is disclosed a cathode ray tube having a structure joined to a cathode ray tube.

That is, according to this cathode ray tube, the vacuum envelope has a substantially rectangular glass panel, a rear glass envelope provided opposite to the panel, and a glass neck joined to each other. And two glass funnels. And between the glass panel and the rear envelope,
The space between the rear envelope and the glass funnel is sealed using frit glass. A deflecting device is mounted outside each glass funnel, and an electron gun is provided inside each glass neck.

In the above-structured cathode ray tube, the electron beams emitted from the respective electron guns are deflected by the magnetic fields generated by the corresponding deflecting devices, and correspond to the phosphor screen integrally formed on the inner surface of the glass panel. Scanning is performed by dividing into two regions. The image drawn on the phosphor screen by the divided scanning is connected by a signal applied to an electron gun or a deflecting device, and reproduces one image without a break or overlap on the front surface of the phosphor screen.

In such a configuration, the rear envelope has substantially the same shape as the glass panel, so that press molding can be performed without any problem. Further, by forming the vacuum envelope in the above-described shape, the strength of the portion between the glass funnels against the atmospheric pressure load can be sufficiently maintained.

[0012]

However, in the above-mentioned cathode ray tube, the space between the glass panel and the rear envelope and the space between the rear envelope and the glass funnel are all sealed with frit glass. In general, the part where glass is sealed with frit glass is weaker than the continuous glass part against atmospheric pressure load, and the reliability of the sealed part between the rear envelope and the glass funnel with respect to atmospheric pressure load is reduced. I do. In this part, the shape of the glass funnel changes greatly and the thickness of the glass funnel is smaller than the thickness of the rear envelope, so a large tensile stress acts on the inner surface of the glass funnel near the rear envelope. As a result, the reliability with respect to the atmospheric pressure load is further reduced.

Further, in the above-mentioned cathode ray tube, since there are many sealing portions made of frit glass, the number of frit glass materials required for sealing and the number of manufacturing steps are increased as compared with ordinary cathode ray tubes, As a result, the production cost of the cathode ray tube is increased. In addition, when there are many sealed portions made of frit glass, characteristics such as withstand voltage and vacuum tightness are reduced, and the reliability of the vacuum envelope is reduced.

The present invention has been made in view of the above points, and an object of the present invention is to provide a cathode ray tube which divides and scans a phosphor screen with electron beams emitted from a plurality of electron guns, in which press molding is easy and large. An object of the present invention is to provide a cathode ray tube which has sufficient strength against an atmospheric pressure load and has high withstand voltage, vacuum tightness and the like.

[0015]

In order to achieve the above object, a cathode ray tube according to the present invention comprises a glass panel having a phosphor screen formed on an inner surface thereof, and a glass rear portion provided to face the glass panel. An envelope, a plurality of glass funnels each having a neck, and a vacuum envelope having a plurality of deflection devices provided on the funnel,
A plurality of electron guns respectively arranged in the neck and scanning the phosphor screen by dividing the phosphor screen into a plurality of regions by an electron beam, wherein the rear envelope and the plurality of glass funnels are heated and welded. It is characterized by being connected by.

According to the cathode ray tube having the above-described structure, the connecting portion between the rear envelope and the glass funnel where a large tensile stress acts can be formed in a continuous glass shape. , And the reliability of the entire vacuum envelope with respect to the atmospheric pressure load can be sufficiently maintained. In addition, the amount of frit glass used and the number of coating and drying steps are reduced, so that it is possible to avoid an increase in the production cost of the cathode ray tube, and to obtain a cathode ray tube having high withstand voltage characteristics, vacuum hermetic characteristics and the like. Can be.

Further, according to the present invention, the rear envelope includes:
It has a flat bottom wall facing the phosphor screen and a plurality of openings formed in the bottom wall, and the plurality of glass funnels are thermally welded to the bottom wall so as to cover the openings. It is characterized by having.

According to another cathode ray tube according to the present invention, the rear envelope includes a curved bottom wall facing the phosphor screen, a plurality of openings formed in the bottom wall, A plurality of annular protrusions respectively formed on a peripheral portion and located on the same plane with each other, and the plurality of glass funnels are thermally welded to the protrusions so as to cover the respective openings. Features.

According to another cathode ray tube according to the present invention, the rear envelope includes a curved bottom wall facing the phosphor screen, a plurality of openings formed in the bottom wall,
A plurality of annular bosses formed by bending a peripheral portion of the opening outward and positioned on the same plane with each other, wherein the plurality of glass funnels each cover the opening. It is characterized by being thermally welded to the part. Further, according to the present invention, the glass panel and the rear envelope are connected by heat welding.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a cathode ray tube according to an embodiment of the present invention will be described in detail with reference to the drawings. As shown in FIGS. 1 and 2, the cathode ray tube according to the first embodiment includes a vacuum envelope 10, which is provided with a panel 12 made of glass and opposed to the panel. A glass rear envelope 14 and two funnels 18 made of glass and each having a neck 16 joined thereto. The panel 12 integrally includes a substantially rectangular face plate 22 having a rectangular phosphor screen 20 formed on an inner surface thereof, and a skirt portion 24 erected on a peripheral portion of the face plate. The panel 12 has a major axis X and a minor axis Y that are orthogonal to each other through the center.

The rear envelope 14 is joined to the end face of the skirt portion 24 of the panel 12 in a state where it abuts. In this embodiment, the space between the panel 12 and the rear envelope 14 is sealed by frit glass 27. The rear envelope 14 has a flat bottom wall 14a facing the face plate 22, and a pair of circular openings 26 are formed in the bottom wall 14a along the long axis X direction.

The two funnels 18 are connected to the bottom wall 14a of the rear envelope 14, respectively. That is, each funnel 18 is joined to the outer surface of the bottom wall 14a while covering the corresponding opening 26. Each funnel 18
Is formed by a method such as pro molding or press molding. In general, when molding glass, symmetric shapes are easy to mold, and asymmetric shapes are difficult to mold. Therefore, each glass funnel 18 is connected to the central axis 2 of the neck 16.
It is desirable to make the shape symmetrical with respect to the shape 8.

Therefore, according to the present embodiment, each funnel 18 is formed symmetrically with respect to the center axis C, and the funnel 18 is connected to the outer surface of the bottom wall 14a of the rear envelope 14. It is formed flat so that substantially the entire surface, including the portion around the opening 26, is coplanar. The space between each funnel 18 and the rear envelope is heat-welded by burner heating.

An electron gun 28 is arranged in the neck 16 of each funnel 18, and a deflecting device 30 for deflecting an electron beam emitted from the electron gun is mounted outside each funnel 18. .

As can be seen from FIG. 2, in the present embodiment, the phosphor screen 20 has two divided areas a and b arranged in the long axis X direction with the short axis Y of the panel 12 as a boundary. . These divided areas a and b have the same shape as each other and are formed symmetrically with each other in the vertical and horizontal directions. The two funnels 18 and the electron gun 28 are divided into the divided areas a,
It is arranged so as to coincide with the normal passing through the center of b.
Thus, the two necks 16 extend substantially parallel to each other.

According to the cathode ray tube having the above-described structure, the electron beams emitted from the two electron guns 28 are deflected by the magnetic fields generated by the corresponding deflecting devices 30, and the phosphor screen 20 is divided into the two regions a and b. Divide each horizontally,
Scan vertically. The images drawn on the respective regions a and b of the phosphor screen 20 by the divided scanning are connected by controlling signals applied to the electron gun 28 and the deflecting device 30, and cuts or overlaps are formed on the front surface of the phosphor screen. Not one
Play two images.

In the cathode ray tube as described above, the rear envelope 14 has no deep drawing portion, and therefore, like the panel 12, press forming can be performed without any problem. Further, in the rear envelope 14, since the portion between the two funnels 18 is formed flat, the strength against the atmospheric pressure load can be sufficiently maintained.

Further, according to the above-mentioned cathode ray tube, a portion where a relatively large tensile stress acts is a connection portion between the rear envelope 14 and the funnel 18, and this portion is formed by continuous welding by heating and welding. Therefore, the strength against the atmospheric pressure load is higher than when sealing is performed using frit glass, and the reliability of the entire vacuum envelope 10 against the atmospheric pressure load can be sufficiently maintained. In addition, the amount of frit glass used and the number of coating and drying steps are reduced, so that it is possible to avoid an increase in the production cost of the cathode ray tube, and to obtain a cathode ray tube with high withstand voltage characteristics, vacuum hermetic characteristics, and the like. Can be.

In the cathode ray tube having the above structure, the two necks 16 are arranged on a normal axis passing through the center of each of the divided areas a and b and extend in parallel with each other. Can be easily performed.

In the above embodiment, the rear envelope 1
Although 4 has a shape having a flat bottom surface 14a, the present invention is not limited to this, and the shape of the vacuum envelope including the rear envelope can be freely selected.

As shown in FIG. 3, according to the cathode ray tube according to the second embodiment of the present invention, the bottom wall 1 of the rear envelope 14 is formed.
4a is formed in a dome shape as a whole, and in the outer surface of the bottom wall, a region where the funnel 18 is thermally welded, that is, a region around the opening 26 has an annular convex portion so that the welding surfaces are all on the same plane. 34 are formed. Other configurations are the same as those of the above-described first embodiment, and the same portions are denoted by the same reference numerals and detailed description thereof will be omitted.

According to the present embodiment, the connection between each annular projection 34 and the funnel 18 is joined by heating and welding by burner heating to form a continuous glass shape. I have. As a result, it is possible to provide a cathode ray tube in which the strength of the connecting portion against an atmospheric pressure load is increased, and the manufacturing cost of the cathode ray tube can be avoided, and the withstand voltage, the vacuum sealing property and the like are highly reliable. Can be.

As shown in FIG. 4, in the cathode ray tube according to the third embodiment of the present invention, the rear envelope 14 is formed so as to have a smooth curved surface as a whole, and the funnel 18 Are welded, that is, the periphery of each opening 26 is bent outward to form an annular boss portion 36. The welding surfaces of these boss portions 36 are processed so as to be located on the same plane. Other configurations are the same as those of the above-described first embodiment, and the same portions are denoted by the same reference numerals and detailed description thereof will be omitted.

According to the present embodiment, each annular boss 3
The connection between the 6 and the funnel 18 is joined by heating and welding by burner heating to form a continuous glass shape. The rear envelope 14 has a smooth curved surface as a whole, and the stress is further reduced as compared with the above-described embodiment. As a result, the reliability of the vacuum envelope 10 with respect to the atmospheric pressure load is further improved, and the production cost of the cathode ray tube can be prevented from increasing, and a cathode ray tube having high reliability regarding withstand voltage, vacuum tightness, and the like is obtained. Can be.

In each of the above-described embodiments, the rear envelope 14 is formed such that the regions where the funnels 18 are thermally welded are located on the same plane, but the present invention is not limited to this. Glass funnel 1 without
If the moldability, vacuum atmospheric pressure characteristics, explosion-proof characteristics, etc. of the mold 8 do not matter, as shown in FIG. 5, the area where the funnel 18 of the rear envelope 14 is heat-welded is a curved surface, and the center axis of the neck 16 is Glass funnel 18 asymmetrical to C
May be used as the vacuum envelope 10.

In each of the above embodiments, a cathode ray tube having two funnels 18 and two electron guns 28 has been described. However, the present invention is not limited to this, and the number of funnels and electron guns is three or more. Is also good. For example, as shown in FIG. 6, according to the cathode ray tube according to the fourth embodiment of the present invention, three funnels 18 are heat-welded to the rear envelope 14, and the inside of the neck 16 of each funnel is formed. Is provided with an electron gun 28.

The three necks 16 extend parallel to each other. The phosphor screen 20 formed on the inner surface of the panel 12 is divided into three divided areas a arranged in the long axis X direction by the electron beams emitted from the three electron guns 28.
Scanning is divided into b and c. The other configuration is the same as that of the above-described embodiment, and the same portions are denoted by the same reference characters and detailed description thereof will not be repeated.

Furthermore, in the above-described embodiment, the structure is adopted in which the space between the rear envelope and the funnel is heated and welded by burner heating. However, the present invention is not limited to this, and various other heat welding methods are selected. It is possible. As an example, when the thickness of the heat-welded portion is large, the glass is heated by a burner and an AC voltage is applied to the glass to energize the glass.
An electric welding method in which the glass is further heated and welded by the Joule heat is effective. Even in this case, the connection portion between the rear envelope and the funnel can be formed in a continuous glass shape, and a cathode ray tube having sufficiently high strength against the atmospheric pressure load of the vacuum envelope can be obtained.
In addition, it is possible to select various methods such as a method of irradiating a bonding surface with a carbon dioxide gas laser and performing heat welding.

According to each of the above embodiments, the glass panel and the rear envelope are sealed by the frit glass 27, but the reliability of the entire vacuum envelope against the atmospheric pressure load is improved. In order to further increase the heat resistance, this portion may be heated and welded to form a continuous glass shape. In recent years, interest in environmental issues has increased, and a large amount of lead is used in frit glass at present. Therefore, a method using heat welding is also effective in terms of the environment.

In each of the embodiments described above, a cathode ray tube having no shadow mask has been described. However, the present invention is not limited to this, and other cathode ray tubes having a shadow mask, a beam index type cathode ray tube, etc. It can be applied to various types of cathode ray tubes.

[0041]

As described in detail above, according to the present invention,
In a cathode ray tube which scans a phosphor screen by dividing the phosphor screen into a plurality of regions by electron beams emitted from a plurality of electron guns, a rear envelope and a glass funnel are thermally welded to each other so that a large tensile stress acts on the rear envelope. The connecting part between the vessel and the glass funnel is made of continuous glass, and the strength against atmospheric pressure load is improved compared to sealing with frit glass, so that the reliability of the entire vacuum envelope against atmospheric pressure load can be sufficiently maintained A simple cathode ray tube can be provided. With such a configuration, it is possible to avoid an increase in the manufacturing cost of the cathode ray tube, and to obtain a cathode ray tube having excellent withstand voltage characteristics, vacuum hermetic characteristics, and the like.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a rear side of a cathode ray tube according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view along the major axis direction of the cathode ray tube.

FIG. 3 is a sectional view of a cathode ray tube according to a second embodiment of the present invention.

FIG. 4 is a sectional view of a cathode ray tube according to a third embodiment of the present invention.

FIG. 5 is a sectional view of a cathode ray tube according to a fourth embodiment of the present invention.

FIG. 6 is a sectional view of a cathode ray tube according to a fifth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Vacuum envelope 12 ... Panel 14 ... Rear envelope 14a ... Bottom wall 16 ... Neck 18 ... Funnel 20 ... Phosphor screen 22 ... Faceplate 27 ... Frit glass 28 ... Electron gun 30 ... Deflection device

Claims (7)

[Claims] 1. A vacuum having a glass panel having a phosphor screen formed on an inner surface thereof, a glass rear envelope provided opposite to the glass panel, and a plurality of glass funnels each having a neck. An envelope, a plurality of deflecting devices provided on the funnel, and a plurality of electron guns respectively arranged in the neck and scanning the phosphor screen by dividing the phosphor screen into a plurality of regions by an electron beam. A cathode ray tube, wherein the rear envelope and the plurality of glass funnels are connected by heat welding. 2. The rear envelope has a flat bottom wall facing the phosphor screen and a plurality of openings formed in the bottom wall, and the plurality of glass funnels include the opening. The cathode ray tube according to claim 1, wherein the cathode ray tube is thermally welded to the bottom wall so as to cover the bottom surface. 3. The rear envelope has a curved bottom wall facing the phosphor screen, a plurality of openings formed in the bottom wall, and a plurality of openings formed in a peripheral portion of the opening and coplanar with each other. And a plurality of annular projections located at a distance from each other, wherein the plurality of glass funnels are thermally welded to the projections so as to cover the openings, respectively. tube. 4. The rear envelope is formed by bending a bottom wall facing the phosphor screen, a plurality of openings formed in the bottom wall, and bending a periphery of the opening outward. And a plurality of annular bosses positioned on the same plane with each other, wherein the plurality of glass funnels are thermally welded to the bosses so as to cover the respective openings. Item 7. The cathode ray tube according to Item 1. 5. The apparatus according to claim 1, wherein each of said glass funnels is formed symmetrically with respect to a central axis of said neck and said electron gun, and said plurality of necks extend in parallel with each other. 5. The cathode ray tube according to any one of 4. 6. The rear envelope has a curved bottom wall facing the phosphor screen, and a plurality of openings formed in the bottom wall. The cathode ray tube according to claim 1, wherein the cathode ray tube is thermally welded to the bottom wall so as to cover the opening. 7. The cathode ray tube according to claim 1, wherein said glass panel and said rear envelope are connected by heat welding.