Vintage Pittsburgh Plate Glass Co. Non Glare Glass Advertisement in Cardboard

[valhom]

Measures approx. 18" x 16.5". I couldn't find anything like it on eBay nor Google image search, etc. Is this rare, since it's still in an advertisement form? Collectible? Contains real glass in it. Thank you!

[KC]

PPG History
http://corporate.ppg.com/Our-Company/company-history.aspx

The only Non-Glare Glass patent I could find for PPG was 1985
http://www.google.com/patents/US4636439

[valhom]

PPG History
http://corporate.ppg.com/Our-Company/company-history.aspx

The only Non-Glare Glass patent I could find for PPG was 1985
http://www.google.com/patents/US4636439

Thank you for your help with the company history information and the patent you found. I really appreciate it. 

[mart]

https://www.google.com/patents/US3326715

Here is one from 1963 !!  I think they had several patents for similar glass !!

[KC]

Thanks Mart!  My internet has been wacky during/after the storms!

[valhom]

https://www.google.com/patents/US3326715

Here is one from 1963 !!  I think they had several patents for similar glass !!

Thanks! Much appreciated, Mart. 

[mart]

That was the one that sounded closest to the ad !!  They also revised or improved glass they already held a patent on so hard to figure when the original was issued !!