Color cathode ray tube and glass frit for color cathode ray tubes

• US 6,734,615 B2
• Filed: 06/05/2002
• Issued: 05/11/2004
• Est. Priority Date: 11/22/2000
• Status: Expired due to Fees

• Current Assignee: Asahi Glass Company, Limited (AGC, Inc.)
• Original Assignee: Asahi Glass Company, Limited (AGC, Inc.)
• Inventors: Segawa, Yutaka, Ichikura, Eiji, Sugawara, Tsunehiko, Tanabe, Ryuichi
• Primary Examiner(s): Wong, Don K.
• Assistant Examiner(s): TRAN, THUY V
• Application Number:
  US10/161,759
• Publication Number:
  US 20030067261A1
• Time in Patent Office: 706 Days
• Field of Search: 313/480, 501/15, 501/17, 501/21, 501/22, 501/26, 501/76, 501/79
• US Class Current: 313/480
• CPC Class Codes: C03C 8/14 Glass frit mixtures having non-frit additions, e.g. opacifiers, colorants, mill-additions
• CPC Class Codes: C03C 8/24 Fusion seal compositions being frit compositions having non-frit additions, i.e. for use as seals between dissimilar materials, e.g. glass and metal; Glass solders
• CPC Class Codes: C03C 8/245 containing more than 50% lead oxide, by weight
• CPC Class Codes: H01J 2209/264 Materials for sealing vessels, e.g. frit glass compounds, resins or structures
• CPC Class Codes: H01J 29/863 Vessels or containers characterised by the material thereof
• CPC Class Codes: H01J 9/26 Sealing together parts of vessels

Abstract

The present invention relates to a color cathode ray tube and a glass frit to be used for it, and provides a color cathode ray tube which uses a glass frit containing as a crystallizing filler, an α-4PbO.B₂O₃ crystal powder and/or a Pb₃O₄ crystal powder, and corpuscular α-alumina, and at least one member selected from the group consisting of MgO, Fe₂O₃ and monoclinic ZrO₂, for improvement of the strength at a sealed portion and for weight saving of the color cathode ray tube, wherein the maximum tensile stress generated at the above sealed portion is from 7 to 10 MPa when the inside is vacuumized, and the area ratio of crystal is at least 50% at the interface at the above sealed portion at at least the region at which the above maximum tensile stress is generated.

Claims

1. A color cathode ray tube having a sealed portion at which a glass panel and a glass funnel are sealed by means of a sintered glass frit, wherein

a maximum tensile stress generated at the sealed portion is from 7 to 10 MPa when an inside of said color cathode ray tube is vacuumized,

the sintered glass frit contains at least a low expansion filler containing α

-alumina and a crystalline low melting glass, and

an area ratio of crystal is at least 50% at an interface at the sealed portion at at least a region at which the maximum tensile stress is generated.

2. The color cathode ray tube according to claim 1, wherein the sintered glass frit contains a low expansion filler containing α

-alumina and a crystalline low melting glass, wherein contents of the low expansion filler and the crystalline low melting glass represented by mass percentage based on the sintered glass frit are as follows;

crystalline low melting glass;

90-99%,

low expansion filler;

1-10%,

and content of the α

-alumina is from 0.1 to 7% based on the sintered glass frit.

3. The color cathode ray tube according to claim 2, wherein part of particles of the α

-alumina is corpuscular α

-alumina having a particle size not larger than 3 μ

m, and a content of the corpuscular α

-alumina is from 0.1 to 5% represented by mass percentage based on the sintered glass frit.

4. The color cathode ray tube according to claim 2, wherein the crystalline low-melting glass consists essentially of, represented by mass percentage based on following oxides:

5. The color cathode ray tube according to claim 1, wherein the sintered glass frit contains a low expansion filler containing α

-alumina, a crystalline low melting glass and a crystallizing filler containing MgO and/or Fe₂O₃, and contents of the above respective components represented by mass percentage based on the sintered glass frit are as follows;

crystalline low melting glass;

90-98.9%,

low expansion filler;

1-9.9%,

and a content of the α

-alumina is from 0.1 to 7% based on the sintered glass frit.

6. The color cathode ray tube according to claim 5, wherein a sum of masses of the MgO and Fe₂O₃ is from 0.1 to 5% represented by mass percentage based on the sintered glass frit.

7. The color cathode ray tube according to claim 1, wherein the above sintered glass frit contains a low expansion filler containing α

-alumina, a crystalline low melting glass and monoclinic-ZrO₂ as a crystallizing filler, and contents of the respective components represented by mass percentage based on the sintered glass frit are as follows;

crystalline low melting glass;

90-98.99%,

low expansion filler;

1-9.99%,

and a content of the α

-alumina is from 0.1 to 7% based on the sintered glass frit.

8. The color cathode ray tube according to claim 7, wherein a content of the monoclinic-ZrO₂ is from 0.01 to 1% represented by mass percentage based on the sintered glass frit.

9. The color cathode ray tube according to claim 1, wherein the low expansion filler contains at least one member selected from a group consisting of zircon, cordierite, mullite, lead titanate, silica, β

-eucryptite, β

-spodumene and β

-quartz solid solution.

10. A glass frit, for color cathode ray tubes, which comprises

a crystalline low melting glass powder,

a low expansion filler containing α

-alumina, and

a crystallizing filler consisting of an α

-4PbO.B₂O₃ crystal powder and/or a Pb₃O₄ crystal powder,

wherein part of the α

-alumina is corpuscular α

-alumina having a particle size not larger than 3 μ

m, and

contents of the above respective components represented by mass percentage based on said glass frit are as follows;

crystalline low melting glass powder;

90-99%,

low expansion filler;

1-10%,

and a content of the α

-alumina is from 0.1 to 7% based on a sintered glass frit, and

a content of the corpuscular α

-alumina of the α

-alumina is from 0.1 to 5% based on the sintered glass frit.

11. The glass frit according to claim 10, wherein the crystalline low-melting glass powder consists essentially of, represented by mass percentage based on following oxides:

12. The glass frit for color cathode ray tubes according to claim 10, wherein the low expansion filler contains at least one member selected from a group consisting of zircon, cordierite, mullite, lead titanate, silica, β

-eucryptite, β

-spodumene and β

-quartz solid solution.

13. A glass frit for color cathode ray tubes, which comprises

a crystalline low melting glass powder,

a low expansion filler containing α

-alumina, and

a crystallizing filler containing at least one member selected from a group consisting of an α

-4PbO.B₂O₃ crystal powder and/or a Pb₃O₄ crystal powder, MgO, Fe₂O₃ and monoclinic-ZrO₂,

wherein contents of the respective components represented by mass percentage based on the glass frit are as follows;

crystalline low melting glass powder;

90-98.99%,

low expansion filler;

1-9.99%,

crystallizing filler;

0.01-5%,

and a content of the α

-alumina is from 0.1 to 7% based on the glass frit.

14. The glass frit according to claim 13, wherein the crystalline low-melting glass powder consists essentially of, represented by mass percentage based on following oxides:

15. The glass frit for color cathode ray tubes according to claim 13, wherein the low expansion filler contains at least one member selected from a group consisting of zircon, cordierite, mullite, lead titanate, silica, β

-eucryptite, β

-spodumene and β

-quartz solid solution.