Localized heating via an infrared heat source array of edge seals for a vacuum insulating glass unit, and/or unitized oven with infrared heat source array for accomplishing the same
View Patent ↗Certain example embodiments of this invention relate to edge sealing techniques for vacuum insulating glass (VIG) units. More particularly, certain example embodiments relate to techniques for providing localized heating to edge seals of units, and/or unitized ovens for accomplishing the same. In certain example embodiments, a unit is pre-heated to one or more intermediate temperatures, localized heating via at least one substantially two-dimensional array of heat sources is provided proximate to the peripheral edges of the unit so as to melt fits placed thereon, and cooled. In certain non-limiting implementations, the pre-heating and/or cooling may be provided in one or more steps. An oven for accomplishing the same may include multiple zones for performing the above-noted steps, each zone optionally including one or more chambers. Accordingly, in certain example embodiments, a temperature gradient proximate to the edges of the unit is created, thereby reducing the chances of breakage and/or at least some de-tempering of the substrates.
1. A method of making a vacuum insulating glass (VIG) window unit, the method comprising:
having first and second substantially parallel spaced-apart thermally tempered glass substrates and an edge seal material comprising frit provided at least partially between the first and second thermally tempered lass substrates for sealing an area proximate an edge of the VIG window unit;
pre-heating the thermally tempered glass substrates and the frit to at least one temperature from about 200 to 300 degrees C. below a melting point of the first and second glass substrates and below a melting point of the frit;
providing localized near infrared (IR) inclusive heat from about 1.1 to 1.4 μm proximate to the area proximate the edge to be sealed via a two-dimensional array of heat sources so as to at least partially melt the frit, and wherein the heat sources are individually and selectively activated, in sequence;
cooling the unit and/or allowing the frit to harden in making the vacuum insulating glass (VIG) window unit;
wherein at least some portions of the first and second glass substrates do not lose any more than 50% of original temper strength during formation of the edge seal; and
evacuating a gap between the first and second thermally tempered glass substrates to a pressure less than atmospheric pressure in making the vacuum insulating glass (VIG) window unit.
2. The method of claim 1 , further comprising providing a plurality of spacers between the glass substrates for spacing the glass substrates apart.