Vacuum insulating glass unit including infrared meltable glass frit, and/or method of making the same

1. A method of making a vacuum insulating glass (VIG) unit, the method comprising:

providing first and second substantially parallel spaced-apart glass substrates, the first and second substrates each including one or more edge portions to be sealed, a glass frit being provided at least partially between the first and second glass substrates for sealing said one or more edge portions to be sealed; and

irradiating infrared energy from one or more infrared energy sources towards the one or more edge portions to be sealed in forming an edge seal of the VIG unit,

wherein the glass frit has a glass redox (FeO/Fe 2 O 3 ) that is higher than a glass redox (FeO/Fe 2 O 3 ) of the first and second substrates.

2. The method of claim 1 , wherein the glass frit absorbs infrared energy having a wavelength of 0.9-1.2 microns such that less than 15% of the infrared energy is transmitted through the glass frit.

3. The method of claim 1 , wherein the glass frit absorbs infrared energy such that it reaches a melting temperature in 10 minutes or less.

4. The method of claim 1 , wherein the glass frit melts after exposure to a temperature of 400-450 degrees C.

5. The method of claim 1 , wherein the glass frit is a lead-free glass frit.

6. The method of claim 1 , wherein only the edge portions to be sealed are exposed to infrared energy.

7. The method of claim 1 , wherein the irradiating of the infrared energy causes the first and/or second substrate to reach a first elevated temperature and the glass frit to reach a second elevated temperature, the second elevated temperature being higher than the first elevated temperature.

8. The method of claim 7 , wherein

the first and second substrates are tempered, and

post-infrared energy irradiation, the first and second substrates maintain at least about 65% of their respective temper strengths.

9. The method of claim 1 , wherein the glass redox (FeO/Fe 2 O 3 ) of the glass frit is at least 0.02 higher than the glass redox (FeO/Fe 2 O 3 ) of the first and second substrates.

10. The method of claim 1 , further comprising providing a plurality of spacers between the glass substrates.

11. The method of claim 10 , further comprising causing a gap between the first and second substrates to be at a pressure less than atmospheric.

12. A method of making a vacuum insulating glass (VIG) unit, the method comprising:

having first and second substantially parallel spaced-apart heat treated (HT) glass substrates, the first and second substrates each including one or more edge portions to be sealed;

providing a glass frit at least partially between the first and second glass substrates for sealing said one or more edge portions to be sealed; and

irradiating infrared energy at 0.9-1.2 microns from one or more infrared energy sources towards the one or more edge portions to be sealed in forming an edge seal of the VIG unit,

wherein the glass frit includes an increased amount of ferrous oxide compared to the glass substrates such that the irradiating of the infrared energy causes the first and/or second substrate to reach a first elevated temperature and the glass frit to reach a second elevated temperature, the second elevated temperature being higher than the first elevated temperature and the first elevated temperature being sufficiently low to reduce the likelihood of the first and/or second substrate melting and losing HT strength, and

causing a gap between the first and second substrates to be at a pressure less than atmospheric.

13. The method of claim 12 , wherein the glass redox (FeO/Fe 2 O 3 ) of the glass frit is at least 0.02 higher than the glass redox (FeO/Fe 2 O 3 ) of the first and second substrates, and/or the glass frit absorbs infrared energy having such that less than 15% of the infrared energy is transmitted through the glass frit.

14. The method of claim 12 , wherein the glass frit has a glass redox (FeO/Fe 2 O 3 ) that is higher than a glass redox (FeO/Fe 2 O 3 ) of the first and second glass substrates.