US 6,055,088 · Granted 2000-04-25
The Smart Glass Patent That Lets Windows Change Their Mind
Saint-Gobain patented windows that can shift between clear and tinted (or reflective) using a special active layer underneath a coating. It's like having sunglasses built into your house that adjust automatically—blocking heat and glare while still letting you see out, and they're tough enough to last for years without degrading.
The plain-English version
What it protects
The claim covers a glazing (window or glass pane) that combines an active layer—the part that actually changes optical properties—with a reflective coating applied on top. What's protected here is the specific structure and composition that allows the glass to modulate how light and heat pass through while maintaining durability over repeated cycles of expansion, contraction, and UV exposure.
Why it matters
Variable-property glazing sits at the intersection of energy efficiency and comfort. By allowing windows to actively control light and thermal transmission, buildings can reduce heating and cooling loads, which translates to lower utility costs and smaller carbon footprints. Saint-Gobain's patent locks down a commercially viable method for achieving this durability—critical because earlier smart-glass attempts degraded quickly under real-world conditions.
Real-world use
When sunlight floods through your bedroom in summer, a window using this technology could darken automatically to keep the room cool while still letting you see outside, without burning out or losing effectiveness after a few years.
Original USPTO abstract
A glazing is described, which includes at least one active layer and at least one reflecting coating on the active layer. A pane, partition, mirror, or door is also described that includes the glazing. A method for making is also described. The glazing exhibits superior thermal and radiative durability, and is capable of modulating the optical appearance of the active layer.
Patent details
- Publication number
- US 6,055,088
- Filing date
- 1997-08-22
- Grant date
- 2000-04-25
- Assignee
- Saint-Gobain Vitrage
- Inventor(s)
- FIX; RENAUD, GUISELIN; OLIVIER, LIN; XUE YUN
- CPC class
- B32B17/1077
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