Seal for vacuum devices and methods for making same

A method of sealing a vacuum within a glass envelope that has an outside surface, comprising:

• forming a circular hole that passes through said envelope;
• providing a metal tube having first and second ends;
• flaring out said first end to form a flat flange having an outer rim;
• positioning the flange on said outer surface so as to fully surround the hole;
• covering said outer rim with a glass frit paste and piling the glass frit around the flange;
• heating the metal tube and the glass envelope so that the glass frit softens, thereby forming a glass-metal seal at said outer rim;
• allowing the metal and glass to cool to room temperature;
• using the metal tube as a port, evacuating the glass envelope;
• deforming the metal tube in a manner to cause pinch-off, thereby forming a vacuum tight cold weld;
• and
• removing any excess metal tubing that is not under vacuum.

A vacuum tight enclosure comprising:

• a pair of opposing parallel glass plates;
• four rectangular glass standoffs that separate the glass plates and form the enclosure with them;
• a permanent vacuum inside the enclosure;
• and
• a metal tube, vacuum sealed, by means of externally applied glass frit, at a first end to a hole in the enclosure and pinched off at a second end.