Method of manufacturing a cathode ray tube

• US 6,526,780 B1
• Filed: 08/14/2000
• Issued: 03/04/2003
• Est. Priority Date: 08/13/1999
• Status: Expired due to Fees

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Khalil, Mohammed
• Primary Examiner(s): VINCENT, SEAN E
• Application Number:
  US09/638,553
• Time in Patent Office: 932 Days
• Field of Search: 65/291.9, 65/63, 65/64, 651/03, 651/04, 651/14, 651/17, 651/62, 653/48, 653/56
• US Class Current: 65/64
• CPC Class Codes: C03B 11/127 of hollow or semi-hollow articles or their moulds
• CPC Class Codes: C03B 27/004 by bringing the hot glass product in contact with a solid cooling surface, e.g. sand grains

Abstract

To increase the strength of the glass panel of a CRT, the temperature of the glass panel is reduced during reforming from a temperature above, preferably at least 30° C. above the annealing point, to a temperature well below, preferably at least 80° C. below the strain point. This induces high surface compression in the glass panel, paired with a low rate of compaction. The glass panel is subsequently not subjected to the usual annealing step.

Claims

1. A method of manufacturing a cathode ray tube, in which method a glass display panel is press-formed, reheated and subsequently reformed, wherein, prior to reforming said glass panel is reheated to a first temperature above the annealing point and, during reforming, the temperature of said glass panel is reduced to a second temperature below the strain point and said glass panel is not subsequently annealed.

2. The method of claim 1, wherein said second temperature is at least 80°

C. below the strain point.

3. The method of claim 1, wherein said first temperature is at least 30°

C. above the annealing temperature.

4. The method of claim 1, wherein the reduction of temperature is effected within 5 minutes.

5. The method of claim 1, wherein said reforming step is performed in a reforming press held at or below said second temperature.

6. The method of claim 5, wherein said reforming press is provided with means to increase heat transfer from said glass panel to said reforming press.